青藏高原北部荒漠化加剧的气候因素分析

Analyese on Climatic Factors of Desertification Development in Northern Qinghai-Xizang Plateau

青藏高原的荒漠化近年来显著加剧。通过空间自相关分析方法, 对近50年来高原北部有代表性的5处荒漠化地区的降水、风速等气候因子在年内的时间分配格局及变化趋势进行了研究, 并结合当地影响荒漠化的人为因素, 与实地监测得到的荒漠化现状和动态指标进行了关联度分析。结果表明: 采用空间自相关分析等方法研究气象要素的时空分布特征能合理地揭示气候变化与荒漠化加剧等生态问题之间的因果关系。高原荒漠化加剧是一个受到气候因子、人为因子以及下垫面状况等多种因素综合影响的极为复杂的过程, 气候因子是主导因子。在气候因素中一年内降水时间上分配不均衡趋势的增强对高原北部荒漠化加剧起到了关键作用。

The development of desertification in Qinghai-Xizang Plateau is intensifying in recent years. Climate factors relating to desertification for the last 47 years such as precipitation, wind velocityetc., were studied at five typical desertification sites through spatial autocorrelation analysis methods with focus particularly on their annual temporal distribution patterns and development trend. Further relational analysis was also conducted to find the correlation between desertification trend and the impact of climate factors and human activities. The result shows that the spatial autocorrelation analysis can be effective to explore the causality of temporal distribution of climate features toward environmental problems such as desertification. Various climatic and human factors as well as changeable ground conditions together contributedto the intensified and complicated desertification process in the northern Qinghai-Xizang Plateau, among them it is the ever obvious unevenness of annul precipitation distribution in temporal dimension as shown by the Moran Index that has the most important role to play.