Research on evolution of Western Han Dynasty water basin based on LUCC and NDVI

In order to quantitatively identify the evolution of the runoff time and space of the basin, analyze the factors affecting the changes in the hydrological situation of the basin. This article uses the Western Han Dynasty Water Basin as the research area. Based on remote sensing technology, the impact of LUCC and NDVI changes on the runoff of the area. Firstly, the method of time and space evolution of the elements of various elements in the research area of the research area was analyzed by methods such as Mann-Kendall. Period (1990 to 2020) Vegetarian coverage (NDVI) transferred in space. The results show: (1) From 1960 to 2022, the runoff in the West Han River Basin showed an overall downward trend. From north to south, the runoff in the basin showed an increasing trend of 2.68×10⁸m³, 7.55×10⁸m³, and 12.99×10⁸m³ . The mutation years were concentrated in the 1980s and 1990s. (2) From 1980 to 2020, precipitation in the basin generally showed a slow upward trend in time, and spatially showed an increasing trend from upstream to downstream; temperature changes showed a consistent upward trend with the same increase in time, and spatially showed that the temperature in the upstream was lower than that in the downstream , consistent with global temperature changes. (3) The transformation of LUCC in the West Han River Basin from 1980 to 2020 was mainly due to the increase of forest and grass area and the decrease of cultivated area. (4) The NDVI in the West Han River Basin from 1990 to 2020 was at a medium to medium high level in the time series, and showed an overall upward trend. In terms of spatial distribution, the pattern of "downstream is better than upstream", and the vegetation cover was significantly improved, but contrary to the change of runoff, the increase of NDVI had a decreasing effect on runoff.