جستجوی مقالات مرتبط با کلیدواژه « تغییرات اقلیم » در نشریات گروه « جغرافیا »

Climate change and geographical factors and geographical location on earth have their own precipitation and fluctuations. The geographical features of the place are one of the influencing factors on the rainfall of each region. Also, the role of environmental variables in the amount and distribution of precipitation is undeniable, especially in mountainous areas. Flood vulnerability varies over time and from one region to another, which is due to special natural conditions, human activities, and the risk culture of the society exposed to damage. The effects of environmental factors on climatic elements have caused the increasing use of statistical techniques in climatic studies. Therefore, in the current research, climate change and effective geographical factors in urban floods in Yazd province.In this study, 9 factors of slope, direction of slope, height, network of waterways, rainfall areas, vegetation map, soil map, land use were identified as effective factors for causing floods in the regions. Then the information layers were prepared in the Gis environment. Conclusion According to the conducted research and observations of climate change and geographical factors of the study area, the results show that among the effective factors in causing floods in the study area, the factors of height, slope, amount of rainfall, water network and land use, respectively, are the most important causes of flooding in the region. that the studied area is in a very high-risk category, and the results of the study indicate the high potential of the area in terms of flood risk due to geographical

The land of Iran is located in a belt of dry and desert areas of the earth, which suffers the most unfavorable effects from climate change. Climate change is evident in the Zayandehrud basin, and its effects are evident in the decrease of rainfall and increase in temperature in recent years, as well as the continuation of droughts in the Zayandehrud watershed. With the reduction of river water flow, the allocation of water to the agricultural and environmental sectors in the middle and downstream parts has faced a problem. The need for water in this basin is high, so that during these years, the effort to obtain water in the Zayandehrud basin has entered a new arena in the form of tension, conflict, protests, and social unrest. One of the most important consequences of climate change is that it forces governments to plan inter-basin transfers. As a result of the water transfer policies without taking into account the religious rights and the environmental rights of the Zayandehrud bed and the Gavkhoni wetland, many social differences between the provinces have intensified.                                                                                                  

In terms of its purpose, the current research is an applied research that considering the historical, geographical, economic and political importance of the area, identifies the dimensions and effects of climate change in the Zayandehrud watershed and explains how climate change can increase crisis and tension in the watershed. This can be a useful guide for planners and decision makers in the field. In terms of method and nature, this research is descriptive-analytic, and the method of data gathering procedure is based on library sources, including books, magazines, and databases.                              

The turning of snow into rain at the source of the Zayandehrud and the increase in evaporation has led to the reduction of lands in the downstream part of the river, so that the area of "agricultural" and "pasture" lands has decreased in the middle and downstream parts. The number of wells has increased dramatically in recent years. The number of wells in the middle and downstream parts has increased significantly in this period, the average depth of the wells in the basin has increased by 4.8 meters, which is 6.65 meters in the upstream part, 5.55 meters in the middle part, and 28.28 meters in the downstream part. An average of 6 meters has been added to the depth of the wells. The increase in inter-provincial tensions, of which prominent examples were observed between Khuzestan, Isfahan and Chaharmahal Bakhtiari provinces in recent years, is one of the most important political consequences of climate change, which forces governments to plan inter-basin transfers. Isfahan farmers are the most important group protesting the critical water situation in this basin. One of the most important concerns of the people of the region and the most important cause of strikes and conflicts in recent years is the reduction of water resources and the reduction of agricultural activity. In recent years, the farmers of the region have expressed their protests in various ways, such as breaking and breaking water pipes, strikes, demonstrations and blocking the road with tractors, referring to the province and other ways. Public tension and protests regarding water supply and optimal water management for the residents of Zayandehrud Basin are not limited to the residents and beneficiaries of Zayandehrud Watershed. Hydro-political issues of the Behesht Abad water transfer project in the upper part of the Karun Basin, which has been the cause of local, regional and even national disputes between people and officials at the source and destination. This has caused social and political differences between the residents and beneficiaries of the upstream watersheds and the mentioned watersheds, and due to the ethnic differences of the watersheds, this issue has turned into an internal hydro-political crisis that has created gaps between ethnic groups. Climate change has hit the agriculture sector the most. Also, the first procedural consequence is the increase in the amount of unemployment and the immigration crisis. Immigration has led to the dispersal of kinship relations and the loss of solidarity, ethnic cohesion, and the increase of individualism and isolation, and as a result marginalization and drug addiction. The drying of Zayandehroud riverbed due to climate change has caused numerous cracks and subsidence in different areas of the watershed in Isfahan province. The depth of these cracks is very deep and in some cases they have a depth of more than 10 meters. Cracks have caused serious damages to roads and agricultural land.                                 

Climate change in the Zayandehrud basin is one of the factors that threaten the water resources in the basin. The climate change and decrease in rainfall and the expansion of agriculture and water-bearing industries has led to the destruction of nature and the geographical space and the lowering of the underground water level and even the transformation of permanent rivers into seasonal and seasonal into casual and dry rivers, and to compensate for this situation, the water transfer policy. This approach has caused political and security tensions in this region. Among the hydro-political issues of the water transfer projects in the mentioned catchment basin and its negative social-political consequences can be the intensification of local and regional conflicts and divergences, jeopardizing local and regional security, political activism of people and officials, ethnic diversity and political and regional sensitivities. One of the factors that play a basic role in creating negative political activism caused by water transfer is the strengthening of political regionalism, which itself is caused by weak management policies. This leads to the formulation of "negative hydro-politics" on a national and regional scale, and in turn has negative effects on local, regional and even national security issues.

The aim of this study was to predict the flood zone in the context of climate change based on the scenarios of the Fifth International Climate Change Board's assessment report in Qarahsu Basin (Golestan Province). This research consists of two phases: climatic and hydrological. In the climatic phase, daily data of minimum, maximum temperature, precipitation and sunny hours of Gorgan Hashemabad Synoptic Station in the period 2001-2020 were simulated using LARS-WG statistical model and after ensuring the efficiency of this model in simulation Construction of meteorological parameters in Gharasoo watershed of Golestan province, to investigate the impact of climate change on runoff in the study area, data of three scenarios A2 (maximum scenario), A1B (medium scenario) and B1 (minimum scenario) of the model HadCM3 was scaled in the period 2021-2050 with a small LARS-WG statistical model. In the hydrological phase, precipitation-runoff is simulated using the SWAT hydrological model and after calibration (from January 1, 2012 to December 29, 2016) and validation of this model (December 30, 2016 to December 29, 2018), temperature and precipitation data. The output of LARS-WG model was entered into SWAT model and the changes of runoff due to climate change in future periods compared to the base period were calculated. The results showed that according to the estimation of LARS-WG model for the studied scenarios in the future periods, the average temperature of Qarahsu watershed will increase by 0.56 to 4 degrees Celsius. The amount of precipitation also decreases by 10 to 24% compared to the base period. Finally, the flood of the study basin is zoned in GIS environment by combining the average runoff map under scenario A2, distance from the river and the shape coefficient of the basin using Fuzzy-AHP method. According to zoning, 44% is at high and very high risk.

Today, climate change, in addition to poverty and lack of food resources in rural areas, has caused an increase in the number of immigrants.Drawing the issue of climate change as a security concern has caused 70% of the world's countries to openly declare that the issue of climate change is considered a security issue for them. In this regard, the aim of the current research is to Study of the impact of climate change on the security of rural areas(Case study: Kurdistan province).The approach that governs the space of quantitative-qualitative research and the type of applied research is descriptive-analytical in terms of method. Research information has been collected through two methods library and field (questionnaire).In this research, 10 Extreme under climate change have been used along with 4 security dimensions that make up a total of 40 indicators. In this research, in order to evaluate the future climate conditions of Kurdistan province, the HadGEM2-ES model based on the MARKSIM micro scale method has been used during the period from 2010 to2095under two scenarios RCP4.5 and RCP8.5. SPSS software was also used to analyze the questionnaire data. The results of the study of climate change scenarios showed that in the two stations of Sanandaj and Saqez, the trend of summer days is increasing and freezing days are decreasing. The results of the precipitation indices in Kurdistan Province showed that the changes in the climate and the amount of rain, which previously rained sporadically throughout the year,will rain intensively and heavily in a few days and most of this rain goes out of the region in the form of floods and with great damage.Finally, the results showed a strong relationship between climate indices and profiles with security dimensions at a significant level(0.05),considering the level of confidence and providing upper and lower limits

Climate change is increasingly affecting people's livelihoods around the world and is considered as an important challenge at the global level; in fact, it is an important factor in aggravating social inequalities, especially gender inequalities. Women in the world are not only known as a vulnerable group in front of climate changes but also they are considered an effective factor in creating changes in relation to adaptation. Therefore, there is a need for research on the factors influencing the intention and behavior of farmers to adapt to climate change from the perspective of women and men. This study addresss this important issue using the developed model of health beliefs. The statistical population of this research included both male and female farmers. The number of sample members using Karjesi and Morgan Table included 200 male farmers and 150 female farmers. Random stratified cluster multistage sampling was used to select the farmers. The data collection tool was a questionnaire which its face validity was confirmed by the faculty members of the Department of Agricultural Extension and Education. In addition, to determine the degree of reliability, pre-test and Cronbach's alpha coefficient were used. The results of the structural equation model analysis showed that the variables guiding action, self-efficacy, social support, motivation and perceived obstacles were the variables which would affect the male farmers' intention in a positive and direct way and would affect their behavior in a positive and indirect way. Finally, these variables could predict 53 and 37% of the changes in the variables of male farmers' intention and behavior, respectively. Action guiding variables, perceived intensity and self-efficacy were found to be the variables influencing the intention of female farmers in a positive and direct way and their behavior in a positive and indirect way. These variables in total were 63 and 19 respectively to predict the percentage of changes in the variables of intention and behavior of female farmers. The data obtained in this research and the understanding of such gender differences can facilitate the development of gender-sensitive policies and programs  to improve sustainable and inclusive adaptation strategies.

In recent decades in Iran, due to the effect of climate change and population growth, the extent and depth of water in wetlands have been largely decreased. Therefore, it is worth finding the main reasons of the changes and if possible to reduce the rate of changes. Great advances in remote sensing technology offer valuable opportunities to monitor the trend of changes in natural environment. Landsat satellites from 1970s has the largest archive of remote sensing images. Remote sensing images provide data in wide area with high temporal resolution with low cost. Anzali Wetland is one of the most important international wetlands of Iran which has been registered in Ramsar Convention. In recent decades, population growth and expansion of cities and farm lands near Anzali wetland, climatic changes in this region and also changes in Caspian Sea’s water level changes, this wetland is going to be drained. The present study investigates wetland depth changes using Landsat imagery. Furthermore the depth changes have been thoroughly explained concerning rain fall, temperature and the Caspian Sea’s water level changes over a 30-year period from 1988 to 2018. Our Findings emphasizes that the depth of water depth in this wetland is more related to the changes of the Caspian Sea’s water level and the rainfall and temperature are not the main reason of decreasing of wetland.

Beside the improvement plans and climate change increasing during the last years and its effects on Azarshahr plain aquifer system, reveals the necessity of precise and applicable study about the aquifer situation. For this aim, Using the Artificial Intelligence, simulation and prediction of rainfall and run-off time series was done and expanded overall the plain by Empirical Bayesian Kriging(EBK), the forecasted total water budget of the plain and the other data were imported into the plain Aquifer dynamic system, in WEAP software. The response of the aquifer against the stresses was evaluated during the reference period from 2013 to 2021, applying the population growth and agricultural water demand increasing. The plain aquifer dynamic system, showed the reservoir capacity losing about 7% at the end of stress period (2021) in consequence of 2 and 1% increasing of population and agricultural water demand respectively. Present study shows the high performance of artificial intelligence and system dynamic conjugation in system response to the future climate changes and it can be useful for the water resources management and prediction of future vital actions.

In general, loess sediments are one of the most widespread forms of eolian sediments. During the past few decades, loess stratigraphy studies played key role in global climate changes. These sediments are usually yellowish in color and silt makes 70 to 90 percent of it volume. In Iran, loesses outcrop often in northeast of south Caspian Sea. The previous studies revealed that loess/paleosol sequences correspond to cold/ warm period of climate, especially during quaternary period. Therefore, loess deposits are the most important natural archive of climate changes and are ideal for reconstruction of paleoclimate and geomorphological change in Quaternary. The thick loess/paleosol sequences of northeast Iran provide unique opportunity to reconstruct the terrestrial paleoclimate changes recorded in these sediments.
A number of loesse-paleosol sequences contain a magnetic record of palaeoclimate through the Quaternary period. Anisotropy of magnetic susceptibility (AMS) was mentioned as a good tool to determine paleocurrent or paleodirection. AMS measurements were mostly used in the investigation of igneous, metamorphic and sedimentary rocks with an increasing number of applications in Quaternary loess and paleosol studies since the end of the1980s. The sediment magnetic properties depend on the magnetic content and characteristics of the source material and post-depositional weathering/soil formation processes. Loess in north of Iran is part of world loess belt and such as another loess sediments are evidence of paleoclimate change in continent.
In this study, Azadshar (Nowdeh Loess Section) was selected to reconstruct Late Quaternary climate change. The Nowdeh loess section with about 24 m thickness were sampled in 10 cm intervals for magnetometry analysis. For this aim, sampling location and method was determined after consecutive study area. This study used of reformed review of library references and lab practices combination. Magnetic susceptibility of all samples was measured in Environmental and Paleomagnteic laboratory based at Geological Survey of Iran, Tehran, Iran. All samples were placed in an 11 cm3 plastic cylinders to be used in magnetic measurement instruments.
Magnetic susceptibility was measured using AGICO company made Kappabridge model MFK1-A instrument. Magnetic susceptibility of all samples were measured. Base on this study results, samples with high frequency in magnetic susceptibility (increasing or decreasing) were selected for another studies of magnetic parameters.
The variation of magnetic susceptibility signal in the Nowdeh section suggests variation in climate conditions and mechanisms during the Late Quaternary. The magnetic susceptibility relationship with Loess/paleosol deposits resulted in low magnetic susceptibility values in cold and dry climate periods (Loess) and high magnetic susceptibility values in warm and humid climate periods (paleosoil). Therefore one can say that Loess and paleosol sequences studied here was formed at glacial and interglacial periods and under different climate condition. Results of this study showed that Magnetic Susceptibility, Natural remanent magnetization, Saturation isothermal remanent magnetization and HIRM in loess was less than paleosol. Instead amount of S_0.3 in loess layers was more than paleosol. Results of this study show that Nowdeh section has seen 8 periods of hot and humid climate (paleosol layers and similar paleosol layers with high magnetic susceptibility) in cold and dry periods (loess layers with low magnetic susceptibility) during past 150 ka.
This study was conducted to investigate and evaluate the capability of magnetite properties in reconstruction of Late Quaternary paleoclimate condition recorded in loess/paleosol deposits of Nowdeh section in Golestan province, northeast of Iran. Nowdeh loess/paleosol sequence is an indicator for periodic dry- cool (deposition of loess) and moist-warm (formation of paleosol) conditions. Formation of the studied loess and paleosols, have probably taken place in glacial and interglacial cycles with different climatic conditions, respectively. Nowdeh section magnetic properties completely is match with Neka sediment result that has obtained by mahdipour et al (2013). In 20 to 48 ka of past years show that in two sediment sections magnetic susceptibility was similar and wherever increased, hot and humid period integrated with paleosol layer formation. Also results of this research are accordance to with bear and storm (1995) in saturation of beryllium in Xifeng section and isotope δ18 of marine sediment.this is indicate that climate change event in two section are simultaneous.
Finally, should be say that magnetic properties because of depending of sensible mineral to climate change, is a very useful variable for climate change reconstruction.