Impacts of land use/land cover dynamics on land surface temperature using geospatial techniques in Anger River Sub-basin, Western Ethiopia

Land surface temperature (LST) is increasing due to land use land cover (LULC) conversion in the world. Global warming was caused by highly expansion of agricultural land, expansion of human settlements and removal of vegetation cover. Here, we analyzed the impacts of LULC dynamics on LST from the year 1991 to 2020 in the Anger River Sub-basin, western Ethiopia. The LST and LULC changes were derived from thermal infrared and multispectral band of Landsat 5 TM (1991), Landsat 7 ETM+ (2003) and Landsat 8 OLI/TIRS (2020), respectively. The LULC map of the study area was produced using the supervised classification method with the maximum likelihood algorithm. Our study results revealed that agricultural land was increased by the rate of 30.4 km(2)/year. Between 1991 and 2020, about 650.3 km(2) of grassland was converted to agricultural land while 305.4 km(2) was converted from forest to agricultural land. The mean minimum LST was 21.2 degrees C in 1991 and increased to 23.50 degrees C and 26.80 degrees C in the years 2003 and 2020, respectively. Thus, the mean LST of the study area was increased by 5.6 degrees C between 1991 and 2020. Consequently, the conversion of LULC is the main factor for the increment of the LST. The LST was highly increased when forestland and grassland were converted to agricultural land. Similarly, when forestland was converted to bare land, the LST was increased. Our results suggest the need for environmental protection to respond to the increasing trend of LST and rapid conversion of LULC change in the study area.

Automated summary

This study analyzed the impact of land use and land cover changes on land surface temperature (LST) in the Anger River Sub-basin, western Ethiopia from 1991 to 2020. The results showed that LST significantly increased during this period, with the expansion of agricultural land being the main contributing factor. Conversion of forest and grassland to agricultural land, as well as forest conversion to bare land, also led to increased LST. Hence, environmental protection measures are needed to address the increasing trend of LST and rapid land use change in the study area.