Investigation of Trend Changes in the Caspian Sea Surface Temperature from 1989 to 2019

Water surface temperature or surface temperature in open waters and seas is known as one of the indicators for measuring oceanographic and meteorological features. In this study, to analyze the spatio-temporal Sea Surface Temperature (SST) of the Caspian Sea, the AVHRR data (0.25 Degree) were selected for the period from 1989 to 2019. Evaluation of the trend of temperature changes in the Caspian. sea water level was prepared by calculating the average monthly, seasonal and annual temperatures from daily data.The results of data analysis of SST show that 2003 with an average annual temperature of 14.7 degrees Celsius as the coldest year and 2010 with an average annual temperature of 16.56 degrees Celsius as the warmest year. Average monthly, seasonal and annual temperatures were obtained from the daily data. The results indicated that the southern parts, especially the southeastern Caspian Sea, are the warmest regions and the middle Caspian sea has a lower temperature than the other regions, although in some seasons and months, the effect of latitude prevails and the northern parts show the lowest temperatures. The annual time series of SST in the Caspian Sea have a completely increasing trend. However, from a spatial point of view, it should be said that the northern parts of the Caspian Sea have the lowest temperature and the temperatures increase with decreasing latitude to the south. The overall average surface temperature over the 30 years is about 15.6 degrees Celsius. The result also indicated that SST of the Caspian Sea it is completely increasing in terms of annuals, and in terms of seasonality and the temperatures show an increasing trend. And it shows the exact state of the image, that is, the temperature increases with increasing latitude.