Spatial Difference between Temperature and Snowfall Driven Spring Phenology of Alpine Grassland Land Surface Based on Process-Based Modeling on the Qinghai–Tibet Plateau

As a sensitive indicator for climate change, the spring phenology of alpine grassland on Qinghai–Tibet Plateau (QTP) has received extensive concern over past decade. It been demonstrated that temperature and precipitation/snowfall play an important role in driving green-up grassland. However, spatial differences snowfall driven mechanism onset are still not clear. This manuscript establishes set process-based models to investigate variables their differences. Specifically, using 500 m three-day composite MODIS NDVI datasets from 2000 2015, we first estimated land surface (LSGO) QTP. Further, combining with daily air precipitation built up LSGO 86 meteorological stations The optimum separating drivers spatially suggest is: (1) controlled by north, west south QTP, where during late winter is less than 20 mm; (2) combination middle, east southwest regions higher (3) more likely both dominant regions, since snow-melting process negative effects temperature. result dictates rainfall should be concerned separately improvement model ecosystem.