Investigating the surface temperature of the earth and its trend in Iran during the winter season based on the output of the CORDEX project

Introduction
Temperature anomaly means deviating from the reference value or the long-term mean. A positive anomaly indicates that the observed temperature is warmer than the reference temperature. Temperature anomalies, especially in the cold period of the year, may have devastating effects on agricultural products, loss of plant and animal life, ecology, facilities and structures, food security, and etc. Rising ground temperature will increase evapotranspiration, decrease the level and depth of snow, change crop phenology and finally a serious threat to food security in the country. Therefore, studying temperature anomalies in different ways is very important.
Materials and methods

A) In this study, temperature data were collected for 45 units during the statistical period of 1980 to 2018. For selecting the modules, in addition to considering the different climatic regions of Iran, an attempt was made to select one module from each province.
B) Using the open analysis database, the modified GFDL-NOAA-ESM2M model was conducted to study temperature changes in Iran during the statistical period of 1975 to 2005.
C) In this research, the MOD11C3 product of MODIS satellite data was used.
D) In order to evaluate the trend of surface temperature and its anomalies in Iran, non-parametric Mann-Kendall test was used.
E) In order to evaluate the analyzed the obtained data from the SM2M-GFDL-NOAA model and the provided satellite data, different methods such as the R- Square, mean square error and mean square error data were used.

Results and discussion
The main focus of the maximum temperature in this month is in the northwestern regions of Iran. The coastal provinces of the Persian Gulf and the Sea of   Oman are among the regions with the highest surface temperatures. By passing from low latitudes to high latitudes, the surface temperature of the earth has gradually decreased and the minimum temperature has appeared in the northwestern parts. According to satellite data, the maximum anomaly was observed in the northwestern, western and southwestern regions, as well as the highlands of Khorasan Razavi and North Khorasan. Minimal anomalies in the northern strip from Ardabil province in the northeastern regions, Kerman province, South Khorasan and Sistan and Baluchestan. The ESM2M-GFDL-NOAA model had the best performance compared to satellite imagery and was therefore used to find the model trend and change gradients. The slope of the trend in the interior places of the country, specially around the Kavir desert and Jazmourian hole is estimated to be 0.1 degrees Celsius. This means that the surface temperature in January during the period during the year increases by 0.1 per year in these areas. In the highlands of South Khorasan and the northern parts of Fars province, the slope of the trend is 0.03 to 0.01 degrees Celsius. This trend is decreasing and the ground temperature decreases between the mentioned values   every year. The northern regions of Khorasan Razavi, the eastern regions of Sistan and Baluchestan and the northern regions of the Lut plain are among the regions in which the trend slope increased in February during the statistical period 1975 to 2005 and the LST increased between 0.17 and 0.19 degrees Celsius per year.
Conclusion
The results of the surface temperature assessment using treaa MODIS data during the statistical period (2001 to 2018) indicate that the surface temperature is affected by topography and latitude, so that during the period which the minimum surface temperature of the day at the Caspian coast and in The Alborz mountain range and the northwestern regions of the country were observed.The pattern of the earth's surface temperature prove that as we go from north to south and from west to east, the earth's temperature has increased.The results of night surface temperature anomaly monitoring showed; In the cold months of December, January and February, the maximum surface temperature anomalies were observed overnight in the Alborz highlands and around the western mountains of the country. In March, October and November, the Caspian coast had the least anomalies. In the warm months of July to September, the interior and eastern regions of Iran showed the least surface temperature anomalies. In June Southeastern regions of Iran near Sistan and Baluchestan province had a significant upward trend in the level of 5% confidence and other regions of Iran showed different trends in different months. In June Southeastern regions of Iran near Sistan and Baluchestan province had a significant upward trend in the level of 5% confidence and other regions of Iran showed different trends in different months. Ground surface temperature trend slope based on non-parametric Sense test of simulated data of ESM2M-GFDL-NOAA model, where the trend slope is different and there is a positive and negative trend slope in different seasonal situations.