batool zeynali

In order to monitor dust storms in Khuzestan province, statistical data were first obtained from the General Meteorological Department, and the days with dust reports with minimum horizontal visibility of less than 10 km were selected as free days. The results of zoning and the average dust concentration map by calling MODIS satellite data in Google Earth Engine revealed that the density of this phenomenon was in the western, southwestern and central regions of the province. For the synoptic investigation of this phenomenon, the most intense dust storms were selected for 9 synoptic stations and these days were analyzed by drawing synoptic maps; And the movement path and origin of this phenomenon and its density were displayed through the HYSPLIT model. The results indicated that in the majority of dust storms in the south of Iran, thermal low-pressure systems were active, and in Europe, high-pressure systems prevailed, and the slope of the pressure gradient between these two systems led to the direction of westerly currents with high wind speed at high altitudes towards the study area. And the prevailing rotating situation in the region has added to the instability of the air. The western winds have also passed through the deserts of North Africa, the north of the Arabian Peninsula, Iraq and Syria, parallel to the Nave canal in the west of Iran, and have led the hot and dry air of these regions to the atmosphere of the region.

Text Landslides are one of the types of large-scale processes that cause many human and financial losses in many parts of Iran and the world every year. The increase in population and the expansion of human settlements in mountainous areas, the difficulty of predicting the occurrence of landslides and the numerous factors influencing the occurrence of this phenomenon, reveal the necessity of landslide risk zoning. Identifying the effective factors in the occurrence of this phenomenon and its risk zoning is one of the basic and practical methods to achieve its forecasting, control and monitoring solutions. By using field studies, geological and topographical maps, and by reviewing the researches and studies done in this field, as well as examining the existing conditions in the studied area, 9 factors of elevation, slope, slope direction, lithology, distance from the fault. , the distance from the river, the distance from the communication roads, land use and rainfall were investigated as factors affecting the occurrence of landslides. Therefore, the purpose of this research is to investigate and analyze the most important factors involved in creating the risk of landslides in Garami city and to identify the prone areas that will probably be involved in landslides in the near future. In this research, the zoning of prone areas was done with the Aras multi-criteria algorithm in the Edrisi software environment, and according to the results of landslide risk zoning; The criteria of land use, slope, and lithology are the most important factors involved in creating the risk of landslides in the study area with weight coefficients of 0.187, 0.152, 0.152, and 0.142, respectively, and are 361.99 and 450.32, respectively. A square kilometer of the area has a very high probability of danger. Finally, it can be said that the most important factor involved in increasing the amount and potential of landslides in Germi city is the change of land use and the increase of agricultural land and livestock pastures.

The Land surface temperature (LST) is an important Quantity that affects the cycle of energy and moisture between the earth's surface and the atmosphere. (xin et al, 2023). In fact, land surface temperature is an important index related to climatic, meteorological, hydrological, and environmental phenomena and processes and is widely used in climate change investigation, hydrological process modeling, drought monitoring, and fire risk assessment (Yang et al, 2020). One of the methods of measuring temperature is meteorological stations, which are less used due to problems such as lack of proper spatial distribution and difficult access to data, especially on a large scale. (Heidari and Akhundzadeh, 2019). Thermal infrared remote sensing is an efficient approach in this field and has attracted the attention of researchers. (Yi et al, 2023). Considering that Ardabil city, located in the northwest of the country and on the foothills of Sablan mountain, is considered one of the big cities of Iran and is affected by climate changes, including the increase in temperature (Malkian et al, 2018), it is necessary to investigate climatic factors, including temperature, in this region. The purpose of this study is to investigate the temperature in different land uses by LANDSAT9 satellites by applying the split window (SW) algorithm and Sentinel3 using the SLSTR sensor and its LST tool. Checking the temperature using two different images, by applying different algorithms and checking these temperatures in different uses in the study area can be considered as an innovation of the present study.

Ardabil city with an area of 2165 square kilometers is one of the big cities of Iran and the capital of Ardabil province. In this study, Landsat 9 and Sentinel 3 images from 20/7/2022 have been used to extract the land surface temperature (LST). For this purpose, the split window algorithm was implemented on the Landsat 9 image, and the LST algorithm of the SLSTR sensor was implemented on Sentinel 3. To check the results related to the temperature, the data from the meteorological station has been used. Also, the land use map of the region has been extracted using the Landsat 9 image on 5 residential and industrial floors, vegetation, agricultural land, water areas, and soil cover using the object-oriented technique to check the temperature in different uses.

The land use map of the studied area was extracted with overall accuracy and a kappa coefficient of 98 and 97%, respectively. Investigations showed that in Landsat image 9 agricultural land use with an average temperature of 35 degrees Celsius is the minimum temperature and soil cover use with an average temperature of 42 degrees Celsius is the maximum temperature. In the image of Sentinel 3, in the same way, agricultural land use and soil cover have minimum and maximum temperatures of 37 and 42 degrees Celsius, respectively. The minimum and maximum temperatures obtained by both sensors show close values with a difference of one degree in the maximum and 3 degrees in the minimum temperature. The temperature of the station related to Landsat 9 and Sentinel 3 is estimated to be 35 and 36 degrees, respectively, which are close to each other and show a difference of one degree. However, the temperatures obtained from the Landsat 9 sensor have a smaller difference from the temperature of the meteorological station, and this Temperature compliance is especially noticeable in the minimum temperature with a difference of 10 degrees Celsius. It should be mentioned that the spatial resolution of 30 meters of Landsat 9 and 1 km of Sentinel 3, also the location of the weather station should be considered.

The minimum and maximum temperature has been estimated using the split window algorithm on the Landsat 9 image, 22 and 51 degrees Celsius, and using the SLSTR sensor on the Sentinel 3 image, 25 and 52 degrees Celsius. The split window algorithm has high accuracy and capability and is considered one of the most effective and widely used algorithms in extracting land surface temperature in many studies (Grace et al, 2020), (Eon et al, 2023), (Zhang et al, 2019). SLSTR is also a high-precision infrared radiometer and enables more accurate LST measurements using common algorithms as well as the development of new algorithms (Kuppo et al, 2016), (Sobrino et al, 2015). The obtained temperatures show that reasonable and close values were obtained by both sensors and are by different uses. The results of this research show that the temperature calculated using the satellite images of both sensors is consistent with the data obtained from the meteorological station, however, the temperatures obtained from Landsat 9 show a greater agreement with these obtained data, especially in the minimum temperature. Regarding the maximum temperature and the station temperature, the difference between the Landsat 9 temperature and the station temperature is one degree less than the Sentinel 3 temperature. LST for each pixel in remote sensing is equivalent to the average temperature of different earth surface covers (Alavi Panah, 2017), Therefore, it seems that the high spatial and radiometric resolution of the Landsat 9 sensor has not been ineffective in the high accuracy of the obtained values.

Water erosion is the result of interactions between various environmental factors such as topography, soil characteristics, climate characteristics, runoff and land use and management. Sediment production is highly dependent on runoff, so doubling the speed of runoff increases its leaching capacity and transportability up to five and six times. Knowing the effective factors in sediment production plays an important role in determining the amount of sedimentation of a watershed and understanding the phenomenon of erosion and its consequences, and it can be used in prioritizing the sub-basins of a watershed. The purpose of this research is to investigate the relationship between morphological characteristics and the amount of sediment production in the catchment area of the Gharasu River in Ardabil using principal component analysis and multivariate regression, in this regard, using 16 independent variables and 1 dependent variable in 13 sub-basins of the Gharasu River.

As one of the sub-basins of the Aras catchment basin, Gharasu catchment is located in the geographical coordinates of 47°31' to 48°47' east longitude and 37°47' to 38°52' north latitude. In this study, 1:100,000 scale geological maps, 1:25,000 scale topographic maps, and discharge and suspended sediment statistics and information of 13 hydrometric stations of Gharasu River sub-basin were used in the 50-year period from 1350 to 1399. In order to check the correlation between independent and dependent variables and to test the normality and normal distribution of data, Shapiro-Wilk and Kolmogorov-Smirnov tests were used in SPSS software. Also, in this research, the OLI Landsat 8 satellite images were used to extract the vegetation cover index (NDVI). For this purpose, step-by-step linear regression is used to determine the most effective variables and to determine the most appropriate statistical relationship between suspended sedimentation and the variables used, and principal component analysis is used to determine the most effective factors of suspended sediment production in the watershed.

In this study, the average annual suspended sediment of the basin was considered as dependent variable and other parameters as independent variables, and Pearson correlation method was used to check the correlation between independent variables and dependent variable. The variables of time of concentration, length of the main waterway, area, Slenderness ratio, perimeter and slope have a higher correlation with the amount of sediment production in the basin than other variables. Based on the models obtained from sediment correlation analysis, the amount of sediment produced with the concentration time variable had a positive correlation and was significant at the 5% level. The results of the analysis of the principal components show that the four factors of area, length of the main waterway, concentration time and slenderness ratio of the basin have an eigenvalue greater than 1, and the number of extracted factors is 4 factors. The first factor (area) has been able to explain 37.230 percent of the variance of all research variables. This value is 24.735, 16.950 and 9.849 percent for the second factor (length of the main waterway), the third factor (concentration time) and the fourth factor (slenderness ratio) respectively.

The present research was conducted with the aim of investigating the relationship between geomorphic parameters, vegetation and erodible formations of selected sub-basins of Gharasu basin with the average annual sediment. For this purpose, the statistics and information of 17 variables (16 independent variables and 1 dependent variable) were obtained for 13 sub-basins of Gharasu basin from the regional water of Ardabil province. The relationship between geomorphic parameters and annual precipitation was determined using stepwise multivariate regression method. The research results indicate that geomorphic parameters have a high correlation with the amount of annual sediment production and can be used in sediment prediction. Meanwhile, the variables of concentration time, length of the main waterway, area, slenderness ratio, perimeter and slope have a higher correlation with the amount of sediment production in the basins than other variables. Among these variables, the basin concentration time variable was used in the final step-by-step regression model and was selected as the sediment predictor variable. This variable alone can predict 98% of annual precipitation. In order to ensure the appropriateness of the data, the KMO coefficient was used to analyze the main components. The value of KMO = 0.78, as a result, the data will be suitable for factor analysis. The results showed that the four factors of area, main waterway length, concentration time and elongation factor could explain 88.754% of the variance of all research variables.

The intensification of air pollution under the influence of various factors, including population growth and urbanization, is the concern of activists in this field. It is necessary to check the pollutants carefully using precise techniques. In this study, elements of NO2, CO, and Particulate Matter effective in air pollution were analyzed spatially and temporally (monthly, annually) using the TROPOMI instrument of Sentinel 5 sensor in East Azerbaijan province. Investigations showed that in the cold season, more areas of the region experience the presence of CO and NO2 pollutants, which are mainly caused by fossil fuels, industries, and residential areas. But their concentration is high in the hot and cold seasons respectively. Evidence shows that in densely populated areas, we are facing high concentrations and the presence of NO2. A high concentration of suspended particles is also seen in the summer season. According to the findings, all three elements have a high distribution in the cold season; on the other hand, the concentration and spatial distribution of pollutants is influenced by factors such as weather, topographical conditions, and industrial centers.

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

Land use change has a direct impact on hydrological components and water resources and plays an important role in aggravating possible risks such as drought and floods. Therefore, it is necessary to investigate the effects of land use on water components such as runoff. Thus, in this study, the runoff condition of the Kiwi Chai Basin, one of the most important basins in Ardabil province, from an environmental point of view in terms of land use change is investigated using the SWAT model.

ArcGIS 10.1, Envi 5.1, and Ecognition software are used for data processing, classification, and analysis. Also, the method based on radiative transfer models, such as FLAASH, is used as the best method for atmospheric correction. Multiresolution algorithm is applied for segmentation and the nearest neighbor algorithm is used for classification. Then, educational samples are collected from the area using field visits and Google Earth satellite images and used to evaluate the accuracy and precision of the classification. At the end, the Thematic change dynamic detection method is applied in Envi5 to identify the changes that have happened over the years. The SWAT hydrological model is additionally used to investigate the effect of land use changes on the basin's runoff. After extracting the effective parameters in the basin’s outlet, the model is calibrated and validated with SWAT-CUP software and SUFI-2 algorithm. Nash-Sutcliffe indices and coefficient of determination are used to evaluate the results of this stage.

In this research, after applying object-oriented land classification, land use map in seven classes of Rainfed agriculture, irrigated agriculture, garden, forest, residential, pasture and water are provided. In the land use map of the basin, pasture cover is the dominant land use class; however, a significant decrease from 1224.18 square kilometers to 1046.59 square kilometers has been observed between 1987 and 2019. The values obtained for R-Factor, P-Factor, R2, NS indicators in the calibration period are, respectively, for Abgarm station (0.53, 0.47,0.71,0.69) and for Firozabad station (0.32,0.3,0.67,0.64) and in the validation period, for Abgram station (0.09,0,0.62,0.56) and for Firozabad station (0.13,0,0.53,0.51), respectively. Based on this, the results obtained in the calibration and validation stage are evaluated as acceptable. The evaluation of the SWAT model's response to land use also shows that, on an annual scale, the amount of flow in Firozabad station has decreases from 3.08 to 2.81 cubic meters per second -8,77percent) and in Abgarm station from 1.11 to 0.96 cubic meters per second (-13.51), which can be attributed to changes in land use, especially the change in the use of pastures and its conversion to rainfed agriculture, gardens, and forests.

The trend of land use changes in the basin between 1987 and 2019 has been accompanied by a decreasing trend in rainfed, pasture and water uses and an increasing trend in irrigated agriculture, garden, forest, and residential uses. The high value of the fit of the indicators used in the evaluation of the model indicates that the model has a good capability in simulating the runoff of the basin. Moreover, the model implemented for different land uses illustrates that the flow of the basin in both hydrometric stations in most of the months increase in the short term and decrease in the long term average with the land use change. Continuous land use change is becoming a serious threat to watersheds. Land use change should be controlled in catchment areas, and measures should be taken to stabilize land use change.

Heatwaves are one of the natural and intrinsic phenomena of the climate in different parts of the world whose frequency of occurrence as a result of global fluctuations in climate over recent years is similar to other climatic phenomena. Rising air temperatures due to periodic droughts or because of heating The world is very likely in the coming years .To evaluate the temperature in Ardebil province data on the maximum daily temperature of the stations of Ardebil Parsabad Khalkhal and Meshkinshahr for the years 1991 to 2016 were obtained from Ardebil's meteorological conditions. In this study in order to study the heating periods in different months of Ardebil province also to illustrate the changes The period of continuity and the return period of heat waves have been identified and the Markov chain has been usedAccordingly in no fish the waves are the most frequent and the short and long wave were the highest in April and the lowest in September.Using these tables of the period of continuity and the calculated return period of the heat wave during the warm year the level of stations in the province of Ardabil we find that in April May and June Parsabad station has the least heat recovery period and the months of July August And in September Ardebil station has the shortest period of return. The most frequent return periods were observed in April May June July and August at Meshkinshahr Station and observed in Khalkhal Station in September.Also, the existence of Azores dynamic high pressure in Iran has caused a strong heat rule in our study area.

Climate change has negative effects on water resources and human societies, especially in arid and semi-arid regions. Remote sensing is widely used in studies such as monitoring the environment, agriculture, and climate of the earth. This technology makes it possible to research and investigate such studies in large areas with the high spatial and temporal resolution, especially inaccessible areas or areas that do not have ground measurement stations (such as synoptic stations) provides. Considering the expansion of the cold semi-desert climate in the northwestern region of the country and the changes in land use in the Meshkinshahr region in recent years, the purpose of this research is to investigate the interrelationship between climatic components of temperature, precipitation, and soil moisture with land use changes.

Meshkinshahr city is located in the northwest of Iran and is one of the important cities of Ardabil province. In the present research, the studied area using satellite images of Landsat 5 for 2002 and Landsat 8 for 2021 in seven classes of irrigated agriculture, rain-fed agriculture, residential area, water areas, snow cover, good pasture, and poor pasture for investigation of the changes in land-use has been classified. In the following, temperature and precipitation components (along with verification with ground data) respectively using the single-channel algorithm and GPM database and soil moisture using the optical thermal algorithm (TOTRAM) by applying LST and NDVI parameters as a time series were reviewed for the years 2002, 2006, 2011, 2016, 2019 and 2021.

By examining the resulting maps, it has been observed that there have been significant changes in different land uses, and most of these changes have been related to the increase of irrigated agricultural lands and poor pastures, and the loss of quality pastures. Also, temperature and precipitation fluctuations in the studied years are quite clear and do not have a regular trend, so for example, in 2011, a sudden increase in precipitation to the amount of 46 mm is observed. But the minimum temperature compared to its maximum in different years shows a greater increase compared to 2002. Vegetation and soil fertility do not have a particular upward or downward trend and show different values ​​in different years, but the maximum vegetation cover, i.e. value 1 in the case of the NDVI index, is observed in 2002.

According to the results and fluctuations in the values ​​of climatic components, especially sudden changes in some years, signs of climate change can be observed in the region, but a definite opinion cannot be expressed regarding the trend of land use changes and climate changes. Examining the results shows that land use changes, especially in the agricultural sector, can be affected by climatic conditions. The dependence of climatic components on each other and the influence of soil moisture and vegetation on these components are other results of this study. So, with the increase in temperature, we see a decrease in the amount of humidity and the level of vegetation. The times when soil moisture is higher than in other years, due to the cooling role of evaporation, low temperature, and vegetation cover are favorable. As a result, there is a clear dependence between the different components and the change in one parameter affects the other parameters, but it seems that the temperature component plays a more colorful role than the other parameters.

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.

Heavy rains every year in all parts of the world, especially in arid and semi-arid regions, cause great damage to the environment and humans. For this purpose, precipitation data of 4 stations of Astara, Bandar Anzali, Rasht (airport) and Manjil from 2021-1993 were obtained from the Meteorological Organization of Gilan Province. Days with heavy rainfall were selected using 95% percentile and were examined for 11/6/2018 due to the brevity of the analysis. Heavy rainfall trend was also evaluated using non-parametric methods of Mann-Kendall, Sense Stimulator and simple linear regression methods. The results of these tests showed that Astara station had a positive, ascending and significant trend, but in other selected stations, despite being ascending, The trend has not been significant. To analyze the representative's day, NETCDF data were obtained from Nova site and maps of sea level pressure, geopotential height of 500 hPa, rainwater, tavaei, wind river, humidity and Huff Müller special humidity were plotted in Gardes software. The maps show that the dynamic clockwise movement in Eastern Europe leads to the flow of westerly and northerly winds towards the study areas, and on the other hand, by placing study stations in front of the landing axis of the bipolar block, which causes rotational and upward movements of the air. And the positive values of Tavaei have proved it, and finally it has led to atmospheric turbulence. The movement of westerly winds has brought the moisture of the Black Sea and the Mediterranean Sea to the atmosphere of the studied areas, especially with increasing wind speed on the day of peak rainfall has increased the amount of special humidity in the lower levels of atmosphere and rainwater.

The importance of precipitation in human societies and all living organisms in general, has caused this climatic phenomenon to be a fundamental issue in climate studies. In terms of geographical location of Iran due to its location in arid and semi-arid regions, the annual rainfall conditions are small, short-term and with severe fluctuations that cause floods and drought at high and low levels, respectively (Asgari et al., 2007 and Quoted from Soltani et al., 2011). Gilan province can be mentioned as one of the important areas in this country where rainfall is a prominent feature. Cloudy and rainy weather is one of the climatic features of this province. Statistical evidence shows that this province is due to the existence of high Alborz mountains in the south; During the passage of migratory rotational systems and the establishment of synchronous patterns and northern rotation, the influx of heavy and super heavy precipitation is not unreasonable; Therefore, suitable conditions are provided for the occurrence of heavier rainfall in Gilan. Ultra-heavy rainfall is one of the various geographical elements that has dangerous life and financial effects that can affect nature and humans (Azizi et al., 2011 and quoted by Zolfaghari et al., 2014). A large amount of rainfall in a short period of time leads to heavy rainfall and gradually to super-heavy rainfall. This phenomenon causes a lot of damage in most places at the time of the event, especially in low-rainfall areas (Arabi, 2000, quoting Khorshid Doust et al., 2016). There is no complete definition of heavy and super heavy rainfall that can be used equally for all different areas, because in each area, depending on the physical, local and synoptic conditions, a certain amount of rainfall can cause a flood. In the popular definition, rainfall that occurs in the region more than 30 mm per hour is called heavy rainfall. It is one of the oldest studies on heavy rainfall conducted by (AII this 1948). He concluded that at the 500 hPa level, landings within the positive rotation forward range caused more intense rainfall. (Maddox, 1978) In a synoptic comparison between the heavy floods of Rapids City and Big Thompson, it was concluded that the main cause of this type of flood is winds that blow at low levels and cause high humidity to reach these two areas. Roughness also causes climbing and eventually heavy rainfall. (Aboutaleb et al, 2007) examined the changes of the annual series of relative humidity in Jordan. Their work showed that there is a significant increasing trend in the annual series of relative humidity. (Bourdieu et al, 2007) investigated the amount of Farin wet and dry periods for the island of Sicily. (Carbolut et al, 2008) In the Samsun region of Turkey, during their studies on the trend of precipitation and temperature, they concluded that there is no significant positive and negative trend between temperature and precipitation (Sen Roy, 2009) in India to study patterns Farin rainfall has shown that the high altitudes of the northwestern Himalayas cause heavy rainfall. (Lupi et al, 2010) A study was conducted over a period of 55 years (1951-2006) of seasonal rainfall in southern Poland, eastern and central Germany. According to their findings, the trend of increasing rainfall is observed in all seasons of the year, but in Poland this trend is reversed. These characteristics are more established in winter.

The purpose of this study is to investigate the statistics and synoptic of super heavy rainfall in Guilan province, during which data related to daily rainfall (24 hours) of Astara, Bandar Anzali, Rasht (airport), Manjil stations of Guilan Meteorological Department in a period of 29 years ( 1371-1399) was extracted. In the present study, the ultra-heavy precipitations of each station have been filtered in 95% percentile according to the topographic conditions and its geographical location. Among the main methods of this research, the non-parametric method of Mann-Kendall and Sens-Eastmotor statistical tests and the simple linear regression method were examined and analyzed to prove its significance or not. Finally, 11/6/2018 was selected as the peak day of precipitation and the modeling of synoptic systems was studied. For this purpose, upper atmosphere data from the National Environmental Prediction Center (NCEP-NCAR) were used to draw and analyze the day of heavy rainfall and the day before. These maps include sea level pressure, 500 hPa geopotential level, rainwater at ground level to the upper atmosphere, Tavaei level at 500 hPa, 250 hP wind and humidity at 500 hPa, especially in Hoffmol. Gardes software was drawn.

In this research, the influence of the polar jet streams on the daily rainfall of synoptic stations in Iran in the cold season (autumn and winter) during a period of 30 years (1988-2017) has been studied. Based on the threshold of rainfall exceeding 30 mm as heavy rainfall and based on the 95th percentile, 972 days were identified and clustered as days of heavy rainfall in 31 synoptic stations of Iran, and the representative days of each cluster were selected. In the following, in order to find behavioral patterns and investigate the interaction of the polar jet stream on the intensification of the processes of frontal formation and the occurrence of heavy precipitation, the data of the zonal and meridian wind component, divergence, geopotential height, vertical velocity of the atmosphere (omega), vorticity, relative humidity, specific humidity, temperature and average sea level pressure were studied. The results of these analyzes showed 6 circulation patterns in the region, each of these patterns, due to the dominance and establishment of numerous troughs and ridges in the atmosphere, on the path of the polar front jet stream transfer to the middle latitudes of the earth and also the fluctuations of its seasonal average position have been influential. The results showed that the meridian mode of the jet stream axis has caused the creation and production of cores for the rate of occurrence of more rainfall in the western region of Iran.

The purpose of this study is to investigate drought using meteorological, hydrological, and remote sensing indicators in the Gharasou basin located in Ardabil province with an area of 495 square kilometers. Therefore, to calculate the SPI index was used monthly rainfall values related to 22 rainfall stations (1985-2015) and to calculate the SDI index, the monthly discharge values of 14 hydrometric stations (1985-2015). Then, SPI and SDI indices were compared with each other on a time scale of 1, 3, 6, 9, and 12 months, as well as seasonal and half a year. To study vegetation drought and calculate NDVI and VCI indices, were used MODIS images, with a spatial resolution of 500 meters for 15 years (2000-2015). The results of the meteorological drought time series in Gharasou showed that the drought occurred comprehensively in the years (2001-2000, 2006-2005, 2008-2007, and 2014-2013).  So that the most affected areas of drought were related to the northern and northeastern of the basin (Namin and Abarkooh). The results showed that meteorological drought has been more persistent in recent years and has been significantly correlated with hydrological drought with a delay of 1 to 3 months. NDVI and VCI indices showed that in identifying drought periods, these indices are consistent with meteorological drought, but are different correlation values. Finally, the comparison of NDVI and VCI indices with the SPI index showed that the VCI index with a value of r = 0.44 has the highest correlation with the SPI index. However, the correlation between NDVI and SPI indices is r = 0.38. The results of the VCI index showed that in drought conditions, only in the east of the basin and in the areas around Sabalan mountain, favorable vegetation conditions are observed, but in other areas of the basin, moderate and weak drought has occurred.

Morphological Assessment will be necessary to understand the current situation and the potential for possible river changes in the future. Natural factors such as floods, soil erosion, landslides and human factors such as land use change and sand removal from the riverbed affect the morphology. River systems have always been of interest to humans as one of the most vital elements of the Earth's surface. Humans also change the face of the earth by changing their use, destroying natural resources, plowing the land in the direction of the slope, planting trees in the riverbeds. Any Manipulation into the riverbed will change the process of erosion and sedimentation along the river. Understanding the characteristics of flow and sediment is the basis for evaluating the behavior of rivers and deciding on engineering activities. Therefore, it is necessary to obtain the necessary information on how they work before starting engineering projects for rivers.

In this study, geological maps at a scale of 1: 100000 of the Geological Organization, topographic maps at a scale of 1: 50,000 digits of the Geographical Organization of the Armed Forces, Landsat satellite images, 2020 April, November 1995, Climatic data Temperature and precipitation (1399-1374) of Lorestan Meteorological Organization and Digital elevation model of 30 meters has been used. Arc GIS software was used for spatial analysis and ENVI software was used for processing satellite images. The normalized water difference index is the first index of water extraction in images and remote sensing data. In this indicator, two green and infrared bands are used. Positive values of this index indicate water and negative values indicate phenomena other than water. Researchers have proposed different methods for studying changes in river channels. The transect method is used to evaluate changes and displacements in river channels. In this method, lines with specific distances on both sides of the river route are drawn as baselines. These lines are constant for the time periods studied. River channel displacements relative to these lines are quantified. To further evaluate the Kahman River canal, the canal migration rate method was used. The Kahman river Canal was divided into two areas, mountainous areas and plain and agricultural areas, based on topography and land use.

To calculate the area to the right and left of the transects, the Kahman river channel was cut separately with a transect layer in 1995 and 2020. Calculation of changes in the area of transects shows that about 185.85 hectares of land adjacent to the Kahman river (1995-1999) have been eroded. On average, about 7.43 hectares of these lands have been destroyed annually. The maximum value of this index in transect 30 is calculated at 8.27 hectares. In order to better understand the changes and dynamics of the Kahman river Canal, the migration rate index (Rm) was also used. First, two fixed lines were drawn around the Kahman river channel. The area between the two was calculated using Arc GIS software functions. The average migration rate of Kahman river (1399-1374) was 2.51 meters per year. The lowest level of this index occurred in Trasket 49 at 0.18 meters per year. The mountain factor and stabilization operations along the river have been the most important reasons for its control and stabilization. The highest rate of migration occurred in transects 4, 32 and 30 at 4.80, 5.5 and 6.12, respectively. Shortcuts and land use changes have been the main reasons for the high rate of duct migration in these transects. The largest amount of lateral changes in the Kahman river route occurred in parts of the plain and agricultural areas, including transects 30 to 35. The most important factor was the high lateral changes of the Kahman river route in the plain area due to the high erosion of the coastal and floodplain materials. Most of the constituents of the bed and banks of the Kahman river in these periods are from fine to coarse sands.

Duct migration rate index showed that the average displacement of Kahman river canal (1374-1399) was 2.51 meters per year. The lowest value of this index was 0.18 meters per year and the maximum value was 6.12 meters per year. Calculation of changes in the area of transects showed that about 185.85 hectares of land adjacent to the Kahman River (1374-1399) has been destroyed. On average, about 7.43 hectares of these lands are lost every year. In the mountainous area, the effects of the mountains were the most important factor in determining the morphological changes of the Kahman River channel. The presence of erodible materials along the Kahman River in the plains and agricultural areas has increased the lateral migration of meanders and the width of the valley and floodplains adjacent to the river has increased significantly. Therefore, it can be said that the Kahman River has had more geometric changes in the plains and agricultural lands.

In synoptic climatology, relying on the principle of changes in the analysis and explanation of environmental conditions of the earth's surface from changes in pressure patterns, the most climatic phenomena of the earth's surface can be explained, analyzed and predicted. One of the most important of these phenomena is the temperature (especially the minimum temperature temperature). Scientists believe that climate change occurs in the form of extreme temperature events, especially extreme temperature. Understanding the interactions between different components of tourism is one of the desirable solutions that are studied to study climate change and public climate. Flavors, especially in mid-latitudes, are among these components. Therefore, the purpose of this study is to analyze the synchronous minimum temperature of Tabriz.

Using daily average data during the period 1988 to 2017 from the synoptic station of Tabriz city, a hybrid synoptic map (500 HP level, surface, omega and vortices) prepared by GRADS software and examined. Data were selected in SPSS software using hierarchical clustering method and representative days to investigate the relevant issue.

The results show the positive effects of vortex (at the level of 500 HP) on the occurrence of extreme temperatures due to the presence of blocking systems, cold air subsidence of high latitudes at the upper level and high pressure systems (anticyclones) at ground level. The amount of omega at the level of 500 HP was positive on all days in the study area.

Finally, a positive vortex at the level of 500 HP has caused a drop in temperature at the ground level. In addition, anticyclone systems at the ground level have subsequently reduced the temperature and the occurrence of extreme temperature in Tabriz city station.

Snow and ice cover is a vital resource and is very sensitive to climate change. Accurate measurement of the spatial distribution of snow and ice at regular intervals is essential for water resources management. In this research, the snow cover of Sabalan Mountain is extracted using Landsat 5 satellite images for 2000 and Landsat 8 for 2020 using object-oriented classification and also using NDSI and NDSINW spectral indices. The results of the classification maps extracted from the object-oriented method showed that the area covered by snow for the years 2000 and 2020 is 2500 and 1954 square kilometers, respectively, with a kappa coefficient and an overall accuracy of 99%. And 0/99 for both years. Then the snow covered area was extracted using NDSI spectral indices and NDSINW index. Both of these indicators are able to extract the snow cover surface with appropriate relative accuracy in cold and winter regions. However, because the NDSI index does not distinguish between snow and water, it may produce different results in areas with waterlogging associated with snow extraction. The NDSINW index, on the other hand, is more accurate in eliminating waterborne backgrounds. In relation to the present study, the NDSI index has extracted 2610 and 2577 square kilometers of snow cover and the NDSINW index has extracted 2577 and 1937 square kilometers for 2000 and 2020, respectively. The area obtained from the NDSINW index has been extracted by the object-oriented classification is closer.

Heavy rains often lead to destructive floods, so discovering the prevailing pattern any climate system will allow for optimal analysis and forecasting. The present study was conducted to explain the synoptic of heavy rainfall leading to floods on 22 January 2020 in southern Sistan and Baluchestan province. Maps of different levels of the atmosphere were analyzed before a day the flood. In order to accomplish this, the required data have been extracted from NCEP/NCAR affiliated with the National Organization of the Oceanography of the United States. In the next step, the geo-potential height, vorticity, omega, wind direction, wind speed, specific humidity, Moisture Flux Convergence maps and Hoff Miller diagram was drawn and analyzed. The results showed that settle of trough vorticity in Saudi Arabia zone in the middle of the atmosphere along with the jet core at the upper levels provided favorable conditions for unstable weather and ascent in the southeastern region of Iran, so that the omega reached 0.45 Pascal per second. Special humidity maps also showed that at the same time as the settle of trough vorticity in region, considerable moisture flowed from the Arabian Sea and the Persian Gulf to southeastern Iran. Therefore, rapid conversion of atmospheric moisture to precipitation in trough vorticity has been the main cause of heavy rainfall on the above day.

In the present study to identify and analyze the drought and rain in the catchment area of river valley in North West Iran, were used The annual rainfall data of 38 stations for Climatology and synoptic during a period of 25 years (1990-1991 to 2014-2015). Initially, the use of SPI gamma index, as well as the Deciles drought index, were identified drought and wet periods in the study area. Stations studied In terms of homogeneity Using Agglomerative hierarchical clustering (AHC) method in three homogeneous classes. In the following Drought results with simple Kriging method, with a Semi-Variogram Spherical model with the lowest RMS erro, Zoned in ArcGIS software. Using appropriate variogram, cells with dimensions of 1 * 1 km were extended to perform spatial analysis on the study area. In order to explain the pattern of drought in the region From Global and local statistics of Moran were used as spatial data exploration approaches. The results of the application of Moran's index about identifying spatial distribution of drought patterns showed that The values of the different years during the period, have a positive a positive coefficient close to 1 (Moran's I> 0.95) and this shows that The spatial distribution of drought is clustered. Also the results of the standard score Z values and the P-Value proved the clustering of spatial distribution of drought. Eventually from General Statistics G Was used to identify spatial patterns of the drought. The results showed that the east and north-east of the region have a very severe drought pattern whose significance level is 0.99

One of the most important natural hazards that is affecting a large number of people, due to extensive damage, is drought. Drought is also a phenomenon directly related to the issue of water scarcity and because of its reversibility, it can affect the various aspects of human life and the environment. The drought affects almost all the determinants of the hydrological cycle from the onset of precipitation and then the surface water flow and eventually storage in groundwater. Therefore, in this research, due to the results of the stable process of precipitation and temperature in the Ardabil DareRood basin, SPI Index which relies on precipitation, with the RDI index which combines the parameters of potential evapotranspiration and precipitation, were compared and evaluated in different time intervals.

In this study, in order to identify drought and wet periods, it was used from monthly precipitation data, Minimum and maximum monthly temperature for seven synoptic stations, for a 30 years (1985-2014) in the Ardabil DareRood basin in the northwest of Iran. In order to identify the trend in the precipitation and temperature series in this research was used Man-Kendall (MK) and Sen's slope (Sen) models. Also, to assess the long-term stability of the trend in the time series was used the LOWESS curve (at a significant level of 5%). Also using Aridity index, four stations in the arid area and three stations in the semi-arid region were established. In order to calculate the RDI index, the values of potential evapotranspiration were use. The amount of PET in the RDI index using monthly temperature values, and was obtained by the Hargreaves method. Finally, SPI and RDI indices were compared in 3, 6, 9, and 12-month scales.

The results of the LOWESS curve showed that the annual temperature at all stations follows an incremental scenario. While the precipitation behaves differently and often is decreasing. The results also showed that SPI and RDI indices are very similar in different time scales, and R2 is in most cases greater than 0.90. The extreme drought the observed in SPI and RDI models is related to the Ardabil station in 2010-2011 on a 3-month scale, whose values were respectively -3/11 and -3/09. Also, the results showed that the RDI index that Extreme and severe wet values it’s larger than SPI. Eventually, both indices are many similarities with each other but because of RDI's use of PET, It can be used more widely for arid and semi-arid regions of Iran

this research, two SPI and RDI indices were used to compare the drought events in the DarehRood Ardabil basin of the northwest of Iran.Due to the dry and semi-arid climate of most regions of Iran, It is very probable that the amount of precipitation is zero in some seasons. Therefore precipitation-based indices such as SPI may have less efficiency than RDI index, which, in addition to rainfall, uses potential evapotranspiration (PET) in their formulation. Considering the importance of PET parameter in agriculture and water resources management in Iran, It is necessary to examine the RDI index in other regions of Iran, such as the northwest and mountainous regions of Iran and its results can be compared with other indicators such as the important and highly applicable SPI indicator.

One of important and successable new energy is wind energy that many developed and developing countries use wind energy to supply power. The aim of this reasearch is to evaluate wind energy potantial in North-West of Iran with fuzzy allgorithme. The data of this applied- analytical research were collected from Country Meteorological Organization form 2000 to 2008. Then, the collected wind speed frequency were based on the standard 4 meters per second and more that were classified in Matlab software. FCM algorithm was used extensively in the regional frequency analysis. Also, WINROSE software was used to determine the prevailing wind and wind direction. The results indicated that Ardabil station (first cluster) among all stations in the study has the highest frequency of wind occurrence whit speed of 8 knot and more. The frequency of this cluster is 5183 in studied statistical period. Urmia and Parsabad stations (cluster 5) have the lowest frequency of wind occurrence with speed of 8 knot that the average of this cluster is 577 times in studied statistical period. This reasearch found that First, second and third clusters for use of wind energy were very suitable and the fourth and fifth clusters were unsuitable to use of wind energy.

IntroductionThe interaction between mesoscale convective cells and the synoptic conditions results in heavy precipitation which causes flooding in certain regions. Deep and dump convection, which are product of interaction of processes in various time-zone scales are different. When the moist troposphere which is conditional unstable and unstable air masses which are able to climb a medium scale systems, in that place at the moment, we can expect formation of a deep moist convection which results in heavy rainfall. Heavy rainfalls can be one of the most dangerous risks in most parts of the world as we have seen floods that killed many people around the world. In Iran and also in this region, heavy rainfalls occur in different parts of the country. But according to the country's arid and semi-arid climates and nature destruction and manipulation by humankind, such phenomena face with severe reaction, leading to severe flooding and destruction is in the range of Iran.
The Study AreaChaharmahal-O Bakhtiari province with 533/16 square kilometers occupies 1% area of the country, and is a high area which has located in spread of Central Iranian Plateau and along the Zagros Mountains. In terms of geographical location it has located, between 31 degrees and 9 minutes to 32 degrees 48 minutes north latitude and 49 degrees 30 minutes to 51 degrees 26 minutes east longitude. Nearly 80 percent of this province is occupied with mountains and hills. This mountains has 16 peaks with more than 3,500 meters high. The highest one is the Zardkouh with 4548 high in north west of the country and 4548 meters in the north west and the lowest region of the country with 800 meters high, is located in exiting part of the Karoun river in joint of the Khorasan river to the Karoun. Precipitation in this area is as much as supplying 10 percent of the country's water which can feed central parts of Iran and Khuzestan plain as 4.7 billion cubic meters of water, in a year, exits from this province and is stored in Shahid Abbaspoor, Des and Zayandehroud dams.
Material and MethodsIn this study, three sets of data, data from ground stations, data from upper atmosphere, and TRMM satellite data have been used to analyze heavy rainfall wave of Chaharmahal-O Bakhtiari. This was an 8-day study from April 25, 2009 to May 2, 2009. Data used from the upper atmosphere re-analyzed data elements of geopotential height, Omega orbital wind, meridional wind, especial humidity, relative humidity, sea level pressure that have been obtained from website of the National Center for Environmental Prediction (NCEP ). Also, we used 3B42 data of TRMM satellite for satellite analyzing. TRMM 3B42 data of seventh version of this satellite were available for anyone to use from May 22, 2012. This version has spatial resolution of 0/25 degrees latitude and 0/25 degrees longitude and temporal resolution of 1 day and 3 hours. For this purpose, at first according to data obtained from upper levels, atmospheric maps were designed and analyzed. For detecting occurred rainfall and estimating amount of it, after getting TRMM satellite's data, we prepared a data base in Excel. For zoning TRMM satellite rainfall data, some small amounts of data were transferred to GIS software and then Geostatistics model and Kriging method for precipitation zone were used, which had less error zone compared with other methods for estimating TRMM rainfall data.
Results and DisscussionDrawing and analyzing atmospheric maps showed that the pressure gradient between anticyclone located on Central Europe, the North Caspian and West China, with cyclone located on the North West of Saudi Arabia, the Persian Gulf, the West Indies and North West Africa and on the other hand, domination of cyclonic conditions in last days of study in earth with blocking event on upper levels and stretching deep descending’s of them, on studied region in 500, 600, 700 and 850 HP, and ascendance of airflow in atmosphere (negative omega) which is indicator of air ascending and reinforcement of convection flows in mentioned levels that causes extreme divergence and instability. Atmospheric eddies with negative balance of 850, 925, 1000, HP has provided favorable conditions for the occurrence of heavy rainfall. In addition, supplying and feeding of humidity by the Red Sea at levels of 500, 600, 700 HP and the Persian Gulf at levels of 850, 925, 1000 HP, and at the end, existence of all mentioned conditions with domination of strong jet stream in most parts of Iran in period of study has caused rising atmospheric divergence and instability in studied region and resulted in 551 mm heavy rainfall. Considering precipitation estimated by TRMM satellite and comparing it with recorded values by observation stations, it is obvious that TRMM satellite does not have adequate accuracy for estimating rainfall in this region. And in most stations, the estimation was more than which has been observed. The correlation and coefficient determination between them is 22/0 and 05/0 percent.According to atmospheric maps analysis, we can say that pressure differences between anticyclone in the northern area and low pressure located in south of it, along with occurrence of blocking in the upper atmosphere and also locating the region in the East, along with this, domination of negative conditions of eddy and omega in atmosphere of studied area, with adequate moisture and with association atmospheric jet streams the proper condition for precipitation of heavy cloud has been prepared . TRMM satellite rainfall estimation results of the evaluation of this heavy precipitation cloud wave indicate not so good accuracy of this satellite in this area. TRMM satellite in most stations have had surplus estimation in comparison to other recorded data. Therefore, we can say that in complex topographical areas like Bakhtiari region due to being located in the Zagros mountainous region that has complex topography, we cannot trust estimated values of this satellite.