Spatiotemporal Variations in Dianchi Lake's Surface Water Temperature From 2001 to 2017 Under the Influence of Climate Warming

Lake Surface Water Temperature (LSWT) is one of the most important biological environmental conditions that determine the biological status of lakes. It is the most important indicator that affects the decomposition of matter and the metabolism of living things, and directs the biomass production processes in lakes. Variations in LSWT are the main factor causing changes in the physical and chemical processes, as well as dynamic phenomena in lake water. In this study, MODIS (Terra) remote sensing images of 2001-2017 were used as the data source, and the LSWT of Dianchi Lake from 2001 to 2017 were extracted with the MOD11A2 LST product. Analysis was then conducted on the temporal and spatial variatons of the lakes's LSWT across the past 17 years, and the influences of climate change on LSWT. The research results show that overall, Dianchi LSWT has been on the rise over the past 17 years. This trend was especially evident in the lake's average annual daytime and nighttime temperature, which has significantly increased by about 0.12 degrees C/yr(-1) (P<0.002) and 0.09 degrees C/yr(-1) (P<0.05), respectively. Correlation analysis reveals that the correlation between air temperature and the average annual water temperature of Dianchi Lake was low, with daytime correlation coefficient being r = 0.041, and nighttime correlation coeffIcient being r = 0.012. On the other hand, average monthly air temperature presents a high correlation with monthly average water temperatures. The coefficient with nighttime monthly water temperature is r>0.82 (P<0.001), and the coefficient with daytime monthly water temperature is r>0.63 (P<0.02).