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Dr. Firouz Mojarrad, Mrs. Samira Koshki, Dr. Jafar Masompour, Dr. Morteza Miri,
Volume 4, Issue 4 (1-2018)
Volume 4, Issue 4 (1-2018)
Abstract
Thunderstorm is a destructive atmospheric phenomenon, which annually causes a lot of damage to various parts of human activities. Due to the accompaniment of thunderstorm with rainstorm and hail and its effective role in creating sudden floods, the analysis of the behavior of this hazard has been widely studied both in terms of agriculture and in terms of financial and life damages throughout the world. The study of thunderstorm as a hazardous atmospheric phenomenon using instability indexes in Iran has been less considered due to lack of observation stations. Convective Available Potential Energy (CAPE) and Vertical Wind Shear (VWS) are two indexes that are often used to describe and detect thunderstorm environments. This study evaluates the thunderstorms in Iran with reanalysis data using CAPE and VWS indexes.
Thunderstorm data in 7 different conditions at 8 times a day for 42 synoptic and upper air stations during a 37-year common period (1980-2016) was received from the Iranian Meteorological Organization. At first, frequency, trend and time of occurrence of thunderstorms in Iran were investigated during the statistical period. Then, the ERA-Interim reanalysis dataset of the European Centre for Medium-Range Weather Forecasts (ECMWF) with spatial resolution of 0.5 ° was used for the analysis of thunderstorms. To evaluate the ERA-Interim dataset, the CAPE and VWS values for the 80 selected thunderstorm events that were calculated using the RAOB software were compared with ERA data and their accuracy was confirmed. After confirming the accuracy of ERA data, the average values of CAPE and VWS indexes in 42 stations of the country were calculated based on 4,542 thunderstorm events at 00 and 12 GMT during the study period, and the maps of these two indexes were drawn up using the IDW method. Then, using an equation, the thunderstorm severity thresholds across the country were determined using ERA data with 4,542 thunderstorm events to distinguish between mild, severe and very severe storms. To ensure the selection of important storms, storms with CAPE values of less than 50 were removed to exclude poor environments for convection occurrence. As a result, out of 4,542 thunderstorms, 535 events were eliminated and 4007 events remained. On this basis, a "2 x 2 contingency table" was prepared that compares thunderstorm events and forecasts. This table provides the information required to compute warning performance statistics including POD (Probability of Detection), FAR (False Alarm Ratio) and CSI (Critical Success Index). But the results of these statistics did not match well with the conditions of thunderstorm events in Iran. Therefore, the discriminant analysis was used to differentiate the intensity of thunderstorms and to discriminate mild, severe and extremely severe thunderstorms.
The results of the study showed that thunderstorms in Iran are increasing during the statistical period with a regression slope of 0.23 events per year (8.5 events in the statistical period). The highest frequency of thunderstorms was observed in the month of May with an annual number of 111, and the lowest was observed in January with 12 events. Most thunderstorms occur around 21:30. The highest average frequency of annual events at stations was related to the stations of Urmia, Tabriz, Khorramabad and Bushehr respectively. The proper capability of ERA data to estimate instability indexes in Iran was proved. ERA data provides a very near estimate for VWS, but estimates for the CAPE index are slightly more than observational values. The highest values of the CAPE index are observed in southern provinces, as well as in the southwest of the Caspian Sea coasts, and the highest values of the VWS index are found on the Persian Gulf coasts. When the storm severity breakdown equation for the 400 selected storm events was obtained and the "2 x 2 contingency table" was prepared, it was found that this equation was not satisfactory with respect to the POD, FAR, and CSI indexes. Hence, using the discriminant analysis, the storm severity breakdown relationships and their discriminant equations were obtained. These equations categorized 60% of the surveyed thunderstorms correctly. There is no significant difference between the mean values of CAPE and VWS in the three storm intensity groups. The role of the VWS index was higher in determining the type of storm.
Yousef Ghavidel, , ,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
Climatic geography of Tropical Cyclone hazards Affective on the southern coasts of Iran
The occurrence of any climatic fringes, including annual tropical storms, leave irreparable risks in its dominated areas. Understanding these events and knowledge of the time of their occurrence can be helpful in managing the unexpected incidents caused by them. Tropical cyclones are important natural turbulent processes in tropical and middle ecosystems in a number of regions of the world. Among the dynamic conditions of the atmosphere for the formation of tropical storms, there are three basic conditions: 1. The vertical wind shear should be limited between the 850 to 200 mb and the wind speed between these levels should be less than 10 meters per second. Such a situation allows the formation of a straight column, without breaking, to initiate tropical storms. 2- The formation state of tropical storms should be such that at least it is five degrees of latitude distant from the equator. Such conditions provide the minimum of Coriolis force to provide the tropical cyclic rotation along with other fundamental and apparent forces of the atmosphere and they occur following the pressure forces, Coriolis and centrifugal forces, cyclostrophic winds, and cyclic circulation in the center of the low pressure. 3- The presence of turbulence or discordance with vorticity and the convergence in the lower troposphere, or the anticyclone rotation and divergence in the upper levels of the atmosphere before the onset of activity, and the formation of tidal disturbances. Tropical storms are created by the presence of various dynamic and thermodynamic factors such as sea surface temperature and moisture content (thermodynamic properties), and flow and vertical winding functions (dynamic characteristics).
The parameters studied in this study for the dynamic and thermodynamic analysis of the tropical rotation of 1948 generally included the mean sea level pressure, geopotential heights, zonal and meridional components of wind, convection available potential energy, convective stabilization index, vertical velocity, relative vorticity, Sea surface temperature, humidity, and cloud cover levels which are drawn from the European Center for Medium Forecast Scale (ECMWF) with spatial resolution of 0.75 applying GRADS software. The study of combinational maps of 500 milligrams of geopotential heights and vorticity advection on the first day of the cyclone (1948/06/05) indicates the presence of a very strong low-altitude center with seven closed curves on the Arabian Sea. The most inner curve of this low-altitude center has the lowest elevation with 5650 geopotential meters height and the maximum vorticity advection and downright negative velocity of 10 and 0.5 Pascal to seconds, respectively. The above-mentioned Jetstream map with a maximum speed of 16 m / s, which covers the east of the center of the altitude, contributes to the greater divergence of this system. The formation of a very strong negative eddy in the 500-mb equilibrium also indicates intense instability at the site of the tropical cyclone and is actually a factor in the formation and reinforcement of such cyclones .The above-mentioned low altitude continues its cyclonic rotation at the level of 850 mb with two closed curves, and the maximum vorticity advection and downright negative velocity of 16 and 0.6 Pascal to second, respectively, due to the presence of lower level radar with a maximum speed of 20 m / s on the south side and similarly, in the south-east, it continued to circulate more rapidly at a rate higher than 500 mb, which results in the formation of the first pressure packet with a central
pressure of 997.5 mb on the sea surface. The high amount of specific humidity of 850 mb from the start of cyclone activity (12 g / kg), and the increase in this parameter in the next days of activity reaches 14 g / kg and also 4.5 g / kg at 500 millimeter equilibrium point to the high humidity at the location of the low-pressure center and the optimum conditions for the extraction of heavy rainfall in the eye wall of cyclone. Cloud cover maps also indicate a climber air density of up to 500 mb and the formation of a cloud at different levels of the atmosphere at the site of the formation of tropical rotation. The results show that the formation of the lower Jetstream, along with the tropical cyclone event (from 05 to 08 of 1948) affecting the southern coast of Iran, has been able to create severe air mass divergences in the left half of the nucleus and following this mechanism and the relationship between this velocity nucleus and the lower levels of the atmosphere and the sea level in the vertical direction, with the convergence of the mass, has been accompanied with the reduction of density and, finally, the reduction of pressure and the formation of turbulence, as the first ring for the development of tropical cyclones; therefore, the altitude of 850 mb and jet stream located at this elevation affected by the high-rise phenomenon on the western shores of the ocean (sometimes in the east of Madagascar) is considered as one of the most effective dynamic factors for the birth and development of this tropical cyclone on the southern coast of Iran. The tropical cyclone was formed from June 5 to June 8, 1948, at approximately 16 degrees north and 60 degrees east on the Arabian Sea. And, in general, the interaction between high pressure tongues on Saudi Arabia, Tibet and Iran, and the tropical cyclones has prepared the conditions for the activity and displacement of the tropical rotation. Previous studies of tropical storms have considered other synthetic systems, such as cyclones over Europe, and the integration of cyclones on the Mediterranean and Oman, as well as the displacement of the axis of tropical cyclones at middle and upper levels of the atmosphere affective in the escalation and displacement of the storm. It is also believed that the southern coast of Iran is also effective, and in general, less attention is paid to the causes of the development of the storm.
Key words:Tropical Cyclone, dynamic and thermodynamic analysis, low level jet stream, Thermodynamic parameters, Southern coast of Iran
The occurrence of any climatic fringes, including annual tropical storms, leave irreparable risks in its dominated areas. Understanding these events and knowledge of the time of their occurrence can be helpful in managing the unexpected incidents caused by them. Tropical cyclones are important natural turbulent processes in tropical and middle ecosystems in a number of regions of the world. Among the dynamic conditions of the atmosphere for the formation of tropical storms, there are three basic conditions: 1. The vertical wind shear should be limited between the 850 to 200 mb and the wind speed between these levels should be less than 10 meters per second. Such a situation allows the formation of a straight column, without breaking, to initiate tropical storms. 2- The formation state of tropical storms should be such that at least it is five degrees of latitude distant from the equator. Such conditions provide the minimum of Coriolis force to provide the tropical cyclic rotation along with other fundamental and apparent forces of the atmosphere and they occur following the pressure forces, Coriolis and centrifugal forces, cyclostrophic winds, and cyclic circulation in the center of the low pressure. 3- The presence of turbulence or discordance with vorticity and the convergence in the lower troposphere, or the anticyclone rotation and divergence in the upper levels of the atmosphere before the onset of activity, and the formation of tidal disturbances. Tropical storms are created by the presence of various dynamic and thermodynamic factors such as sea surface temperature and moisture content (thermodynamic properties), and flow and vertical winding functions (dynamic characteristics).
The parameters studied in this study for the dynamic and thermodynamic analysis of the tropical rotation of 1948 generally included the mean sea level pressure, geopotential heights, zonal and meridional components of wind, convection available potential energy, convective stabilization index, vertical velocity, relative vorticity, Sea surface temperature, humidity, and cloud cover levels which are drawn from the European Center for Medium Forecast Scale (ECMWF) with spatial resolution of 0.75 applying GRADS software. The study of combinational maps of 500 milligrams of geopotential heights and vorticity advection on the first day of the cyclone (1948/06/05) indicates the presence of a very strong low-altitude center with seven closed curves on the Arabian Sea. The most inner curve of this low-altitude center has the lowest elevation with 5650 geopotential meters height and the maximum vorticity advection and downright negative velocity of 10 and 0.5 Pascal to seconds, respectively. The above-mentioned Jetstream map with a maximum speed of 16 m / s, which covers the east of the center of the altitude, contributes to the greater divergence of this system. The formation of a very strong negative eddy in the 500-mb equilibrium also indicates intense instability at the site of the tropical cyclone and is actually a factor in the formation and reinforcement of such cyclones .The above-mentioned low altitude continues its cyclonic rotation at the level of 850 mb with two closed curves, and the maximum vorticity advection and downright negative velocity of 16 and 0.6 Pascal to second, respectively, due to the presence of lower level radar with a maximum speed of 20 m / s on the south side and similarly, in the south-east, it continued to circulate more rapidly at a rate higher than 500 mb, which results in the formation of the first pressure packet with a central
pressure of 997.5 mb on the sea surface. The high amount of specific humidity of 850 mb from the start of cyclone activity (12 g / kg), and the increase in this parameter in the next days of activity reaches 14 g / kg and also 4.5 g / kg at 500 millimeter equilibrium point to the high humidity at the location of the low-pressure center and the optimum conditions for the extraction of heavy rainfall in the eye wall of cyclone. Cloud cover maps also indicate a climber air density of up to 500 mb and the formation of a cloud at different levels of the atmosphere at the site of the formation of tropical rotation. The results show that the formation of the lower Jetstream, along with the tropical cyclone event (from 05 to 08 of 1948) affecting the southern coast of Iran, has been able to create severe air mass divergences in the left half of the nucleus and following this mechanism and the relationship between this velocity nucleus and the lower levels of the atmosphere and the sea level in the vertical direction, with the convergence of the mass, has been accompanied with the reduction of density and, finally, the reduction of pressure and the formation of turbulence, as the first ring for the development of tropical cyclones; therefore, the altitude of 850 mb and jet stream located at this elevation affected by the high-rise phenomenon on the western shores of the ocean (sometimes in the east of Madagascar) is considered as one of the most effective dynamic factors for the birth and development of this tropical cyclone on the southern coast of Iran. The tropical cyclone was formed from June 5 to June 8, 1948, at approximately 16 degrees north and 60 degrees east on the Arabian Sea. And, in general, the interaction between high pressure tongues on Saudi Arabia, Tibet and Iran, and the tropical cyclones has prepared the conditions for the activity and displacement of the tropical rotation. Previous studies of tropical storms have considered other synthetic systems, such as cyclones over Europe, and the integration of cyclones on the Mediterranean and Oman, as well as the displacement of the axis of tropical cyclones at middle and upper levels of the atmosphere affective in the escalation and displacement of the storm. It is also believed that the southern coast of Iran is also effective, and in general, less attention is paid to the causes of the development of the storm.
Key words:Tropical Cyclone, dynamic and thermodynamic analysis, low level jet stream, Thermodynamic parameters, Southern coast of Iran
Shamsallah Asgari, Ezatollah Ghanavati, Samad Shadfar,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
Quantitative assessment of landslide sedimentation in the ILAM dam Basin
Information on the accurate volume of landslides and sedimentation in landslides is a research necessity, with the assumption that the bulk of sediment accumulated in the ILAM Dam (located between , E and , N) is related to the surface landslides of the basin. Although the role of landslides in erosion, sediment transport and sedimentation of slippery basins is confirmed and different experts understand and determine the relationship between the fluctuation of slopes and the fluctuation system in many respects more important than other areas. Because according to the results they can assess the widespread environmental changes, but comprehensive research on the scale of catchment basins has done very little (Harvey 2002). So far, the study of wet landscapes in Iran has been more sensitive to the factors, their sensitivity and their hazards, and there has been no study on the sedimentation of landslides.
Data and Method
First, using a geomorphologic system methodology with topographic maps of 1: 50000, geological map of 1: 100000, aerial photography1: 20000, Landsat TM1988 ETM2002,2013 satellite imagery, and Google Earth in the GIS environment in the following sub-basins and landslide events at the following levels The basin was drawn. The discharge data of the water and sediment flow of three hydrometric stations GOLGOL,CHAVIZ and MALEKSHAHI Station were provided from the waters of the ILAM province. Two models of estimated MPSIAC and EPM models have been used to estimate soil erosion and subsoil sedimentation. The Moran spatial correlation model was used to introduce the spatial pattern of landslides, and the fuzzy logic model was used to determine the relationship between the dependent landslide to the independent variables and the potential risk of landslide hazard in the basin. In order to elucidate the quantitative results of landslide sedimentation, empirical models of estimation of sediment erosion, hydrological model of discharge curve and sediment, observational statistics of sediment during statistical period, landfall time occurrence in compliance with the hydrometric station sediment peak during the statistical period of computation Estimated a small amount of sedimentation of the landslides of the ILAM dam basin.
Result and Discussion
The spatial correlation model of Moran showed that the data have spatial correlation and cluster pattern. The average total sediment production in the MPSIAC model in the GOLGOL basin was estimated to be 13.3 tons per hectare per year under the CHAVIZ basin of 10.3 tons per hectare for one year and 4.00 tons per hectare in the sub-basin MALEKSHAHI. Using hydrological model of discharge-sediment curve, the mean sediment was calculated during the statistical period at the hydrometric station of the sub-basin of GOLGOL 18.8 ton per hectare, the station CHAVIZ 10.4 tons and the station MALEKSHAHI 0.9 tons of sediment per hectare per year was calculated. According to the results of the research methodology, the observation of the sediment in the two stations of GOLGOL and CHAVIZ compared to estimated sediment is related to the events occurring in these two sub-basins.
The data of 16 active landslides were recorded. Under the GOLGOL basin, 9 landslide events occurred, and in the CHAVIZ basin, 7 landslide events, the time of landfall occurrence recorded with sedimentary peaks, the length of the statistical period, the precipitate in the sub-basins was almost synchronized. Average relationship between suspended period of the statistical period - average of the peak delayed flight time of the statistical period coinciding with the occurrence of landslide = the amount of suspended load of landfall occurrence in the basin.
The amount of suspended land slip under the GOLGOL 75088.19 - 315.85=74772.34
Landing slope under the Chavez Basin 19907.30 - 20.24=19887
The area of the sub-basin is about 29,000 hectares and the active landslide area is about 100 hectares. According to the calculations, 77772.34 tons of suspended sediment is a sedimentary passage passing at the GOLGOL hydrometric station, which shows with a coefficient of 1.4 times the suspended sediment load of approximately 104681 tons of landslide sedimentation in this sub-basin, which shows the amount of sediment yield 100 hectares of landslide, so each landslide hectare had an average of 1046. 81 tons of sediment deposited at the GOLGOL hydrometric station. The area under the Chavez Basin is about 14000 hectares and the active landslide area of this sub-basin is about 65 hectares. According to the data of the discharge data, the sedimentation of the Chavez hydrometric station is 19887 tons of suspended sediment load, which shows a 1.4 equivalent of 27842 tons of landslide sedimentation in this sub-basin, equivalent to a slope of 428.33 tons per hectare.
Conclusion
According to the calculations, it is concluded that in the sub-basin of flowering GOLGOL, 37.35% is equivalent to 4.9 tons per hectare per year, the increase of sediment is related to landslide events. As a result, 28.2 tons of sediment per hectare were introduced in one year Dam reaches ILAM. The results showed that in the CHAVIZ sub basin, 38.2 percent is equivalent to 4.6 tons per hectare per year for the increase of sediment related to landslide events. As a result, an amount of 14.5 tons of sediment per hectare has entered ILAM dam in one year. In the sub-basin MALEKSHAHI, there was no increase in sediment during the period without active landslide occurrence. A total of 1237314 tons of landslide deposition have entered the ILAM Dam. To control this threat, the appropriate action by the executive office for sustainable development should be applied.
Faryad Shayesteh, , ,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
The role of tropospheric vertical anomalies in rainfall solid Case study: the hazard of hail in Kermanshah
Climate risks is one of the Types of hazards that damages human communities such as the phenomenon of hail, in the micro-scale, it causes financial losses and casualties. Hail is associated to the atmospheric elements and geo-location factors. Whenever weather conditions and appropriate physical processes are combined with geo-location creates and intensifies this phenomenon.
Losses resulted from hail has been more effective in the agricultural sector and in the effect of damaging the crops When growth and budding. However, it disorders in other sectors such as, blemishing residential buildings, Losing large and small animals also, damaging to the aircraft flight and its components. Hail considerable damage in Kermanshah province every year so that Farmers insure their crops against this Phenomenon and the government will incur heavy costs for
damage that is inflicted on the sector of activity.
Research methodology
The current weather data has been used with 3-hour intervals in the statistical period of 65 years (1951 to 2016) from synoptic stations of Kermanshah Province that includes the stations of Kermanshah, West Islamabad, Ravansar, Kangavar, West Gilan, and Sar-e-Pole-Zahab.
Among the 100 present weather code, Codes 99, 96, 91, 90, 89, 87 and 27 have been considered that including hail phenomenon by varying intensities and includes any appearance of this phenomenon in Hours scout and three hours earlier. Then, based on the above code, Were coded in Excel to identifies Codes 96, 91, 90, 89, 87 and 27 When entering from the Meteorological Data To the desired program among Group VII of the data, And when the written code, were identified, Hail days were marked.
Given that in this study Hail is studied regarding the synoptic conditions and temperature anomalies. Therefore, for the synoptic situation, Pressure data, vorticity, Special moisture, Components U and V, Omega transverse profile And outgoing longwave radiation, And for the temperature anomaly, Temperature and isothermal anomalies components Were getting from esrl.noaa.gov/psd site And using the software Grads were drawn maps for a selected day To determine the formation of hail.
Commentaries Results
The frequency of occurrence of hail has reached 187 in the period 65 years in Kermanshah province. This phenomenon generally occurs from mid-September to mid-June. The most number has been in Kermanshah station and the Least in Sar-Pol-Zahab station.
April has had the highest number of hail frequencies in Kermanshah province and the greatest losses in the month related to the agricultural sector. Therefore, Select System hail seems essential to examine how the temperature anomalies and the formation of hail in the month.
On the day of the event, trough hail has been formed in the East Mediterranean.Wrying the trough axis From North East to South West resulted in cold air from high latitudes to the East of the Mediterranean.
The establishment of trough in the middle and low pressure level in sea level and its following Convergence in the balance has created positive omega until balance of 200 hPa and most serious it is at the level of 400 hPa. Negative omega has maintained its association from ground surface until High levels in the study area.
The airflow of vorticity balance 1000 and 500 Hpa Suggests vorticity positive settlement area on the case study. Establishment of short wave in the vicinity of the study area and intensifying ascending conditions also Prolong Positive trough conditions from surface of Earth until 500hpa balance have been The necessary dynamic conditions for Hail in this day.
Special moisture and wind Vector with 700hpa balance of Moisture transfer has been done by two opposite vorticity system. Trough rotary motion Based on the Mediterranean and along the Red Sea on the one hand and Moving anticyclone over the Arabian Sea And the Persian Gulf and Oman Sea on the other, have conveyed Moisture of all moisture sources from The seas around to The study area.
Also OLR anomalies for the hail event day indicates being Negative in the study area and the sharp decline of Outgoing longwave in this day Compared to its long-term average And hence the conditions of cloudiness and the formation and intensification of convection has been provided.
1000 hpa positive anomaly 2 ° is representative the Higher than the average temperature conditions and in the 500hpa anomaly balance Minus 2 degrees Celsius is representative Lower than normal temperatures in the balance. These factors aggravate the vertical temperature gradient in the study area these days. 20+ degrees Celsius the Isothermal curve and -20 ° C. Respectively, the levels of 1000 and 500 Drawn to the area of study And has created a large temperature difference Between the upper and lower levels.
Keywords: Synoptic analysis, Hail hazard, Tropospheric anomalies, Vorticity, Kermanshah Province
Climate risks is one of the Types of hazards that damages human communities such as the phenomenon of hail, in the micro-scale, it causes financial losses and casualties. Hail is associated to the atmospheric elements and geo-location factors. Whenever weather conditions and appropriate physical processes are combined with geo-location creates and intensifies this phenomenon.
Losses resulted from hail has been more effective in the agricultural sector and in the effect of damaging the crops When growth and budding. However, it disorders in other sectors such as, blemishing residential buildings, Losing large and small animals also, damaging to the aircraft flight and its components. Hail considerable damage in Kermanshah province every year so that Farmers insure their crops against this Phenomenon and the government will incur heavy costs for
damage that is inflicted on the sector of activity.
Research methodology
The current weather data has been used with 3-hour intervals in the statistical period of 65 years (1951 to 2016) from synoptic stations of Kermanshah Province that includes the stations of Kermanshah, West Islamabad, Ravansar, Kangavar, West Gilan, and Sar-e-Pole-Zahab.
Among the 100 present weather code, Codes 99, 96, 91, 90, 89, 87 and 27 have been considered that including hail phenomenon by varying intensities and includes any appearance of this phenomenon in Hours scout and three hours earlier. Then, based on the above code, Were coded in Excel to identifies Codes 96, 91, 90, 89, 87 and 27 When entering from the Meteorological Data To the desired program among Group VII of the data, And when the written code, were identified, Hail days were marked.
Given that in this study Hail is studied regarding the synoptic conditions and temperature anomalies. Therefore, for the synoptic situation, Pressure data, vorticity, Special moisture, Components U and V, Omega transverse profile And outgoing longwave radiation, And for the temperature anomaly, Temperature and isothermal anomalies components Were getting from esrl.noaa.gov/psd site And using the software Grads were drawn maps for a selected day To determine the formation of hail.
Commentaries Results
The frequency of occurrence of hail has reached 187 in the period 65 years in Kermanshah province. This phenomenon generally occurs from mid-September to mid-June. The most number has been in Kermanshah station and the Least in Sar-Pol-Zahab station.
April has had the highest number of hail frequencies in Kermanshah province and the greatest losses in the month related to the agricultural sector. Therefore, Select System hail seems essential to examine how the temperature anomalies and the formation of hail in the month.
On the day of the event, trough hail has been formed in the East Mediterranean.Wrying the trough axis From North East to South West resulted in cold air from high latitudes to the East of the Mediterranean.
The establishment of trough in the middle and low pressure level in sea level and its following Convergence in the balance has created positive omega until balance of 200 hPa and most serious it is at the level of 400 hPa. Negative omega has maintained its association from ground surface until High levels in the study area.
The airflow of vorticity balance 1000 and 500 Hpa Suggests vorticity positive settlement area on the case study. Establishment of short wave in the vicinity of the study area and intensifying ascending conditions also Prolong Positive trough conditions from surface of Earth until 500hpa balance have been The necessary dynamic conditions for Hail in this day.
Special moisture and wind Vector with 700hpa balance of Moisture transfer has been done by two opposite vorticity system. Trough rotary motion Based on the Mediterranean and along the Red Sea on the one hand and Moving anticyclone over the Arabian Sea And the Persian Gulf and Oman Sea on the other, have conveyed Moisture of all moisture sources from The seas around to The study area.
Also OLR anomalies for the hail event day indicates being Negative in the study area and the sharp decline of Outgoing longwave in this day Compared to its long-term average And hence the conditions of cloudiness and the formation and intensification of convection has been provided.
1000 hpa positive anomaly 2 ° is representative the Higher than the average temperature conditions and in the 500hpa anomaly balance Minus 2 degrees Celsius is representative Lower than normal temperatures in the balance. These factors aggravate the vertical temperature gradient in the study area these days. 20+ degrees Celsius the Isothermal curve and -20 ° C. Respectively, the levels of 1000 and 500 Drawn to the area of study And has created a large temperature difference Between the upper and lower levels.
Keywords: Synoptic analysis, Hail hazard, Tropospheric anomalies, Vorticity, Kermanshah Province
Amir Saffari, Amir Saffari, Jalal Karami,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
Investigation about the influence of land-cover and land use changes on soil erodibility potential, case study: Gharesou, Gorganrood
Land use and land cover (LUC) change associated with climatic and geomorphologic conditions of the area have an accelerating impact on the land degradation. Natural as well as human-induced land use land cover change (LUCC) has significant impacts on regional soil degradation, including soil erosion, soil acidification, nutrient leaching, and organic matter depletion. Since the last century, soil erosion accelerated by human activities has become a serious environmental problem. It has a manifold environmental impact by negatively affecting water supply, reservoir storage capacity, agricultural productivity, and freshwater ecology of the region. In recent years, many researchers have highlighted the environmental consequences of soil erosion.
Soil erosion estimation at a regional scale is influenced by the complexity of the soil erosion process and the availability of data describing the soil erosion factors. In the last decade, regional and national level assessments of soil erosion were carried out using different approaches, ranging from indicator or factor-based approaches to process-based models. However, the revised universal soil loss (RUSLE) and its modifications are still widely used because of its simplicity and a greater availability of input parameters.
Gharesou basin is one of the sub-basins of Gharesou, it suffered from severe erosion in some areas over the past years. This erosion has occurred for different reasons and one of them is land use change and weak management of water and soil resources. The purpose of this research is to investigate the effects of land-cover changes on the potential of soil erosion in Gharesou Basin, a sub-basin of Gorganrood, in Golestan province. For this, we have employed RUSLE Model and used landsat satellite images from the sensors of TM, ETM, and OLI for 1985, 2000, and 2015. The potential soil erosion in this study was estimated using RUSLE model, which can be described using following equation:
A = R × K × LS × C × P
where A is amount of soil erosion calculated in tons per hectare per year, R is rainfall factor , K is soil erodibility factor , L is slope length factor, S is slope steepness factor, C is cover and management factor, and P is erosion control practice factor. To run the RUSLE model in GIS, first, rainfall raster layer, soil, slope, Digital Elevation Model, and also layers of soil protection range were created. Each of the involved factors was calculated in separate units in the basin level. In this research, Gharesou basin was analyzed based on raster network data with 30 meters cell size, because, from one hand it's small
enough to show heterogeneity of the basin and on the other hand, it matches pixel dimensions of landsat satellite images.
The results of land-cover changes have revealed a decrease in dense forest areas, low forest areas and the mixture of orchard, forest and pastures in a thirty years period. According to the results of RUSLE, changes of the classes indicate a general trend to the soil loss in the basin. Therefore, Gharesou basin is a basin with increasing soil erosion potential. In the plain and coastal plain areas of the basin, that is the mainly cultivated area, the amount of erosion is different from the other areas, and soil loss process is decreasing. It's due to the changes of cultivation method from traditional to modern, increase of irrigated farming area, choosing more environmentally friendly plants, and also, increase in the area of cities and villages from 7.14 percent to 29.04 percent during 30 years. In the study classes, for output of RUSLE model, in every 3 years of study, the maximum area relates to the classes of 100 to 200 Ton per year that is more seen in the mountainous regions. In these regions, all factors except vegetation are toward soil loss. Also, during 30 years, the amount of dense vegetation decreased from 34.56 to 31.55. In fact the only factor in protecting soil in (prone to erosion) areas has given its place to less effective vegetation, so, the area of this region has increased and Gharesou basin is in danger of soil loss in mountainous and forest parts. Also, areas with more than 200 Ton in hectare, with the lowest amount, have had a tangible increase during 30 year of study and its amount has increased from 11.74 to 12.50. These areas are usually located in mountainous parts with no vegetation. Also, the average of soil erosion potential estimated in Gharesou basin for 1985, 2000 and 2015 is 102.02, 103.11, and 103.76 (ton per hectare per year). This amount was found in the sub-basins too and except the sub-basin 4 located in coastal plain areas of the basin, with farming use, the amount of other sub-basins is increasing. According to the results of study, mountainous parts of Gharesou basin, has the most damage due to the accumulation of involved factors in the potential increase of soil loss. So, the necessity of watershed management is observed. Also modification of cultivation pattern and soil conservation training in farming lands of foothills and hillsides are required.
Keywords: RUSLE Model, soil erosion, Gharesou, Remote Sensing, land-cover changes
Land use and land cover (LUC) change associated with climatic and geomorphologic conditions of the area have an accelerating impact on the land degradation. Natural as well as human-induced land use land cover change (LUCC) has significant impacts on regional soil degradation, including soil erosion, soil acidification, nutrient leaching, and organic matter depletion. Since the last century, soil erosion accelerated by human activities has become a serious environmental problem. It has a manifold environmental impact by negatively affecting water supply, reservoir storage capacity, agricultural productivity, and freshwater ecology of the region. In recent years, many researchers have highlighted the environmental consequences of soil erosion.
Soil erosion estimation at a regional scale is influenced by the complexity of the soil erosion process and the availability of data describing the soil erosion factors. In the last decade, regional and national level assessments of soil erosion were carried out using different approaches, ranging from indicator or factor-based approaches to process-based models. However, the revised universal soil loss (RUSLE) and its modifications are still widely used because of its simplicity and a greater availability of input parameters.
Gharesou basin is one of the sub-basins of Gharesou, it suffered from severe erosion in some areas over the past years. This erosion has occurred for different reasons and one of them is land use change and weak management of water and soil resources. The purpose of this research is to investigate the effects of land-cover changes on the potential of soil erosion in Gharesou Basin, a sub-basin of Gorganrood, in Golestan province. For this, we have employed RUSLE Model and used landsat satellite images from the sensors of TM, ETM, and OLI for 1985, 2000, and 2015. The potential soil erosion in this study was estimated using RUSLE model, which can be described using following equation:
A = R × K × LS × C × P
where A is amount of soil erosion calculated in tons per hectare per year, R is rainfall factor , K is soil erodibility factor , L is slope length factor, S is slope steepness factor, C is cover and management factor, and P is erosion control practice factor. To run the RUSLE model in GIS, first, rainfall raster layer, soil, slope, Digital Elevation Model, and also layers of soil protection range were created. Each of the involved factors was calculated in separate units in the basin level. In this research, Gharesou basin was analyzed based on raster network data with 30 meters cell size, because, from one hand it's small
enough to show heterogeneity of the basin and on the other hand, it matches pixel dimensions of landsat satellite images.
The results of land-cover changes have revealed a decrease in dense forest areas, low forest areas and the mixture of orchard, forest and pastures in a thirty years period. According to the results of RUSLE, changes of the classes indicate a general trend to the soil loss in the basin. Therefore, Gharesou basin is a basin with increasing soil erosion potential. In the plain and coastal plain areas of the basin, that is the mainly cultivated area, the amount of erosion is different from the other areas, and soil loss process is decreasing. It's due to the changes of cultivation method from traditional to modern, increase of irrigated farming area, choosing more environmentally friendly plants, and also, increase in the area of cities and villages from 7.14 percent to 29.04 percent during 30 years. In the study classes, for output of RUSLE model, in every 3 years of study, the maximum area relates to the classes of 100 to 200 Ton per year that is more seen in the mountainous regions. In these regions, all factors except vegetation are toward soil loss. Also, during 30 years, the amount of dense vegetation decreased from 34.56 to 31.55. In fact the only factor in protecting soil in (prone to erosion) areas has given its place to less effective vegetation, so, the area of this region has increased and Gharesou basin is in danger of soil loss in mountainous and forest parts. Also, areas with more than 200 Ton in hectare, with the lowest amount, have had a tangible increase during 30 year of study and its amount has increased from 11.74 to 12.50. These areas are usually located in mountainous parts with no vegetation. Also, the average of soil erosion potential estimated in Gharesou basin for 1985, 2000 and 2015 is 102.02, 103.11, and 103.76 (ton per hectare per year). This amount was found in the sub-basins too and except the sub-basin 4 located in coastal plain areas of the basin, with farming use, the amount of other sub-basins is increasing. According to the results of study, mountainous parts of Gharesou basin, has the most damage due to the accumulation of involved factors in the potential increase of soil loss. So, the necessity of watershed management is observed. Also modification of cultivation pattern and soil conservation training in farming lands of foothills and hillsides are required.
Keywords: RUSLE Model, soil erosion, Gharesou, Remote Sensing, land-cover changes
Mr Seyed Abdolhossein Arami, Professor Majid Ownegh, Dr Ali Mohammadianbehbahani, Dr Mehri Akbari, Professor Alireza Zarasvandi,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
The analysis of dust hazard studies in southwest region of Iran in 22 years (1996-2017)
Dust storms are natural hazards that mostly occur in arid and semi-arid regions and there are many harmful consequences. According to the topographic-climatic conditions in Iran and the significant increase in the number and severity of dust storms occurrence in recent decades, especially in the West and Southwest regions where the dust storms are the most important environmental crisis. Studying this phenomenon is necessary for better management its harmful effects.
Since most of the research are implemented as different case studies, and there is no comprehensive study that review a wide range of existing researches with overall results in the southwestern parts of Iran, in this study a comprehensive overview of available literature reviews are addressed including dust spatio-temporal variations, modeling, detection, and health issues.
This research is based on a library research and search of valid national and international scientific articles about the dust crisis and no data-processing. We attempted to analyze temporal and spatial variations in the south and southwest of the country using the available studies and the challenges of this phenomenon in the past and present to provide a new perspective to apply a comprehensive land management and managing environmental hazards in Iran with all the problems.
A review of the history of dust storm studies from information sources showed that most researchers (61.40%) used a synoptic method to study dust storms, and the most important indicators that were considered by the researchers in physical properties were frequency and density, 34.21% and 34.21% of the studies respectively.
Dust detection methods show that the use of thermal or reflective bands cannot detect dust phenomena with high precision, therefore, a model which applies both bands simultaneously should be developed. In other words, applying a combination of reflective and thermal
spectra of Military Origin Destination Information System (MODIS) could offer better
results in detection of dust storms in the study area. Studies indicate that most of the storms
originate outside of Iran. Moreover, exposure to airborne contaminants, especially when the
dust storms occur in the Middle East, can lead to an increase in the related disease outbreak
in the study area. For instance, there was a 70% increase in referring to medical centers for
lung related problems when a dust phenomenon occurred.
The Results showed that in cold seasons where low height and western waves is formed on the European and Mediterranean Sea, due to the heaviness, cold air in these days, can penetrate low latitudes and their trough is located over the Middle East area. Under warming condition, the front of rough is formed as ridge, then engendered turbulence and wind. In the warm seasons, thermal low pressure is rapt to ward in the high latitude, and severe dryness
of the area is also due to the fact that the dusty phenomenon is intensified in the area. Dust
storm occurrence in the summer due to bareness of the land, transparency of the atmosphere,
dryness of the air and the vast plains, which can reduce the formation of local instability in
the case of a sharp rise in air temperature. The dispersal of deserts and sand sea is mainly in
the northwest of Khuzestan province, especially in Fakkeh and Moussan which are located in the western borders of Iran with Iraq, which cover most of the Azadegan plain and west of the Karkheh and Mollasani and Maroon Rivers, and ultimately end in the Omidiyeh and Aghajari regions. Results show that the border between Syria and northwest Iraq, west and southwest of Iraq to east and northeast of Saudi Arabia are the main sources of dust in the studied region
. Synoptic conditions considering simultaneously with the occurrence of dust
storms showed the significant role of cyclonic systems in the occurrence and transfer of this
phenomenon. With the phenomenon occurrence during the warm period, the significant
strengthening in low pressure of Iraq along with the trough formation in Zagros causes the
formation and transfer of dust towards Southwest Iran. Simulation studies of dust particles
movement paths have shown that most of the paths are from the northern and central parts
of Iraq and Syria and the source of dust storms are deserts and dry regions of the northern
and central parts of Iraq and Syria. In addition, the study of the transmission paths of particles
in dust storms indicates the presence of a lower level jet, which causes horizontal
displacement of dust particles in a shallow layer and prevents its vertical propagation in the
higher layers of the atmosphere. In general, although the dust phenomenon is transnational
and uncontrollable, it can introduce limitations in terms of circulation patterns and statistical
properties at different time intervals to the different planners via its time and scope which
will necessitate appropriate programs for combating and adaptation.
Keywords: Dust, Air pollution, Spatio-temporal pattern, Southwest, Iran.
Dust storms are natural hazards that mostly occur in arid and semi-arid regions and there are many harmful consequences. According to the topographic-climatic conditions in Iran and the significant increase in the number and severity of dust storms occurrence in recent decades, especially in the West and Southwest regions where the dust storms are the most important environmental crisis. Studying this phenomenon is necessary for better management its harmful effects.
Since most of the research are implemented as different case studies, and there is no comprehensive study that review a wide range of existing researches with overall results in the southwestern parts of Iran, in this study a comprehensive overview of available literature reviews are addressed including dust spatio-temporal variations, modeling, detection, and health issues.
This research is based on a library research and search of valid national and international scientific articles about the dust crisis and no data-processing. We attempted to analyze temporal and spatial variations in the south and southwest of the country using the available studies and the challenges of this phenomenon in the past and present to provide a new perspective to apply a comprehensive land management and managing environmental hazards in Iran with all the problems.
A review of the history of dust storm studies from information sources showed that most researchers (61.40%) used a synoptic method to study dust storms, and the most important indicators that were considered by the researchers in physical properties were frequency and density, 34.21% and 34.21% of the studies respectively.
Dust detection methods show that the use of thermal or reflective bands cannot detect dust phenomena with high precision, therefore, a model which applies both bands simultaneously should be developed. In other words, applying a combination of reflective and thermal
spectra of Military Origin Destination Information System (MODIS) could offer better
results in detection of dust storms in the study area. Studies indicate that most of the storms
originate outside of Iran. Moreover, exposure to airborne contaminants, especially when the
dust storms occur in the Middle East, can lead to an increase in the related disease outbreak
in the study area. For instance, there was a 70% increase in referring to medical centers for
lung related problems when a dust phenomenon occurred.
The Results showed that in cold seasons where low height and western waves is formed on the European and Mediterranean Sea, due to the heaviness, cold air in these days, can penetrate low latitudes and their trough is located over the Middle East area. Under warming condition, the front of rough is formed as ridge, then engendered turbulence and wind. In the warm seasons, thermal low pressure is rapt to ward in the high latitude, and severe dryness
of the area is also due to the fact that the dusty phenomenon is intensified in the area. Dust
storm occurrence in the summer due to bareness of the land, transparency of the atmosphere,
dryness of the air and the vast plains, which can reduce the formation of local instability in
the case of a sharp rise in air temperature. The dispersal of deserts and sand sea is mainly in
the northwest of Khuzestan province, especially in Fakkeh and Moussan which are located in the western borders of Iran with Iraq, which cover most of the Azadegan plain and west of the Karkheh and Mollasani and Maroon Rivers, and ultimately end in the Omidiyeh and Aghajari regions. Results show that the border between Syria and northwest Iraq, west and southwest of Iraq to east and northeast of Saudi Arabia are the main sources of dust in the studied region
. Synoptic conditions considering simultaneously with the occurrence of dust
storms showed the significant role of cyclonic systems in the occurrence and transfer of this
phenomenon. With the phenomenon occurrence during the warm period, the significant
strengthening in low pressure of Iraq along with the trough formation in Zagros causes the
formation and transfer of dust towards Southwest Iran. Simulation studies of dust particles
movement paths have shown that most of the paths are from the northern and central parts
of Iraq and Syria and the source of dust storms are deserts and dry regions of the northern
and central parts of Iraq and Syria. In addition, the study of the transmission paths of particles
in dust storms indicates the presence of a lower level jet, which causes horizontal
displacement of dust particles in a shallow layer and prevents its vertical propagation in the
higher layers of the atmosphere. In general, although the dust phenomenon is transnational
and uncontrollable, it can introduce limitations in terms of circulation patterns and statistical
properties at different time intervals to the different planners via its time and scope which
will necessitate appropriate programs for combating and adaptation.
Keywords: Dust, Air pollution, Spatio-temporal pattern, Southwest, Iran.
Mrs Masoomeh Niyasti, Mr Seyed Amir Hossein Garakani,
Volume 5, Issue 1 (6-2018)
Volume 5, Issue 1 (6-2018)
Abstract
Study of vulnerability of settlements in rural areas A comparative study of salvage towns and villages in the eastern part of Golestan province
There are important choices to be made after the various accidents and the numerous financial and psychological effects of rural settlements, including decisions on how to intervene in rural settlements and the adoption of reconstruction policies. This intervention is identified as four types of identification, relocation, continuous development, or integration and integration for the reconstruction of damaged or destroyed villages due to natural hazards.Many scholars and scholars believe that among the above models, aggregation and integration have economic advantages in supplying facilities and services. The ruler's insight has led to less attention to its economic, social, physical and environmental implications. It seems that this indifference has led to the implementation and implementation of relocation and integration plans of rural settlements with the change in their vulnerability in the economic, social, physical and environmental dimensions and the development of the vulnerability of affected society Increase against future accidents. Extreme rainfall in the eastern province of Golestan province in August 2005 resulted in two devastating floods, one of the most damaging floods in the country. The Islamic Revolutionary Guard Housing Foundation has been providing housing for the affected population and in order to reduce the resettlement of villages due to the occurrence of future floods, the eleven villages in the city of Kalaleh, which had been damaged in recent floods in Golestan Province, were displaced. This research is descriptive-analytic and its data have been collected in two sections of library and field. The statistical population of this study is a collection of residents of the walled city and villagers who have returned to the villages of Chatal, Ghapan Oliya and Sofla. To test the vulnerability in two samples, independent samples t have been used. Comparison of two sample returns in villages Chatal, Gapan Oliya and Sofla with the displacement and aggregation of villages in the recreational city showed that each of the studied samples had weaknesses and strengths in different dimensions of vulnerability. The vulnerability of the Faragi city in the economic dimension, using the average for each of the three villages and the city of recreation (3.18 and 2.89, respectively), shows that the resettlement policy in the area of study has increased the vulnerability, especially in the outskirts of the Faragi city Is. The results of this research in the economic sector are consistent with the results of Firouznia and colleagues (2011) and Stadekelai et al. (1394). Regarding the role of resettlement in social vulnerability after examining the criteria, the average for each of the three villages and the Faragi city (3.21 and 2.77 respectively) shows that the resettlement policy from the social perspective in the scope of the study increases the level of vulnerability especially in the Faragi city. The results of this research in the social section are consistent with the results of Montazarian (2011), Mohammadi, Professor Kalayeh et al. (1394), Zaharan et al. (2011), Peik et al. (2014) and Navara et al. (2013). In the physical dimension of the environment, it can be said that resettlement in general has reduced the level of vulnerability and improved life indicators in the Faragi city. The average for each of the three villages and the Faragi city (2.89 and 3.57, respectively) shows that the resettlement policy from the physical-environmental perspective in the study area has reduced the amount of vulnerability in the outskirts of the Faragi city to the three villages. On the other hand, the zoning of physical-permafrost
range shows that although the physical injuries of the outskirts of the Faragi city are lower than the three villages, but considering the location of the Pishkamar's site in the zone with moderate damage, the physical-peripheral city of leisure also vulnerable. In most post-traumatic reconstruction programs, the policy of removing the entire or part of the settlement as a suitable technical solution to reduce the vulnerability and safety of phenomena such as floods, landslides and so on Considered
. However, the review of various experiences suggests that displacement of settlements, although effective in reducing physical morbidity, is mainly due to numerous social and economic consequences. The displacement and consolidation of 11 villages of Golestan province in the post-flood Pishkamar site of 1384 were unsuccessful due to the lack of planning and designing, with macroeconomic and social costs, in reducing the dimensions of vulnerability of a settlement, including social and economic. This has led to the return of villagers to their old villages. The quantitative results of this research also confirm the hypothesis that increasing the migration to cities, returning to old villages, ethnic conflicts, reducing production levels, increasing bank debt and the prevalence of insecurity in the outskirts of the Faragi city are one of the most important factors in increasing the vulnerability in the social and economic dimensions of the study area. The investigations indicate an increase in the amount of vulnerability in recreational areas in terms of economic and social dimensions and reducing its physical-environmental vulnerability to three villages. Since reducing the vulnerability of settlements is subject
to control and reduction of damage and damage in all aspects, it seems that the
reconstruction of rural settlements after the flood of 2005 in Golestan province has been
effective in increasing the vulnerability of this area.
Keywords: Vulnerability, Relocation, Resettlement, Faragi city, Golestan Province.
There are important choices to be made after the various accidents and the numerous financial and psychological effects of rural settlements, including decisions on how to intervene in rural settlements and the adoption of reconstruction policies. This intervention is identified as four types of identification, relocation, continuous development, or integration and integration for the reconstruction of damaged or destroyed villages due to natural hazards.Many scholars and scholars believe that among the above models, aggregation and integration have economic advantages in supplying facilities and services. The ruler's insight has led to less attention to its economic, social, physical and environmental implications. It seems that this indifference has led to the implementation and implementation of relocation and integration plans of rural settlements with the change in their vulnerability in the economic, social, physical and environmental dimensions and the development of the vulnerability of affected society Increase against future accidents. Extreme rainfall in the eastern province of Golestan province in August 2005 resulted in two devastating floods, one of the most damaging floods in the country. The Islamic Revolutionary Guard Housing Foundation has been providing housing for the affected population and in order to reduce the resettlement of villages due to the occurrence of future floods, the eleven villages in the city of Kalaleh, which had been damaged in recent floods in Golestan Province, were displaced. This research is descriptive-analytic and its data have been collected in two sections of library and field. The statistical population of this study is a collection of residents of the walled city and villagers who have returned to the villages of Chatal, Ghapan Oliya and Sofla. To test the vulnerability in two samples, independent samples t have been used. Comparison of two sample returns in villages Chatal, Gapan Oliya and Sofla with the displacement and aggregation of villages in the recreational city showed that each of the studied samples had weaknesses and strengths in different dimensions of vulnerability. The vulnerability of the Faragi city in the economic dimension, using the average for each of the three villages and the city of recreation (3.18 and 2.89, respectively), shows that the resettlement policy in the area of study has increased the vulnerability, especially in the outskirts of the Faragi city Is. The results of this research in the economic sector are consistent with the results of Firouznia and colleagues (2011) and Stadekelai et al. (1394). Regarding the role of resettlement in social vulnerability after examining the criteria, the average for each of the three villages and the Faragi city (3.21 and 2.77 respectively) shows that the resettlement policy from the social perspective in the scope of the study increases the level of vulnerability especially in the Faragi city. The results of this research in the social section are consistent with the results of Montazarian (2011), Mohammadi, Professor Kalayeh et al. (1394), Zaharan et al. (2011), Peik et al. (2014) and Navara et al. (2013). In the physical dimension of the environment, it can be said that resettlement in general has reduced the level of vulnerability and improved life indicators in the Faragi city. The average for each of the three villages and the Faragi city (2.89 and 3.57, respectively) shows that the resettlement policy from the physical-environmental perspective in the study area has reduced the amount of vulnerability in the outskirts of the Faragi city to the three villages. On the other hand, the zoning of physical-permafrost
range shows that although the physical injuries of the outskirts of the Faragi city are lower than the three villages, but considering the location of the Pishkamar's site in the zone with moderate damage, the physical-peripheral city of leisure also vulnerable. In most post-traumatic reconstruction programs, the policy of removing the entire or part of the settlement as a suitable technical solution to reduce the vulnerability and safety of phenomena such as floods, landslides and so on Considered
. However, the review of various experiences suggests that displacement of settlements, although effective in reducing physical morbidity, is mainly due to numerous social and economic consequences. The displacement and consolidation of 11 villages of Golestan province in the post-flood Pishkamar site of 1384 were unsuccessful due to the lack of planning and designing, with macroeconomic and social costs, in reducing the dimensions of vulnerability of a settlement, including social and economic. This has led to the return of villagers to their old villages. The quantitative results of this research also confirm the hypothesis that increasing the migration to cities, returning to old villages, ethnic conflicts, reducing production levels, increasing bank debt and the prevalence of insecurity in the outskirts of the Faragi city are one of the most important factors in increasing the vulnerability in the social and economic dimensions of the study area. The investigations indicate an increase in the amount of vulnerability in recreational areas in terms of economic and social dimensions and reducing its physical-environmental vulnerability to three villages. Since reducing the vulnerability of settlements is subject
to control and reduction of damage and damage in all aspects, it seems that the
reconstruction of rural settlements after the flood of 2005 in Golestan province has been
effective in increasing the vulnerability of this area.
Keywords: Vulnerability, Relocation, Resettlement, Faragi city, Golestan Province.
Dr Mohammad Mahdi Hoseinzadeh, Miss Sepide Imeni,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
In Iran, there is a general risk of runoff and flood, and since this country has a dry to semi-arid climate, its predominant rainfall is not evenly distributed in terms of time and place. Routine runoff at the earth's surface can lead to risks such as groundwater abatement, social issues such as population migration, erosion and loss of soil fertility, sedimentation in reservoirs and water quality in rivers. Also, damage to the agricultural sector, subsidence, the destruction of residential buildings and the reconciliation of the urban, rural and nomadic order are all examples of controversy about the risks that runoff and flooding are due to. The severity of these hazards in the Afje watershed is due to the geographical location, the specific climate, geology and pond factors, and a large volume of flooding every year causes the destruction of residential areas, agricultural lands and many financial and financial losses.
In this research, data collection was carried out through library and field resources. The main tools of this research were topographic map of 1: 25000 which was used by GIS software for the separation of layers and determining the boundaries of the basin; Land use maps and user data and hydrologic groups of the study area were also used to estimate runoff height using curve number method and Arc-CN Runoff instrument. Then Arc-CN Runoff tool was used to prepare layers and curve number map (CN). Finally, the runoff height of the studied basin was prepared in the GIS software.
Soil Hydrology Group: According to the studies, in terms of breadth and extent, the Hydrologic Groups C has the largest area with relatively high runoff potential. By matching the map of Hydrologic Soil Groups and the mineralogical units of the basin it can be stated that the green mass tuff and thick conglomerates are in the hydrologic group D, and the thick layers of green tuff, marl and sandstone in the hydrologic group C and the rocky layer of limestone in The hydrological group B is located.
Land use: The hydrological status of the land and types of uses in the Afje watershed basin are as follows. Most of the catchment area is covered by medium-sized meadows, which comprises 53.77% of the basin area and is located in the hydrological group C with relatively high potential of runoff production. The rock outcrops are in the next rank, which is in the hydrological group D.
Runoff curve number (CN): Land use maps and soil hydrologic groups were combined and extracted for each curve number range (CN) and CN map was prepared. The Afjeh basin has a curtain number of 66 to 100. The highest value of the curve number is 100, which is related to the outflow of the Afjeh watershed basin, which is practically inert, so all precipitation becomes runoff. The Afjeh basin has a curtain number of 66 to 100. The highest value of the curve number is 100, which is related to the outflow of the Afjeh watershed basin, which is practically Impervious, so all precipitation becomes a runoff. In fact, the curve number 100 in stone is 5.59 square kilometers from the area of the Afjeh watershed. But gardens and Agricultural land have the lowest CN (curve numbers 66 to 77) in the Afjeh basin, and include 4.53 square kilometers of basin area. Therefore, the lower parts have a lower CN than the upstream of basin.
The runoff height in the four seasons was calculated based on the daily precipitation values occurring at mentioned times.
Based on the average daily rainfall of spring with a value of 10.79 mm and runoff classification, in a small part of the gardens in catchment area due to high permeability of the soil, 2.54 mm of precipitation has become runoff, although it is due to stone due to The Impervious of the surface, 10.66 mm of precipitation, turned into runoff.
According to the studies carried out and according to the potential maps of runoff production in the Afje watershed, in the garden with the value of the curve number 66 and daily precipitation (for example, in the winter with a rainfall of 4.04 mm), the runoff height is 0.76 mm And the peak of discharge of 0.47 cubic meters per second And has the lowest runoff potential. In winter, the upstream sediments of the basin with curve number 100, runoff height of 3.81 mm and peak of discharge of 2.65 cubic meters per second and almost all rainfall becomes runoff. Therefore, the shortage of water resources, the presence of dry and semi-arid climates in the country and the achievement of sustainable development leads to the optimal use of water resources.
keywords: hazard, Arc- CN Runoff, GIS, high runoff, catchment Afjeh
Armaghan Nickandish, Soolmaz Dashti, Gholamreza Sabzghabaei,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
The most important role that the managed areas will play to attain sustainable development goals would be protecting ecosystem and genetic diversity to achieve the scientific, aesthetics, social and economic potential benefits in future. Proper management of protected areas requires a full understanding of the present conditions, detailed and exact implementation, planning, regular monitoring and risks changes detection in protected areas to understand how are they, how they would effect on nature, recovery and rehabilitation processes and to protect them in long term is very important. Karkhe National Park and protected area is one of the most valuable and most strategic areas in the country that can be protected. This study aimed to identify and analyze threatening risks in Karkhe protected area and national park. The Study area is located with an area of 15828 hectares (sum of national park and protected area) on both side of Karkhe river in Khuzestan province. In this research based on field visits and using the Delphi technique, that there were 15 experts and specialist joint it, 28 risks in two terms of the natural and anthropogenic environment (physicochemical, biological, economical, social and cultural) are identified. Then to order the identified risks, The TOPSIS method was used according to the three fectors, severity, probability and sensitivity of the host environment. The results showed that the risk of lack of conservative officer by closeness coefficient (CC) 1 is the highest risk in the area and The risk of soil pollution with heavy metals by closeness coefficient 0.149 is the lowest priority. The most obtain risks has been socio-economic risks. After ordering the environmental risks was found that existing risks in the region has been in a considerable level. Finally, strategies to control risk in the region was presented. As a result, management solutions should be provided to reduce, control, or eliminate the most important risks. In the meantime, strengthening the existing environmental laws and the necessary guarantees for their implementation seems necessary.
Dr Moslem Savari, , , ,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Farmers frequently cope with risks due to the uncertainty of climatic conditions. Population growth, changes in agricultural policies, environmental regulations and the degradation of natural resources such as soil and water also present farmers with numerous challenges. Although farmers have experience in coping with a certain degree of uncertainty, increased climate variability and changes may cause severe problems. Drought in particular is a climatic disaster that creates substantial costs for farmers and affects their agricultural systems extensively. Drought is the most complex of all natural hazards, making the arid and semi-arid regions of the world vulnerable. Although drought has not been well documented, the resource-dependent sectors such as agriculture are the most vulnerable to the impact of this phenomenon. A review of the long-term annual precipitation trends indicated that drought had a worldwide return frequency of every 20e30 years. However, in the last 50 years, some countries such as Iran and Bangladesh have experienced approximately 27 and 19 drought events, respectively. Therefore, for arid and semiarid regions, drought is a recurrent feature that could lead to the loss of crop production, food shortages and starvation) if not managed appropriately. According drought impacts could be managed at macro (national), meso (local) and micro (village and household) levels. However, the micro-level management (i.e., what the farmers do in response to drought) is of great importance. A review of the studies of farmers’ decision-making in response to climate variability revealed that most research has focused on the decision event and not on the entire process argued that the wrong assumption of farmers’ homogeneity neglected different aspects of decision-making in response to drought. Also indicated that farmers made different decisions when utilizing the same data. Additionally, many studies have focused on single strategies that were used to mitigate drought. However, there is a lack of knowledge about the combination and sequence of coping strategies that are used to mitigate drought. Concentrating on the decision-making process could help policy makers assess the needs and prioritize interventions, as well as enable farmers to efficiently manage drought. Farmers utilize various strategies to reduce the impacts of drought. Some strategies have a limited impact on drought mitigation. Some practices also increase farmers’ woes during drought. In addition, when resources (natural, physical and financial) are scarce, the need for an accurate appraisal of coping strategies becomes acute. Therefore, outcome prediction (i.e., the efficacy of mixed coping strategies) is a critical issue in drought management. Consequently, this study is concerned with the description of the farmers’ decision-making process and decision outcomes. First, the impacts of drought on the agricultural production in arid or semi-arid countries, specifically Iran, are described. Then, the farmers’ decision-making process during drought is explained then, the farmers’ decision-making process during drought is explained. The focus then shifts to the design and explanation of the proposed research methodology, followed by an analysis of the results and concluding remarks. Approximately $84 million. Under such conditions, Iran imported significant amounts of wheat and rice, and it seemed likely that continuous drought would lead to import expansion. Furthermore, dairy production also experienced a decrease of 8.2 percent during this same period. The drought of 2008e2012 was one of the worst on record. This drought drastically reduced the cultivation area, even in irrigated lands. During this time, the river waters fell to critical levels. Most of the traditional ground water irrigation systems (qanats) either completely dried up or experienced a reduced water release. In the central and southern regions of Iran, the cultivation areas were reduced by half during the spring-summer seasons due to these low water levels. During this period, farmers experienced rising costs due to the use of management strategies such as deepening wells and constructing water storage in order to cope with the drought. Other economic impacts that were experienced by the farmers were increased livestock feeding expenses, increased interest rates, and increased debts. These depleted resources and diminished incomes forced those in rural areas to migrate to the cities in pursuit of jobs. Important factors, as previously mentioned, are livelihood risks that so far have not been given much attention so this research was to Patterns Design Out of the Challenges of Livelihood Sustainability of Small-Scale Farmers in Drought Conditions in Kurdistan Province.
The statistical population consisted of small farmers in Kurdistan province who were in drought conditions. The research paradigm is qualitative in two ways: Grounded theory and phenomenology. Using theoretical sampling, 29 of them were selected for study. The research data were collected using a deep interview and group discussion and analyzed with three open, axial and selective coding methods.
The results of the research in the phenomenology of Livelihood Behavior Behaviors included 16 primary codes and classified into adaptive behaviors, resiliency and non-response. Also, the results of studying the livelihood sustainability challenges of small scale farmers in the form of foundation data methodology included 61 initial codes. Finally, in order to design a model out of the challenges of the stabilization of 9 mechanisms (economic, productivity, production factors, services and facilities, Education and information, management and capacity building, culture, technology, formations, and equilibrium) were designed based on the challenges of sustainability and incorporated into the Strauss model.
Keyword: Sustainability, Sustainable Livelihoods, Climate Risks, Small Scale -Farming
Mr Vahid Safarian Zengir, Dr Batol Zenali, Mr Yusuf Jafari Hasi Kennedy, Miss Leyla Jafarzadeh,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Investigation and evaluation of dust and microstrip phenomena is one of the important values in the management of climate and environmental hazards in the Middle East, especially in the arid, western, southern and central parts of Iran. Methods and plans for studying this phenomenon and its management are of great importance and great value. According to studies on dust phenomena based on predictive methods with low error, contradictory and low, the evaluation of the characteristics of dust and its prediction will reduce the irreparable damage that results from it. To do this, in this research, dust monitoring and assessment of its prediction in Ardebil province was performed using the ANFIS model. The data used in this study is the amount of dust in the relevant statistical period to each station from its inception until 2016. The dust phenomenon was used in the observed and predicted time intervals to assess the dust and the ANFIS model for predicting dust phenomena. According to the findings of this study, in the monitoring and prediction of dust situation, the frequency of occurrence in observed years in the maximum amount of dust in Ardabil station with 74% and the lowest in Mashgin is 8%. In the years to come, the maximum amount of dust at Khalkhal Station was 61.67% and the lowest was 10% in Mashgin. In terms of amount of dust, the Ardebil station is more intense than the rest of the stations. In terms of the severity of drought that has been studied, each of the 5 stations studied has a dust concentration of more than 74%. For the 5 stations studied for the next 18 years using manually generated codes, the stations were divided in time series, with the highest average error of training at Pars-Abad Moghan Station with 0.091% and less The highest value was obtained at the Grammy station with a value of 0.001%.
Dr Mohammad Ghasem Torkashvand,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Dust phenomenon is a natural occurrence that occurs widespread in arid and semi-arid regions of the world, especially in the sub-equatorial latitudes. This phenomenon is among the greatest environmental problems in the world. The release of this destructive climatic phenomenon in a scattered manner in the atmosphere varies in size, time and concentration. Since this phenomenon is influenced by the specific conditions of climate effects, its effects may continue to be as close as 16,000 kilometers from the source and cause abnormal environmental effects on the one hand, and numerous damage to agriculture, industry, transportation and telecommunication systems on the other hand. Dust storms, as an atmospheric destructive phenomenon, have created adverse environmental impacts for the west of Iran and caused many problems for the inhabitants of this region. Therefore, studying this phenomenon is necessary in order to achieve a comprehensive approach to deal with it. The present study was conducted with the aim of identifying the instantaneous atmospheric conditions, conduction and source of the dust storms with a synoptic modeling approach.
In this study, in order to investigate the dust storms structure in the southwest of Iran, the dust storm occurred on May 15, 2015 was selected. The reason for choosing the present day, based on reports from the Observatory and Monitoring Center of Ilam’s Environmental Protection Office, was the most polluted day of 2015, so the amount of aerosol recorded was 1200 µg/m3 in the air of Mehran City. To analyze the storm structure, a combination study was performed using NECP/NCAR reanalyzed digital data and output of dynamic and regional models. The first group consisted of three regional models of NAAPS, DREAM 8b and NMMB/BSC, and the second group included HYSPLIT dynamic model with backward method. NECP / NCAR data are also used in the synoptic analysis of the storm.
The average slope of air pressure in the sea level at the time of the dust storm in the west of Iran has increased and a high pressure difference of 20 hPa is observed between east and west of Iran, which is accompanied by a high pressure difference and severe winds in the southwestern borders of Iran. Also, the surface moisture flux of the soil has fallen sharply for the day of the storm occurrence in the study area. High advection in the Western part of Iran has been accompanied by a change in the density and mass of the air with heat, resulting in very rapid and intense air rotational movements around the Earth's surface; on the other hand, the coincidence of the positive and negative vorticity in a single significant amount in the formation of the lower level jet has caused the emergence of the dust storm to occur in the mentioned day. On the day of the dust storm, the orbital component of the wind speed was Western, and its velocity was more than 5 meters per second on the western borders of the country. The meridian component of the wind speed was also Southern. Therefore, the effect of present pattern on west of Iran during the day of storm dust has played a significant role. The optical depth index and surface dust concentration index in the NAAPS model have shown that dust concentrations ranged from 640 to 1260 µg/m3 to the west. Besides, the amount of sulfate in the region was estimated to be between 1 and 2 µg/m3. Comparison of the output of DREAM Bb and NMMB / BSC models showed an increase in concentration values per Dust surface unit on the day of storm occurrence. Based on the results of two models of DREAM Bb and NMMB / BSC in the case of western dust in Iran, it can be concluded that the effect of local factors and close proximity to the centers of the dust source have a significant role in the occurrence of present phenomena for western Iran. The simulation of the Dust storm direction with the HYSPLIT dynamic model and the backward method has shown two routes of dust entering the west of the country; a) Northwest - Southeast; b) West-East direction. The main origins of the first route, the northwest of Iraq and the east of Syria, and the second route were the center of Iraq.
Keywords: Spring dust storms, Regional modeling, HYSPLIT model, particles optical depth, West Iran
Mrs Hajar Pakbaz, Dr Mahmood Khosravi, Dr Tagi Tavousi, Dr Payman Mahmoudi,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
As 7 Stations include; Ardebil, Sarab, Shahrekord, Ahar, Takab, Zanjan, and Saghez were experiments on average every year less than 30 days with thermal stress. From these 7 stations, Ardebil and Sarab regions, having 3 and 7 days with thermal stress, respectively, have the least amount of days with heat stress. All the days with the heat stresses obtained for these stations have been the days of the first class of heat stress map, and all of them were randomly distributed over the warm period of the year.
But in contrast to this stations that had the fewest days of thermal stress, southern Iranian stations, especially those stationed at the Persian Gulf and the Gulf of Oman Sea coasts, were the most frequent days of heat stress.
The two Jask and Chabahar stations with the annual average of 304 and 301 days, with the highest thermal stress, were the most frequent regions of Iran. The lower latitudes, lower elevation, higher temperatures and relative humidity are factors that make the conditions for having the most frequencies of days with heat stress in this part of Iran.
The spatial pattern of five classes this index also show different patterns in comparison with each other so that as all stations in Iran experience at least 3 days of thermal stress in the first class during the year. But with increasing intensity classes, the number of stations that experience the conditions of these five classes over a year will be reduced. As for the second class, 16.2% of the stations, for the third class, 55.4% for the fourth class, 83.7 %, and finally for the fifth class, 90.5% of stations, do not experience comfort in any way during one year. Finally, with regard to the important role of the elevations in the spatial distribution, the relationship between the total frequency of days with thermal stress and elevation was modeled using classical linear regression model. The results of this model showed that per 100 meters above sea level, 9 days from the total frequency of days associated with Iran's thermal stress is reduced. This downward trend is such that there is no thermal stress in Iran at 2300 m above sea level. In other words, the height of 2300 meters is the elevation border between the occurrence and absence of days with thermal stress in Iran.
Hamzeh Ahmadi, Gholamabass Fallah Ghalhari, Mohammad Baaghideh, Mohammaf Esmail Amiri,
Volume 5, Issue 2 (9-2018)
Volume 5, Issue 2 (9-2018)
Abstract
Climate change stand as the most important challenge in the future. Horticulture is one of the most sensitive and vulnerable sectors to the climate change. Climate change and global warming will endanger the production of agricultural products and food security. Because of required longer time to fruit production, fruit trees are heavily susceptible to damage from climate change. The purpose of this study was to investigate the impacts of climate change on thermal accumulation pattern in Apple tree cultivation regions of Iran based on the outputs of new CMIP5 models and radiative forcing (RCP) scenarios.
The present study was carried out using a statistical-analytical method. In this study, two types of data was used; baseline data for past period and model output simulation data for the future period. Observation data for baseline period for 53 weather station was extracted from the Iran meteorological organization (IMO). Afterwards, the data for the upcoming period up to the 2090 horizon were processed using the HadGEM2-ES model from the series of CMIP5 models of the MarksimGCM database based on the radiative forcing scenarios RCP8.5 and RCP4.5. The future period will be refined in the mid-term (2020-2055) and the far future (2056-2090). Afterwards, based on the thermal thresholds, thermal accumulation in Apple tree cultivation areas in Iran processed.
The results showed that based on statistical indices on the output of CMIP5 models, the output of the HadGEM2.ES general circulation model is accompanied by fewer simulation errors in illustrating the climate change of the future period than the observation or baseline period. In fact, based on the evaluation criteria or error measures, this model shows a higher compliance with observational data. In general, the model has a lower accuracy than precipitation in the simulation of rainfall, which is due to the complexity of the precipitation process as well as the structure of the climatic models. One of the fundamental issues that have emerged in recent decades is the change in the potential status or heat accumulation of different regions due to the increase in air temperature. The results showed that due to temperature increase, in the mid and far future heat accumulation will increase compared to the baseline period in Apple tree cultivation areas. Increasing of heat accumulation will reduce the length of the Apple tree growth period, and in fact the Apple tree will complete its vegetative and reproductive cycles sooner. This condition will have negative effects on the quality, taste and color of the Apple varieties. For example, according to the RCP8.5 scenario in the physiological threshold of the apple tree 4.5 C° , in the mid term (2020-2055) and far future (2056-2090) will be 1132 and 2171 active degree days respectively compared baseline period. These conditions equivalent to the 51% and 42% respectively. Based on the RCP4.5 scenario, these conditions will be 390 and 680 active degree day, equivalent to 9.3% and 15.1%, respectively, compared to the baseline period.
The results showed that the heat accumulation in Apple tree cultivation areas in the future period will increase compared to the baseline period. One of the most important effects of climate change on the Apple tree cultivation will be due to increased heat accumulation in the upcoming period. Increasing the heat accumulation will reduce the length of fruit tree growth period, and in fact the fruit tree will complete its vegetative and reproductive cycles earlier. According to these conditions, the areas of Apple tree cultivation in the future will be extended to higher regions. These conditions are important for cold regios fruit tree such as Apple tree, in facr increase in heat accumulation will reduce the length of the growing season and, as a result, reduce the quality and yield of the fruit. Based on the spatial distribution, the least heat accumulation in the highlands, especially Northwest and central Alborz, will occured. In natural landscapes of low elevations, valleys and plains in the Northeast, central Southern part of the Zagros and around Lake Urmia, higher heat accumulation will occured in the future. Therefore, one of the effects of climate change on fruit trees will be due to increased heat accumulation in the upcoming period. Increasing the potential or heat accumulation will reduce the growth period of the fruit trees, in fact, the fruit trees will complete their vegetative and reproductive cycles sooner.
Sayedenegar Hasheminasab, Reza Jafari,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Introduction
Trend of increasing natural resource degradation in many parts of the world, is a serious threat to humanity. Desertification is one of the manifestations of the damage that has already suffered as a scourge of many countries, including developing countries are. At present, remote sensing is one of technologies with timeliness data and accuracy suitable for monitoring land use changes in the areas of natural resources. Desertification monitoring and tracking changes, which seeks to desertification that the change could be for any reason and also collect and analyze data from activities, projects, plans and programs that may desertification range condition assessment and reporting to provide them. The purpose of this study was to evaluate changes in land use on desertification monitoring using remote sensing techniques to the agricultural lands around zayandeh rood in the East region of Isfahan.
materials and methods
In this study, the image sensor of TM to date 1987, 1998, ETM+ to date 2002 and OLI to date 2014 related to the Landsat 5,7 and 8 to obtain the land use map used and then was performed radiometric and geometric correction.Then was used the color combination, the main component analysis, vegetation index and supervised classification method for detection of complications and the maximum likelihood algorithm as the most appropriate method for supervised classification in classes 9 of land cover. After production the land use map correctness evaluating operations with calculation error matrix and then was performed detection operations for these maps. Finally, for desertification of monitoring, land use years 27 changes around zayandeh rood using the comparison method is paid changes to identify and was obtained the area of each use.
Results and discussion
For investigate the the process of desertification, land use changes in the period of 27 years. In order to select the appropriate bands in supplying the best color composite satellite images and operations classified in order to reconstruct the images, index optimization factor was applied. The results of accuracy assessment shows that For all the images above the 80% overall accuracy and Kappa statistics indicate that almost 80 percent. Generally good agreement between the classification and classes of users on the ground there. By comparing bit images specified land use changes in the period of 27 years, riverbank has the greatest changes during this period. So during these 27 years the river high Zayandehrood degradation, which could be due to the expansion of agricultural activities in rivers. This degradation is generally represents gradual drying of the river and go surrounding cultivated by farmers. This degradation process in the margins of the river and the gradual drying of the river towards the desertification situation in the region shows.
Conclusion
In year 27 time period, Zayandeh Rood neighboring rivers has changed dramatically, so 86.43% of neighboring rivers was destroyed due to the expansion of agricultural activities vicinity of the river and drying river. Another significant changes, loss of agricultural land is notable such that 64% of this land has been reduced compared to 1987. Of reasons for the loss of agricultural land will be noted the region drought and Zayandeh Rood river drying up and Low rainfall, land use change and the proximity of the region desert. Also, has become about hectares 324.99 Of salt marsh lands to agricultural land. Moreover, the developed urban areas to its development contributed agricultural land and rangeland. Bayer lands around Zayandeh Rood Increase and also in region of rangeland lands Low and has increased Bayer lands and somewhat until agricultural land which inappropriate use of this land shows in order to the agricultural. That this is the desertification progress in the region. Generally desertification process in this period years 27 has been a growing trend.Therefore multi-temporal and multi-spectral satellite data for enhancement, especially for desertification monitoring was large capability and classification after comparison method is helpful for determine the type and direction of changes occurred. Since the development of desertification, limited to a small area and is not recommended range is therefore more effective, in addition to work sheets, other sheets around the area also evaluate the process of desertification is to allow for planning and management in the field of combating desertification exist.
Dr. Mostafa Karimi, ُsir Seyfollah Kaki, Dr. Somayeh Rafati,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Global temperatures have increased in the past 100 years by an average of 0.74°C (IPCC, 2013), with minimum temperatures increasing faster than maximum temperatures and winter temperatures increasing faster than summer temperatures (IPCC, 2013). Total annual rainfall tends to increase at the higher latitudes and near the equator, while rainfall in the sub-tropics is likely to decline and become more variable (Asseng et al., 2016). Considering probability of occurrence climate change and its hazardous impacts, it seems essential to clarify future climate. General Circulation Models is widely used to assess future climate and its probable changes. Although the outputs of these models are not appropriate for small-scale regions because of its coarse resolution. Thus, statistical or dynamical techniques are used to downscaling the outputs of these models using observed data in weather stations. Despite the fact that frequent researches has done in relation with climate and climate change, but it is unclear yet future climate, especially climate change, in Iran. The goal of this study was to present the results of climate change predictions which has been done so far in Iran, in order to help prospective studies in this field. This step can be important to consider new questions and challenges. In this study, we assessed future climate change in Iran using results of statistical downscaling studies of atmospheric-oceanic General Circulation Model’s outputs. To do this, studies on prediction of precipitation and temperature parameters in Iran by different emission scenarios, atmospheric-oceanic General Circulation Model’s outputs and statistical downscaling techniques were gathered. Then a comprehensive view about Iran's future climate and specifically the climate changes presented by descriptive-content based analysis and comparison of their results. Used downscaling techniques in these researches were included: LARS-WG, SDSM, ASD, Clim-Gen and used General Circulation Models were: HADCM3, BCM2, IPCM4, MIHR, CGCM3, CCSM4 and finally used emission scenarios were A1B, A1, A2, B1, B2, RCP4.5. Based on climatically geographical differences in Iran, the results discussed separately in six different regions across Iran. The results of various regions are different because of usage of different models and different climatological and geographical conditions. These models simulate temperature more accurate than precipitation, because of more variability and temporal discontinuity of the precipitation relative to temperature. Assessment of results in 30-year periods from 2011 to 2099 showed that in North West of Iran (Ardebil, Azarbayejan- Sharqi and Azarbayejan- Qarbi provinces), precipitation will be decreasing, decreasing- oscillating, decreasing- transitional and temperature will be increasing. Decreasing- transitional trend, in other words decrease precipitation in cold seasons and increase of it in warm seasons, lead to a decrease in the snow occurrence and an increase in the rainfall occurrence. Thus, it can affect the frequency of floods occurrence. In west and southwest region of Iran precipitation has been predicted to have different changes in various sections of it. It will be decreasing-oscillating in Kermanshah and Kordestan provinces and oscillating in Hamedan province. Precipitation will increase in Lorestan and finally it expected to decrease in Khoozestan, Chaharmahal-va-Bakhtiari, and Ilam. However Temperature will rise across this region. In south and south east region of Iran (Fars, Hormozgan, Kerman and sistan-va-Baloochestan provinces), precipitation will be decreasing, decreasing-oscillating, oscillating and increasing-oscillating. Also in this region, temperature expected to increase similar to other regions. In east and north east of Iran (Khorasan Shomali, Khorasan Razavi and Khorasan Jonobi provinces), temperature predicted to be increasing-oscillating, that it is different with other regions. Changes in precipitation will be oscillating and decreasing-oscillating. In the northern coasts of Iran (Gilan, Mazandaran and Golestan provinces), precipitation changes will be decreasing and increasing-oscillating and temperature changes expected to be increasing and increasing-oscillating. Thus, it expected to increase heat wave, drought, and aridness condition as the results of these changes. Precipitation changes in south of Alborz region and center of Iran (Semnan, Tehran, Qazvin, Markazi, Esfahan and Yazd provinces), will be decreasing, oscillating, increasing-oscillating. Also temperature will be increasing in this region. Considering the decreasing trend of precipitation and the increasing trend of temperature in the most of Iran, it is probable to increase the occurrence of climatic and environmental hazards such as flood, drought and heat waves in the future. These events can have serious effects on water resources, agriculture and tourism, especially in regions such as Iran where have sensitive environment.
Abolfazl Ghanbari, Ehsan Pashanejhad Silab,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Environment, development and sustainability are the three significant issues of worldwide concern. Environmental vulnerability and assessment of natural and anthropogenic activities impacts represent a comprehensive evaluation approach. The main purpose of this study is to present a comprehensive and novel framework in order to environmental vulnerability assessment using by spatial data and techniques. The method of this research is analytical-descriptive. The basic premise is that the finding of this study can be applied in the local planning system and policy making process of environmental conservation particularly to cope with rapid environmental change. The environmental vulnerability is defined and governed by four factors: hydro-meteorology signatures, environmental attributes, human activities and natural hazard. Based on data availability and vulnerability status of different areas, there is no general rule for selecting how many variables are required to assess the environmental vulnerability. In this study, 18 variables were taken into account and organized into four aforementioned groups. The process of environmental vulnerability index is proposed to integrate AHP approach, remote sensing indices and GIS techniques. The environmental vulnerability showed distinct spatial distribution in the study area. Furthermore, the distribution of heavy and very heavy vulnerability patterns mainly occur in low and medium lands where the human activities have been developing rapidly and is the nearest region to Urmia lake in the west region.
, , ,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Introduction
Atmospheric boundary layer (ABL), is the lowest part of the atmosphere. Its behavior is directly influenced by its contact with earth surface. On earth it usually responds to changes in surface radiative forcing in an hour or less. In this layer physical quantities such as flow velocity, temperature, moisture, etc., display rapid fluctuations (turbulence) and vertical mixing is strong. Above the ABL is the "free atmosphere" where the wind is approximately geostrophic while within the ABL the wind is affected by surface drag and turns across the isobars. The land use/cover changes affecting the surface radiative forces lead to ABL spatio-temporal variation. The main object of this study is to analysis the association among ABL height and built-up spatial growth in Kermanshah city.
Data and methods
Multi-temporal satellite images from Landsat imagery data for 1990 to 2015 series of sensors TM, and OLI (Landsat 5 and 8) were taken from USGS database. Data of the Atmospheric Boundary layer height (ABL height) for the city of Kermanshah also were taken during 1990- 2015 from ECMWF – Eran-Intrim website at 0.0125 ° spatial resolution. Firstly, we analysis the temporal trends of ABL height of Kermanshah in summer and winter using linear regression in 0.95 confidence level (P_value = 0.05). The built up area of Kermanshah has been extracted from TM and OLI images using supervised classification method and maximum likelihood classification(MLC) algorithm in GIS image analysis. The Pearson correlation analysis has been used to reveal the relationship between annual ABL height variation and built-up growth of Kermanshah.
Result
The results of long term trend of Built up growth of Kermanshah that extracted using MLC algorithm as can be seen in figure 1 indicated that the built up area in Kermanshah has been growth by 1.02 square kilometer annually.According the figure 2, The results of annual trend of ABL height in summer and winter also reveals that in summer there is no significant trends in ABL height while in winter the significant increasing long term trend has been observed in ABL height.
Miss Khatereh Azhdary Mamooreh., Mr Amir Gandomkar, Mr Keivan Kabiri,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Sea surface temperature is one of the most effective physical parameters that affects the health of coral reefs communities.High frequency of the bleaching phenomenon has extensively occurred in the Persian Gulf in the recent years due to the increase in temperature and increased changes in the sea surface temperature (SST) resulting in great mortality in the coral communities. The aim of this research is to determinate a temperature threshold which may function as a warning for the incidence anticipation of this phenomenon. Data on the variation of the SST that has been taken from National Oceanic and Atmospheric Administration (NOAA). Information related to bleaching in the regions of the southern Persian Gulf was extracted from the published papers and reports. Each of these sources also has been extracted for a 35-year statistical course (1980-2015) and by the index of degree heating weeks (DHWs) determined for the same statistical course in this research for the assessment and anticipation of bleaching phenomenon. For reviewing of the work accuracy, Peirce Skill Score (PSS) technique was used to quantify the accuracy of previous and subsequent anticipations. According to the derived results, DHWs threshold for the study region was determined to be 7.13. the threshold 7.13 for DHW is suggested as a caution threshold for bleaching incidence in southern regions of the Persian Gulf that is whenever the values of weekly positive temperature DHW show number 7.13 and higher, there is an expectation of bleaching phenomenon incidence of corals for these regions. And the score of PSS= 0.72 derived from the amounts of H= 7/8= 0.87 for the Hit rate and F= 4/26= 0.15 for the False alarm rate of the bleaching was obtained for the southern regions of Persian Gulf and study region. In northern regions of the Persian Gulf the threshold 5.3 for DHW is suggested as a caution threshold for bleaching incidence. The rate of pss = 0.62 derived from the amounts of (3/4 = 0.75) for the Hit rate and ( 3/23 = 0.13) for the False alarm rate of the bleaching was obtained for the northern regions of Persian Gulf and study region. Difference in DHWs values of the south and north of Persian Gulf shows more resistance of the corals of south Persian Gulf against DHW changes and SST anomalies. Also the amounts of DHW alongside SST can help more completely to the anticipation of bleaching phenomenon.
Ma Mahmoud Ahmadi, Fj Farzane Jafari,
Volume 5, Issue 3 (12-2018)
Volume 5, Issue 3 (12-2018)
Abstract
Problem statement
The occurrence of terrible floods due to climate change has caused much damages in different parts of the world in recent decades, and the effect of these changes is more pronounced in dry areas. Floods are the most common environmental damage. On average, 60 floods occur annually in Iran, with an average annual flood loss of 141 people, meaning more than 2 deaths per year per flood event.
Research Methodology
The study area consists of six stations located in Hormozgan, Kerman, Yazd, Kohgiluyeh, and Fars provinces. In this study, two types of ground and high data are used as follows:
A) - Using daily rainfall data of the 44 years (1967-2014) statistical stations of the region obtained from the country's Meteorological Organization
B) Use of high-level data. Includes revised data for geopotential heights, sea level pressure, wind direction, meridian wind, omega, and humidity, from the National Center for Environmental Excellence at Colorado. To conduct synoptic analysis, the circular environmental method was used; after observing the daily rainfall during the statistical period of all rainfall over 50 mm in selected stations of Yazd, Jiroft, Shiraz, Bandar Abbas, and Yasuj, 118 heavy rainfall events were investigated. After identifying and separating days, 105 observation systems were identified and analyzed.
After the evaluation and control of the pressure maps of the sea of the systems of landing, 4 patterns were selected and identified.
Explain and interpret the results
The results showed that heavy precipitation occurred in the months of December, December, February, February, and November, respectively. Since November, with the retreat of high-performance dynamic systems to the southern latitudes and the influx of western winds from high latitudes on the area, conditions for the occurrence of heavy rainfall are provided. Most centers with 9 heavy rainwater systems of Sudan's lowland, 6 the moderate Sudanese-Mediterranean component of the Middle East has been on Iraq, and the four satellite systems have been the Mediterranean-Sudan-Mediterranean integration. The most frequent Sudanese pattern in 2-day continuity with 17 cases was Sudan-Mediterranean integration pattern with 7 cases in 3-day continuation, Sudanese-Mediterranean integration pattern in the Eastern Mediterranean, 4-day continuity with 7 events, and equidistant Mediterranean pattern The continuity of 2 to 4 days has been due to the increased load of Mediterranean systems ranging from 70 to 90 mm.
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