Variations of snow cover in the source regions of the Yangtze and Yellow Rivers in China between 1960 and 1999

Abstract

Variations in annual maximum and accumulated snow depths, snow-cover duration, precipitation and air temperature have been analyzed using daily snow depth, monthly air temperature and monthly precipitation data from 1960 to 1999 from six meteorological stations in the source regions of the Yangtze and Yellow Rivers in China. Annual maximum snow depth, snow-cover duration and precipitation increased by ∼0.23, ∼0.06 and ∼0.05% a-1, respectively, during the study period, while annual accumulated snow depth increased by ∼2.4% a-1. Annual mean air temperature increased by ∼0.6°C over the study period. An unusually heavy snow cover in 1985 coincided with historically low air temperatures. Data from Tuotuohe and Qingshuihe meteorological stations are used to examine inter-station variability. The annual maximum and accumulated snow depths increased by ∼0.35 and ∼10.6% a-1 at Tuotuohe, and by ∼0.42 and ∼2.3% a-1 at Qingshuihe. However, from the late 1980s until 1999 the climate in the study region has become warmer and drier. The precipitation decrease in the 1990s (and not the rapid rise in measured temperature) is thought to be the primary cause of the decrease in snow depth in those years.