Analyzing the Temporal-Spatial changes of the Land surfaceTemperature Daranjir desert

Land surface temperature is one of the key parameters in the study of climate change, which helps in the real assessment of the environmental situation at local to global scales. Investigating the trend of land surface temperature and its long-term changes is necessary to evaluate climate processes in arid and semi-arid regions. The MODIS probe was successfully launched by NASA on December 18, 1999. This sensor is installed on two satellites Terra and Aqua. These two satellites take pictures of the entire surface of the earth twice a day and collect data in 36 spectral bands (wavelengths of 0.4-14.4 micrometers) with a resolution of 250, 500 and 1000 meters. In this research, the daily data of the MYD11A1 product with a spatial resolution of 1000 meters was extracted from the NASA website for 7305 days from 1/1/2003 to 12/30/2023. By choosing this product and the Aqua satellite, due to the convenient time of its passage over the region, a more detailed investigation of the surface temperature of the Daranjir desert basin was carried out. Since Terra's Khurshid Song satellite passes over Iran at 10:30 am and 10:30 pm, it cannot provide an accurate picture of the energy balance, for this reason Aqua satellite monitors Iran at 1:30 pm and 1:30 pm. Slow is selected. The main reason for this choice is the high energy balance in the middle of the day and the middle of the night. Since the statistical period of Terra is longer than that of Aqua, this satellite should have been chosen for Al-Qaeda, but Aqua satellite data is used more for the reasons described (Wan, 2013).

Examining the long-term surface temperature trend of the Daranjir desert during the last two decades shows that in a large part of the Daranjir desert (about 72%), the ground surface temperature trend has been positive (increasing). This trend of increasing temperature can be clearly seen especially in the bed of Shore Siriz River and Shore Rafsanjan River. It seems that the increased values of these areas are due to its drying and as a result, a sharp decrease in surface humidity in the long term. Also, Lale-Zar Mountains are among the areas that have shown a positive trend in surface temperature in the last two decades. Since this positive trend happened mostly in the cold seasons of the year (autumn and winter), one of the main reasons can be the reduction of snow cover in the last two decades (Key Khosravi Kiani and Masoudian, 2016). On the other hand, the presence of dams built in the south of Kerman, Rafsanjan and Chale Bafgh and their waterlogging in recent years shows the negative trend (decrease) of the surface temperature in these areas. These areas cover about 25% of the basin area. The rest of the surface of the Daranjir desert, which includes about 3% of the area of the basin, does not show any trend.

The results of the long-term seasonal trend showed that in the winter season, a large part of the Daranjir desert (about 95% of the area) has increased the surface temperature trend. It seems that the increase in surface temperature in winter can be due to the decrease in rainfall, snow and vegetation in recent years. In summer, the situation is different. In this season, about 70% of the area of Daranjir desert has a negative (decreasing) surface temperature trend and about 30% of its area has a positive (increasing) trend. It seems that the positive trend in the axis of Kerman-Zarand and Rafsanjan-Anar can be caused by the drying of the Shor Siriz River and the Shor Rafsanjan River during the last two decades. This issue seems normal because with the drying of the river and the decrease in the humidity of the river bed, its surface temperature has increased drastically. In the autumn season, due to the recent droughts, in addition to the above-mentioned axes, the Bafaq hole also shows an increasing trend in surface temperature. The research conducted on the surface temperature of Iran is consistent with this idea (Moradi et al., 2015; Karbalaei et al., 2014; Abad et al., 2015). The results of the long-term annual trend showed that during the last two decades, the temperature of the earth's surface has been increasing in 75% of the surface of the Daranjir desert basin. Due to the drying of the rivers and as a result the decrease of their surface moisture, part of this increasing trend can be seen in the bed of the Shor Siriz and Shor Rafsanjan rivers. Another part of this increasing trend can be seen in the heights of Lale-Zar. One of the main reasons for the increasing trend of surface temperature in this region can be due to the decrease of snow cover during the last two decades (Keikhosravi-Kiani and Masoodian, 2016; Kefayat Mutlagh et al., 2024). Further investigations showed that the presence of dams built in the south of Kerman, Rafsanjan and Bafaq hole and their waterlogging in recent years is the cause of the negative trend (decrease) in the surface temperature in these areas (Azizi et al., 2016; Keihosravi Kayani and Masoodian, 1400).