Spatial and temporal characteristics of NDVI on based hydrogeological division in Golmud River watershed of Qinghai-Tibet Plateau，China

Abstract

Abstract The hydrogeological conditions of the piedmont diluvium are one of the key controlling factors for the growth of local vegetation. This paper analyzes the spatial-temporal variation of vegetation in the Golmud River watershed by the linear slope method, Sen’s slope method and Hurst index method based on the hydrogeological division using the MODIS data of NDVI from 2000 to 2018 in the Qaidam Basin on the Qinghai-Tibet Plateau. The results show that the vegetation coverage in the study area is closely related to the hydrogeological conditions, and the hydrogeological unit of the watershed determines the zonal distribution of surface vegetation. Fraction Vegetation Coverage (FVC) is larger in the mountains and fine soil overflow division, but less than 0.1 in the piedmont Gobi, the wetland salt lake and the northern diluvium division. From 2000 to 2018, FVC has improved greatly in the mountains and fine soil overflow division. In the past 20 years, the area of high coverage vegetation in the watershed has nearly doubled, while desert area has been continuously reduced by 20%, these changes mainly occurred in the mountains and fine soil overflow division. The vegetation coverage of degradation is scattered along the southern coast of Dabson Lake, around the Huolanguole River, and around Yuzhu peak. The vegetation of consistent improvement in the future is mainly distributed in the mountains and fine soil overflow division. The vegetation of consistent degradation is mainly distributed around the upper reaches of Holangole River, the upper reaches of Jiaga Riqu, around Yuzhu Peak, and the south bank of Dabson Lake. Meteorological factors are the driving force of continuous improvement of vegetation coverage. This study has scientific significance for local ecological environment protection.