Snow cover changes on the Tibetan Plateau and Eurasian continent and their relationship with precipitation in China

Abstract

Abstract The empirical orthogonal function (EOF) and correlation analyses were used to study the winter and spring snow cover changes on the Tibetan Plateau (TP) and Eurasian continent and their relationship with precipitation in China based on satellite, ground observation and reanalysis data. The results show that the winter and spring snow cover in Eurasia not only indicates a decreasing trend due to global warming (the first EOF mode, its variance accounted for 24.4% of the total variance) but also exhibits significant interannual variation (the second EOF mode, its variance accounted for 10.2% of the total variance). The spatial distribution of the second EOF mode is characterized by a west-east dipole pattern, which plays an important role in regulating winter precipitation in China during the same period, leading to some extent to the precipitation in the middle and lower reaches of Yangtze River Valley and South China, and the opposite trend of precipitation in the east and west of the TP and the south. Moreover, this mode is significantly correlated with the meridional quadrupole summer rainfall pattern, with excessive rainfall over northeast China and the Yellow River basin and deficient rainfall over Inner Mongolia and southern China. The EOF mode of spring snowmelt in Eurasia also reflects the decreasing trend of snow depth, and its influence on summer rainfall in China cannot be ignored. Larger spring snow cover in Eurasia leads to excessive rainfall in Northeast China and eastern TP and less precipitation in the Yangtze River Valley and southern TP.