Abstract: Land surface temperature (LST), as an important indicator of the earth’s surface energy exchange process, plays a crucial role in the stability of ecosystems. Based on the 2001-2021 MOD11A1 V6 time-series LST data, combined with land cover types, NDVI(normalized difference vegetation index), and elevation data, this study employed Theil-Sen trend analysis, Mann-Kendall nonparametric tests, correlation analysis, centroid migration model, and an improved radius method to conduct a multi-scale, multi-dimensional comprehensive analysis of the spatiotemporal distribution and evolution characteristics of LST in Gansu Province at different temporal scales (seasons and years) and for different land cover types. The results showed that: 1) Between 2001 and 2021, the annual mean LST in Gansu Province was maintained at 21.25 ℃ with the area of cooling regions larger than that of warming regions, and an overall decreasing trend of 0.12 ℃ per decade.LST rises significantly in Spring while LST cools down significantly in Summer.LST in the Hexi region was generally higher than in other areas of Gansu Province, forming a north-high, south-low geographic distribution pattern. The centroid of high-temperature regions continuously shifted northwest, whereas the centroid of low-temperature regions moved southeast. 2) Significant differences in LST were observed among different land cover types. Bare land had the highest annual mean LST at 26.30 ℃, while glaciers had the lowest at -1.77 ℃. Vegetation cover was significantly negatively correlated with LST. 3) Among the six selected representative local cities, most exhibited varying degrees of heat island effects. Jiuquan City showed the most significant heat island effect, followed by Lanzhou and Qingyang; Longnan and Gannan cities had relatively weak heat island effects, while Wuwei City displayed a cold island effect.

Key words: land surface temperature, Gansu Province, China, spatial and temporal evolution, heat and cold island effect, center of mass transfer