جستجوی مقالات مرتبط با کلیدواژه « northwest of Iran » در نشریات گروه « جغرافیا »

The extended periods of drought, decrease in vegetation, and enlargement of the salt playa at Lake Urmia have resulted in the formation of local dust hotspots on the periphery of Lake Urmia in East Azarbaijan province. The objective of this study was to examine the spatial and temporal distribution of wind erosion in East Azarbaijan province using the DSI index. To achieve this, a set of weather data recorded over the past 30 years at specific codes in meteorological stations was compiled. Subsequently, the Mann-Kendall test was employed to assess the presence of a trend in the data series. Following this, the frequency of dust storms was calculated using the DSI index, and a spatial distribution map was generated in the GIS. The results of the Mann-Kendall test indicated that the slope of the trend for both local and extra-local dust storms in the province is on the rise. However, only the trend in extra-local dust storms is statistically significant at the 95% confidence level. The findings of the research revealed that the majority of the observed dust storms originate from outside the local area in East Azarbaijan province. Nevertheless, there has been a relative increase in the frequency of local dust storms in recent years, which can be attributed to the prolonged droughts resulting in reduced vegetation and the expansion of the playa of Lake Urmia. In this context, the highest frequency of dust storms has been observed at the Tabriz, Sahand, and Maragheh meteorological stations near Lake Urmia.

Soil erosion is one of the serious environmental threats that can affect the political, social and economic aspects of countries. One of the widely used experimental models for estimating the amount of soil erosion is the modified global soil erosion equation known as the RUSLE model. The purpose of this research is to analyze and zonate the amount of soil erosion and its relationship with hydrogeomorphic indicators and vegetation cover of Khiavchai Meshkinshahr watershed in Ardabil province. RUSLE model factors include rain erosion (R), soil erodibility (K), topography (LS), vegetation (C) and protection operations (P). respectively, by using rainfall data, soil texture layer, digital model of height and land use were prepared in the environment of geographic information system (GIS) and after overlapping the layers, the amount of annual soil erosion between 0 and 150.54 tons per hectare per year in The area level was estimated. In the next step, the hydrogeomorphic and vegetation indices that are effective in soil erosion include topographic moisture index (TWI), waterway capacity index (SPI), domain curvature index (Curvatore), section curvature index (Profil Curvatore), surface curvature index (Plan) Curvatore) and Normalized Vegetation Index (NDVI) were created in ArcMap environment and zoning maps were prepared. The results of this research also showed that the topography factor with a correlation coefficient of 0.92% had the greatest impact on the estimation of annual soil erosion by the RUSLE model. In another study, the relationship between hydrogeomorphic indices and vegetation cover with annual soil erosion rate was conducted, and the results showed that normal vegetation cover indices and cross-sectional curvature were the most and least effective with correlation coefficients of 0.57 and 0.05, respectively, compared to other indices.The results of this research confirm the possibility of combining the effective indicators of hydrogeomorphic and vegetation on erosion, as well as the possibility of using other effective indicators and the capabilities of RS and GIS to quantitatively estimate the amounts of soil erosion.

Horizontal visibility variations represent changes in air quality. This study is carried out to investigate trend in horizontal visibility in northwest of Iran during 1985-2020. In this regard hourly observational visibility data from 27 meteorological stations was obtained from IRIMO. After screening and selecting the reliable data series, extinction coefficient was calculated by Kashmeider's approach. Ridit analysis and Mann-Kendall statistical tests were used to detect trends in visibility and extinction coefficient. Also, 5 visibility categories were determined and the percentages of each category got calculated. Results showed that the annual regional-average of horizontal visibility (extinction coefficient) was calculated as ~11.4 (0.173) km in the studied period. Ridit output variations showed that visibility improvement / weakening periods was observed in different times according to the environmental conditions of each station. In most stations, the increasing trend of horizontal visibility often formed through the reduction of average visibility percentages; increase in good and very good visibilities and finally stability in bad and very bad visibilities. The highest (lowest) seasonal extinction coefficient obtained for winter (summer) with 0.179 (0.168) km. A perfect inverse correspondence was observed between ridit outputs and extinction coefficient in terms of fluctuation periods and trend direction in all stations. Spatial distribution of parameters showed that the highest (lowest) values of ridit (extinction coefficient) were obtained in several stations located in the north of the studied area. In 18 stations out of 27 studied stations, the increasing (decrease) trend of ridit (extinction coefficient) was detected, which both indicate the increasing trend of the horizontal visibility in the northwest of Iran.

Investigating of extreme temperature changes due to Global Warming, drought and the occurrence of cold and frost is very important. Therefore, in this research, the trend and projection of changes in temperature extremes in northwest Iran in the base period (1985-2014) and three periods of the near future (2021-2050), the medium future (2051-2080) and the far future (2081- 2100) was paid. For this purpose, two extreme temperature indices including frost days (FD) and ice days (ID) and the Maan-Kendall trend test were used to check the changes. In order to anticipate the changes in the future period, the best model after evaluating 7 General circulation models (GCMs) from the Coupled Model Intercomparison Project phase 6 (CMIP6) under three The Shared Socioeconomic Pathway including SSP1-2.6, SSP3-7.0 and SSP5- 8.5 was used. Spatial distribution of the trend of changes in extreme temperature in the base period showed that by moving from north to south and from west to east, the ice days increase. The core of the maximum ice days has also been studied almost in the south of the region. According to the results, the average frost days and ice days in the base period are 101 and 19 days per year, respectively, and the maximum and minimum frost days are 146 and 52 days, respectively, for Sarab and Parsabad stations, and the maximum and minimum frost days are also, with 42.32 and 1.23 days, it is related to Zarineh and Parsabad stations. Also, the trend of changes in frost days and ice days in the base period in most stations is a decrease, which is significant at the 0.05 level. The evaluation of different models with different error measurement indices showed that MRI-ESM2-0 and MPI-ESM1-2-L models have the best performance in simulating extreme temperature in the study area. The evaluation of the trend of changes in frozen days and ice days using the Mann-Kendall test in the basic period showed that the trend of changes in most stations is significant at the 1% level. The distribution of changes in the future period also showed that the trends are similar to the base period, so that the decreasing trends in the studied indicators will intensify in each period, especially based on the SSP5-8.5 scenario. Thus, at the end of the 21st century, frost days and ice days have decreased by 45 and 13 days, respectively, and the largest decrease is related to the cold stations of the region, which shows that with the increase in temperature, the index Frosts and icy days will decrease.

In this study, in order to investigate the general conditions of wind stress in the west and northwest of Iran, wind stress and velocity data at an altitude of 10 meters above the ground from the MERRA-2Model database of the TRMM sensor during the period 2018-1990 in coordinates 30 to 37.5 degrees north latitude and 45 to 52.5 degrees east longitude were obtained. GIS software was used to extract wind stress satellite data at Urmia, Tabriz, Zanjan, Hamadan, Sanandaj, Kermanshah, Khorramabad, Ardabil, Ilam and Ahvaz synoptic stations. To calculate wind stress, temperature, pressure and wind data were obtained from the Meteorological Organization. To evaluate satellite data and station data, the statistical criteria of correlation coefficient (CC), mean error (ME) Root Mean Square Error (RMSE) were used. The maximum (RMSE) is 0.060516 and the minimum is 0.000576. The correlation coefficient between observational and satellite data was calculated from 0.16 to 0.87. Wind stress trend analysis was calculated using non-parametric Mann-Kendall method. According to the results, the highest amount of wind stress in winter was observed in February in Ardabil station and the lowest in Kermanshah and Sanandaj stations. In spring, the highest wind stress was in Zanjan station in April and the lowest in Hamedan station in the same month. In summer, the highest amount of wind stress was observed in Ahvaz station in August and the lowest amount was observed in Sanandaj station in July. In autumn, the highest amount of stress was observed in Zanjan station in December and the lowest amount in Kermanshah station in the same month. Wind stress has a seasonal trend whose monthly changes are significant. There is a significant difference in the direction of wind stress flow due to the change of seasons.

Because of rapid urbanization, urban warming has become a serious problem along with global warming. In this study, the impacts of urbanization on minimum and maximum temperature variations were investigated in Iran's Northwestern urban areas. For this purpose, the meteorological (1987-2017) and urbanization data from the general census as well as the housing population (1365-1395) in conjunction with Pearson Correlation-coefficient and Mann-Kendall Test were used. Based on this test, a positive and significant trend was observed at minimum and maximum temperatures among urban stations. The analysis of decade's changes also shows the impact of urbanization on climate. The results of the relationship between minimum and maximum temperature with the number of population in urban areas are positive.The correlation between the minimum temperature in Khalkhal and Khoramdareh (small towns) was 0.8, in Maragheh and Khoy (average cities) 0.7 and Maximum temperature was 0.61 in Mahabad city and there was a significant relationship between the big cities of Ardebil and Zanjan At 0.7, 0.75, but in Urmia and Tabriz (a very large and metropolitan city), the population with a minimal temperature was relatively small, but maximum temperatures in both cities with a coefficient of 0.68, 0.61, indicating the significant role played by the urbanization on the urban climate. In small and medium-sized towns, significant changes were observed at minimal temperatures. At all stations, the demographic changes and the minimum and maximum temperature increases were observed. Major changes in the decades of 1375-1385 and 1385-1395, in which population growth is increasing.

The aim of this study was to predict changes in temperature, precipitation and evaluate the effects of climate change on the status of surface runoff in the Aras catchment. Climatic conditions were simulated in LARS-WG software environment under RCP8.5 scenario. Using the modified Trent White experimental model, the amount of potential evapotranspiration was estimated for both observation and simulation periods. To ensure the validity of the model, the mean error orthography (RMSE), and the determination coefficient and Nash-Sutcliffe efficiency coefficient (ENS) were used. Also, modeling of surface runoff changes in GIS software environment and SWAT plugin was performed. After forming hydrological units (HRU), the baseline model for surface runoff changes was selected to calibrate and validate the model. The results show that by modeling climatic data during the simulation period, the amount of temperature, evapotranspiration and transpiration will increase, and in contrast, the amount of precipitation has occurred and the flow rate will decrease superficially. The results of validation showed that the accuracy of the model in the selected stations was high and for the precipitation parameter due to its discontinuous nature, the correlation between the data is less than the temperature parameter and different. The results of hydrometric modeling of the basins showed that the Nash-Sutcliffe value is close to 1 and the correlation coefficient between the data is 0.99, which indicates the high efficiency of the model for simulating and estimating climate change and its effects on surface runoff.

Changes in erosion and sedimentation of the basin are one of the most important factors that affect different parts of human life and natural life. it is very necessary to receive these changes quantitatively, which mainly take place under temperature fluctuations and climate changes in different regions, in order to be more prepared to deal with its negative consequences. In this research, erosion and sedimentation changes in Hajiler watershed were investigated and predicted using GeoWEPP and SWAT models. Based on this, first, by using the data of the current situation of the Ahar synoptic station and using the SDSM model, the changes of the statistical period2020-2040 in three scenarios RCP2.6-RCP4.5-RCP8.5 were investigated, then simulation and prediction of erosion changes was carried out. and sedimentation was done under the influence of climate change by using popular models. The output of the SDSM model indicates an increase in temperature and a decrease in rainfall for the basin until 2040.And the analysis of the simulation results of the sedimentation rate of the models showed that in the studied basin, the GeoWEPP with the selection of the domain method has a suitable level in estimating the sedimentation rate compared to observational statistics. The final model was chosen to predict the amount of sediment in the mentioned period of the basin. Using the downscaled results of the atmospheric general circulation model, the sediment changes in the statistical period of 2020-2040 under the above mentioned three scenarios were estimated as -1.97, 4.45, and 2.98, respectively.

Frost is one of the natural events whose early and late occurrence can affect different aspects of human life. Therefore, this research has been carried out with the aim of predicting the atmospheric factors of this phenomenon with an environmental approach. For this purpose, the environmental data related to the daily minimum temperature of 2001-2017 for 9 synoptic stations located in Ardabil, Urmia and Tabriz provinces were obtained from the Meteorological Organization of the whole country and the days with temperature below 0 degrees Celsius that cover 40% of the studied area in were selected and using the ward hierarchical clustering method that was applied on the average sea level pressure maps related to ice days, the classification of the free days was done. In order to determine the representative of each class using scripting in the MATLAB environment, Lund's correlation was calculated between the maps of different days of each class of 2 to 5 groups with a coefficient of 0.5; And the days that had a correlation coefficient of 0.5 and the most similarity with the majority of days of that class were introduced as the representative of the group. After determining the representative day, atmospheric data was prepared from the Nova site and maps of sea level pressure, geopotential height, wind vector, temperature of 500 hPa and atmospheric thickness were drawn in Gurdes software. The results of the 4 patterns for ice days showed that the most effective systems on the northwest of Iran were high pressure systems in Siberia, low pressure systems near the Arctic and high pressure systems in Northern Europe, and the studied areas were located in the front of Faraz and the negative circulation of air brought stable conditions. In most of these patterns, the western winds that have moved in the polar ice channel have brought cold air from the northern latitudes into the atmosphere of the study areas and caused low air temperatures.

Geodiversity is recognized as an important aspect of nature conservation in itself and is a material consideration in planning decisions in developed countries. In recent decades, many researchers have turned their attention to the definition of geodiversity and its relationship to biodiversity, natural environment protection, ecosystem services, and geotourism. In the emerging science of geodiversity, geomorphodiversity evaluates the shape of the surface features of a place or region. Different geomorphological landforms may occur in a geographical environment that creates a variety of landforms called geomorphodiversity. The purpose of this study is to provide an indicator of geomorphodiversity as an attempt to replace landforms with DEM-derived morphometric parameters and finally to prepare geomorphodiversity maps of the study area; Geomorphodiversity Index (GmI). DEM As the only input data, this approach makes it possible to achieve topographic variables with different horizontal resolution and vertical accuracy and to test more than one topographic data for an area. Thus, the GmI method uses geomorphological data only for result validation and not as input parameters to avoid the limitations mentioned in geomorphological thematic mapping. The Mishu Mountains contain a variety of geomorphological phenomena.
this mountain are less popular today among different regions due to habitat destruction and species extinction. In the past, it was one of the most valuable regions in the country in the regional network and was considered an irreplaceable region. Due to the recent droughts and the lack of codified management plans and also due to the lack of attention in control and supervision of miners and also one of the main conflicts in the Mishu Mountains, we can point to the imbalance between livestock and rangeland. This area has witnessed many destructions over the past years. Mainly the geodiversity of the Misho Mountain region has been involved in its development, providing both opportunities and constraints that need to be managed and understood. With the advent of new approaches in geodiversity, geographical spaces such as Mount Misho can be used effectively.

The study area is located in northwestern Iran. Its highest peak is Ali Alamdar with a height of 3155 meters. In terms of morphological and geological characteristics, it is divided into two parts, Eastern Misho and Western Mishu. In this study, the GMI Quantitative Geomorphodiversity Index presented by Melelli et al. (2017) is used to evaluate. Analysis of indicators and using advanced software such as GIS software, Land Face software and SAGA increases the validity of research findings and results. This analysis includes five factors taken from Melelli et al. The sum of these five parameters shows the geomorphodiversity of the region (Equation 1).
1 : GmI = Geov + Ddv + Rgv + Spv + Lcv
GmI Index of geomorphodiversity:1. Geov is a classified raster map of geological diversity.
2. DdV is a categorized raster map factor for drainage density variability.
3. Rgv Classified raster map is a factor of roughness variation.
4. Spv is a categorized raster map.
5. LcV Classified Raster Map is a factor in Landform classification diversity.
It is necessary to mention that except for the geological map factor, in other factors, the maps went through two stages of processing. The first step is to extract the raw data. The second stage is normalization using natural ruptures. This algorithm reduces the variance within the groups and maximizes the variance between them. Normalization uses the ArcGIS 10.7 reclassification tool to create five classes for each factor. V1 is the lowest while V5 is the highest diversity class (V). This formula is classified into five categories (very low) to (very high). The focus of the research method of this model is the spatial analysis of indicators obtained from Dem 12.5 meters. To evaluate the variability of each parameter, a focal function (neighborhood statistics function) is applied as a result of the variability.

The results of this study showed that the range of geomorphodiversity of the study area decreases from the peaks to the plain and areas with low geomorphodiversity value are located in the plain. The lowest diversity (V1) consists of Quaternary deposits and the highest diversity (V4 and V5) is composed of carbonate formations, intrusive masses, and volcanic formations because they are the rarest type of rocks all over the earth's surface, located mainly in the eastern Mishu. The high values of diversity in the geological factor are related to the erosion-resistant geological substrate (such as volcanic compositions and intrusive masses) and the lowest values of diversity are related to the Quaternary deposits along valleys and plains. The geological factor, waterway network, and landform classification show the highest percentage of area in the upper classes of diversity compared to other parameters of the geomorphodiversity equation (Equation 1). In geological factor due to the large area of carbonate and alluvial assemblies. In the other two factors,

The results of the present study showed that the range of geomorphodiversity of the study area decreases from the peaks to the plain and areas with low geomorphodiversity value are located in the plain. Also, the lowest diversity (V1) consists of Quaternary deposits and the highest diversity (V4 and V5) consists of carbonate formations, intrusive masses and volcanic compounds because they are the rarest type of rocks all over the earth, which are mainly in The eastern parts of Misho are located. The high values of diversity in the geological factor are related to the erosion-resistant geological substrate and the lowest values of diversity are related to the Quaternary deposits along the valleys and plains.The geological factor, waterway network and landform classification show the highest percentage of area in the upper classes of diversity compared to other parameters of the geomorphodiversity equation (Equation 1).

Thunderstorms are local, medium-scale weather systems of 20 to 50 km that depend on the height of boiling clouds. They are associated with thunderstorms and indicate the high level of development of convective conditions in the humid air. The occurrence of thunderstorms is a part of the nature of Iran's climate, which causes a lot of human and financial losses in different regions every year, including the damage caused by thunderstorms in Khuzestan province during the study period 2001-2006. West and northwest of Iran are among the areas where the occurrence of severe thunderstorms with heavy rainfall has a high frequency. This study tries to identify the dynamic and atmospheric factors affecting thunderstorms in the west and northwest to provide appropriate information about the situation of this phenomenon for forecasting and prognosis, damage reduction, crisis management, and increasing the level of productivity of provided water resources.

To achieve the effect of atmospheric circulation on the pervasive occurrence of thunderstorms in western and northwestern Iran, the current weather codes that indicated the occurrence of thunderstorms in the region were selected, which include codes 29, 95, 96, 97, and 99, Data related to these codes were obtained from the Meteorological Organization. Also, to determine the prevailing atmospheric circulation conditions during thunderstorm days in the study area, sea level pressure (SLP), geopotential height (hPa), and air temperature data were extracted for 850 and 500 hPa levels on a daily scale. These data were Prepared from the network databases of the National Center for Environmental Prediction / Atmospheric Science (NCEP-NCAR) with a spatial resolution of 2.5 * 2.5 degrees and the European Medium-Term Forecast Center (ECMWF). With 1 * 1 degree spatial separation. The hierarchical method was used to determine the prevailing atmospheric circulation patterns on days with thunderstorms, which were clustered based on geopotential elevation data at the level of 500 hPa. After identifying the atmospheric patterns that caused the storm, the average maps of the patterns at the desired levels were drawn using Surfer software. The composite temperature map was drawn at two levels of 850 and 500 hPa at the time of the phenomenon and all maps were compared with the anomaly maps because this shows the difference between the prevailing values at the time of the phenomenon and the average values. Then, the Nova HySplit model was used to identify the air mass affecting the occurrence of this phenomenon. The input of this model is meteorological data of sea level pressure, geopotential altitude, and air temperature, which were obtained from two databases of the National Center for Atmospheric Research and data of the European Center for Medium-Range Forecasting.Discussion and

In the 29-year statistical period (1986-2014), a total of 27 days of widespread thunderstorms were identified. Examination of the monthly, seasonal and annual cycle of thunderstorms showed that the maximum occurrence of thunderstorms is in May and spring, and also the years 2005 and 2010 with 4 events had the highest frequency of thunderstorms. In terms of location, the provinces located in the west of the study area, including the provinces of West Azerbaijan and Kurdistan, experienced the most thunderstorms with a total of 49 cases, and Lorestan province, which is located in the south of this region, had the least thunderstorms with 8 cases. Maps of average sea level pressure during the days of thunderstorms showed that the occurrence of thunderstorms in the western and northwestern regions of Iran is associated with a low-pressure system throughout the region with values between 1007 and 1011 hPa. That is, the occurrence of thunderstorms in the region is possible under the negative anomalies of sea level pressure. In addition, average temperature maps at the 850 hp level during thunderstorm events show that the temperature has decreased to the northwest, and the map of temperature anomalies at the 850 hPa level shows that throughout the study area, the temperature decreases relative to Have experienced the average. Similar conditions were prevalent in the Middle Troposphere (500 hPa). The results of hierarchical clustering showed that the occurrence of thunderstorms is affected by three atmospheric patterns of blocking systems, cut-off-low, and shortwave, among which, cut-of-low with 14 cases, and the main pattern in the occurrence of thunderstorms in western and northwestern Iran. Back trajectory paths selected for thunderstorm days each pattern for 48-hour infiltration of air masses showed that the thunderstorm originated from different systems. The Mediterranean system is the main source of air mass affecting the western and northwestern regions during a thunderstorm, followed by the Sudanese system and the integration system in second and third place.

Thunderstorms are atmospheric phenomena that sometimes cause human and financial losses to humans. The results of this study showed that despite the local and regional nature of thunderstorms and their rarity, it is possible to study the atmospheric circulation conditions and the temperature of the lower and middle troposphere during the days of this phenomenon. The results of the statistical study showed that spring and April and May had the highest frequency of seasonal and monthly occurrence in the study area. Also, in the synoptic study, it was found that the occurrence of thunderstorms in the west and northwest of Iran, not only with sea surface pressure anomalies and 500 hPa but also with negative temperature anomalies in both levels. In the occurrence of thunderstorm atmospheric phenomena in the western and northwestern regions of Iran, atmospheric circulation patterns including blocking systems, cut-off-low, and shortwaves play a role in the middle level of the atmosphere. At the same time, Mediterranean, Sudanese and fusion pressures are forming on the Earth's surface. This adaptation of low surface pressure to high divergence enhances surface convergence and high divergence. This leads to increased vertical transmission and air ascent and instability, eventually leading to hurricanes.

Increase temperatures and decrease rainfall can lead to the drying up of wetlands, lakes and rivers, the formation of aerosol centers, which directly and indirectly change the structure of society and the ecological conditions of lakes around the world; As a result, it leads to changes in the distribution of animal and plant species, ecological diversity, changes in the plant phonological cycle, factors, growth and organisms, and ecological metabolism. These changes also severely affect vegetation in arid and semi-arid climates. Finally, changes in surface conditions caused by human activities may also affect various hydrological processes. Thus, the twenty-first century is facing many environmental problems, one of the most important of which is the variability of environmental and climatic parameters. Lake Urmia is one of the most important water areas in Iran and one of the largest salt lakes on earth. The lake plays an important role in the climatic, environmental and economic situation and a national and international natural heritage in the northwest of Iran.variability of environmental and climatic parameters is one of the most important challenges for human specific in arid and semiarid environment such as Iran. The purpose of this study is to investigate the changes in environmental and climatic parameters in the catchment of ​​Lake Urmia in the last two decades. The purpose of the above was to answer the question of how the changes in environmental and climatic parameters in the basin and the relationship between these changes in the current conditions of the basin ​​Lake Urmia.

Research data includes six categories: 1) TOPEX and Jason 1 to 3 satellites data to study of changes in altitude level of Lake Urmia, 2) Landsat 7 satellite images of 2000 and Landsat 8 of 2019 for extract lake water area changes and 3) Precipitation data from GPM[1] satellite product (IMERG[2]) 4) Vegetation index products of Modis sensor (Mod13A3 v006) to identify vegetation changes, 5) LST Night and daytime of Modis sensor (MOD11A2 v006) and finally 6) gridded reanalysis data (ERA5) to detect of trend air temperature, were used.First, the changes in the water level of the lake were extracted using the data of TOPEX and Jason 1 to 3 satellites, and in the next step, the trend of changes in its was calculated. Landsat 7 images of 2000 and Landsat 8 of 2019 using the Normalized Differential Water Index (MNDWI) were used to achieve changes in the lake's water area. Then LST (day and night) of MOD11A2 v006 products were converted into monthly data using MATLAB software. Finally, the trend changes in precipitation data, 2 m air temperature, LST (day and night) and vegetation (NDVI) were investigated using Mann-Kendall test (Mann, 1945; Kendall, 1975).

The highest changes in water level in the last two decades are from 2000 to 2010. The decrease in level is evident from the year 2000, from that year to 2010, the water level of the lake decreased by 4 meters and the highest slope of the decrease in it observed in the same period. The change in the area obtained from the MNDWI index is 2740 km2, which has caused the lake to decrease from 5143km2 to 2400km2 in 2019. The decrease of the lake level in its southern and eastern part has been more than the western and northern part. The trend of monthly precipitation changes shows two different temporal and spatial patterns. It is important to note that there is a monthly decreasing trend every three months in January, August and December in the central and southern parts of the basin. In contrast, in May and July, a marked increasing trend is observed in the eastern and southern half of the basin. Spatial displacement of incremental changes in air temperature indicates a clockwise movement from north to east and then south and west from May to August. The trend of day of the LST changes indicates a spatial contrast between the Lake and around it. This behavioral contradiction is more pronounced with the increase of the lake surface temperature and the decreasing trend in the southern and western regions corresponding to the agricultural areas in August, September and October. Changes in LST at the basin level from November to February, in which scattered and small incremental zones are observed, can also be due to reduced vegetation in the cold period of the year. In contrast to the daytime LST, at night what is most noticeable is large zones of temperature rise, especially from June to September throughout the basin. NDVI in the period 2019-2000 has had an increasing trend in all months, but with varying intensity and extent. Three temporal patterns are understandable in the process of basin vegetation change. Increased from January to May, then start decreasing trend from June to August and again increasing trend that continued until December. The lowest increasing trend is observed during the summer months from June to August.

Lake Urmia has experienced a continuous decrease in water level since 2000, so that during the last twenty years, the water level has decreased by more than seven meters. The results of the present study also showed that there was a significant increasing trend in the NDVI index at the basin, especially with the southern of the basin. However, at the basin level, the trend of rainfall changes in this period (2000-2000) is not generally significant and also due to the occurrence of numerous droughts in the basin, which has also had an increasing trend and the expansion of irrigated lands, Demand for groundwater has increased. Therefore, this issue indicates various reasons other than changes in climatic parameters, especially precipitation in reducing the water level of Lake Urmia. In addition to the above, daytime and nighttime LST have increased during the warm period of the year as well as the air temperature on the lake. This increase increment evaporation, especially during periods when recharge is reduced due to seasonal dry. Although precipitation has increased at the end of spring, but with increasing temperature, precipitation increases with increasing evapotranspiration and water requirement of plants is neutralized. Therefore, the simultaneous change of environmental and atmospheric parameters can be considered as aggravating the conditions of hazardous events in this basin.

Based on the evaluation done in this study, it can be concluded that the basin of ​​Lake Urmia is vulnerable. Therefore, the three main and significant effects of environmental variability in these areas are increasing ground temperature, vegetation and reducing water resources. The result of these conditions on the one hand and the increase of water needs of plants on the other hand will increase the stress on water resources, especially groundwater. Decreasing the lake surface and increasing consumption and reducing water resources can lead to the spread of bare surfaces and the occurrence of dust.

Heat waves are one of the most important weather disasters, and their destructive environmental effects require knowledge and forecast. The purpose of this study is to forecast the future conditions of heat waves in Ardabil, Tabriz and Urmia during the years 2020-2050 using SDSM downscaler and Baldy index. For this purpose, the maximum daily temperature data of selected cities from 1961 to 2005 after preparation were entered into SDSM software and analyzed with CanESM2 model with 2٫6, 8٫5and RCP 4٫8 scenarios and with the output of the model, the maximum temperature trend of the three stations during the next 30 years was investigated and their heat waves were Forecasted using the Baldy index. According to the results of the error measurement of the model, the simulations performed had acceptable accuracy. Due to the fact that each of the cities showed the least error in one scenario, so the heat wave prediction of each station was done using the least error scenario. Based on the results the average maximum temperature will decrease from late winter to late spring compared to the base period and will increase slightly in mid-summer. In general, we will see a decrease in the average maximum temperature in Ardabil and an increasing trend of the mentioned parameter in Tabriz and Urmia cities during the years 2020-2050. Also, the study of the predicted heat waves in the next thirty years showed that one-day waves in Ardabil and Urmia will be a slight increase and in Tabriz will be almost without trend. Two-day heat waves will decrease in Tabriz and Urmia and will increase in Ardabil. The trend of three-day heat waves in Ardabil and Urmia will be decreasing and increasing in Tabrizthe highest continuity of heat waves was four days, which was forecast in Urmia. The highest frequency of two- and three-day heat waves in all three cities will be in the cold seasons of the year.

The Dust storm is one of the most important climatic phenomena of the present age in arid and semi-arid regions of the world. Due to its characteristics, this phenomenon can have various environmental and climatic effects in different atmospheric systems, oceans and continents. Dust storms play a very important role in the earth's atmospheric cycle, so that dust particles are one of the factors of atmospheric warming, as well as reducing air quality and affecting human health. Dust particles have direct effects on absorbing or scattering radiation waves, which results in a significant decrease in visibility. The west and the northwest of Iran are facing the dust storm phenomenon and its problems periodically.

In this study, the frequency of dust phenomenon and its occurrence causes have been analyzed in the northwest and west of Iran, including Ardabil, East Azerbaijan, West Azerbaijan, Kurdistan, Zanjan, Hamedan, Kermanshah and Ilam provinces. At First, the occurrence of dust in the study area was investigated. To identify the source of the dust storm, dust storms of 15-20 July 2000 & 17-22 June 2012 (as case study) were described using MODIS satellite images. Modis sensor images were used to detect and monitor the dust storms. The reason for choosing these days for analysis was the high intensity and concentration of dust in those days in most of the stations. For the synoptic analysis of dust storms, re-analyzed data of sea level pressure, geopotential height, vector wind, vorticity, wind direction and omega at 500mb level were used. These data were obtained from National Oceanic and Atmospheric Administration (NOAA) which was prepared by the National Center for Environmental Prediction (NECP). The maps were drawn and synoptically analyzed using Grads software.

The results showed that the highest frequency of dust storm codes occurred in the studied stations was related to code 6, which indicated the presence of dust in the sky. In terms of monthly distribution, June, July, April, and May has the dustiest days in the studied area. The occurrence of dust had an increasing trend from the early hours of the night to noon. The frequency of dusty days in different years indicated an increasing trend from 2000 to 2018. The frequency of dusty days was higher in 2008 and 2012 compared with other years. The results also showed that the main sources of dust in the west and northwest of Iran are the desert areas of Iraq, the Arabian Peninsula, and the African Sahara. At sea level, the most important cause of dust storms in the west and northwest of Iran was the existence of a low-pressure center in Saudi Arabia and Iraq. In other words, dust storms in the west of Iran were transitional and have originated from the western neighbors of Iran (Iraq, east of Syria, and northern Saudi Arabia), where in the most severe event, the dust has spread to central Iran. At 500 mb level, the most important factor in creating dust storms in the west and northwest of Iran was the rule of the Azores sub-tropical high-pressure tongue and the location of the region below it. Due to the high pressure of the Azores on Iran, migratory cyclones and troughs due to lack of penetration into the region, had little effect on the formation of instability and dust storms, which the main reason for this phenomenon should be found in surface pressure systems. The extreme warming of the earth's surface had caused the instability of the atmosphere of Iran in summer up to a height of 2-3 km above the earth's surface. The low-pressure thermal cell was stretched from Pakistan to the south of Iran, and from there to the deserts of Saudi Arabia, Iraq and Syria on all days under study. The Iran-Pakistan low-pressure system, which appeared as a focal point in the southeast of Iran, was a low-pressure, high-suction system that created dust storms in the region.

The results of dust storms monitoring in northwest and west of Iran using satellite images showed that remote sensing techniques due to extensive and continuous coverage in space, monitoring natural disasters and also monitoring dust storms, intensity and dynamic tracking, can play a major role in dust monitoring. The results also showed that the Aqua and Terra satellites have a high capability in detecting and tracking dust storms due to their high temporal, spatial, and spectral resolution.

Identification of landforms and the way of their distribution is one of the basic needs in applied geomorphology and other environmental sciences and landform maps show the shapes of the earth's surface. This project aims to identify the landforms of the Qaranqu catchment area using object-oriented classification methods including nearest neighbor algorithm and thresholding. Landsat satellite imagery for 1990 (TM) and 2020 (OLI) was used for this purpose. First, to apply the classification, atmospheric and radiometric corrections were applied to the images, then to better identify and extract the phenomena, principal component analysis (PCA), and MNF algorithms were used to classify satellite images using classification methods. Object-oriented, which included the nearest neighbor method and thresholding was used. For the accuracy of the maps produced using the two methods of Kappa index and the overall accuracy of the use, the results revealed that the nearest neighbor method is more accurate than the thresholding method. The classification results showed that the highest rate of decreasing changes during 1990-2020 is related to dense rangeland because it has decreased by 12.49 percent and the highest rate of incremental changes is related to irrigate agriculture which is 10.83 percent. The most important reason for this increase is the construction of Sahand Dam over time. In the absence of well-organized planning and the adoption of appropriate policies, the destruction of rangeland will continue and turning it into arable land, which leads to irreparable environmental and economic losses in the region.

The Tamtaman area is located between 37◦38/00//-37◦44/00//north and 44◦40/30//-44◦59/30// east in northwestern Iran, approximately 15 km northwest of Urmia. This study aims to identify and zoning the potential development of karst in the area of Tamtaman cave in west Azerbaijan province using the AHP method. In this study, the information layers of lithology, tectonics, topography, slope, aspect, hydrology, land use, and climate have been considered as factor maps. The above layers have been called to extract the karst potential model in the GIS environment. Different information layers were classified as Criterion maps by applying expert judgment and assigning the weight of each layer in Expert Choice software and field visits. Finally, according to the obtained weight, the karst development zoning map in the Tamtaman area was obtained. The results obtained in this region exhibited a total area, of 6.68% within the very poorly developed class, 15.64% in the less developed class, 42.50% in the normal developed class, and 35.18% in the developed floor are located. The results show that in the Tamtaman region, the lithological and tectonic factors have the highest weight and are the most important factors controlling potential karst growth, while the land-use factor has the least impact on karst formation.

The transportation sector in Iran produces about a quarter of the total carbon dioxide in the country, which is a significant share. Transportation in the cities of Jolfa and Jananlo, located in the Aras Free Zone, as medium size cities, plays a significant role in the production of carbon dioxide. This study aimed to identify the variables influencing the carbon reduction of Jolfa and Jananlo cities.

This study was carried out using the descriptive-analytical method in 2022 using structural analysis using the MICMAC method. Effective indicators on carbon reduction were prepared by studying the research background and interviewing the expert panel. 30 experts in sustainable urban development were selected using purposeful sampling and interviewed. The indicators were extracted using text coding and were provided to the expert panel to measure priority. Data reliability was confirmed in MICMAC software. Data were analyzed using extracting influential variables and their relationship using MICMAC software.

The key variables included electronic transportation, smart transportation, and the use of renewable energy. Intermediate variables included fuel cost, transportation infrastructure, management decisions, the mix of uses, urban compaction, transportation management, substitution, use of renewable energy, appropriate accessibility, public transportation culture, non-motorized transportation, and travel time reduction.

Macro-management policies, improvement of urban infrastructure in various fields, including urban transportation, application of electronic transportation technologies, and improvement of inner and outer city road networks, respectively, have the highest effectiveness in creating low carbon city in Jolfa and Jananlo cities.

Identifying pressure patterns during thunderstorms and Widespread precipitation is important. One of the methods of studying the climate of a region is the study of atmospheric phenomena in relation to the pressure pattern prevailing in that region. Classification of atmospheric patterns is a useful tool for managing a huge and unlimited continuity of atmospheric patterns. Classifications by identifying a number of representative patterns called moment patterns, simplify the physical reality of the atmosphere. One of the purposes of synoptic classifications is to help describe the effects of atmospheric circulation on the surface climate, which is the main task of synoptic climatology. In this paper, atmospheric pressure patterns are studied using factor analysis method. Then, by drawing synoptic maps of each pattern, the characteristics of the desired pattern were examined.

The present study investigates the recognition of prevailing atmospheric patterns during precipitation and Widespread thunderstorms in northwestern Iran. To conduct this research, first rainfall and thunderstorm data were received daily from 18 synoptic stations with a common statistical period of 20 years (1993-1992) from the Meteorological Organization. Then, to determine the selected days, the days that were reported in 5 stations and more rain and thunderstorms were selected. Then 108 days were selected by principal component analysis (PCA). Six components out of the total components that explain more than 73% of the total variance were selected for the next analysis. Then, using Euclidean distance and ward’s method, a cluster analysis on the matrix, Factor scores were performed. Then the clustering tree was drawn and the observations were divided into 5 clusters. To analyze the atmosphere in the obtained patterns, re-analyzed data were prepared with a resolution of 2.5 * 2.5 degrees from the National Center for Environmental Prediction and Atmospheric Research, USA (NCEP / NCAR). Using these data, synoptic maps in each pattern were drawn and analyzed.

Investigations showed no compression patterns with Widespread thunderstorms in March. Because this month has winter features, extensive local climbs are less common this month. Therefore, Widespread thunderstorms in this month and other cold months of the year are considered a random phenomenon. It can also be said that hot and cold fronts can not create Widespread thunderstorms without local thermal rise. In other words, in summer due to lack of sufficient humidity and in cold seasons due to lack of surface heating we do not see the occurrence of Widespread thunderstorms.At the time of the occurrence of rains and Widespread thunderstorms in northwestern Iran, It is often located at the 500 hpa level of Trough in central Iraq to the eastern Mediterranean. Differences in the location, depth and extent of this trough have caused the patterns to differ from each other, resulting in differences in the occurrence of atmospheric events in the study area. In this study, pattern three had the highest number of events compared to the 5 extracted patterns. Patterns that are limited to April and the cold days of May are more widespread. Also, patterns that occur limited to June and hot days in May are less widespread. In the Deep trough and minor Trough pattern, the precipitation is mostly influenced by local moisture sources and moisture sources close to the study area (such as the Caspian Sea). Also, in these patterns, the sources of moisture in the lower levels of the atmosphere play a greater role in the occurrence of precipitation. At the time of the Deep Trough and Minor Trough patterns, it is the combination of western systems with local ascent that creates Widespread precipitation. These patterns are limited to May and June. During these months, the ground receives the energy it needs to climb locally. The integration of the local ascent with the western system strengthens it and creates Widespread thunderstorms and rainstorms.In patterns closed low, blocking , the Eastern Mediterranean Trough, the Red Sea and the Mediterranean Sea are the most important sources of moisture, respectively. In the mentioned patterns, moisture sources at the levels of 700 and 500 hPa play the most important role in creating Widespread precipitation. During the occurrence of closed low, blocking and trough patterns in the eastern Mediterranean, the surface temperature decreases and the role of western systems becomes more prominent. From pattern one to pattern five, the surface temperature decreases, respectively. In the Deep Trough and Minor Trough patterns, the study area experiences a temperature of 295 degrees Kelvin. In the closed low pattern, a temperature of 287 degrees Kelvin is observed in the northern half of the study area; But in the blocking pattern, the temperature of 287 is transferred to the more southern parts. In the Trough pattern of the eastern Mediterranean, the temperature of 283 degrees Kelvin is seen in the northern parts of the study area. In other words, from model one to five in the study area, the surface temperature decreases and from one model to another, the surface temperature decreases. As a result, with decreasing temperature, the effect of local ascent compared to the first and second patterns has decreased and it can be said that a significant part of thunderstorms in addition to local ascent, is affected by the front systems passing through northwestern Iran; But fronts alone cannot create widespread thunderstorms without integrating with local thermal rise.

The result was that the closed low pattern had the highest and the Deep trough pattern had the lowest repetition. Deep trough and minor trough patterns have less geographical extent than other patterns. When occur patterns closed low, blocking and trough eastern Mediterranean, the study area experiences a lower surface temperature. Also, precipitation is more extensive in these patterns and the maximum vertical air flow is observed at the level of 700 and 500 hPa. Widespread thunderstorms are more likely to occur in the spring. In winter, due to the lack of surface heating, we do not see Widespread storms. In hot seasons, too, Widespread thunderstorms cannot occur due to lack of moisture. In other words, Widespread thunderstorms in northwestern Iran occur when a local ascent is combined with a dynamic ascent resulting from the passage of a low-pressure system through the study area.

Precipitation is the most important hydrological variable that connects the link between atmosphere and surface processes. Three-quarters of the atmosphere heat is the result of releasing the latent heat of evaporation. Therefore, climatic zoning of autumn precipitation is necessary for achieving comprehensive development in different spatial-temporal dimensions. For this purpose, the daily data of autumn season at 18 synoptic stations of the study area have been analyzed with a joint statistical period 32 (1989 - 2018). In this study, Kolmogorov-Smirnov test was used to find out the normality of the data and Mann-Kendall test was used for the process of their changes. Then by applying factor analysis based on principal component analysis and with orthogonal rotation of Varimax it was found that there are two effective precipitation factors in the climate of the region which in total account for more than 68.16% of the variance of the region's autumn precipitation climate. By performing hierarchical cluster analysis and by integrating the matrix of factor scores, two main and sub-regions were identified. These areas are: Areas of high precipitation and moderate precipitation. It can be said that in the high precipitation areas of the territory are located on the rainy of the Zagros, Sahand and Arasbaran mountain belts, stretching as a narrow strip from the north to the south parts of the region.