Showing 62 results for Climate
Tayebeh Dehghani, Mohammad Saligheh, Bohloul Alijani,
Volume 18, Issue 49 (3-2018)
Abstract
In order to detect climate change, a variety of climate indicators can be used which is often considered temperature and precipitation. In order to investigate the effect of climate change on the amount of precipitation in the north coast of the Persian Gulf, it simulated the precipitable water for 2017-2050 based on the RCP4.5 model of the Hadcm3 model. The NCEP / NCAR base-station data with an arc-value of 0.125 was used to analyze the past and present precipitable water patterns and to reveal the process of this time series. Time series analysis of precipitable water was performed using two SENS tilt estimators and Man-Kendall test. The results indicated that the annual time series of rain water was increasing in the region, every year, 0.05 mm, the precipitated water increased and it tended to become more homogeneous, this increase in the significance level of 0.95. The precipitation rate in the eastern part of the region was higher than other areas. Before 1989, several fluctuations were observed in the rainy season of precipitable water, but none was statistically significant at the confidence level of 95%, but since 1989, the trend has increased significantly at a confidence level of 0.95. This spatial behavior of precipitable water can actually have occurred in response to the increase in the overall temperature of the area and can be considered as a profile of climate change in the region.
Ali Ahmadabadi, Zahra Sedighifar,
Volume 18, Issue 51 (6-2018)
Abstract
Climate change is one of the most important challenges that has affected various parts of human life on Earth. In the present study, in order to investigate the climate change, three synoptic stations of Karaj, Mehrabad and Dashan Tepeh with the help of the statistical statistic downscaling model (SDSM) model were used to predict the statistical period of 2016-2045. Finally, the effects of climate change on the hydrologic conditions of the basin with the help of the model (SWAT) was simulated by the Soil and Water Assessment Tool. The amount of surface runoff and runoff at the study area is 10.59 mm in the studied observation period, but this rate was estimated to be 21.27 mm for the predicted period due to the increase of urbanization and changes in utilization. The results of the research, while highlighting the importance of the effects of climate change, are necessary for their application in applying proper management to adapt to climate change in the future policies of the basin management.
Hossein Imani Pour, Abdolreza Kashki, Mokhtar Karami,
Volume 18, Issue 51 (6-2018)
Abstract
Heating requirements are one of the most important human issues in the fields of agriculture, tourism and energy management in the present and future .Knowing the extent of these changes can be very effective in making decision makers. The purpose of this study is to examine the changes in the requirements of the heating degree day in conditions of climate change in southern Khorasan province. For this purpose, daily data from the minimum and maximum temperature of 11 stations of the South Khorasan province were received from the Meteorological Organization of Iran during the period of 1990-2015. The latest available scenarios of the fifth report of the Climate Change Interagency Panel (AR5 2014) include RCP scenarios from the Canadian Climate Change website and, using the SDSM macroeconomic statistics software, the data for the upcoming period (2016-2046) in the study area was thrown off. Using the Matlab software capability, the monthly and annual heating requirements of the stations were calculated in the current and future period. Finally, using the Kriging interpolation method, the zoning maps for cooling requirements for the current and future period are mapped in ArcGIS software. By examining the effect of geographic features (latitude and longitude and station height) on the heating needs in the area, it was determined that the role of heights is very effective in changing the heating needs. In the cold months of the year (Azar, Dey and Bahman), the highlands (Qain, Arsak, Fath Abad, Aryan Shahr, Darmian) require higher energy levels due to the need for higher temperatures. Increasing the temperature and warming of the air in the future, especially in the months of Farvardin and Mehr in most places, requires less use of exhaustible equipment in the future.
Dr Batool Zeinali, Sima Khalili, Saideh Eiyni,
Volume 19, Issue 53 (6-2019)
Abstract
The aim of current research is atmospheric hazards climate zoning in Iran Northwest. So meteorological organization data were used in cases such as mean temperature , minimum temperature , maximum temperature, precipitation in monthly and daily scale for 13 synoptic stations in range of East Azerbaijan province, West Azerbaijan province) and Ardebil province during 26 years. (1990-2015) in this research , it was investigated 10 main atmospheric hazards such as famine or drought , hailstone,, heavy snow , thunder storm, severe precipitation, margin precipitation , blizzard , fogging , dust storm in range of Northwest bound. Then happening frequency maps were prepared with separating form for hazards by using Geographic information system. (GIS) Also spatial zoning maps were prepared for every class. Finally by combining all of hazards investigation; it was prepared Northwest region atmospheric hazards extensive map. Results show that, East, Southeast, center and West parts in Northwest region are located among most hazard zones based on happening frequency. But Northeast parts and zones have the least hazards. Also results express that blizzard and dust storm are main atmospheric hazards at Northwest regionThe highest hazard frequency in Northwest region relate to blizzard with 4148 hazards during 1990-2015 study period. The highest blizzard frequency in Ahar station is observed with 514 hazards. The second hazard in Northwest relate to dust phenomenon with 1948 cases. The highest frequency of mentioned case was observed in Maragheh station with 410 hazards. The third case in Northwest relate to thunder storm phenomenon with 1773 hazards. The sixth case relate to icing phenomenon with 1315 hazards meaning. The highest icing frequency is observed in Khalkhal station with 144 hazards. The seventh case relate to hailstone phenomenon at Northwest with 341 hazards. The highest of hailstone frequency is observed in Maragheh station with 56 hazards. The eighth case relate to fogging phenomenon with 333 hazards. The highest of fogging is observe in Ahar station with 135 hazards. The ninth case relate to famine or drought phenomenon at Northwest with 168 hazards. The highest of famine or drought frequency is observed in Urmia and Ardebil stations with 16 hazards totally. The highest margin precipitation is observed in Parsabad station with 19 hazards. The lowest frequency of margin precipitation relate to Makou and Khalkhal stations with 4 hazards totally.
Shadieh Heydari Tasheh Kaboud, Younes Khoshkhoo,
Volume 19, Issue 53 (6-2019)
Abstract
The aim of this research is the study of the climate change impacts on the seasonal and annual reference evapotranspiration time scales in some selected stations located in the West of Iran. To this purpose, four stations including Sanandaj, Saghez, Khorramabad and Kermanshah synoptic stations with enough long-term data were selected and the climate change impact on the reference evapotranspiration of these stations under two RCP2.6 and RCP8.5 scenarios in three future time periods including 2011-2040, 2041-2070 and 2071-2100 in comparison with the 1970-1999 base period was studied. The FAO-Penman-Montieth method was applied to calculating reference evapotranspiration and the CanESM2 general circulation model and SDSM downscaling method were used to simulating future climate conditions under the climatic scenarios. The results showed that the mean reference evapotranspiration in the annual and autumn and winter time scales in comparison to the base period will significantly increase for all of the studied stations under all of the scenarios and periods at the 0.01 confidence level. For spring season, the only significant change of the future period mean reference evapotranspiration compared to the base period in the all of the studied area will be a significant increase at the 0.01 confidence level in the 2071-2100 period under the RCP8.5 scenario and for the summer season, this significant increasing rate will occur in the 2041-2070 and 2071-2100 periods under the RCP8.5 scenario. The overall results of this research showed that the highest increasing rate of the future periods in comparison with the base period for all of the seasonal and annual time periods and for all of the studied area will under RCP8.5 scenario and in the 2071-2100 time periods. by comparing the reference evapotranspiration change rates between the different seasonal and annual scales, the results showed that the increasing rate of the mean reference evapotranspiration at the West of Iran will be very remarkably in the autumn and winter seasons compared to the other time scales.
Mohammadreza Goodarzi, Atiyeh Fatehifar,
Volume 19, Issue 53 (6-2019)
Abstract
In the present time, with the increase of industrial activities and the neglected environmental issues, the effects of climate change have become more evident and poses this phenomenon as a global difficult. Increasing the probability of occurrence of extreme climatic events such as flood and increasing the frequency and intensity of the effects of climate change. The northwest of the country is one of the most vulnerable areas of the country due to its semi-arid and mountainous climates and high rainfall variability. Therefore, zoning due to climate change is essential. Therefore, in this study, in order to investigate the risk of flood in the Azarshahr basin, due to climate change, using the CanESM2 general circulation model under RCP8.5 scenarios negativity according to the assessment report fifth IPCC, rainfall and temperature variables were down scaling by Statistical down scaling model (SDSM). Then,with hydrological model SWAT the daily runoff, the basin map and the lines of the canals are achieved. The results of the evaluation of the SDSM model with a coefficient of determination and Nash-Sutcliff 0.95 on average represent the good performance of the model in the down scaling of large scale data. The results show an increase of 0.23 ° C and 4.53% rainfall and maximum discharge. The basin is zoned with the combination of the maximum mean discharge map, the coefficient and distance from the river with the AHP approach. Due to the zoning they are 41.55% of the area of the basin, at very low and low risk, 27.23% at average risk and 31.2% at high and very high risk. Also, with the final map, it became clear that the mid-basin had a high risk due to its prerequisite conditions and that it needed to carry out managerial actions.
Esmail Heydari Alamdarloo, Hassan Khosravi, Sahar Nasabpour Molaei,
Volume 19, Issue 54 (9-2019)
Abstract
Proper climate and adequate knowledge tourism and can be as an attractive or unpleasant factor for tourists. The purpose of this research is to evaluate the tourism climate of Yazd province as one of the most important provinces in the arid regions of the country. For determining the tourism presence comfort in the Yazd province, Tourism Climate Index (TCI) was used. In order to investigate tourism climate index data from 17 meteorological stations was used. Then by calculation sub-indexes and TCI, zoning of TCI and sub-indexes for Yazd province was done with ArcGIS environment. The results showed that October, May, November and April are the best months for tourism activities in Yazd province, and January, July, February and December have the lowest average of TCI index respectively. The most changes in TCI occurs in July and the lowest changes is in October. According to Scott & McBoyle classification, the TCI annual classification shows that Yazd province is placed in two classes: Bi-modal shoulder peak and Dry season peak. Generally, the mountainous area with an altitude of more than 2,700 to 3,000 meters and their surrounding areas when rainfall and lower temperatures is not a limiting factor have the best tourism conditions in the dry season. Other areas with less height of 2700 to 3000 meters have the best climatic conditions for tourism in the spring and autumn.
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.
Mehdi Shafaghati, Zahra Hejazizadeh, Hasan Afrakhteh,
Volume 20, Issue 56 (3-2020)
Abstract
Each geographical location, topography, landscape, flora and fauna, air and climate natural resources for tourism and recreation form. Given that every business needs a bed a place in the geography of this place, defined geographical space.This geographical space supplier of tourist activities. Many factors affect the tourism industry, one of the most important climates. Along with geographic location, topography, landscape, flora and fauna, water and air as one of the most important local resource base plays a role in the development of tourism industry. Gilan province is one of the countries northern even with Mesa 14711 square kilometers .The province has two different morphology of the southern part of the province of North Alborz heights shown and the foothills and plains in coastal areas. The province because of the special circumstances of the geographical, exquisite natural scenery and abundant water resources in the row is one of the most tourist areas of the country. In this study, with the presentation of applied research, analytical and application software, Excel, Google Earth, ArcGIS10 to check the status of existing and potential climate in Gilan province was one of the country's Northern provinces. Which has convenient facilities in the field of tourism is also significant to analyze the specific situation of the province and also to discuss tourism and its development will conform to discuss climate. The result of climatic classification methods Domarten temperature and precipitation maps also will be show that there are good conditions for tourism development in the province and Finally, using the climate index TCI zoning province, and the results were presented in the field of tourism.
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.
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.
Morad Kaviani Rad, Meysam Toulabi Nejad, Farid Rezaei,
Volume 20, Issue 57 (6-2020)
Abstract
The purpose of the present study is to investigate the effects of climate change on the border security of Thalassa Babajani villages. The study area consists of 11 villages of Salas Babajani city with a population of over 2500 people. 333 questionnaires were designed using Cochran formula. The research method was a descriptive-analytic and statistical questionnaire. The results showed that the impacts of climate change were firstly on food security and consequently security in the border villages of Thales Babajani so that most of the population in the study area were concerned about climate change such as flood and drought. Forced to change their livelihoods due to lack of food. The results also showed that with climate change, some former farmers have moved to their village boundaries for daily livelihoods due to climate change and food scarcity, which could in the future be the third border region and its villages. Serious challenges lead to insecurity. Because these people will face the same dangers as engaging in border guards between the two countries, Iran will result in the risk of death for those who were once farmers or ranchers and the security of the area would also be compromised.
Masoud Yazdanpanah, Tahereh Zobeidi, Hajar Zaery,
Volume 20, Issue 58 (9-2020)
Abstract
Greenhouse emissions from agricultural as a consequence of human activities are causing climate change. Small changes in agricultural practices have a large potential for reducing greenhouse gas emissions. Intention of Agriculture Experts in order to mitigation climate change Can play an important role in finding appropriate solutions for each region in climate change mitigation and deliver them to their farmers. However Intentions to take mitigation actions are, most likely, influenced by a range of factors. The purpose of this study was to investigate of factors influencing on Agriculture Experts in order to mitigation greenhouse gases. This research in terms of purpose is an applied research and in terms of methodology is survey research. The statistical population of this research consisted of 520 Agriculture Experts in Khuzestan Province. A sample of 320 persons was selected through Random Stratified Sampling method. The survey instrument was a questionnaire which its validity confirmed by experts. The reliability of the questionnaire using Cronbach's alpha coefficient (α= 0/67-0/87) has been approved. Our analysis reveal, direct experience were predictors of risk perception, self-efficacy and environmental attitude. The changes in self-efficacy and environmental attitude were also strong predictors of changes in intention. The variables of self-efficacy and environmental attitude could predict 61 percent of variations in willingness to mitigating climate change. Therefore experience indirectly affected on the mitigation intention. Lastly we provide recommendations on how these findings can be used to climate change mitigation.
Dr. Sadegh Karami,
Volume 20, Issue 59 (12-2020)
Abstract
Importance of climate change is global. This issue to some extent has been out of human control. Human beings can only provide security and the community with knowledge and management against its negative consequences. On the basis of this research, the present paper analyzes the impact of climate change on Iran, on a small scale and applied to the central catchment area. The findings of the research indicate that climate change has shown the geographic region of Iran in terms of changing the rainfall pattern, decreasing precipitation and increasing its temperature. In the next step, these cases resulted in excessive withdrawal of groundwater aquifers and it has reduced the quality of underground water. This chain has led to the design of inter-basin water transmission projects, which is at least the result of the cycle of social tensions that has occurred in recent years. Considering the geographical extent of the basin and its belonging to one of the most frequent aspects of Iran's civilization, the set of consequences of climate change in the central catchment area, in addition to its impact on various social, political, economic and environmental layers, also has several scale effects. And its destructive effects go beyond national scale and to an extent beyond the scope of Iranian culture. In this regard, the research findings indicate that climate change in the central watershed is influential in many aspects of society and the country, so that if the current process continues, the current Iranian civilization will face a strategic challenge. To this end, at the end of the research, good water governance, as the best way to confront and control the negative consequences of climate change on the central catchment area, and Iran in general, has been argued.
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.
Mr Zahra Sadat Jalali Chimeh, Dr Amir Gandomkar, Dr Morteza Khodagholi, Dr Hossein Battoli,
Volume 21, Issue 62 (9-2021)
Abstract
Agriculture, as one of the most important human economic activities, is closely related to the climatic conditions, and any changes in the climatic conditions can have dramatic changes in agriculture. The main objective of this study is to investigate the spatial changes of the Agro Climatic Feasibility Rosa damascena mill Cultivation in Climate change Condition in northern part of Isfahan province including Kashan, Natanz, Ardestan and Aran Bidgol, under the four carbon dioxide emission pathways (RCPs)of 2050. Two groups of factors involved in agroclimatic feasibility of Rosa damascena mill cultivation including environmental factors (topography, soil) and climatic factors were extracted. Based on these factors, suitable zones of Rosa damascena mill cultivation, were identify using Fuzzy gamma function. In the next step, by simulating the climatic elements of the region in 2050, under the four carbon dioxide emission pathways, the fifth report of the IPCC, replacing the simulated climatic variables of 2050 under the four lines, by re-implementing the fuzzy gamma function, favorable areas of cultivation Rosa damascena mill was identified in each region in each scenario. In the next step, by simulating the climatic elements of the region in 2050, under the four carbon dioxide emission pathways, the fifth report of the IPCC, replacing the simulated climatic variables of 2050 under the four lines, by re-implementing the fuzzy gamma function, favorable areas of cultivation The Rosa damascena mill was identified in each region in each scenario. The results showed that in the base period climate, about 0.33% of the area (9025 km2) has a climate suitable for cultivating Rosa damascena mill and more than 67% of the area of the region has a weak talent. The results of the simulation of the climatic conditions of 2050 under four carbon dioxide emission lines indicate that, under all scenarios, favorable areas for cultivating Rosa damascena mill in the studied area have increased. In the trajectory of 8/8 release, the highest class of agro-colliery was the cultivation of the flowers of Mohammadi gardens
Anoshiravan Ravand, Shahriar Khaledi, Davod Hasanabadi,
Volume 21, Issue 63 (12-2021)
Abstract
The purpose of this study is to determine and predict the effects of climate change on architecture using climate models. By clarifying the consequences of the impact of urban architecture on climate change while using the data of surrounding stations with library and field data methods. The climatic parameters of precipitation, temperature and relative humidity of the synoptic station of Miyaneh city during a full period of 32 years (2018-1987) and the possibility of climate change with the models in this city were examined and after obtaining the relevant data Climate change was predicted for the next 84 years through the GCM and SDSM microscale and the AR4 (2007) - HADCM3 (Run 1) - SR-A2 scenarios. In order to evaluate the effects of climate change on the comfort climate of the region, among the bioclimatic models used, the Tarjong model was considered for two periods of 16 and 42 years. In the next 84 years, compared to the last 32 years, the cold months of May, June, July and August will turn into pleasant heat, and in September, the heat will have a great impact on the skin, which indicates a warm climate in the next 84 years. Architectures must be considered.
Ali Saadat, Mohamad Saligheh, Mohamadhosin Nassrzadeh,
Volume 21, Issue 63 (12-2021)
Abstract
The goal of this research is studying the effect of recent climate changes, espeeially heat rise on the amount of effective rainfall in the lorestan peovince. Effective rainfall is the amount of fall which, after evaporation, is absorbed in the ground. in the ground.in USDA method and the us agriculture, the amount of rain abstorbed in a growth perlod of a plant and available for its consumption is called effective raifoll. The results showed that the amouent of rainfall in the first period is more than that of the second. The frequency of raining days got reduced in the after-climate- change period. Heat got increased in the second period. Evaporation was more in the second period. Relation humidity got decreased in the second compared to the first period, and wind speed increased by studying the process of the data changes, it became evident that climate change leads to the increased inconsistent rainfalls in the studied climate variables indicate that under the effect of climate change , Based on Vibol method, droughts caused by effective rainfalls were calculated, and the probability of effective rainfalls in 5 time periods was accounted for. It was shown that in the years 1369 to 1396, effective rainfall in the region was scarce, so it was very influential. With Dobif Model, effective rainfall was analyzed, and years with the least effective rainfall for dry farming with positive signal, that is, appropriate conditions, and negative, that is, inappropriate conditions were recorded. Based on linear coefficient, rainfall trends in the three stations of Khorramabad, Aligudarz and Borujerd. Geographical distribution analysis of effective rainfall showed that in the south and south-east of the province, the coefficient of effective rainfall was more than the rest of the province. This coefficient was decreasing when it comes to the south-west of the province. Effective rainfall decrease was more due to increasing evaporation happening in this part. the effective rainfall in the studied region got decreased, therefore, preserving underground water resources, on which natural life depend, should be considered more than ever.
Mahnaz Aziz Ebrahim, Mohammad Saligheh, Mohammad Hossein Nassrzadeh, Bohlol Alijani,
Volume 22, Issue 64 (3-2022)
Abstract
In this research, we are trying to determine the “beginning time” as well as the “end” of the climatic seasons; and we will focus on identifying the displacement of these dates, which is influenced by the “climate changes” and “descriptionAbstract
The purpose of this study is to investigate possible changes and displacements in Iran's climatic seasons due to climate change. To do this, temperature, relative humidity, water vapor, wind and cloud data for 36 stations were received from the Meteorological Agency over 40 years. The data were divided into two 20-year series to allow comparison. Daily temperature data for each clustering time series were determined, then by considering 7-day sequences, the beginning and end of the seasons. The designated times were tested using the Rayman model. The results of comparing the seasons in the two time series indicated that in all stations, changes in climatic seasons occurred from Insignificant to significant. Climatic seasons in Iran do not correspond to calendar seasons, and climate change, especially temperature changes in recent decades, has caused the seasons to shift and shorten and lengthen. Although the beginning and end of the seasons do not generally correspond to their calendar dates, most of the days of these seasons occur in its calendar periods. The changes that have taken place have not only affected the length of the seasons, and these shifts have also changed the quality of the natural seasons.
Keywords: Climate change, natural seasons, cluster analysis, Rayman model of the qualitative conditions” created in them, compared to the past climatic periods. “Meteorological Organization” data has been used in this research. Forty years of received data, was divided into two groups of 20. Applying SPSS, each group was divided into four stages representing each seasons. From these stages, the beginning time and the end of seasons were determined and the accuracy of the obtained dates was controlled with the comfort indicators of the Rayman model. The results of the comparison of seasons in two time series indicated that, the changes occurred in natural seasons from an almost non-existent one in all stations. Climatic seasons in Iran are not compatible with the summer season and climate change, especially the change in temperature in recent decades, has caused changes and shortening of seasons. Most of the days in these seasons occur during its monthly periods, although the beginning and end of the seasons generally do not match their calendar dates. Changes have not only affected the duration of the season, and these changes have also led to a change in the natural quality of the season.
