Climatology
Yaghoob Rezazadeh; Bohloul Alijani
Abstract
Cold and freezinginthe North West ofthe country(Iran), has arrived allyearirreparabledamages to thetransportsectors, roadaccidents, gardens andagriculturalproductsandcrippled thenormal lifeof people incityand villagesAt first, theverycolddays of 18 stationsin the statistical periodwere extracted then ...
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Cold and freezinginthe North West ofthe country(Iran), has arrived allyearirreparabledamages to thetransportsectors, roadaccidents, gardens andagriculturalproductsandcrippled thenormal lifeof people incityand villagesAt first, theverycolddays of 18 stationsin the statistical periodwere extracted then of thestatistics, the number of 43 Severe and pervasive wave was selected..Finally, for Synopticanalysis ofcoldwaves, tworepresentativewaves on February1991 and January 2007were determined. The maps of Earth and the500Hpa pressuressurfaceof thefreezing from theNCEPwebsitehas been prepared andanalyzed. The results showed that in most cases of severe frost in the top level, a deep descends in the Iran west established and polar regionsCold Weatherwill leadtoIran. The establishment of above thebarrier in the East of this descends was due relativestagnation of descends and the continuity of cold inthe region intensifies. At the surface of Earth, west migrant high-pressures and the spread of Siberian high-pressure tab add to intensityat 500Hpa levels. Accordingly, we can at least 5 days prior to the deployment of these systems in the vicinity of the study area, predicted cold conditions, the managers and farmers are prepared to deal with cold.
Climatology
Mostafa Karimi; Elahe Ghasemi
Abstract
General circulation models (GCMs) are an important tool in the assessment of climate change. These numerical coupled models represent various earth systems including the atmosphere, oceans, land surface and sea-ice and offer considerable potential for the study of climate change and variability. However, ...
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General circulation models (GCMs) are an important tool in the assessment of climate change. These numerical coupled models represent various earth systems including the atmosphere, oceans, land surface and sea-ice and offer considerable potential for the study of climate change and variability. However, they remain relatively coarse in resolution and are unable to resolve significant subgrid scale features such as topography, clouds and land use. Bridging the gap between the resolution of climate models and regional and local scale processes represents a considerable problem for the impact assessment of climate change. Thus, considerable effort in the climate community has focussed on the development of techniques to bridge the gap, known as ‘downscaling’. In this study two statistical downscaling techniques (lars WG and SDSM) and Proportional Downscaling method have been sued , which are combination to TOPSIS approach.The result shows SDSM is more ability technique of downscaling. And climate change will reduce monthly rainfalls up to 39% and increase the temperatures up to 2 °C.
Climatology
Ali Mohammad Khorshiddoust; Robab Razmi; Nasim Maiali Ahari; Karim Abbaszade
Abstract
Subsidence is a natural phenomenon which can be reinforced by the interferences and activities of human beings. Ghaleh area in Tasuj is located in North Eastern part of Uremia Lake. The frequent occurrences of draught, expansion of agriculture and the over-population and thus over-exploitation of the ...
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Subsidence is a natural phenomenon which can be reinforced by the interferences and activities of human beings. Ghaleh area in Tasuj is located in North Eastern part of Uremia Lake. The frequent occurrences of draught, expansion of agriculture and the over-population and thus over-exploitation of the water belonging to underground beds and the delicate texture of soil have caused subsidence in some parts of the area. Regarding the existing evidences, the researchers are going to investigate the source of such a phenomenon in this area. To do so, we have used Geomorphologic and geologic data plus fault maps and hypsometric levels during 11 years period (2001-2011). integration and analysis of the maps by using ARC GIS software and the preparation of isopies maps for each of the monthly and annual by using Surfer win software and the cluster analysis based on tree diagram, showed that during the 11 years the amount of subsidence has increased due to the considerable reduction of underground water levels in some parts of the area such as Ghaleh village. On the other hand human factor has been recognized as the most important factor for the subsidence in the area.
Climatology
Mohama Raheimi; Mohamad Reza Yazdani; Moslem Asadi; Nafise Pegahfar; Mohammd Taleb Haydari
Abstract
Abstract The aim of this study is to investigate possible deviations from normal for Some climatic parameters in the Kurdestan. Calculation and analysis is done based on variables such as temperature, precipitation, humidity and maximum wind speed. Period examined in this study is a 30-year period between ...
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Abstract The aim of this study is to investigate possible deviations from normal for Some climatic parameters in the Kurdestan. Calculation and analysis is done based on variables such as temperature, precipitation, humidity and maximum wind speed. Period examined in this study is a 30-year period between 1983 and 2012 and is included Sanandaj, Saghez, Ghorveh, Marivan, Zarina Stations and Bijar At first, will identify data changes using the Mann-Kendall test. Then Characterized type and time of change. At the end Pearson correlation test was applied between variables. The results of data analysis indicate that start time of more changes is sudden and includes both the trend and fluctuation. Also, the results of the pearson correlation test suggests in most stations, there is positive significant correlation between rainfall and humidity and also negative significant correlation between temperature and humidity parameters.
Climatology
Majeid Rezaee Banafshe; Tahare Jalali
Abstract
According to important role of climate parameters such as radiation, temperature, precipitation and the evaporation in water resource management, The purpose of the present investigation, is evaluation of climate change in Tasuj basin and Groundwater level response to these changes in period 2013-2030 ...
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According to important role of climate parameters such as radiation, temperature, precipitation and the evaporation in water resource management, The purpose of the present investigation, is evaluation of climate change in Tasuj basin and Groundwater level response to these changes in period 2013-2030 by scenarios A2, B1, A1B. To do this research, was used the data of Chrchr and Sharafkhaneh evaporation stations and Khoy synoptic station for the period 1985-2012 and water levels data of tasuj basin for the years 2012-2000. Data of temperature, precipitation and sunshine with software LARS-WG and groundwater levels were predicted by artificial neural networks for mentioned period. The results revealed a decrease in precipitation and rise in temperature in each of the three studied scenarios.Maximum decline in water level in A2 scenario and minimum decline in groundwater levels will happen in B1 scenarios. Also study cross-correlation showed the impact of rainfall on groundwater levels is with time lag of 2 months.
Climatology
Hossein asakereh; Farieba Sayadi
Abstract
Artificial neural networks as a nonlinear techniques in climate and hydrology studies are important to have. Climate change and the global warming of the climate phenomenon known as persistence of drought followed Number of dry days. In this study, the data of daily rainfall during the period (1976-2008) ...
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Artificial neural networks as a nonlinear techniques in climate and hydrology studies are important to have. Climate change and the global warming of the climate phenomenon known as persistence of drought followed Number of dry days. In this study, the data of daily rainfall during the period (1976-2008) and artificial neural network in MATLAB software is used to predict the number of dry days Tehran station. Feed-forward type of network used by the algorithm reduces the gradient and Levenberg Marquardt is in the process of teaching and learning. Various structures in the input and hidden layers were tested during the training phase. Finally, a network with 4 inputs and 5 neurons in the hidden layer and 1 neuron in the output layer to best structure (4-5-1) with the highest correlation to predict the optimal answer. The results showed that the aforementioned stations, dry days predicted by the network during the period under review increased compared with that by calculating the probability of dry days during the period (2018-2009) using a Markov chain, the above been approved. The correlation coefficient values predicted dry days without a genetic algorithm combined with 86 percent .After teaching network as genetic algorithm combined with 88 percent that able providing algorithm combined to network result passable showing
Climatology
amanollah fathnia; Saeid Rajaee; Farzane Borzo
Abstract
In this study, using Gorgan station data for the period 2010-1980 was studied precipitation trends. In order to extract precipitation trend the moving average and Mann-Kendall test was used. Also, using by SPI (standard precipitation index) drought period and by Markov chain probability event each of ...
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In this study, using Gorgan station data for the period 2010-1980 was studied precipitation trends. In order to extract precipitation trend the moving average and Mann-Kendall test was used. Also, using by SPI (standard precipitation index) drought period and by Markov chain probability event each of the different states drought or wet period was calculated. Then, using NOAA-AVHRR images fluctuations vegetation affected by the precipitation trend and by Markov chain probabilities alternation for each class were examined. Results showed has occurred in 2001-2007 and 1990-1994 Years wet period and in 1982-1986 and 2005-2010 drought period. Study of drought index showed precipitation trend in same period and has occurred wet period in 2001-2005 and drought period from 2005. According to Markov Probabilistic matrix probability alternation from severe drought to same is 0.6 and severe drought to moderate drought is 0.13. In same trend, have decrease semi-dense vegetation from with 494479 hectares in 1985 to less than 380,120 hectares in 2000. Density and area of Vegetation have increased from 2000-2005, but for the reason of drought decrease recently and with 0.48 probabilities will remain non vegetation class in same conditions. The most probability changing is related to sparse vegetation to non-vegetation with 0.41. On this basis, may be will changed 214060 hectares to non-vegetation.
Climatology
Masoud Jalali; Ali SHahbai; Vahab Kamrian
Abstract
In this paper, we attempted to identify the synoptic patterns of Summer heavy rainfall in the southern coast of the Caspian Sea by using environment- to- circulation method. To attain this aim , by using statistics of daily Precipitation of 40 synoptic and climatology stations located in the region for ...
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In this paper, we attempted to identify the synoptic patterns of Summer heavy rainfall in the southern coast of the Caspian Sea by using environment- to- circulation method. To attain this aim , by using statistics of daily Precipitation of 40 synoptic and climatology stations located in the region for periods of 20 years of 1991 to 2010 and by percentile method , 29 days have rain more than 15 mm which have occurred in at least 30 percents of region stations , were determined as days with heavy rain. By using factorial analysis and cluster analysis methods , 3 synoptic patterns were determined as agent of creating rain in 29 days that the first pattern 48.3 percent , second pattern , 30 percent and the third pattern have allocated 21.7 percent of days of heavy rain in the studied region. In order to synoptic analysis of these patterns , maps of sea level pressure , 500 hectopascal level , omega (atmosphere vertical motions) , vorticity and moisture flows of level of 850 hectopascal related to two days before rain was used until rain day and finally it is determined that the main cause of occurring heavy summer rainfall in southern coast of the Caspian Sea is the penetration high-pressure system and after that formation of cool and moist northern flows as well as incidence of vast convection in the region. Each three patterns emphasize on occurrence of this condition and their difference is the place of deployment of high-pressure system and consequently the number of rainy days and severity of rain in these days.
Climatology
Broomand Salahie; Mahdei Aeli Jaham; Saiede Ainei; Jafar Derakshei
Abstract
The purpose of this study is forecasting the moderat and severs frost of three stations in Kermanshah, Kangavar and Sarpolezahab using output of the LARS-WG downscale model in the next two decades. The Input data's of models used in this study are: precipitation, minimum temperature, maximum temperature ...
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The purpose of this study is forecasting the moderat and severs frost of three stations in Kermanshah, Kangavar and Sarpolezahab using output of the LARS-WG downscale model in the next two decades. The Input data's of models used in this study are: precipitation, minimum temperature, maximum temperature and radiation in daily scale during the period 1992 - 2012. In the present study, using the output of two climate models, HADCM3 and BCM2 Under A1B Scenario, the initiation and end of the moderat and sever frost in these three periods 2030-2011, 2065-2046 and 2099-2080 have been evaluated. The results of the LARS-WG model process by the means of two Scheme Bcm2 and Hadcm3 indicate the warming of these stations in the coming years. The initiation of the moderat frost in these pointed stations is going to April by passing time. Between the stations in which are under study, Kangavar and Kermanshah stations have similar behavior but the Sarpolezahab station because of its tropic characteristic, showed a different behavior rather than the two stations in the coming years. The beginning of sever frost of these stations delayed with passing time and proceeds toward spring and in the other side, the end time of the last sever frost by passing time and getting close to the end of the anticipated period, is toward the beginning of winter and even at the Sarpole-zahab station until February. According to the results of the processing these models, the number of days with the moderat and sever frost in these stations will be dwindled in the coming years and the trend of temperature in these stations will be increased.
Climatology
Saeed Jahanbakhsh Asl; Shahnaz Rashedi; Mehdi Eslahi
Abstract
Freezing is one of the weather phenomena that almost happen in parts of the east Azerbaijan province such as Maragheh causing significant losses in agriculture, industrial activities, and transportation. The end of this research is studying of distribution and freezing return periods in Maragheh synoptic ...
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Freezing is one of the weather phenomena that almost happen in parts of the east Azerbaijan province such as Maragheh causing significant losses in agriculture, industrial activities, and transportation. The end of this research is studying of distribution and freezing return periods in Maragheh synoptic station during 48 year period (1343-1391) based on the minimum daily temperature. The methods of this study is Gumbel distribution method, three parameter log-logistic method and log-logistic method to analyzing probability of freezing parameters occurrence (starting date, ending date, length of the freezing season, length of the growing season).The Results of the computation of the spring and fall freezing return periods show that the first freezing in the fall starts on 10 Aban and the last freezing end on 17 Farvardin. Also analyzing of the beginning and end freezing trend shows that fall's freezing have an ascending trend , in other words, the dates of the occurring fall freezing goes ahead and spring's freezing have a descending trend. It means that, the dates of spring freezing go back. Therefore, length of the cold season according to the global warming becomes shorter.
Climatology
Hosein Asakereh; Mehdi Doostkamian
Abstract
The purpose of this study was to climate regionalization precipitation water atmospheric Iran. Therefore, the pressure data and specific humidity of the NCEP / NCAR database during 1950-2010 dependent of the United States National Atmospheric and oceanographic organization was extracted and analyzed. ...
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The purpose of this study was to climate regionalization precipitation water atmospheric Iran. Therefore, the pressure data and specific humidity of the NCEP / NCAR database during 1950-2010 dependent of the United States National Atmospheric and oceanographic organization was extracted and analyzed. For the calculation used software programming environment of Matlab and Grads software and Surfer software used to perform graphics operations. In the study for the perceptible water climate regionalization use from cluster analysis and in order evaluate the results, used of discriminant analysis. In the data archive mean and Coefficient of Variation precipitation water month review and analysis the method cluster analysis ward composition, than dendrogram graph recognized three regionalization climates: a) climate regionalization whit high precipitation water, b) climate regionalization whit median precipitation water. b) Climate regionalization whit low precipitation water. The result archives from discriminant analysis indict that 98.24% from of pixels doing so as true in relative group.
Climatology
Ataollah Nadiri; Keyvan Naderi; Asghar Asghari Moghaddam; Mohammad Hasan Habibi
Abstract
No permanent surface water resources in many parts of the country resulted in overdraft of limited underground water resources. Duzduzan plain is one of the UromiaLake sub basins. In this area, indiscriminate harvesting of groundwater resources has caused an average decline of 76 centimeters per year. ...
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No permanent surface water resources in many parts of the country resulted in overdraft of limited underground water resources. Duzduzan plain is one of the UromiaLake sub basins. In this area, indiscriminate harvesting of groundwater resources has caused an average decline of 76 centimeters per year. The purpose of this research is Groundwater level spatiotemporal predicting using Artificial intelligence models and Geostatistics model. To predict the groundwater level in the duzduzan plain, initially the piezometera in the plain were classified. The groundwater level in each piezometers category were introduced as output for each of AI models and input of these models include a evaporation and a precipitation and grounwater level of the considered piezometers with one time delay (t0-1), respectively. Ann's model and Sugeno fuzzy (SF) model applied to predict groundwater level. The resulted values of Groundwater level were evaluated by statistical measures, includes root mean square error and correlation coefficient. The obtained results showed ANNs model has better performance. Then the result of ANNs model, including two year monthly groundwater level prediction data in selected piezometers, were used as inputs of geostatistics model (Kriging and Co Kriging) for predating spatially ground water level in the study area. Obtained results showed Co Kriging model has better performance.
Climatology
asadollah khoorani; zahra jamali
Abstract
The aim of this paper is assessment and comparison of potential impacts of climate change on drought indices in an arid and a semiarid station. For this purpose, daily data of minimum and maximum temperature, sunshine and precipitation are used. This data were downscaled statistically by using ...
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The aim of this paper is assessment and comparison of potential impacts of climate change on drought indices in an arid and a semiarid station. For this purpose, daily data of minimum and maximum temperature, sunshine and precipitation are used. This data were downscaled statistically by using LARS-WG model based on A2, B1 and A1B scenarios. These climatic parameters are projected for 2011-2040, and RDI index was extracted for both observed (1961-1990) and projected data from HADCM3 model. The research outcomes show drought severity has increased under each scenario in both stations, except for Shahrekord under B1 scenario. For Bandarabbbas station, percent of droughts are about 6.7, 10 and 10 under A1B, A2 and B1 scenarios respectively. This parameter is 6.7 and 3.3 percent under A1B and A2 in Shahrekord station and the number (percent) of droughts will decrease about %10 under B1 scenario in this station.
Climatology
Ali Mohammad Khorshiddoust; Ali akbar Rasouli; Ali Slajegheh; Mojtaba Nassaji Zavareh
Abstract
One of the important arguments in variability and climate change assessment is the accuracy of climatic time series analysis. Therefore time series to be used should be homogeneous. Annual and seasonal maximum and minimum temperatures of 5 synoptic stations that contain long time series have been assessed ...
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One of the important arguments in variability and climate change assessment is the accuracy of climatic time series analysis. Therefore time series to be used should be homogeneous. Annual and seasonal maximum and minimum temperatures of 5 synoptic stations that contain long time series have been assessed in this study. For so doing, we utilized direct and indirect methods. We used metadata through indirect method and absolute and relative standard normal homogeneity test through direct routine. Results showed inhomogeneity which was identified by statistical methods corresponding to metadata. Relative standard normal homogeneity test is more suitable than absolute standard normal homogeneity test in this concern. Assessment of homogeneity between annual and seasonal minimum and maximum temperatures indicates that the parameter of minimum temperature has more inhomogeneity in the data. Comparison of homogeneity results between temperature of warm and cold season reveals that the temperature is more stable during relocation and other changes in cold season than in warm season. Relocation of many stations was not proved to be the cause of inhomogeneity in annual and seasonal maximum temperatures.
Climatology
Bohlul Alijani; Ali Bayat; Mehdi Doostkamian; yadollah Balyani
Abstract
Precipitation is one of the most essential and variable climate components whose understanding has long been a concern for climatologists. The main objective of the current paper is to investigate and analyze the precipitation cycles in Iran. In order to realize this objective, the annual precipitation ...
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Precipitation is one of the most essential and variable climate components whose understanding has long been a concern for climatologists. The main objective of the current paper is to investigate and analyze the precipitation cycles in Iran. In order to realize this objective, the annual precipitation data of isometric station of Iran were extracted. These data have been collected by the country’s meteorological organization since the establishment of the station until 2008 which adds up to more than 40 years of statistics. Then, in order to investigate and analyze the precipitation cycles, spectral analysis (co-structural analysis) was utilized. Regarding the calculations, the programming utilities of Matlab were used and the Surfer software application was exploited for drawing operations. The results obtained from analyzing the cycles show that there are significant 2 to 3 year cycles, 3 to 5-year cycles, 2 to 6 year cycles and sometimes 11 or more- year cycles governing Iran’s precipitation patterns. Hence, in east and southeast of Iran, 3 to 5-year cycles are prevailing and in west and northwest 2 to 3-year cycles are dominant and finally in north east 2 to 6-year cycles are customary. The most numerous and the most variable cycles happen in south and south east, mainly due to the mountainous regions of Zagros as well as the proximity to Persian Gulf. The north western regions, much like the southwestern regions, indicate variable cycles due to the mammoth mountains of Sabalan and Sahand. Moreover, the presence of those cycles which have a return period equal to the statistical period has been seen in various parts of Iran, which indicates a precipitation trend in this country.
Climatology
Hasan Zolfagari; Bahman Farhadi; Hamid Rahimi
Volume 20, Issue 56 , August 2016, , Pages 89-105
Abstract
The evaluation of environmental conditions in particular climatic conditions of crops such as soybean that have a great economic importance for the country. In this regard, climate regions, with a minimum requirement of soybean cultivation were identified. By choosing a 20-year period from 1989 to 2008 ...
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The evaluation of environmental conditions in particular climatic conditions of crops such as soybean that have a great economic importance for the country. In this regard, climate regions, with a minimum requirement of soybean cultivation were identified. By choosing a 20-year period from 1989 to 2008 and precipitation map of Iran on the basis of all available stations over 20 years of daily data completed, three regions with annual rainfall of over 500 mm in the North, West and South West were then determined. To increase precision, creating a virtual stations on the basis of daily maximum and minimum temperatures, areas outside of the internal parts were removed and each of the relevant area, was approved to determine the ultimate potential. Using CGMS software, the minimum temperature, maximum vapor pressure, sunshine hours and wind were estimated for rainfall estimation from Completely Regularized Spline (CRS) method, and Spline Regularize (SR) method was used to estimate relative humidity. In the next phase, the mean rate of deficit in soybean yield in dry land conditions was determined using the CROPWAT. Then, three valuable layers of precipitation, relative humidity and maximum temperature were explained by the use of AHP to determine the weight of each layer which was overlapped. The results showed that in the West and South West regions, with the percentage deficit crop yield of over 50%, conditions are low to moderate but the western half of the country's northern region can be considered suitable for soybean cultivation. Calculations showed that the deficit efficiency of the crop in this region, was less than 10 percent and thus has good potential for rain-fed soybean cultivation. It also became clear that to start rain-fed soybean cultivation in all regions, the month of Ordibehesht was more suitable than other months.
Climatology
Majied Rezaee Banafshe; Fateme Jaafari Shendi; Fereshte Hosseinalipour Ghazi; Majied Alimohammadi
Abstract
In this study, frequency and location of Moisture Flux Convergence (MFC) related to heavy rainfall have been analyzed using environmental to circulation approach. Based on the threshold of upper 99 percent, we selected 106 days of the super and overall heavy rainfall from IRIMO data base. MFC’s ...
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In this study, frequency and location of Moisture Flux Convergence (MFC) related to heavy rainfall have been analyzed using environmental to circulation approach. Based on the threshold of upper 99 percent, we selected 106 days of the super and overall heavy rainfall from IRIMO data base. MFC’s frequency and their locations have been detected from 00 to 1200 E and 00 to 800 N in the five levels (1000, 925, 850, 700, 600 and 500 HPa level) at 00:00, 06:00, 12:00 and 18:00 UTC. Analysis of MFC indicated that among upper levels, frequency of MFC in 850 hPa, due to high frequency is very important
Climatology
MohammadHoseein Rezaei Moghaddam; Khalil Valizadeh Kamran; Mehdi Belvasi; Hoseein KheiriAstiyar; Sayad Asghari Saraskanroud
Volume 20, Issue 56 , August 2016, , Pages 127-148
Abstract
One of the most important procedures in the water sources studies is the estimation of the local distribution of precipitation in different time scales. The study of precipitation is a basic element in the water balance studies and is an important factor in the natural sources programs of each country. ...
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One of the most important procedures in the water sources studies is the estimation of the local distribution of precipitation in different time scales. The study of precipitation is a basic element in the water balance studies and is an important factor in the natural sources programs of each country. Also, because of the rain-evaluation stations deficiency and their discreteness, it is necessary to use a special model. Besides the interpolation of precipitation amounts of stations, this model should interpolate topography, moisture and the slope direction of precipitation. In this work, at first, some data were gathered, in one year. These data were connected with the precipitation and moisture of 9 synoptic stations and 31 rainevaluation stations. These stations were located in the Lorestan province. Second, using the least square method and with the help of Maple software, the relations between precipitation and moisture was extracted. Third, by using the Python programming language, these relations were linked into the GIS. Finally, by so doing, the digital precipitation modal was achieved. The results obtained from the digital precipitation model show that, the precipitation amounts are different from the measured data in the stations, from 0.02 to 11.6 mm. Also, to investigate the efficiency of the considered model, the data obtained from this model were compared with the precipitation data achieved from TRMM radar at 21 April 2010. The concluded result show that, the determination coefficients are 79 and 86% for the TRMM data and for the digital precipitation model, respectively
Climatology
Behrouz Sobhani; Mohammad Framarzi
Volume 20, Issue 56 , August 2016, , Pages 171-191
Abstract
Crop production ability and its potential are significantly up to climate, topography and land use which are the most important environmental factors. In this study, using climatic data such as temperature, precipitation, number of frost days, sunny hours and relative humidity related to phonology steps ...
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Crop production ability and its potential are significantly up to climate, topography and land use which are the most important environmental factors. In this study, using climatic data such as temperature, precipitation, number of frost days, sunny hours and relative humidity related to phonology steps of saffron growing, Also ground resource data such as topography, land use layers which are prepared by Landsat 8 satellite imagery dated 14/5/2013. Evaluating each of these parameters have been taken in relation to the climate and ecology needs of saffron. Information layers of them were prepared by adjusting data to the surface, and processing them by GIS technology. Multi-criteria decision analysis methods (MCDM), based on vikor were used in order to prioritize and evaluate information layers and their weights in connection with each other. Then layers were weighted based on the criteria and subject model also these layers were overlapped and analyzed in GIS environment. Consequentially, the final layer of land suitability was prepared for saffron cultivation. In this study, 10.23, 45.25 and 45.52 percent of the total area are good, average and weak suitability lands respectively. According to this research, vikor method can have an acceptable function over selecting the fitness values for each class.
Climatology
Yousef Ghavidel Rahimi; Manochehr Farajzadeh Asl; Daryoush Hatami Zarneh
Volume 20, Issue 56 , August 2016, , Pages 239-255
Abstract
The NCP as one of the effective teleconnection patterns in level of 500 hpa have an important role in thermal and hydro-climatic variability in East Mediterranean region. In this study to investigate the correlation between the NCP and maximum temperature fluctuations Iran for a 60 years period (1950-2010) ...
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The NCP as one of the effective teleconnection patterns in level of 500 hpa have an important role in thermal and hydro-climatic variability in East Mediterranean region. In this study to investigate the correlation between the NCP and maximum temperature fluctuations Iran for a 60 years period (1950-2010) have been studied. Pearson correlation analysis as the main method used in this study show an inverse relationship between maximum temperatures and selected stations and NCP index. This shows decrease of temperature in positive phase of the NCP and rise of temperature in negative phase. In terms of time correlation coefficients were calculated and showed a significant negative correlation between the temperature of stations and the NCP in months of January, February, March and almost direct relation most stations in August. At monthly interval in the monthly correlation between stations with 0.342 were computed in January. Seasonal correlation of shows a significant correlation of maximum temperatures in winter to be -0.212. In terms of period, the results indicate a strong correlation between cold period in most stations and mentioned index. Atmospheric circulation in 500 hpa at positive and negative phases showed in positive phase, settlement of deep trough on the Caspian Sea, Iraq, Turkey and Iran, and also the location of Iran in the eastern part of the trough axis on the other hand, indicates establishment of a ridge on the North Sea and Europe which leads to transfer of cold temperatures of northern Europe and its adjacence of polar section to Iran. But on the negative phase placement of Iran beneath the ridge axis leads to the creation of a barotropic atmosphere with weak zonal wind and warm temperatures to Iran. So with blowing warm air from Africa, Arabia and low latitude Iran's temperature rises.
Climatology
nader pir moradian; hossein hadinia; afshin Ashrafzadeh
Abstract
Abstract Prediction and evaluation of meteorological data in effect of climate change is very important especially in water resources management. LARS is a model that generates weather data and predicts weather parameters by downscaling global circulation models (GCM). In this study, in order to evaluate ...
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Abstract Prediction and evaluation of meteorological data in effect of climate change is very important especially in water resources management. LARS is a model that generates weather data and predicts weather parameters by downscaling global circulation models (GCM). In this study, in order to evaluate 15 GCM models performance in simulating the minimum and maximum temperature, radiation and precipitation in Rasht synoptic station (2011-2012), statistical downscaling of each model was performed by LARS model. Then, the mentioned data were predicted on the basis selected GCM models for 2013-2042 and 2043-2072 periods. The results showed that the highest increase in annual average of minimum and maximum temperature will occur during the 2043-2072 periods with 1.3 and 2.0 °C, under A2 scenario, respectively. The amounts of radiation will decrease in future periods for all seasons. The highest decrease (143.4 MJ m-2) of radiation will occur in 2013-2042periods in winter under A2 scenario. The seasonal precipitation will often increase in future periods. The highest increase of seasonal precipitation (55.5 mm) will occur under B1 scenario in 2043-2072 periods for autumn.
Climatology
mohammad ali goorbani; surur poorbabak; hosein Jabari; esmaeil asadi; mohammad hasan fazelifard
Abstract
Abstract Classification of Meteorological stations, causing a large volume of data to be allocated a smaller homogeneous groups, Ease of use in modeling and also can help to spread the information to point to the lack of regional data to Statistics regional statistic. Meteorological stations in ...
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Abstract Classification of Meteorological stations, causing a large volume of data to be allocated a smaller homogeneous groups, Ease of use in modeling and also can help to spread the information to point to the lack of regional data to Statistics regional statistic. Meteorological stations in the region has a crucial role in the management and effective use of information. In this study, 112 stations were analyzed in order to classify regions with fuzzy cluster analysis and Kohonen artificial neural Networks. Four parameters, namely mean annual temperature, longitude, latitude and elevation are considered as the classification criteria for grouping to obtain the optimal number of groups the lowest value of Davies- Bouldin index were used. Demarton climatic zonation was performed to evaluate the spatial distribution of clusters obtained from various methods. The results showed that the fuzzy clustering technique with the Demarton climatic zones is more consistent.
Climatology
hamid galilvand; hosein zarean; hojjat allah yazdanpanah; saeed movahedi; mehdi momeni; nabi allah yarali
Abstract
Abstract Knowledge of past climate needs long-term and accurate climatic data for future planning and predicting. In this study, we reconstructed the average maximum temperature in spring and minimum temperatures in fall and winter by applying the width of annual ringsofQuercusPersica through multiple- ...
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Abstract Knowledge of past climate needs long-term and accurate climatic data for future planning and predicting. In this study, we reconstructed the average maximum temperature in spring and minimum temperatures in fall and winter by applying the width of annual ringsofQuercusPersica through multiple- regression. With this goal in mind, two growth heights were selected in Dena Forests and 40 growth samples from 20 bases in two geographical directions of southwest and northeast were extracted at breast height and measured with AutoCAD software with an accuracy of 3 microns. After cross dating stage, to eliminate non-climate effects, all climatic parameters and tree rings time series were standardized. The calculated Residual Chronology (RES) was calibrated with climatic variations of the period 1881-2011 and positive and significant correlation with the width of growth rings was confirmed. Based on the relations and correlation between the calculated chronology and joint statistical climatic data the reconstruction of annual rainfall was performed and it was found that the average rainfall of the last three decades had a 4 percent increase in comparison to the average rainfall of the last century.
Climatology
mohammad ali khorshiddoost; mojtaba fakhari
Abstract
Abstract One of the most important issues in arid and semi-arid regions is water resources management. Thus the study of the occurrence or non-occurrence of precipitation behavior can improve management water resources in these areas. In this study, the occurrence of days with precipitation in the south ...
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Abstract One of the most important issues in arid and semi-arid regions is water resources management. Thus the study of the occurrence or non-occurrence of precipitation behavior can improve management water resources in these areas. In this study, the occurrence of days with precipitation in the south west of Iran using daily rainfall synoptic stations in the 1994-2009 periods and adapting Markov chain was performed. The frequency matrix, switching matrix and stable matrix as well as continuous rainfall and the rainfall return periods of 2 and 5 days were calculated. The results show that the minimum probability of rain is in the plain area while the highest probability of rainfall belongs to the mountainous area. Also the highest probability of monthly precipitation is in January and the minimum is that of summer. The minimum of return period and the maximum continuous rainfall are in the mountainous stations and the maximum of return period and minimum continuous rainfall are in the plain area. Also unlike the other months, the maximum of probability rainy days in June is in eastern parts of mountains.
Climatology
Rasool Daneshfaraz
Volume 19, Issue 54 , February 2016, , Pages 127-142
Abstract
This study performs a sensitivity analysis to evaluatethe meteorological parametersthat affect daily pan evaporation rate. To this end, five meteorological parameters namely, daily mean temperature, relative humidity, sunshine hours, solar radiation, wind speed and pressure for period of 1386 to 1390 ...
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This study performs a sensitivity analysis to evaluatethe meteorological parametersthat affect daily pan evaporation rate. To this end, five meteorological parameters namely, daily mean temperature, relative humidity, sunshine hours, solar radiation, wind speed and pressure for period of 1386 to 1390 were used at the Tabriz City, Iran. At first, the pan evaporation rate was estimated using Artificial Neural Network (ANN) and the best structure of the ANN was distinguished. Then, weight matrix of selected structure of the network along with the Garson algorithm were used for sensitivity analysis of the input parameters and determine relative importance of the input parameters. The results indicated that the daily mean temperature and relative humidityare the most effective variables. However, the sunshine hours, solar radiation, wind speed and pressure have less effect on the evaporation rate at the Tabriz station.
