摘要
利用青藏高原1960—2004年近45 a气象台站年降水记录,对高原中东部年降水做了空间变化分析,发现高原以唐古拉山为界,高原南北降水变化存在明显差异,特别是高原南部和东北部降水几乎成相反的变化.进一步分析5个重建的长时间降水序列,发现青藏高原南北降水在百年时间尺度上也存在明显的差异.在百年时间尺度上,过去600 a高原南北降水变化都在1740年和1850年左右发生突变.1740年以前,整个高原北部降水都在波动中增加,而高原南部在减小;1740—1850年期间,高原北部降水在波动中减小,而高原南部在增加;1850年以后,高原北部降水又在波动中增加,而高原南部降水在减小.高原南北降水变化的空间差异主要是由季风和西风带决定的.
A detailed analysis of the spatial and temporal changes in annual precipitation over the period of 1961-2004 in the Tibetan Plateau （TP） is presented based on a developed daily precipitation dataset of 45 weather stations with altitudes over 2000 m above sea level. Data from the 45 stations in the central and eastern TP are selected for rotated empirical orthogonal functions （REOF） analysis with a relatively uniform distribution of the station network. In detail the first REOF mode describes the coherent precipitation variation over the southern TP. The second REOF mode emphasizes the coherent precipitation variation over the central TP. The third REOF mode emphasizes precipitation variation over the northern TP. The fourth mode describes the precipitation variation over the northeast TP. But generally, precipitation varies much differently between Tanggula Range, which the north and south of is the boundary of the southern and northern TP. Meanwhile, five time series of precipitation reconstructed from ice cores and lake sediment in the TP have been discussed. These reconstructed period ranges from 1400 to 2000, making it is possible to determine the precipitation variability in the TP at secular time scale. The results indicate that precipitation also varies differently in the southern and northern TP in a secular time scale. In the past 600 years, both precipitations in the southern and northern TP changed abruptly at around 1740 and 1850. In the period from 1400 to 1740, precipitation increased （decreased） in the northern TP （the southern TP）. While during the period from 1740 to 1850, precipitation decreased in northern TP and increased in the southern TP. Then since 1850 precipitation has increased in the northern TP and decreased in the southern TP. It is revealed that precipitation variation is much different between the northern and southern TP, both in decade and secular time scales, which is due to the monsoon prevailing in the southern TP and the westerly prevailing in the northern TP.
出处
《冰川冻土》
CSCD
北大核心
2008年第5期726-732,共7页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(40771209)
国家重点基础研究发展计划(973计划)项目(2005CB422004)
中国科学院知识创新工程重要方向项目(KZCX2-YW317-1)
国家杰出青年科学基金项目(40525001)资助
关键词
青藏高原
降水
差异
Tibetan Plateau
precipitation
difference
