地理学报 ›› 1993, Vol. 60 ›› Issue (6): 505-515.doi: 10.11821/xb199306004

• 论文 • 上一篇    下一篇

中国西部积雪变化特征

李培基   

  1. 中国科学院兰州冰川冻土研究所,兰州 73000
  • 出版日期:1993-11-15 发布日期:1993-11-15
  • 基金资助:
    国家自然科学基金项目

DYNAMIC CHARACTERISTIC OF SNOW COVER IN WESTERN CHINA

Li Peiji   

  1. Lanzhou Institute of Glaciology and Geoeryology, Chinese Academy of Sciences
  • Online:1993-11-15 Published:1993-11-15

摘要: 综合中国西部175个地面气象台站1957—1987年逐日积雪深度、密度和月积雪日数资料,1978年-1987年SMMR周积雪深度资料,1973—1987年NOAA周积雪面积资料,以及50余幅DMSP影像图,本文阐述中国西部积雪空间分布、季节变化及年际波动特征,并对中国西部积雪大尺度气候效应和青藏高原第四纪冰期问题作了初步讨论。

关键词: 积雪覆盖, 年循环, 气候效应, 青藏高原, 中国西部

Abstract: The dynamic characteristics of spatial distribution,annual cycle and secular variation of seasonal snow cover in western China were investigated by using the best information concerning microwave derived snow depth charts produced by NASA data from SMMR(1978一1987),operational NOAA digitized weekly snow cover extent charts(1973一1987),short wave DMSP imagery(1978一1987),in conjuction with daily snow depth records in 175 ground climate stations covering the period from 1957 through 1987. Of all seasons,winter(dec. ,Jan. and Feb. )has the greatest snow volume and areal extent. It is the most variable season too. Year一to一year variability of snow volume is more prominent than that of snow area. The increase in snow cover area is succeeded by the increase in snow volume during growing progression of snow cover .whereas in decaying phase,the decrease in snow volume is followed by the decrease in snow cover area. The large interannual snow cover anomalies over the Tibetan Plateau are the most ,striking feature. The seasonal progress of snow covet in the Tibetan Plateau is opposite to that in the lowlands. It is characterized by a rapid grow and a slow decline. All generated time series of snow volume,snow cover area,and number of snow covered days by using SMMR snow charts。NOAA snow charts ,and ground station data demostrated that the periods with above normal snow cover have included the late I970s and mid 1980s, while the mid 1970s and early 1980s were on the low side. The years with greatest snow volume and snow cover extent in western China were 1976/1977,1977/1978 and 1985/1986,while winters with the least snows were 1973/1974。1984/1985. There is a clear indication of long term trend in 30一year records over the Tibetan Plateau .increasing with the global warming. Time evolution for the recent 30-year events suggests that both excessive Tibetan snow cover and poor Indian summer monsoon rainfall are mainly result from the global anomalies of oceanic and atmospheric pattern referred as the El一Nino一Southern Oscillation. The eastward excursion of the West Pacific warm pool leads to a poor Indian summer monsoons. The wintertime atmospheric anomalies and the northern hemisphere teleconnection with ENSO events bring more snowfall on the Tibetan Plateau. Empirical and modeling studies indicate that snow cover over the Tibetan Plateau plays a significant role in seasonal atmospheric conditions. Our study fails to confirm the widely-accepted view. Perhaps,the fact is that the dearth of snow cover limits the snow-albedo effect and snow-hydrological effect on climate. The implication of these results for the Ice Age issues are also briefly discussed.

Key words: snow cover, annual cycle, interaction between snow cover and climate, Tibetan Plateau, Western China