Effect of heavy snowfall on ground temperature, northern Tibetan Plateau

Abstract

Very heavy snowfall occurred in the Amdo-Nagqu region during winter 1997/ 98, and enormous numbers of sheep and yaks died due to starvation and low temperatures. Some observation sites of the GEWEX (Global Energy and Water Cycle Experiment) Asian Monsoon Experiment (GAME)-Tibet are located in this area. In this paper, the variation of the ground temperature (GT) on the northern part of the Tibetan Plateau and its relationship with the heavy snow cover is analyzed based on the GAME-Tibet in situ observational data at several sites. The temporal and spatial differences of the variations of the daily maximum, daily minimum and range in GT are significant in 1997/98 in the northern part of the Tibetan Plateau. For example, at site D110, the daily range in GT fluctuated only 0.2°C from the end of December 1997 to mid-April 1998, but in the north, at site D66, the daily range in GT fluctuated between 5°C and ∼20°C at the same depth and during the same period. At the southernmost site, MS3637, the daily range in GT fluctuated within 1.0°C from mid-November to early February. From mid-February to mid-March, the daily range in GT increased and the peak was 8.1°C. The temperature variation was related to the heavy snowfall that occurred on the northern Tibetan Plateau in winter 1997/98. The snow-cover conditions at different sites on the northern Tibetan Plateau were evaluated quantitatively from the variation of the GT at shallow depths.