Dr. Ebrahim Fattahi, Shookat Moghimi,
Volume 19, Issue 54 (9-2019)
Abstract
In this study in order to monitor snow cover, the Moderate Resolution Imaging Spectroradiometer (MODIS) optical images were used, while for detection of snow covered areas, the snow index-NDSI, was applied. The results showed - according to the climatic conditions of the region- during the following months: December, January, February and March, most of the area is covered by snow and the maximum extent of snow cover occurred in January. In West Azerbaijan province there is found a negative trend of snow cover with a drastically reduction in January, as well as the provinces East Azerbaijan and Ardebil showed the decreasing of snow cover in this month. The results of this study show that, changes in snow cover imply a rise in temperature in this region leading to the reduction of snow cover in January. This trend represents global warming and climate change impacts on snow cover in the study area. Investigation of extreme indices confirms the assumption that by taking temperature increase into consideration, regional winter precipitation pattern has been changed from snow to rain, causing the reduction of snow storage in the catchment of study area. In addition ,the extreme temperature index study in the period of 2011- 2040 and the baseline by considering climate change approach in North West of Iran by using outputs of general circulation models under A2 scenario and downscaling models LARS-WG indicates the number of frost days or the number of icy days decreased compared to the baseline which is not unexpected according to reports by the Intergovernmental Panel on Climate Change (IPCC) as well as several studies confirmed global warming. Moreover, indices such as growth period increased, while diurnal temperature variation decreased compared to the baseline confirming snow cover reduction in the region as a threat of snow storage in the region.
Msc. Graduated Student Najmeh Daneshvar-Marvast, Dr Somayeh Soltani-Gerdefaramarzi, Dr Samaneh Poormohammadi,
Volume 19, Issue 55 (12-2019)
Abstract
The phenomenon of evapotranspiration causes water and moisture losses from water, soil and vegetation levels. Due to the small amount of atmospheric precipitation and water resource constraints in Iran, it is important to calculate it through a suitable method. The present research attempts to evaluate the evapotranspiration reference crop (ETo) and present it in the form of zoning map as a basic tool for water management. In this study, the long-term average of seven meteorological stations and evaporation pan data were used to determine the appropriate ETo estimation method. Evapotranspiration of reference crop was calculated to 14 methods the based on climatic information in each station. Computational methods including combinational methods Penman-based, radiation-temperature method, temperature method and radiation method. The most appropriate computational method was selected based on the R2 and Nash -Sutcliffe statistics. The zoning of evapotranspiration of reference crop was carried out based on the geographic information of the meteorological stations and the GIS software. The results of the research indicate that the best method for this region as the cold and moderate climate are FAO radiation and Blaney-Criddle. Also, the zoning result shows that west of the catchment has less evapotranspiration rather than its east. Sunshine hours, maximum temperature and wind speed were the most effective factors for evapotranspiration in this area by sensitivity analysis.
Hosseinali Roohbakhsh Sigaroodi, Mostafa Karampoor, Hooshang Ghaemi, Mohammad Moradi, Majid Azadi,
Volume 19, Issue 55 (12-2019)
Abstract
Investigating the variability of the spatial-temporal pattern of rainfall, which can lead to climate change, due to its strong impact, is of interest to various scientists. For this purpose, after receiving the daily precipitation data of 27 stations for the period of 60 years (2010-1951), its quality and the total monthly precipitation and statistics necessary for the continuation of the research process such as mean, coefficient of variation, skewness, probability estimate of 20% The upper limit of the maximum and minimum rainfall average were calculated experimentally for a period of 60 years and two 30-year periods (1951-1980 and 1981-2010) and two periods of 10 years (1951-1960 and 2010-2001) for each of the spring and summer seasons Was calculated. The studies show relatively modest variations in spring and summer precipitation patterns on the Caspian coast, Northwest-West, 30 and 10 years old, compared to the 60-year, 30-year, and 10-year periods. In general, the mean of precipitation decreases from north and northwest to south and south east and increases the amount of coefficient of change and skidding. Except for the Caspian Basin, in the remaining stations, the average spring precipitation is higher than the average summer rainfall. There is a clear difference in the long-term characteristics of precipitation and its changes. It is worth mentioning that the increase in the coefficient of variation of the 30-year and 10-year periods is comparable to the corresponding periods at all stations, which indicates a decrease in the monthly and seasonal mean of spring and summer precipitation, which confirms the results of the decade and the first decade of the second decade. The greatest decrease occurred in the northern and western parts. In the second 30 years, the incidence of dry sunshine and drought-affected stations has increased. Therefore, it confirms the climate change for the Caspian and the Southwest coast.
Hossein Naserzadeh, Fariba Sayadi, Meysam Toulabi Nejad,
Volume 19, Issue 55 (12-2019)
Abstract
This research was carried out with the aim of understanding the spatial displacement of rainfall nuclei as an effective factor in the future hydrological conditions in Iran. Two types of databases were used to conduct this research. The first type of data is the monthly precipitation of 86 synoptic stations with the statistical period of 1986-1989 and the second type of predicted data from the output of the CCSM4 model under the three scenarios (RCP2.6, RCP4.5, and RCP6) from 2016 to 2036. After collecting and modeling the data, the maps were mapped to the ARCGIS environment. The results of the study showed that the terrestrial nuclei in the whole of Iran's zone in the four seasons will have changes with a negative trend in the future. The coefficient of rainfall variation in the spring, summer, autumn and winter seasons will be 61.4, 101.4, 58.9 and 55.8 percent, respectively. The results of the triple scenario study showed that the displacement of the spring core from all north north of the country to the northwest of the country is limited to the common borders of Iran, Turkey and Armenia (the Maku and Jolfa region), but in summer, the high core The northern shores and parts of the northwest of the country will be transported to the south of the country (around Khash and Saravan). In the autumn, the high-lying zone, which is located throughout the northern part of the country, will move to two distinct nuclei in the central Zagros (Dena and Zadkouh areas) and southwest Khazars (Anzali and Astara areas), and the core of winter from the central Zagros And the Caspian region will be transferred to the northwest of Kurdistan and southwest of West Azarbaijan, which will be seen in all scenarios. Another point is that, in addition to reducing the boulders, in the future, drought areas will cover more of the country.
Dr Dariush Yarahmadi, Dr Amanolah Fathnia, Mehdi Sherafat,
Volume 20, Issue 56 (3-2020)
Abstract
Abstract
The extention of Snow cover and its spatial and temporal changes considered as a basic parameter in climatic and hydrologic studies. Data from satellite images due to the low cost and the large extention of cover are, effectively help the identifying of the snowy basins. Since the satellites are able to imaging a surface at different times, this will allow snow survey studies to investigate the spatial and temporal distribution of snow. In this research, Snow line changes and the surface temperature line in Alborz Mountains using NOAA-AVHRR satellite images since 2006 from 2015 was studied. The results showed that at the study period, maximum area of snow have been observed in April 2015, with the amount of 12051 square kilometers and the minimum area snow have been observed in June 2008, with the amount of 33 square kilometers. The average of the lowest elevation of snow covered areas, have been observed in April 2007, with the amount of 2662 meters and its highest value have been observed in June 2008 with the amount of 3820 meters. Also the most of the snow line change occurred between the years 2007 to 2008. Moreover, in almost of 15 years, the isoterm of zero degrees Celsius, matches with the snow line and its elevation has changed as the snow area is changed.
Alireza Entezari, Fatemeh Mayvaneh, Froogh Khazaeenejad,
Volume 20, Issue 56 (3-2020)
Abstract
The purpose of this research is to study the comfort conditions and determine the best measures for design and architecture compatible with the climate in Yazd. In this regard, the climatic data of Yazd city has been used in EPW format during the period (1981-2017). The results of the study of temperature and relative humidity also showed that temperatures of more than 38 ° C are visible in June and July. This suggests the need for a shadow in the architecture of the climate. In July, the discomfort conditions prevail over the entire day. From June to October (midday to midnight), midnight hours due to low humidity (38%) and high temperatures, conditions of discomfort and drought are very visible. The highest humidity is in the cold months of the year. In the wind hours of February to May (February to April), there is a discomfort. Also, according to the overall radiation pattern at different hours of the day, it was also shown that 25% of the daylight hours is very high and non-comfort, and 8% are in comfort conditions, which is more related to the cold weather of the year and the early hours And the end of the day. In general, due to the climate of Yazd city and the results of analysis, 20 strategies for architectural design have been used.
In general, due to the climate of Yazd city and the results of analysis, 20 strategies for architectural design have been used.
Mokhtar Karami,, Rahman Zandi,, Jalal Taheri,
Volume 20, Issue 56 (3-2020)
Abstract
In recent years with the development of cities coatings of the Earth's has changed surface. These changes have caused some urban areas to have a few degrees higher than the surrounding temperature. This phenomenon is known as thermal islands. Mashhad is one of the major metropolises in Iran with the problem of thermal islands. Various parameters affect the formation of thermal islands in this city that should be considered. In this study TM, ETM+ and OLI images were used to obtain surface temperature over the period 1987-2016. The study of temporal variations in surface temperature showed that in the studied period, thermal islands were transferred from outside the city to the city. The model for describing the temperature of the surface of the earth has changed and has diminished from the temperature of the city's moderate and cool temperatures, and in contrast, the amount of high temperatures (thermal islands) has increased significantly. The TOPSIS method was also used to obtain the thermal forming factors. 13 natural and human factors affecting the formation of thermal islands were identified. Each expert opinion factor was used to determine the degree of importance. According to experts, the distance from the sanctuary with a weight of %234 and traffic of %155 is the most important and the height with a weight of %022 is least important in the formation of thermal islands. The final results obtained from this model showed that the factors affecting the formation of thermal islands are well recognized and the temperature decreases with these factors.
Mehdi Asadi, Mokhtar Karami,
Volume 20, Issue 56 (3-2020)
Abstract
The purpose of this study is to determine the evapotranspiration in Fars province that in many studies such as hydrological balance of water, irrigation systems design and management, simulation of product volume and management of water resources is very important. To do this, first, required data such as daily temperature, humidity, precipitation, wind speed, solar radiation pressures, solar radiation, etc. was collected. We used 12 stations with the same statistical interval, for the period 1995-2015. In order to estimate the evapotranspiration of the reference plant in different growth stages, Torent White, Penman-Monteith and Hargreaves-Samani methods were used. Results showed that with decreasing latitude, the evapotranspiration rate increased, and the highest rate of evapotranspiration occurs in the south, southeast and the center of the study area. The correlation coefficient R2 between height and White Penman, Monteith and Hargreaves Samani, are 0.9135, 0.53223 and 0.5286 respectively.
Mr Behroz Sobhani, Mr Vahid Safarian Zengir, Ms Akhzar Karami,
Volume 20, Issue 57 (6-2020)
Abstract
The limitations and boundaries of agricultural production is dependent on climatic conditions. Weather is one of the most important factors in human activities, especially agriculture. Corn cultivation in the country's food supply is essential. Kermanshah province, with the potential favorable climate, optimum conditions for corn are cultivated. The aim of this study was to investigate the role of precipitation and temperature in determining the agricultural calendar and to determine suitable areas for planting corn. To do this, climate data from 10 synoptic stations during the period of 20 years (1390-1371) were used. Use, Hoteling test and test observational data were analyzed. According to research, the station is under study, corn crop water demand in the months of June, July, August and September not secure and High temperature areas due to reduced need frequent in the months of May and June and in the lowlands due to a sharp increase in flowering time, seed maintenance and handling problems during the growing season makes this crop. Based on the results of Hotelling test 62 percent of the land area suitable Kermanshah province, 24 percent and 14 percent for maize is unsuitable. And also based on the results of t-test found 47 percent good, 38 percent moderate and 15 percent are unsuitable for corn. As a result, the central area of moderate temperatures for planting, eastern and northern areas of the southern and western areas of the province due to tropical cold and not suitable for maize cultivation.
Reza Reza Borna, Nasrin Nasrin Jafari, Farideh Farideh Asadian,
Volume 20, Issue 57 (6-2020)
Abstract
In order to understand the total consumption of buildings and accurately calculate how much energy each building uses, taking in consideration all the building's lifecycle phases is essential. In order to select the correct methodology for the main study, the researcher began with the determination and the parameters that would have been researched, as well as the analysis and comparison of the different methods used by other researchers to achieve similar goals. The following parameters define the final results and are stabilized or examined to determine their actual effect: A- Constant parameters: 1- Climate data 2- and data on the use of the building: B- variables: 3- Design data: 1- orientation 2- window to wall ratio 3- aspect ratio. This research uses a survey followed by a computer modeling methodology to achieve the goal of providing architects with techniques that reduce energy consumption in building units. To obtain reliable results that are useful to the construction industry in the country, the researcher has ensured that the virtual environment created in the modeling process mimics a typical building environment of Tehran units. Research has shown that passive design techniques have a major impact on the energy consumption of buildings. A significant reduction in consumption (67 percent) was noted when the orientation and percentages of the opening on the wall were changed. In summary, this study has shown that the application of passive, economical and simple design techniques has a major impact on the energy consumption of the unit rooms. If the architects take these ideas into account during the design process, the buildings will take on more responsibility for the environment and consequently reduce carbon dioxide emissions.
Mohammad Hossein Nasserzadeh, Zahra Hejazizadeh, Zahra Gholampour, Bohloul Alijani,
Volume 20, Issue 57 (6-2020)
Abstract
The plant community in an area is the most sensitive indicator of climate. A visual comparison of climate and vegetation on a global scale immediately reveals a strong correlation between climatic and vegetation zones and this relationship, of course, are not co-incidental. The main object of this study is to reveal the spatiotemporal association between climatic factors andvegetation Cover (NDVI) incorporate MODIS and TRMM product in Kohkiloyeh O Boirahmad province of Iran. So that the in this paer we use MOD13Q1 of MODIS product as NDVI layer for study area. MOD11A2 as landsurface temperature and 3B43 TRMM as meanmonthly accumulative rainfall for study area during 2002 to 2012 in 0.25° spatial resolution also were used as climatic factors. We use the correlation and cross-correlation analysis in 0.95 confident level(P_value =0.05) to detection the spatial and temporal association between the NDVI and 2 climatic Factor(LST and rainfall). The results indicated that during winter (December to March) the spatial distribution of NDVI is highly correlated with LST spatial distribution. In these months the pixels which have the high value of NDVI are spatiallyassociated with the pixels which have highest value of LST (6 to 14C°).As can be seen in table 1. Season the spatial correlation among NDVI and LST is so high which is statistical significant in 0.99 confident level in winter. In transient months such as May, October and November,(temperate months in study region ) the spatial correlation among NDVI and LST is falling to 0.30 to 0.35 which is not statistical significant in 0.95 confident level. Finally in summer season or warm months including Jun to September, we found the minimum spatial association among the NDVI and LST.. In temporal aspect we found that the maximum correlation between NDVI and LST simultaneously appears and not whit lag time. The spatial correlation of NDVI and TRMM monthly accumulative rainfall was statistical significant in spring season (April to Jun) by 1 month lag time in remain months we don’t find any significant correlation between NDVI and rainfall.
Leyla Sharifi, Saeed Bazgeer, Hosain Mohmmadi, Alireza Darbaneh Astaneh, Mostafa Karimi Ahmadabad,
Volume 20, Issue 57 (6-2020)
Abstract
In an agricultural system, crop production is related to climatic conditions. Therefore, a deeper understanding of the impact of regional climate change on production ensures global food security. Wheat is one of the most strategic crops and examining different aspects of its production is a necessity of every agricultural community. According to studies, wheat production is affected by various variables including environmental, individual and social, economic and technological. The aim of this study was to estimate the effect of these variables on changes in wheat production in different climates of Fars province. The required data were collected and analyzed through multi-stage random stratified sampling and 522 completed questionnaires through face-to-face interviews with farmers in the province. Farmers' attitudes were measured in the Likert scale and Cobb Douglas, Transcendental and Translog production functions were used to estimate the effect of variables. Results of comparing effective variables in three Cobb-Douglas, Transcendental and Translog functions; demonstrates the superiority of translog. From the perspective of the farmers of the province in the translog function, respectively; Soil moisture at planting time (0.692), effective rainfall during growing season (0.68) and at planting date (0.66), heat wave at harvest time (0.63), damaging rainfall (0.59) , Profit from wheat production (0.51), farmer education (0.49), soil quality (0.49) and cultivation method (0.49) with the coefficient of the mentioned criteria next to them; The most important factors explaining wheat production in Fars province. Independent variables in the translog function explain 92% of the changes in wheat production in Fars province.
Ali Bahri, Younes Khosravi,
Volume 20, Issue 58 (9-2020)
Abstract
Considering the vast application of sea surface temperature in climatic and oceanic investigations, this parameter was studied in Oman Sea from 1986 to 2015. The SST was surveyed using trend analysis and Global and local Moran’s I spatial autocorrelation. In trend analysis, the Mann-Kendall test was used to determine the trend of SST changes and the Sen's Estimator method was used to examine the slope of the changes. Using these methods, it was found that during January, February and December, there was no significant ascending trend in SST values, and only parts of the Strait of Hormuz had a significance descending trend. On the other hand, there was no significant descending trend in March, and the ascending trend in the SST was seen in the southern part of the Oman Sea. Other months of the year had a significant ascending and descending trend in different parts of the Oman Sea, which October had the highest ascending trend. In the annual time scale, it was also found that the southern parts of the Oman Sea had ascending trend in the SST value and Western parts had a descending trend. The occurred changes in the high amounts (positive and negative) were corresponding to the significance ascending and descending trends. The results of Global Moran for the annual time scale indicated an ascending trend of autocorrelation values and cluster patterns of SST data over time, using the local Moran analysis, it was found that warm clusters of SST are increasing in the Oman Sea, and on the other hand, cold clusters of this parameter have been reduced over 30 years. According to the results of trend and spatial autocorrelation analysis, it has been found that SST have been increasing in different parts of the Oman Sea during 30 years, so climate change and global warming may have affected this region.
Dr Yagob Dinpashoh, Miss Masoumeh Foroughi,
Volume 20, Issue 58 (9-2020)
Abstract
Reference evapotranspiration (ET0) is a climatic parameter and can be computed from weather data. It is one of the most important hydrological parameters for calculating crop water demand, scheduling irrigation systems, preparing input data to hydrological water-balance models, regional water resources assessment, and planning and management for a region and/or a basin. The climatic data from synoptic stations with more than 20 years continues record in West Azarbaijan province was used. The well-known FAO-PM56 method was used to calculate the ET0. Then Multiple linear Regression (MLR) was used to estimate the ET0. The RMSE, MEA, NSH, and R2 were used to evaluate the performance of the MLR model. Then, the correlation coefficient (r) between ET0 and each of the meteorological parameters was obtained. And finally, with using Path analysis method, the influence of direct (P) and indirect effects of the meteorological parameters on ET0 was calculated. In the studied synoptic stations, NSH between 0.91 and 0.99, R2 between 0.91 and 0.99, RMSE between 0.05 and 0.15, and MEA between 0.04 and 0.12 were obtained. Also, it was found that the wind speed at all of stations had a significant correlation (at the 0.01% level) with ET0. The path analysis results showed that the maximum value of P (direct effect of meteorological parameters on ET0) in all of the stations belongs to wind speed. The P value of wind speed in Urmia equal to 0.85, Piranshahr equal to 0.99, Takab equal to 0.97, Khoy equal to 0.90, Sardasht equal to 1.06, and Mahabad equal to 0.78 are obtained.
Dr Iran Salehvand, Dr Amir Gandomkar, Dr Ebrahim Fatahi,
Volume 20, Issue 59 (12-2020)
Abstract
Rainfall prediction plays an important role in flood management and flood alert. With rainfall information, it is possible to predict the occurrence of floods in a given area and take the necessary measures. Due to the fact that the three months of January, February and March are most floods and most precipitation is occurring this quarter, this study aimed to investigate the factors affecting precipitation and modeling of this quarter. For precipitation modeling, the monthly rainfall data of the Hamadid and Baranzadeh station in the statistical period (1984-2014) for 30 years as a dependent variable and climatic indexes, large-scale climatic signals including sea surface temperatures and 1000 millimeter temperatures Altitude of 500 milligrams, 200 milligrams of omega and climatic elements have been used as independent variables. Due to the nonlinear behavior of rainfall, artificial neural networks were used for modeling. Factor analysis was used to determine the best architecture for entering the neural network. For prediction of precipitation, the data that showed the most relationship with precipitation was used in four patterns, in January the fourth pattern with entropy error was 045/0, the number of input layers was 91, the best makeup was 15-1, and the correlation coefficient was 94% Was. In February, the third pattern with a correlation coefficient of 97%, entropy error, was 0.36. Percentage, number of input units was 8 units, and the best type of latency layout was 10-1. The precipitation of March with all patterns was high predictive coefficient. The first pattern with entropy error was 0.038, the number of input units was 67, the hidden layer arrangement was 17-1, the correlation coefficient was 98%.
Mrs. Nasibeh Baharvandi, Dr. Firouz Mojarrad, Dr. Jafar Masompour,
Volume 20, Issue 59 (12-2020)
Abstract
The heat wave is a long period of warm climate, compared to the expected conditions in a region over a certain period of the year. Heat waves cause mortality, disease and various problems in different fields of transportation, agriculture, production and energy. It is very important to study the changes in spatial and temporal patterns of these waves to understand the causes of the incident and confront them. In the present study, using the "Heat Wave Magnitude Index daily" (HWMId), which takes into account both the intensity and the wavelength of heat, the heat waves of Iran between 1985 and 2015 have been analyzed in terms of spatial and temporal distribution. For this purpose, using the maximum daily temperature data of 44 synoptic stations of the country and on the basis of the threshold of the 90th percentile, the heat waves greater than or equal to three days were identified at each station. After applying the HWMId on the days of each heat wave, the magnitude of each wave was calculated. Then, the average number and magnitude of all waves, as well as the most severe ones, were calculated in annual and seasonal scales and the corresponding maps and charts were drawn up. The results of the study showed that the highest number of heat waves occurs in the western part of the Zagros Mountains and then the Kavir Plain; while the maximum magnitude of heat waves belong to the south-east and central parts of the country. Autumn and then winter season have a high share of the most severe heat waves during the study period; while the spring and summer heat waves are relatively weaker, and are more limited in terms of expansion. The most severe heat waves during the study period have occurred in the winters of 2008 and 2010. The number and magnitude of heat waves in the country is increasing significantly. The largest increase in the number belongs to the summer and the magnitude belongs to the winter.
Mojtaba Shahnazari, Zahra Hejazizadeh, Mohammad Saligheh,
Volume 20, Issue 59 (12-2020)
Abstract
Abstract
In this research, while studying climate conditions in the current period and analyzing changes in temperature, precipitation level, and the sunlight received, current conditions were also analyzed based on daily data from synoptic stations in the region, which had meteorological data recorded for at least 30 years. Given the environmental conditions necessary for the growth of rice, the availability of its phenological data, its high-low temperature thresholds, the Degree Day systems needed for the completion of its life cycle, and the phenological processes related to its economic production, a suitable agricultural calendar was specified. During the March-July period, this calendar showed variations in different provinces. Based on the current temperature conditions and the probable continued warming trend of the planet in the decades to come, nwoDscale was applied to the output from the atmospheric general circulation model MCdaH3 under scenario using LARS-WG5 model. In this study, years between 1969 and 1990 were used as the base period, while years between 2046 and 2065 were studied as the future period. Temperature and precipitation conditions for the future period were simulated. Obtained output was then studied and compared with temperature conditions that were suitable for the plant to grow in the region. With some differences, results showed that the agricultural calendar for rice in Gilan and Mazandaran provinces will shift to winter. Given the different temperature conditions of Golestan province, its agricultural calendar will shift to spring.
Parisa Ahadi, Shahriar Khaledi, Mahmoud Ahmadi,
Volume 21, Issue 60 (3-2021)
Abstract
Dust is referred to sediments of less than 100 microns in size which are transmitted as suspended particles. Dust storms are events which naturally occur in arid and semi-arid areas, especially in subtropical latitudes. One of the most known sources of dust is the west of Asia, including Arabian Peninsula, Syria, Iraq, and Iran, especially Khuzestan Province. The purpose of this study is to investigate the frequency and trend of dust phenomena on hourly, monthly, seasonal and annual scale between 1995 and 2015 in Khuzestan Province. The method in this study is based on statistical computation of dust parameters and also the trend analysis of data based on Mann-Kendall test and spatial distribution maps of dust phenomena. The results suggests that 78.57 percent of dust event are occurred between 9.30 am to 15.30 pm local time, concurrent with peak of sun radiation and earth surface warming, dryness of soil and local pressure difference. The hourly trend analysis is increasing and significant in all hours and the highest increase occurred at 9.30 pm to 12.30 pm.49 percent of dusty days occurred in June, July and May and also 73 percent of them are in spring and summer as following from temperature increase and water and soil resources drying in the province. The seasonal and annual spatial distribution of dust indicates that most of dusty days in all seasons are located in west of province which suggests dominance of external sources as the main source of dust and the importance of topography factor in this area.The Z value spatial analysis suggests high increase of dust event in recent 20 years in southeast, south and central areas of the province and also on last hours of day which demonstrator development of internal sources activities in increasing trend of dust event in recent decades.
H Hossain Asakereh, M Mehdi Doustkamian, M Mohammad Darand,
Volume 21, Issue 60 (3-2021)
Abstract
The purpose of this study is to investigate and analyze turbulence, fluctuations and jumps of Iranian regions. For this purpose, environmental data has been gathered in two parts. In the first part of the data, the results of the interpolation of the daily precipitation observations of 1434 stations of climate and climate were used from the beginning of 1340 to 1383. After the formation of a database to identify the Iranian regions, a cluster analysis was used on average data and annual and monthly rainfall variation coefficients. Silhouette analysis has been used to validate the Iranian rainy areas. In order to investigate disturbances, mutations and fluctuations in Iran's rainy areas, this study was carried out. The results of cluster analysis indicate that Iran's peripheral areas are divided into six classes. In the meantime, the Caspian region (area 4) has the highest rainfall and the lowest coefficient of variation. The distribution of rainfall regime in each of the six areas shows that Iran's precipitation regime is more frequent in winter and spring and sometimes in autumn. Investigation and analysis of rainfall turmoil has shown that rainfall, except in the 4th district (Caspian region), in other areas of distribution of rainfall occurred along with disturbance. Although most disturbances occur in the zagros area, the highest sequence of disturbances is related to the fifth load region. The least sequence of disturbances occurred in the central and eastern part of the country. The results of mutation analysis and fluctuations indicate that rainfall disturbances, except in the early years of precipitation regions two and five in other regions of the other regions, have no significant mutation, while short-term fluctuations of 3-5 years on rainfall Each of the six domains has dominated.
Hamideh Afsharmanesh, Zahra Hejazizadeh, Bohloul Alijani,
Volume 21, Issue 61 (6-2021)
Abstract
Climate predictions have been made in global, regional and local simulation, and climatic parameters have changed in terms of trends and models in climatology, futures studies are less visible in literature and climatology literature therefore environmental planning and futures analysis are an attempt to look at the long-term future in the field of climatology. Today, one of the most important challenges of the present and future is the increase in temperature and is the lack of climatic comfort. The growth of Tehran's metropolitan area, improving living standards, expanding urbanization and industry, climate change, and the energy shortage crisis are important. The survey forms were prepared by the climatologists and managers of Tehran and data analysis, futuristic techniques such as scenario for data analysis tool in this study was MICMAC software. have been used. In the research process, the most important key factors and drivers in relation to futures studies were identified in relation to the increase of temperature in the city of Tehran.
Mini scenarios and a comprehensive scenario were defined in three cases:
- Improvement of the Micro-Climatic Conditions of Tehran City + Climatic Comfort of Citizens
- Lack of good micro-climate in Tehran + low climatic comfort of citizens
- The lack of improvement in the micro-climatic situation in Tehran + the lack of climate comfort for citizens and increased energy consumption
According to the results of the study, the most important factors in creating a crisis of rising surface temperature can be the lack of attitude to the concept of micro-climate improvement and urban management.