利用中国西北区西部7个农业试验站1981-2001年0~40 cm的土壤湿度、降水、气温、水面蒸发和相对湿度观测资料, 分析了逐站土壤湿度的月变化、年际特征及其气候响应。结果表明:(1)7站土壤湿度月变化分为平稳型和波动型; 新疆各站土壤湿度沿垂直方向年际变化比较一致, 但青海2个测站上下层趋势基本相反; 新疆各站整层年际变化相对较大, 而青海2个测站年际变化相对稳定; 土壤湿度年际变化总体趋势随深度增加而减小。(2)进入20世纪90年代, 多数站点土壤明显干化, 个别站还存在突变现象, 土壤湿度与气温有着显著的负相关。(3)土壤湿度和气候因子之间存在相互响应, 土壤湿度与气温普遍存在负相关, 土壤湿度与降水之间总体响应不明显。

The characteristics of gravimetric soil moisture vertical distribution, temporal variation and its response to the local climate changeover the west of Northwest China are analyzed. The results indicate that:(1) Monthly variation of soil moisture could be categorized into steady-going type and fluctuant type. The depth-time plots of soil moisture anomalies, signs of the moisture anomalies tested at most of stations are vertically consistent, signs are the reverse of the upper and lower layers in two stations. Yining, Wulanwusu and Nuomuhong stations reveal high vertical gradients of soil moisture variation, where as high vertical gradients are found in Tulufan stations.(2) Soil has been getting dry at most stations since 1990's, abrupt changes are found in two stations, Tulufan, Wulanwusu. The soil-drying trend is mainly controlled by air temperature. The main reason is that a negative feed back mechanism exists between soil moisture and air temperature.(3) There is response between soil moisture and climate. Negative correlation exists generally between soil moisture and temperature. A little of response is found between soil moisture and precipitation.