Response of vegetation phenology to hydrothermal variables on the QTP using EVI and MSAVI

Vegetation phenology is a key indicator of how the Qinghai-Tibet plateau (QTP) ecosystem responds to changes in the hydrothermal environment. However, sparse QTP meteorological stations make observed traditional hydrothermal variables (air temperature and precipitation) insufficient for research needs. Building upon analyses of vegetation phenology using enhanced vegetation index and modified soil-adjusted vegetation index, this study adopts alternative hydrothermal variables (land surface temperature [LST], effective moisture and surface albedo). Geodetector and partial correlation analysis were employed to reveal the response mechanisms between vegetation phenology and hydrothermal variables. Results indicate that the length of the growing season (LOS) is primarily driven by the end of the growing season (EOS). From 2001 to 2020, EOS showed a significant positive correlation with LST. Compared to traditional variables, these variables demonstrated stronger explanatory power for vegetation changes. Hurst index analysis revealed vegetation recovery trends. This study provides scientific support for ecological management on the QTP.