毛乌素沙区近期气候振动的研究

本文利用毛乌素沙区近40年的气象资料，论述了促使毛乌素地区沙漠化的气候条件。分析该沙区边缘地带与沙化有关的降水量、蒸发等因子的气候变化趋势及期振动所具有的准周期性，建立它们与各环流因子之间的多元线性回归模型。发现年降水量和年干燥度的3年和8—9年周期在该沙区普遍存在，且准3年周期与北半球冷空气活动、西太平洋副高及赤道东太平洋海温的周期振动有关。利用鄂托克1955—1989年的年干燥度序列可以建立AR（2）模型，并依此预测该地1990和1991年的气候可能较常年干燥，1992年气候可能转变为较常年偏湿。

The Study of Recent Climatic Fluctuation in the Maowusu Sand Region

Based on the meteorological data of seventeen stations in the Maowusu sand region in the recent 40 years, we investigated climatic characteristics of radiation, heat, precipitation and wind sand and revealed that spring is the most severe season of desertification in the region. We also discussed in detail climatic evolution tendencies of various factors related to desertification processes. The power spectra were analysed for the time series (1955—1988) of annual precipitation and aridity degree in the four stations of Etoke, Dongsheng, Yanchi and Yulin, respectively. The pronounced oscillation periods are quasi-triennial and eight to nine years. The quasi-triennial vibration may be associated with the periodic variations of SST, subtropical high, temperature of Tibetan Plateau and cold air activity of the northern hemisphere