Showing 33 results for Climate Change
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.
Dr Behzad Amraei,
Volume 22, Issue 64 (3-2022)
Abstract
Climate change is one of the most important challenges facing water resources management, including surface water and groundwater. The main purpose of this research is to detect the effect of droughts caused by the change in groundwater resources in Birjand plain. In this regard, using two nonparametric trend tests, the SENS and MAN-Kendal gradient estimates to detect the process of underground water level in Birjand city during the statistical period of 1370-1395 according to the statistics of the field of 47 areas of observation area (census water resources) Wentified. Using Pearson correlation matrix, correlation between climatic elements (Birjand station) temperature, precipitation and evapotranspiration and potential transpiration were calculated with the level of local city of Birjand, and based on a multivariate regression model for modeling the annual time series at the level of confidence level of 95 / 0 was developed. Climatic factors of 2080-2065 using the Output of the HADGEM2-ES model through the LARS-WG exponential model for the position of the Birjand station under two scenarios RCP8.5 and RCP2.6 were simulated and based on the regression model, the surface of the water Birjand city was simulated. The results indicated that firstly, in the base period (1370-1395), the surface of water in the area with an annual gradient of 47 centimeters per year was reduced. The correlation analysis indicated that three elements of rainfall, temperature and evapotranspiration were modeled in a linear composition of 75% of the annual changes in groundwater. The results of the microsterge model implemented on HADGEM2-ES data indicate that during the period 2035-2065 under both the scenario, groundwater level between 10 and 13 meters lower than the base period, which resulted from an increase in evapotranspiration And consequently, rainfall will be effective.
Mrs Shahrbanoo Ghanbari Adivi, Dr Morteza Khodagholi, Dr Amir Gandomkar,
Volume 22, Issue 66 (9-2022)
Abstract
The main purpose of this research is to test the agglium of Hormozgan province for the development and development of aloe vera plant cultivars in the base period and the period of change. In this regard, the influential data in the various stages of the aloe vera plant, including the minimum and maximum temperature and precipitation, as climatic agents and height variables, gradients, direction of gradient, soil, as stable elements in the evaluation of aloe vera cultivation areas were used. The multidimensional decision-making technique in the GIS environment was used using fuzzy gamma function for interruption and eventually identifying appropriate arenas for aloe vera plant. The role of climatic changes in two levels of alteration of B1 and A2 was investigated to evaluate changes in Aloe Vera cultivation agriculum in Hormozan province. The results of the implementation of the Fuzzy Gama integration function in Hormozgan province showed that in the base period, 0.35 of the area of the province has good and excellent culture for this plant. These areas are generally consistent with the lowlands of the southern sections of the southern province and are consistent with the soils with tissue and depth and drainage, namely, the arid soils of Sevil and anti-Seville, while in the northern parts of the province, the supply factor, supply The need for an aloe vera plant, tolerance in the year and nightly, the product performance is very weak and the development of aloe vera farms in these areas is not recommended. In the simulated climatic conditions for 2070 under the 2ndretic scenarios, aloe vera arenas will have relatively significant changes compared to the climate of the base period, so that the most variations related to the A2 scenario, in which poorly functional floors are lacking. And moderate culture capabilities have been exposed to an area of 30 to 40 percent, while the two floors of the agricultiva capability and good culture capabilities, under the same system, will show an increase of 20 to 40 percent.
Neamatallah Safarzaei, Alireza Entezari, Mokhtar Karami, Gholamali Khammar,
Volume 22, Issue 66 (9-2022)
Abstract
Today climate change cause increase in concentration of greenhouse gases has been cause increase extreme events and atmospheric hazards. goal of this research, analyze and review climate future is for atmospheric hazards in sistan region. In this study, to simulate minimum and maximum temperature data used from model data CanESM2 under three scenarios (RCP2.6, RCP4.5, RCP8.5) with SDSM statistical scrolling and to simulate rainfall data from the Hadcm3 model under scenarios (A1B, A2, B1) with statistical scrolling LARS-WG. For this purpose, after calibration, validation and data modeling at the selected station, the performance of the model from the viewpoint of the compliance of the base temperature data (1984-2005) and rainfall (1986-2015) with simulation values (2020-2039) evaluated at a significant level of confidence. To adapt base data to simulated data Used of the three criteria root mean square error (RMSE), coefficient of determination (R2) and mean squared error (MSE). According to simulated data were examined four important atmospheric hazard frost, heat waves, extreme precipitation and drought. The results showed that heat waves and drought in the future are serious threats in the region So that in 2021, under release scenario RCP 2.6, Predicted 32 heat waves and the study area will experience more than five heat waves in the year. In addition, most frequent drought forecast in 2020, under release scenario A1B. Extreme precipitation in some years under scenario B1 can be significant threat in the region. Intensity and abundance annual frost under release scenario RCP2.6 more than other scenarios and lower relative to investigated atmospheric threats.
D.r Hossein Jahantigh, Amir Bakhshi, Rezvan Ghorbani Salkhord,
Volume 22, Issue 67 (12-2022)
Abstract
Identifying barriers and adaptation requirements is crucial for the successful implementation of climate change adaptation practices at the local level, especially in mountainous rural communities with limited local resources and technology. Due to the importance of this issue, in the present study, the barriers and requirements for adaptation to climate change in mountainous villages were investigated. The present research is descriptive-analytical in terms of purpose and method. The data collection tool was a questionnaire, free interview and observation of the researcher from the study area. The statistical population of rural households is Papi section of Khorramabad city (N = 2346). Using Cochranchr('39')s formula and sampling method, 330 households were selected as a sample. To analyze the data, descriptive statistics and exponential exploratory co-integration rank test (Johansen method) were used. The results showed that farmers in the mountainous villages of the study area face several adaptation barriers that are more serious institutional, normative, technological and information and cognitive barriers. Given that adaptation conditions are an important factor in reducing or eliminating adaptation barriers and improving farmerschr('39') adaptation capacity to climate change, local economic development, local infrastructure, production technology, and the granting of micro-credentials are the most prominent adaptation requirements in these were the grounds. In addition, due to the effective role of government, cooperatives and villagers themselves in rural development, a rational adaptation framework for selecting optimal adaptation strategies in cooperation with these three, as appropriate regional adaptation measures and policies for research proposals was presented.
Dr Bromand Salahi, Vahid Safarian Zangir,
Volume 23, Issue 68 (3-2023)
Abstract
Global warming and temperature rise will have many effects on different sectors, including agriculture, the warming of the earth will increase the rate of evaporation, and consequently the increase in the demand for agricultural products will increase. In this study, in order to monitor the effect of global warming on Mughan Plain wheat, using the LARS-WG model as a relatively inexpensive and accurate instrument for producing climate multi-yearly climate change scenarios On a daily basis, In Ardabil province, Germi Station was selected as the representative of the three stations in the study area due to the data in the appropriate statistical period. In the present study, to monitor the effect of global warming on precipitation fluctuations, as well as in the production and cultivation of wheat crop in Moghan plain, the LARS-WG model and the HADCM3 climate model output under A1B scenario as well as climate data (minimum temperature, maximum temperature, precipitation and Daily Sunshine) The Germys station was used over a 14 year period (2004-2007).The results of the research show that by comparing the monthly mean of these parameters, this result was obtained that at confidence level 1 there is not a significant difference between the simulation data from the model and observational data in the base period and the mean The climatic parameters of the data obtained from the model and the actual data are similar and there is a high correlation between them. Finally, by comparing observational monthly meanings and modeling of climatic elements of precipitation, minimum and maximum temperatures and sunshine were shown using statistical parameters RMSE, MAE, NA and R2 The model (LARS-WG5) is used to accurately simulate daily data in the parameters of the Mughan Plain, Ardebil province. The results of this study showed that the average decrease in yield of irrigated wheat and the decrease of its production in the study area could be due to the decrease of precipitation and the increase of the regional temperature which is due to global warming.
Zahra Hejazizadeh, Sharifeh Zarei, ,
Volume 23, Issue 69 (6-2023)
Abstract
Abstract
In recent years, attention has been paid to climate change, which could be the result of economic, social, and financial losses associated with extreme weather events. The purpose of this study is to investigate the variation of extreme temperature and precipitation in Kurdistan province. For this purpose, daily rainfall data, minimum temperature and maximum temperature of 6 stations were used during the statistical period (1990-1990). And their changes during the period (2041-2060) using the universal HadGEM2 model under two scenarios RCP2.6 and RCP8.5 and the LARS-WG6 statistical downscaling were investigated. In order to study the trend of climatic extreme indexes, rainfall and temperature indices were analyzed using RClimdex software. The results showed that during the period (2016-1990), hot extreme indicators have a positive and incremental trend. This trend is significant for the "number of summer days" and "maximum monthly of maximum daily temperature" indicators. This is while the cold extreme indexes had a decreasing and negative trend. This trend was significant only for the "cold days" index. Extreme precipitation in Kurdistan province has a negative trend in most stations. ،this trend is significant at most stations, that indicates a reduction in the severity, duration and frequency of precipitation during the study period. The results of the climate change outlook also indicate that the temperature will increase over the next period and rainfall will decrease.
Mr Jaefar Derakhshi, Dr Behroz Sobhani, Dr Saeed Jahanbakhsh,
Volume 24, Issue 72 (3-2024)
Abstract
In this study, the prediction of precipitation and temperature values using the general atmospheric circulation models during 1964-2005 is investigated. Climatic data including daily values of total precipitation and mean temperature were obtained from the Iranian Meteorological Organization. Considering the climate change scenarios RCP4.5, RCP2.6 and RCP8.5 for the coming period 2010-2100 were evaluated under the canESM2 climate change model of Aharchai Basin. Due to the low accuracy of the general circulation models, the SDSM4.2 miniaturization model was used and the changes in precipitation and mean temperature parameters were simulated for future time periods. In this study, to calibrate the SDSM model, among the 26 large scale climate parameters (NCEP), on average, 3 parameters have the highest correlation with the mean temperature and 5 parameters have the highest correlation with the average precipitation in the Aharchai Basin. The results of climatic parameters prediction showed that simulation of climatic parameters mean temperature was performed with higher accuracy than mean precipitation values. The reason is that the precipitation data are not normal and unconditional. The results show that the basin temperature averaged more during the period 2070-2099 under the scenario RCP8.5 than the observations period of 1964-2005 and the basin precipitation during the period 2070-2099 under the scenario RCP2.6 showed the highest increase in the entire study period.
Mrs Somayeh Naderi, Prof. Bohloul Alijani, Prof. Zahra Hedjazizadeh, Dr. Hasan Heidari, Dr. Karim Abbaspour,
Volume 24, Issue 73 (6-2024)
Abstract
Evidence suggests that climate change will create uncertain regional agricultural production stability in the coming decades. This research investigated the impact of climate change on hydrology and sugar beet yield as one of the main crops in the Urmia lake basin using the Soil and Water Assessment Tool (SWAT). To address this, a baseline SWAT model was setup for 1986-2014. Afterward, the output was calibrated (1989-2004) and validated (2005-2014) in the SWAT-CUP software using the SUFI2 algorithm to simulate streamflow of 23 gauging stations and crop yield. The Nash-Sutcliffe efficiency was 0.43 and 0.53 for calibration and validation periods, sequentially. The Percent Bias was 45% and 16% for calibration and validation periods, respectively. As well as the agreement indices of 0.71 and the little Percent Bias (-6% to 10%) for crop production, verified the model's efficiency. The next step was downscaling and bias-correction of the precipitation and temperature data received from 3 climate models, namely GFDL, HadGEM2, and IPSL under RCP4.5 and RCP8.5 using CCT program. Then, the downscaled data were fed to SWAT, and Finally, hydrological fluxes and sugar beet yield were estimated for 2021-2050. Despite a dispersion of precipitation changes ranging from -12% to +35% in most scenarios, results highlight the pivotal role that the warmer temperature (+2.7°C) increases evaporation, resulting in sharpened pressure on water resources and runoff, especially, at the beginning of crop growth season. Finally, the negative impacts on crop productivity (-45%) is not unexpected. This means that sugar beet may suffer from climate change impacts, and the production of this plant will change over the next period in this region.
Keywords: Climate Change, Sugar Beet, Urmia Lake Basin, Sensitivity Analysis, SWAT.
Ms Parisa Ghorbani Sepehr, Dr Zaki Yashar, Dr Seyed Abbas Ahmadi,
Volume 24, Issue 75 (12-2024)
Abstract
Due to its location in low latitudes, Iran is among the countries that has not been spared from the security consequences of climate change. The present study seeks to answer two questions: 1) What are the security consequences of climate change on Iran and which components have the greatest impact on Iran? 2) Which of the pillars of good governance as a solution has the greatest impact on reducing the effects of climate change on Iran?
In this study, the study population is elites and experts familiar with the subject of the study, 100 of whom were selected for snowball sampling and a researcher-developed questionnaire was used to collect data. Data were evaluated using SPSS and MINITAB software. The results of the studies according to the obtained P-value which is equal to 0.000 and is less than 0.05 alpha, indicate the difference between the natural and human consequences of climate change in Iran. The results of the Tukey test indicate that the natural consequences of climate change with an average of 4.0584 are in group A and the human consequences with an average of 3.4460 are in group B. Also, the results of Friedman test on the effect of good governance in controlling and reducing the security consequences of climate change in Iran show that accountability with an average of 5.79 in the first place, rule of law with an average of 5.62 in the second place. and accountability of officials with an average rating of 5.32 are in third place.
Mohammadsaleh Ekhlasi, Dr. Somayeh Soltani-Gerdefaramarzi, Dr. Abolfazl Azizian, Morteza Gheysouri,
Volume 25, Issue 76 (3-2025)
Abstract
In this study, we examined the impact of climate change on the virtual water content of key crops in Kerman province for future periods. Specifically, we utilized the climatic data from the HadCM3 model under the RCP4.5 radiative forcing scenario. The model was calibrated and validated for the base period of 1991-2011. We predicted the precipitation levels, as well as the maximum and minimum temperatures, for selected stations from 2011 to 2070 using data from LARS-WG. These predictions were then compared to the base period. The virtual water content was calculated for three selected crops: alfalfa, barley, and wheat. Our findings indicate that climate change has a significant impact on evapotranspiration and the performance of these crops, consequently affecting future agricultural water productivity. As we project an increase in average temperature during the growing season due to climate change, it is worth noting that the maximum temperature parameter will be more affected by this phenomenon than the minimum temperature. This, in turn, will lead to increased water requirements and plant evaporation-transpiration during this period. Our research also reveals a decrease in precipitation during hot seasons and an increase during cold seasons across all study stations. Notably, the virtual water content for all crops studied demonstrates an upward trend, with barley and wheat showing the greatest average increase in the future period. Specifically, the Kerman station exhibits a substantial increase in virtual water content for barley and alfalfa products, at a minimum of 30% higher than the base period.
Moslem Seydi, Kamal Omidvar, Gholamali Mozafari, Ahmad Mazidi,
Volume 25, Issue 77 (6-2025)
Abstract
Abstract
Climate change is an important environmental issue because the melting processes of glaciers and snow density are sensitive to climate change. Today, a variety of satellite sensors such as AVHRR, MODIS, GEOS, MERIS are available for snow monitoring and are widely used to investigate and investigate the fluctuations and changes in snow cover globally. Modis sensor has been considered more because of its global spatial coverage with suitable spatial accuracy and frequent temporal coverage on different scales , Therefore, in the present study, snow products of this sensor were used. In this study, after collecting statistics and data on snow-related days during the statistical period (1989-2018) in three provinces of Kermanshah, Ilam and Lorestan, they were processed using Modis snow cover data in middle Zagros as well as remote sensing techniques, Finally, the snow cover changes in the study area were studied in detail. NDSI index was used in MODIS sensor products to detect snow cover. Consequently, in order to differentiate pixels and identify different phenomena, the received images were processed in GIS environment. . Investigation of snow cover changes in different seasons using Modis sensor images shows that most of the studied area has a significant decreasing trend, especially in the elevated areas of the study area And only in the western and southwestern regions of the study area, there is no specific decreasing trend. Also, the study of snow covered days during the study period indicates a decrease in middle Zagros snow cover and these changes have been intensified in recent years, especially in snow-covered areas of the region. Also, changes in winter and snow-capped and elevated areas were more and more severe than other seasons and other regions in the study area.