Evaluation and modeling of physical changes in Arjan wetland in relation to climatic parameters using remote sensing

Severe climate change, declining rainfall, rising temperatures, and subsequent increased evapotranspiration have led to significant reductions in water levels in recent decades. In the meantime, the study of fluctuations in the water level of lakes, in order to protect them in terms of importance, has gained a special place in recent years among countries at the national and regional levels. The purpose of this study is to investigate the physical changes of Arjan wetland and the trend of climatic parameters as well as the relationship between the mentioned cases. To achieve this goal, the area of ​​the lakes from 1986 to 2018 was calculated using Landsat satellite images and the NDWI index. The results indicate a reduction in area over the period under study. It has been dried so that Arjan wetland has been completely since 2013. It is the lowest amount of precipitation recorded in this period in 2008 and 2010 with the amount of 127.82 and 107.7 mm, respectively. The average temperature in the study period 2018-1986 was 19.44 degrees Celsius and the temperature in this period has increased by 0.6 degrees Celsius. Among the studied climatic parameters, the precipitation parameter with a correlation coefficient of about 0.53 and the potential evapotranspiration with a correlation coefficient of about -0.43 were more correlated with changes in the area of ​​lakes. The HadCM2 model of Cordex-WAS project under two scenarios of RCP4.5 and RCP8.5 was used to predict the climatic parameters of temperature and precipitation of the study area in the coming decades (2020-2050). The results show a decreasing trend of precipitation. And rising temperatures. Among the factors studied in this study, two main factors, the average annual rainfall of the study area and annual evaporation in recent years were considered as the factors that had the greatest impact and correlation with the physical changes of the wetland.