Land use Planning
Nafise faghih sabzevari; azita farashi
Abstract
Today, climate change and habitat loss are the biggest threats to wildlife. Therefore, accurate information on ecology and habitat requirements conserve species from these changes and identifying the most important factors to attract species and the development of habitat suitability maps can be considered ...
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Today, climate change and habitat loss are the biggest threats to wildlife. Therefore, accurate information on ecology and habitat requirements conserve species from these changes and identifying the most important factors to attract species and the development of habitat suitability maps can be considered a species protection process. After leopards and cheetahs, Caracal is the third biggest member of the cat family (Felidae) in Iran that has a key role in controlling of rodent populations and its habitat is mostly in arid areas. Accordingly, the aim of this study is to consider the effects of climate change on Caracal habitats and the distribution of the species under two climate scenarios RCP2.6 and RCP8.5 in the period of 2061 to 2080 in Iran by using the maximum entropy method. In this study, four groups of environmental variables are used: climat, topography, land cover, and land use. The results showed that distance from the conservation network, distance from sand dunes, and distance from dense forest areas had the greatest impact on the selection of suitable habitat for the Caracal at the present time and for the future time, the variables of mean temperature of warmest quarter and elevation had the highest importance on the distribution of Caracal. In addition, the study of Caracal's habitat suitability maps revealed that these species currently occupy only 13.2% of Iran, which have only 48.2% overlap with the current conservation network. While, in the future, the desired habitat rate of the species under the scenarios of RCP2.6 and RCP8.5 will be reached 30.9 and 27.4, respectively, and the amount of overlap with the current protected network will be reduced to about 66%, and the amount of overlap will have arrived at 17.8%.
Climatology
Hassan Zareh; Saeed Movahedi; Dariush Rahimi
Abstract
Reduction in productivity of horticultural and agricultural products, increase in pests, reduction in quality of agricultural products, and threat to food security are the consequences of climate change. The impact of climate change on agriculture leads to an increase in risk and risk-taking in the field ...
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Reduction in productivity of horticultural and agricultural products, increase in pests, reduction in quality of agricultural products, and threat to food security are the consequences of climate change. The impact of climate change on agriculture leads to an increase in risk and risk-taking in the field of agricultural activities. The results of the observational data review confirm the occurrence of climate change. The annual temperature anomaly of Bushehr province indicated an increase in the frequency of years with temperatures above the average from 1996 to 2021. According to the Pettitt's test, this increase is about 1.2 c˙. In addition, the significant increase in temperature at the 95% confidence level and Z values ≥ 2(in Mann-Kendall test) confirmed the occurrence of climate change in Bushehr province. The estimated data of the model for the future period confirm the continuation of the increasing trend of olive temperature thresholds for the period (2014-2040). The findings of the research indicated that with the increase in temperature for at least the following 20 years, the olive tree's cooling needs will not be met and the flowering season will occur in March instead of April. In the future, more areas will have an annual temperature of more than 26 °C. Therefore, in the future, the olive growing period will increase from 90 days to 150 days. With the increase in the number of days with temperatures above 40°C, the fruit burns more and the quality of olives decreases. Therefore, in addition to Asalouye and Dashtestan counties (1994-2019), Kangan, Jam, Deir and Dashti counties, the northern foothills of the province, and parts of Dilam (2017-2040) are added to the unsuitable olive areas. The favorable areas for olive cultivation will be moved to the west of the province.
Climatology
Shirin Mahdavian; Batool Zeynali; Bromand Salahi
Abstract
Climate diversity and land use / land cover change have a significant impact on hydrological regimes, especially in arid and semi-arid regions with critical water shortage problems. Therefore, estimating and evaluating climate change and land use and its consequences in each catchment is essential. This ...
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Climate diversity and land use / land cover change have a significant impact on hydrological regimes, especially in arid and semi-arid regions with critical water shortage problems. Therefore, estimating and evaluating climate change and land use and its consequences in each catchment is essential. This study examined the climate change of Kiwi Tea Basin using the data of four models of the Fifth Climate Change Assessment Report (CMIP5) under both optimistic and pessimistic scenarios (RCP8.5 and RCP4.5) using the LARS-WG6 microcirculation model. Changes in precipitation and temperature during three different periods (2040-2021, 2060-2041 and 2080-2061) compared to the base period (2019-1987) have been studied and for calibration and validation of LARS-WG6 model, observational data and output data of models with The use of F and T tests as well as RMSE, MSE, MAE and R2 indices were compared and evaluated. Based on the results of most of the models and the average of the studied models, in general, it is expected that the amount of precipitation and the minimum and maximum temperature in all the studied models will increase compared to the base period. Also, the results of evaluating land use changes with object-oriented classification showed that rangeland use with an area of 1224.18 and 1046.59 square kilometers, respectively, covered the largest area in both periods, while in 1987, residential use with an area of 3.66 square kilometers and in In 2019, water use with an area of 3.77 square kilometers had the lowest area. Also, the most modified use of rangeland use was dryland agriculture (181 square kilometers), which indicates thedestruction of rangelands
Climatology
naser pouyanfar; Gholam Ali Mozafari; Kamal Omidvar; Ahmad Mazidi
Abstract
IntroductionPistachio, like many subtropical fruit trees, need a cold period in their annual cycle to allow the buds to bloom naturally after the right conditions are in place. There are several models to calculate the chilling needs of pistachio, of which the chilling hours model, Utah and Utah positive ...
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IntroductionPistachio, like many subtropical fruit trees, need a cold period in their annual cycle to allow the buds to bloom naturally after the right conditions are in place. There are several models to calculate the chilling needs of pistachio, of which the chilling hours model, Utah and Utah positive are the most important of these models. The studied geographical area is Yazd-Ardakan plain located in Yazd province.Materials and methodsIn this study, according to statistical tests based on meteorological variables, the chilling hours model was selected for modeling. To conduct this research, three-hour temperature data of Yazd Synoptic Station during the statistical period of 1367-1396 were used to model and estimate the total monthly chilling hours of pistachio and The daily temperature data of this station during the statistical period of 1961-2005 were used for the SDSM model and the monthly temperature statistics of the years 1385-1397 were used to evaluate the downscaling data of the CanESM2 model under different RCP scenarios and finally modeling for the years 1400 -1429 was done.Result and discussionResults indicate that there is a significant correlation between monthly cumulative hours of temperatures between zero and 7.2 ° C and monthly temperature parameters such as mean minimum temperature, mean maximum temperature and mean monthly temperature, which in the absence of data hourly temperature can be used to model and determine monthly cumulative hours.ConclusionFindings show that the chilling needs of Kalle-Ghuchi, Owhadi and Ahmad- Aghaei species will be met in the coming years and Akbari and Fandoghi species will not be met.
Rural Planning
Mansour Ghanian; Omid M. Ghoochani; latif mohammadzadeh
Abstract
IntroductionClimate change is one of the main environmental challenges facing the world today and the results of studies and forecasts indicate that it is ever expanding. These changes, in addition to the environment, directly and indirectly affect the social, cultural and economic sectors of the countries ...
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IntroductionClimate change is one of the main environmental challenges facing the world today and the results of studies and forecasts indicate that it is ever expanding. These changes, in addition to the environment, directly and indirectly affect the social, cultural and economic sectors of the countries of the world. In recent years due to observing evidences of climate change in hydrological variables, concerns have been arisen regarding variations of renewable water resources under climate change in developing countries. Among various types of economic sectors, agriculture is one of the most sensitive economic sectors in terms of climate change phenomena such as temperature rise and evapotranspiration, decreasing precipitation and melting, reducing surface and underground water resources, and etc. Therefore, the effects of climate change on agriculture have become one of the hottest academic topics around the world. In this regards, farmers are always considered as the most vulnerable groups against global climate change, and the vulnerability of them to the region and even beyond them can be examined. Therefore, this study, with a sociological approach, attempted to identify factors affecting the intention of farmers to adapt to climate change. In this regard, due to the role of traditional beliefs in the management of agricultural affairs in rural communities of Iran, a conceptual framework was designed combining two theories PMT and cultural values.MethodologyA survey was conducted to address the main goal of the present study from July 2018 through February 2019 in Marvdasht Township. The farmers of Marvdasht Township considered as the statistical population of this study, which among them 256 farmers selected based on Cochran formula as the statistical sample using simple random sampling method. The research’s instrument was a researcher-made questionnaire which its reliability was confirmed by using Cronbach's alpha coefficient for the main scales of the questionnaire (α = 0.70 to 0.83) and also, its validity was confirmed by a panel of experts (faculty members of rural developments, agricultural extension, agro-ecology and agro-climate specialists) prior to the launch of the study. Data analysis was carried out using SPSS (V20) and AMOS (V20) software.Results and discussionThe results showed that proposed theoretical framework of this study has a good fit with data and has the predication potential of famers’ adaptation intention towards climate-change. According to the literature review in can be understand that combination of two both theories (protection motivation theory and cultural theory), is suitable for investigating the underlying factors influencing farmers’ adaptation intention towards climate change. For example, Hemayatkhah and Ghorbani (2016), explained 28 of the farmers’ adaptation intention towards climate change using the cultural values theory. Also, Azadi et al., (2014) showed that the protection motivation theory can predict 34% of the farmers' adaptation behavior in confronting climate change. Therefore, it is suggested that in the future studies, the conceptual model of this study should be used to assess farmers' adaptation intentions towards climate change. The results revealed that egalitarianism has a positive influence on farmers’ belief in climate change. Although fatalism has a negative effect on farmers’ adaptation intention towards climate change. This illustrates the contradiction between these two groups of people as well as the accountability of egalitarianism people and the lack of accountability of fatalism people to climate change. The results also, showed that individualism have a negative impact on subjective norms of farmers towards climate change. The results indicated that, adaptation intention of farmers towards climate change is affected by belief in climate change and the adaptation assessment positively, whilst maladaptation to climate change has a negative effect on farmers’ adaptation intention. Moreover, belief in climate change has a positive impact on farmers’ maladaptation to climate change. In this regard, it could be argued that, farmers who have personal experience of the negative consequences of climate change-related events, such as drought, or have seen farms that have been affected by climate change phenomena with severe product cuts, will try to prevent the occurrence of these incidents for themselves by applying adaptive practices.ConclusionThere is a consensus that awareness of farmers' intentions against climate change in order to understand the factors affecting their intention to adapt to environmental threats, such as climate change, in government policies and programs. In other words, recognizing the intentions of farmers as a management element can help planners of various executive sectors, especially the agricultural sector in a sustainable management. Iran experienced an extensive climate change and drawdown trend of the water level in recent years which poses negative impacts on the environment and agriculture. In this way, understanding the farmers’ adaptation intention to climate change can help to generate suitable policy solutions. Based on the results, belief in climate change has the most positive effect on the farmers’ adaptation intention towards climate change. In fact, information is crucial in shaping farmers’ perception of climate change risk and the effectiveness of adaptive measures. Incorrect information may lead to maladaptation which, in turn, influences the adaptation intention and behavioral response. As such, agricultural extension services are important in supporting farmers with technical knowledge of adaptive measures. Also, according to the results, it is important use of farmland visits, training courses on climate change threats, how to adapt to this challenge, and farm management. The lack of timely adaptation in agriculture may hamper prosperous farm developments by neglecting risks and opportunities emerging from climate change. It is also suggested that agricultural extension agents, using cultural values of farmers try to better understand the relationship between farmers and the environment and use it in their work plans. Because each of the groups has separate and unique needs and perhaps their educational and extensional methods are also very different.
Climatology
Hossein asakereh; Seyed Abolfazl Masoodian; Fatemeh Tarkarani
Abstract
Introduction
According to previous investigation and examining climatic elements, the hypotheses of global warming and consequently, global climate change is confirmed by majority of climatologists society around the world. The global changes probably continue for the next decades. The changes in climatic ...
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Introduction
According to previous investigation and examining climatic elements, the hypotheses of global warming and consequently, global climate change is confirmed by majority of climatologists society around the world. The global changes probably continue for the next decades. The changes in climatic elements, by and large, categorized into two types; trends and variation. The trends refer to long term changes, whiles variations indicate vary time interval changes including oscillation, phase, jump (sift), and persistence.
Precipitation is one of climatic elements which can properly reflect chaotic behavior of climate system, and illustrate the nature of changes in the system. Trends, Oscillation, and persistence in this element are investigated in national and international scale, whilst the decadal variations as an index of climate variation can contribute to the current literature. In current study we attempted to illustrate an objective feature of precipitation characteristics and its anomalies over four recent decades by using Asfezari National Dataset (AND).
Data and Methods
In the present study, the gridded precipitation data of the third version of AND with spatial resolution of 10×10 km during the time period of 1970/3/21 to 2016/3/19 (46 years including 16801 days) is used. This dataset adopted from 2188 synoptic, climatology, and rain gauge stations and subjected to interpolation by using Kriging interpolation method. The dataset covers an area from N and E. Accordingly, a pixels cover the area for 16203 days. Consequently, the dataset includes dimensions.
General spatial features of Iran precipitation for the whole under investigation period was studied based on climatological annual precipitation. Next, the same characteristics calculated for four decades ending up to 2016/3/19. Finally, for every decade the anomalies of precipitation in compare with the whole understudy period and its previous decades calculated in order to discover the spatial pattern of decadal fluctuation in precipitation.
Discussion
General characteristics of annual precipitation
Annual mean of precipitation over Iran is 250.5 mm. Due to decline in temperature contrast and strength of fronts in the Mediterranean cyclones, as a main source of precipitation in Iran, the annual precipitation over Iran decreases from west to east, and from north to south.
The annual precipitation in 63.2% of Iran is lower than the climatic annual mean. The annual mean of precipitation in this area which generally located in east and south of the country is approximately 150.5 mm. Thus, the total precipitation in this area is equal to the total precipitation in the rest 36.8% of the country which its annual precipitation is more than the annual precipitation in the country, 422 mm. The spatial variation of precipitation is confirm by other statistics, for instance, skewness, kurtosis, the extreme threshold indices. For instance, a large part of Iran (26.73%) includes 100-150 mm annual precipitation, whiles the precipitation in 15.8% of the country reaches to 150-200 mm. Parts of northeast of Iran, and the coast of Persian Gulf and Oman Sea in the south, in addition to southern slops of Alborz mountain chain experience a precipitation amount of lower than 100 mm. In contrast to the above-mentioned dry regions, the (approximately) wet regions include limited areas for each precipitation class. For example, only 9.1% of the country characterized with 500 mm of precipitation, while the classes of 200-300, 300-400, and 400-500 comprise 20.62, 12.64, and 6.11 percents of the country, respectively.
Decadal variation of precipitation
In current section the spatial distribution and statistical features of precipitation in each decades was illustrated. The following list includes our finding of statistical - graphical analysis of precipitation in four successive decades:
1) The difference between spatial mean and median of annual precipitation increased from the first to the last decades. The increasing in this characteristic refers to increase in spatial asymmetrical distribution of precipitation over the country.
2) A comparison between spatial distribution of precipitation maps showed that generally, the areas experienced precipitation above the decadal and whole period average are decreased from the first and last decades.
3) The increase in spatial skewness from the first decade to the last decade is another evidence of increasing in precipitation spatial differences.
4) The last but not the least finding is the changes in the extreme threshold indices. From the first to the last decade, the range of 10th and 90th percentiles have increased.
Conclusion
Previous studies depicted that the amount of Iran precipitation has decreased over recent decades. In order to investigate the role of each decade in the decreasing values, the gridded precipitation data of the third version of AND with spatial resolution of 10×10 km during the time period of 1970/3/21 to 2016/3/19 (16801 days) is used. General spatial features of Iran precipitation for the whole under investigation period was investigated based on climatological annual precipitation. Next, the same characteristics calculated for four decades ending up to 2016/3/19. Finally, anomalies of precipitation in compare with the whole understudy period and previous decades calculated in order to discover the spatial pattern of decadal fluctuation in precipitation.
Our finding showed that by and large, precipitation has decreased over recent decades. The changes has been more pronounced in southern and northern coastal area, western slopes of Zagros mountain chain, and northern slopes of Alborz mountain chains. Previous researchers attribute these changes to changes in humidity advections in recent years.
Geomorphology
Nayer Aghabeigi; Abazar Esmali Ouri; Raoof Mostafazadeh; mohammad Golshan
Abstract
Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment ...
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Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment yield in ungauged watersheds. Sediment condition shows the upstream characters and using of the obtained data makes a relation between erosion and sediment load. The different parameters such as climate, land use, data accuracy and the applied methods have the effect on the sediment rating curve shape. Agriculture activities such as tillage in the direction of slope lead to accelerated erosion in the watersheds, especially in the Mediterranean area. These decades many studies assessing the effects of climate changes in the future period and it affects on runoff. In this study, the main objective is to obtain sediment changes during the future decade (2011-2030) using the curve rating in sediment estimating. For this purpose, the IHACRES hydrologic model and the LARS_WG climate model were used. Material and Methode The IHACRES model for seven hydrometric stations was calibrated and validated. This model is a rainfall and runoff erosion that require a little data for running including minimum and maximum temperature, rainfall, discharge and study are. This model defined as a lumped model and highly common in watersheds with scarce data. With running this model in all of the models the model parameters were calibrated. Also, the LARS_WG model was used for determining the weather changes that are occurring in the Samian watershed. This watershed has near to 4 thousand square kilometers that have many sub-watersheds. In this study, the watersheds in the west of the Samian watershed were selected for modeling. The average of rainfall in this area is between 220 and 457 mm, and the weather temperature changes in this region are high and that is between -32 to 34 C°. The results of LARS_WG showed the weather changes in each part of the hydrological model inputs that these changes were applied to the IHACRES model and the discharge flow rate was estimated for the future. On the other hand, using the observed discharge and sediment yield were calculated the sediment curve rate. By changes in flow discharge at the study stations, were calculated the suspended sediment discharges for the future period. results and discussion The results of the LARS_WG model showed that the amount of precipitation decreased to 3.68 percent and the minimum and the maximum temperature increased by 16.48 and 5.39 percent, respectively. Decreasing of the input precipitation in most part of the world particularly in Iran watersheds mentioned in many studies. One of the other the most important effect of the climate change in this area is minimum and maximum temperature increase that leads to evapotranspiration increasing and soil moisture loss. The results of the IHACRES model showed that this model has the suitable capability for simulation runoff in the study area, therefore, it was used for estimating the future runoff regarding climate changes. The model output showed that during the next decades the average flow rate in the hydrometric stations will decrease by a total of 16 percent and the number of peak flood events will increase, that the highest increase between the study watersheds observed in the Yamchi hydrometric station with a mean of 2.09 m3s-1 and 16 peak events with over 6 m3s-1. Using the obtained results of the climatic model, hydrological model and the sediment rating curve the suspend sediment changes were estimated for the future period. The result shows that these climatic changes will lead to a 47 percent reduction in the average of suspended sediment load at study stations. Conclusion The consequences of the climate changes have the significant effect on water resources quality and quantity. The aims of this study were calculating the weather changes and it's ruling on discharge and sediment yield changed. the results of this study indicate the effect of climate change on the Ardabil province watersheds is remarkable. Considering the environmental impacts of climate change and dependence on human life on the environment it is necessary to implement an appropriate approach for decent management in Watersheds.
Climatology
Elham Alizadeh; hossein mousavi; Jamshid Yarahmadi; Abdollah Faraji
Abstract
Introduction Climate change is one of the most important phenomena of the present century, which has created many problems and challenges both globally and regionally and nationally. In the second half of the twentieth century, global warming relative to The first half of this century has increased ...
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Introduction Climate change is one of the most important phenomena of the present century, which has created many problems and challenges both globally and regionally and nationally. In the second half of the twentieth century, global warming relative to The first half of this century has increased and it is predicted that this increase in temperature will continue in future periods, resulting in changes in the level of climatic conditions in different parts of the world. Due to the lack of atmospheric precipitation, due to the increase in temperature, the rate of evaporation has increased significantly and can greatly affect the aggravation of water shortage conditions in surface currents, especially evaporation from the surface of lakes behind dams. Percentage by evaporation leads the country to higher values (Farajzadeh and Ghasemifar, 1398). Regarding the changes in Iran's water resources in the horizon of 2100, few studies have been done and most have been case studies (Fahmi, 1393). Although the results of these studies, based on the climatic models and different scenarios used, sometimes show contradictions, so it is necessary to do more studies in this field. Methodology The present research has been done in three specific sections and the output of each section has been used as the input of the next section. In the first part, climate change in the form of precipitation variables in the study area is detected and subsequently, rainwater runoff in the Daryan catchment is simulated. Then, while identifying the characteristics of hydrological drought periods in the basin, the probability of occurrence, intensity and duration of hydrological drought periods are calculated based on the fit of different statistical distributions for different return periods in the third section. Results and discussion Climate change is one of the most important environmental problems of this century. Thus, evaluating the phenomenon of climate change and reducing its effects on both global and regional scales has attracted the attention of many researchers, planners and legislators (Yohe et al., 2007). Proper assessment of these effects requires the existence of climatic information with appropriate spatial distribution and long-term time series, as well as a thorough understanding of its future trends at the regional and local scale. Despite the fact that today the output of public circulation models (GCM) are the main sources of future climate data production. One of the most important consequences of climate change includes changes in the hydrological cycle and river flow regime of watersheds. Therefore, the present study aimed to investigate the possible effects of climate change on rainfall and runoff in the Daryan catchment area north of Lake Urmia. In this study, statistical method (SDSM) and data of CanESM2 Canadian climate model in the form of three scenarios RCP2.6, RCP4.5 and RCP8.5 in order to micro-scale the precipitation data of five synoptic stations adjacent to the sea basin and changes Its future is used. Here, the basic period (1961-2005) and future periods (2049-2020), (2079-2050) and (2080-2100) were selected. In this research, the threshold level method has been used to identify hydrological drought periods and extract its characteristics. The results of the analysis of the last 35 years of hydrological droughts in the Daryan Basin showed that 44 drought events occurred in this basin, which in total, led to a reduction in surface flow volume of about 140 million cubic meters in this basin. Conclusion The simulation results of SWAT model showed that the annual average runoff of the sea basin in the first period (2020-49) in all three scenarios increases by 3.7 and 6%, respectively, compared to the base period. While in the rest of the periods of all scenarios, runoff reduction is predicted compared to the base period. Accordingly, a decrease in surface runoff compared to the base period is predicted for five months of the year (April to August) and an increase in the remaining months. Future changes in precipitation at Tabriz station, which is the basis for modeling runoff in the Daryan basin, are not very noticeable compared to the base period, and only in the period (2049-2020) all three scenarios are predicted to increase by 5, 2 and 8%, respectively, compared to the base period. In the other periods, in all three scenarios, a decrease in rainfall is predicted compared to the base period. Results of evaluating the effects of climate change on rainfall and surface runoff in the Daryan Basin with the results of other researchers in the catchment area of Lake Urmia, including: Goodarzi and Fatehifar (2010) in the Azarshahrchai Basin, Qaderpour et al. (2016), Dariane et al. (2019) ), Sobhani et al. (2015), Goodarzi et al. (2015) and Salehpour and Malekian (2019) are consistent.
Climatology
Nayer Aghabeigi; Abazar Esmali Ouri; Raoof Mostafazadeh; mohammad Golshan
Abstract
Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment ...
Read More
Introduction Estimation of the rivers sediment load has high complexity due to effecting different parameters in this aspect. Regarding the power relationship between discharge data and suspended sediment load use of sediment rating curves is one of the most common methods for determining the sediment yield in ungauged watersheds. Sediment condition shows the upstream characters and using the obtained data makes a relationship between erosion and sediment load. The different parameters such as climate, land use, data accuracy, and the applied methods have an effect on the sediment rating curve shape. Agriculture activities such as tillage in the direction of slope lead to accelerated erosion in the watersheds, especially in the Mediterranean area. These decades many studies assessing the effects of climate changes in the future period and it affects runoff. In this study, the main objective is to obtain sediment changes during the future decade (2011-2030) using the curve rating in sediment estimating. For this purpose, the IHACRES hydrologic model and the LARS_WG climate model were used. Material and Methode The IHACRES model for seven hydrometric stations was calibrated and validated. This model is rainfall and runoff erosion that require a little data for running including minimum and maximum temperature, rainfall, discharge and study are. This model defined as a lumped model and highly common in watersheds with scarce data. With running this model in all of the models the model parameters were calibrated. Also, the LARS_WG model was used for determining the weather changes that are occurring in the Samian watershed. This watershed has near to 4 thousand square kilometers that have many sub-watersheds. In this study, the watersheds in the west of the Samian watershed were selected for modeling. The average of rainfall in this area is between 220 and 457 mm, and the weather temperature changes in this region are high and that is between -32 to 34 C°. The results of LARS_WG showed the weather changes in each part of the hydrological model inputs that these changes were applied to the IHACRES model and the discharge flow rate was estimated for the future. On the other hand, using the observed discharge and sediment yield were calculated the sediment curve rate. By changes in flow discharge at the study stations, were calculated the suspended sediment discharges for the future period. results and discussion The results of the LARS_WG model showed that the amount of precipitation decreased to 3.68 percent and the minimum and the maximum temperature increased by 16.48 and 5.39 percent, respectively. Decreasing the input precipitation in most parts of the world particularly in Iran watersheds mentioned in many studies. One of the other the most important effect of climate change in this area is minimum and maximum temperature increase that leads to evapotranspiration increasing and soil moisture loss. The results of the IHACRES model showed that this model has a suitable capability for simulation runoff in the study area, therefore, it was used for estimating the future runoff regarding climate changes. The model output showed that during the next decades the average flow rate in the hydrometric stations will decrease by a total of 16 percent and the number of peak flood events will increase, that the highest increase between the study watersheds observed in the Yamchi hydrometric station with a mean of 2.09 m3s-1 and 16 peak events with over 6 m3s-1. Using the obtained results of the climatic model, hydrological model and the sediment rating curve the suspend sediment changes were estimated for the future period. The result shows that these climatic changes will lead to a 47 percent reduction in the average suspended sediment load at study stations. Conclusion The consequences of climate change have a significant effect on water resources quality and quantity. The aims of this study were to calculate the weather changes and it's ruling on discharge and sediment yield changed. the results of this study indicate the effect of climate change on the Ardabil province watersheds is remarkable. Considering the environmental impacts of climate change and dependence on human life on the environment it is necessary to implement an appropriate approach for decent management in Watersheds. Keywords: Rating curve, climate change, LARS-WG, discharge, IHACRES.
Climatology
Mohammad Reza Azizzadeyya Varzegan; khadijeh javan
Volume 23, Issue 70 , March 2020, , Pages 227-246
Abstract
One of the most important effects of climate change is increasing in extreme climate events. Change in the frequency or intensity of extreme events can have significant impacts on natural environments and human societies so their analysis is very important. The aim of this study is to identify the trend ...
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One of the most important effects of climate change is increasing in extreme climate events. Change in the frequency or intensity of extreme events can have significant impacts on natural environments and human societies so their analysis is very important. The aim of this study is to identify the trend of precipitation extremes in Lake Urmia basin and to investigate their relation with Teleconnection patterns. For this purpose, daily precipitation data of 7 synoptic stations in the basin during 1987-2014 was used. 11 extreme precipitation indices were extracted using the RClimDex and their trends were calculated by non-parametric Mann-Kendall test. Then the relationship between these indices with Teleconnection patterns was determined by the Pearson correlation coefficient. The results of time series analysis showed that all extreme precipitation indices in Lake Urmia basin have decreasing trend exept consecutive dry days (CDD). The spatial distribution of trend in extreme indices showed almost all indices have a significant trend at the 5% significance level in basin. There is no significant trend in consecutive dry days (CDD). The changes in extreme precipitation could be affected by the El Niño-Southern Oscillation (ENSO), Southern Oscillation Index (SOI), East Pacific-North Pacific (EP-NP), Madden and Julian Oscillation (MJO) and Pacific Decadal Oscillation (PDO).
Climatology
Saeed jahanbakhsh; yagob din pazhoh; mohammad hossein aalinejhad
Volume 23, Issue 67 , April 2019, , Pages 91-107
Abstract
According to the importance of snowfall in supplying water of different regions especially mountainous areas, accurate estimation of snow water equvallent and changes of its coverage would be effective in agriculture, energy, management of reservoir and flood warnings. In this study runoff orginated ...
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According to the importance of snowfall in supplying water of different regions especially mountainous areas, accurate estimation of snow water equvallent and changes of its coverage would be effective in agriculture, energy, management of reservoir and flood warnings. In this study runoff orginated from snow melting in ShahrChay basin under the terms of climate change calculated. For this purpose, snow cover for water year of 2012-2013 were extracted in ENVI software by using daily images of Modis satellite.Then, GIS software the physiographic specification of the basin was obtained. In the next step, data of snow cover, meteorological variables and other necessary parameters to SRM model provided as an input of model and run_off from snow melt was simulated. Then output of the 6 models of atmospheric general circulation with title of 3 scenarios nomely A1B , A2 and B1 converted to a downscaleing by using LARS-WG model. By comparing the output of 6 models in the future period to period based on monthly statistical, the best model and scenario for generation of air temperature and precipitation data in the period 2030-2011 were selected. As a result the HADCM3 model under the scenario A1B was used for generation of precipitation and the MPEH5 under scenarios A2 was used for generation of temperature data. In order to estimate the rate of change of runoff orginated from snowmelt rate of change of monthly data of air temperature and precipitation of the base time period as well as future time period under selected model and scenarios was entered to SRM model in simulation time period. Results for all of the scenarios show that runoff orginated from snowmelt in late spring will be reduced. The peak flow appeared earlier in comparison with base time period and its value would be larger than base time period.
Climatology
mostafa karimi ahmad abad; Adel Nabizadeh
Volume 22, Issue 65 , November 2018, , Pages 265-285
Abstract
Now days ,in order to providing the best mecanisms to damp the impact of climate change , climatology scientists need long term prediction of climatical variables and their changes. This research studies the impacts of climate changes on daily parameters such as: rainfall , min and max temperature and ...
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Now days ,in order to providing the best mecanisms to damp the impact of climate change , climatology scientists need long term prediction of climatical variables and their changes. This research studies the impacts of climate changes on daily parameters such as: rainfall , min and max temperature and sunshine hours in Urmia lake basin. (Tabriz ,saqqez and Urmia synoptic stations) , selected as study stations , have long term gaged data for mitigation and Adabtation from 1980 to 2009. data prediction under as scenario A2 a type of GCM as HADCM3 model was used to simulate climatic parameters in 2011 to 2040 by LARS-WG model downscaled. Results show that prediction time distribution has been limited to short time in comparison to past decades .In other words the number fraindy days has been diminished , as far as in the future April will have the most decrease (7.5%) and February will have the increase (5.8%) in precipitation . overall , the precipitation max and min averay temperature of basin will increase about (4.3%) , (1.35 ) and (0.64 ) respectively in addition, November will have the most increase in daily max temperature (12.7) and January will have the least increase (0.33) in this parameter the sunshine hours of basin will not increase significantly .
Majid Rezaei Banafsheh; Tahere Jalali Ansaroodi
Volume 22, Issue 64 , September 2018, , Pages 59-79
Abstract
Iran is located in semi-arid region and its annual rainfall average is about one-third of the world's rainfall. In recent decades, in addition to population growth, increasing global temperatures led to wide variations in the earth's surface and has resulted changes to the time and place of precipitation. ...
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Iran is located in semi-arid region and its annual rainfall average is about one-third of the world's rainfall. In recent decades, in addition to population growth, increasing global temperatures led to wide variations in the earth's surface and has resulted changes to the time and place of precipitation. According to close relationship between the hydrological cycle and climate system, any change in climate elements such as precipitation, can have an important impact on the availability of water. The purpose of this research is investigate effects of climate change on spatial and temporal variations of water supply in Tasoj basin by using of HADCM3 model results. In this regard, was used from down scaling data of A2 scenario and then recharge for the period 2030-2013 was predicted by HELP3 hydrological model. The results showed that amount recharge of groundwater in this basin is fluctuating from 12 to 67 mm per year under the A2 scenario. In the future, the western region of the study area will be lower recharge than in other parts of the basin. The reason will be the combined effects of geological and climatic factors. Because of the fine-grained sediments along temperature, evaporation increase and reduced precipitation will be effective in reducing the recharge of this region. Also cross-correlation between precipitation and groundwater recharge showed that southern half of the basin than the northern half will responded in a shorter time period to precipitation changes.
Climatology
Yousef Ghavidel Rahimi; Manuchehr Farajzadeh; masood salehian
Abstract
Nowadays, Climate change is a hot topic engaging the scientists around the world as a cause for future human and environmental crises. It has been generally accepted that the main cause for climate change should be increases in the content of atmospheric carbon dioxide due to excessive burning of fossil ...
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Nowadays, Climate change is a hot topic engaging the scientists around the world as a cause for future human and environmental crises. It has been generally accepted that the main cause for climate change should be increases in the content of atmospheric carbon dioxide due to excessive burning of fossil fuels, esp. in industrial countries. In the 19th century, scientists realized that gases in the atmosphere cause a "greenhouse effect" which affects the planet's temperature. These scientists were interested chiefly in the possibility that a lower level of carbon dioxide gas might explain the ice ages of the distant past. At the turn of the century, Svante Arrhenius calculated that emissions from human industry might someday bring a global warming. Other scientists dismissed his idea as faulty. In 1938, G.S. Callendar argued that the level of carbon dioxide was climbing and raising global temperature, but most scientists found his arguments implausible. It was almost by chance that a few researchers in the 1950s discovered that global warming truly was possible. In the early 1960s, C.D. Keeling measured the level of carbon dioxide in the atmosphere: it was rising fast. Researchers began to take an interest, struggling to understand how the level of carbon dioxide had changed in the past, and how the level was influenced by chemical and biological forces. They found that the gas plays a crucial role in climate change, so that the rising level could gravely affect our future.
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
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.
All other Geographic fields of studies , Interdisciplinary
Sadegh Salehi; Karim Soleymani; Zahra Pazokinejad
Volume 19, Issue 54 , February 2016, , Pages 171-187
Abstract
The purpose of this study is to examine students' theoretical and applied knowledge of climate change and social factors influencing it. To conduct the research, descriptive-analytical method was used and 187 students of Mazandaran state universities were selected by stratified sampling. The questionnaire ...
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The purpose of this study is to examine students' theoretical and applied knowledge of climate change and social factors influencing it. To conduct the research, descriptive-analytical method was used and 187 students of Mazandaran state universities were selected by stratified sampling. The questionnaire was applied to collect data then data was analyzed using SPSS statistical software. Results of the study showed that the level of students’ abstract and practical knowledge of climate change is high and there is relationship between environmental information sources, perceived performance and students' knowledge of climate change. The results showed no significant difference between level of knowledge and gender and place of residence of the surveyed students and students’ knowledge of climate change is different to college. Overall, the results indicate that there is a requirement of environmental education and this suggests that the subject matter of climate change and policies should be included in curriculum of all university courses.
Javad Behmanesh; Nasrin Azad Talatape
Volume 19, Issue 51 , April 2015, , Pages 41-58
Abstract
One of the atmospheric cycle properties is climatic changes which can cause the fluctuations in meteorological parameters. These fluctuations in many world regions are considerable and water and soil resources are affected by them. To prepare against undesirable effect of climate change and adopt suitable ...
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One of the atmospheric cycle properties is climatic changes which can cause the fluctuations in meteorological parameters. These fluctuations in many world regions are considerable and water and soil resources are affected by them. To prepare against undesirable effect of climate change and adopt suitable development programs and water resources management, it is necessary to investigate the meteorological variable changes. The objective of this research was to investigate the climate change in Urmia region. In this research, the changes trend of temperature, precipitation, relative humidity, sunshine and potential evapotranspiration were studied. To achieve this goal, Urmia synoptic station daily data with 40 years period (1971-2010) were used. The Mann-kendall statistical test at confidence level of 95% was used to investigate the significance of trend in the mentioned parameters. The results showed that the trend slope of maximum, minimum and average of temperature was positive and this trend in 95% confidence level was significant. Urmia precipitation was decreased with slope of -2.26 so that this decrease was significant. The sunshine had positive slope and significant trend, but the negative trend of relative humidity and the positive trend of potential evapotranspiration (0.0068) were not significant. The monthly investigations showed that the average temperature in all months had positive slope, but this slope was not significant in all months. The other parameters in some months had positive or negative slopes.
Gholamali Mozaffari
Volume 16, Issue 39 , May 2012, , Pages 129-150
Abstract
Abstract
The global warming process during the last century not only has affected meteorological elements, but it also affected onset and end of meteorological elements. For studying probability changes in time series of onset and end date of rainfall thresholds 0.1 and 0.5 mm and more in the country ...
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Abstract
The global warming process during the last century not only has affected meteorological elements, but it also affected onset and end of meteorological elements. For studying probability changes in time series of onset and end date of rainfall thresholds 0.1 and 0.5 mm and more in the country level and deciding on the kind and its direction, daily rainfall data during past 45 years (1962-2006) of 29 synoptic meteorology stations has been used. First, onset and end date of rainfall in Julius code has been implied. The homogeneity of time series was tested by run-test missing value and was constructed by auto-correlation. For distinguishing random data and trend, Mann-Kendal method was used. The type and commencement time trend was calculated and the changes were also calculated on daily basis with Mann-Kendal graphical test and moving average of 5 years. The findings of this research show that there are trends at onset and end date of rainfall in some stations. On the other hand, in some meteorological stations, onset date of rainfall shifted forward and end date of rainfall shifted backward and the rainfall period length in some stations has been decreased.
