毛乌素沙区近期春季气候变化趋势的探讨

本文根据毛乌素沙区鄂托克，东胜、盐池、榆林和乌审旗近40年的春委气象资料，讨论了与沙漠化过程有关因子的气候演变趋势。结果表明，在50年代后期和60年代春季，气候较湿；70年代春季变干；80年代春季变湿。假如这种准10年的气候振荡是客观存在的，那么90年代春季的气候将可能变干。通过对这些台站的春季降水量与春季干燥系数的时间序列的功率变分析，发现存在准3年和8－9年的周期，它可能与北半球冷空气活动及西太平洋副热高压环流的气候振荡有某种内在的联系。本文采用多元线性回归方法建立了降水量和干燥系数的预报模型。利用建国以来的实例讨论了人类对大自然的不同干预将会产生不同的气候效应。

THE RESEARCH OF RECENT CLIMATIC CHANGE TENDENCY IN SPRING IN THE MAO WU SU SAND REGION

By using the meteorological data at five stations (Etoke, Dongsheng, Yanchi, Yulin, Ushenqi)in the Mao Wu Su sand region in spring during recent 40-years, we have discussed in detail climatic evolution tendencies of the factors related to desertification processes. These factors include aridity coefficients, cloud cover, precipitation, humidity, wind speed and wind sand days. The results show that it was wetter in the 1960's and became drier in the 1970's and wetter in 1980's in spring. If it is true to exist a quasi-ten years oscillation, it would be drier in spring of 1990's. The power spectrums have been analysed for time series(1955-1988) of precipitation and aridity coefficient in spring at the five stations, respectively. The pronounced period throgh significance test at significance level of 0.05 are two to three and eight to nine years for both precipitation and aridity coefficient each station. The oscillation of 2-3 years may be associated with SST of tropical oceans, the subtropical high over the western Pacific and cold air activity in the northern hemisphere that all have the same periodic oscillation. The regression prediction models have been set up for both precipitation and aridity coefficient in spring each station, respectively. Based on theses models, we can predict the precipitation and aridity coefficients in spring in this region for three months or half a year in advance. Finally, we discuss the impact of human activity on desertification. We point out that different human intervention on nature will bring about various climatic effects in the same climatic environment.