1980-2012年青藏高原土壤湿度时空演变特征

基于美国气候预测中心（CPC）土壤湿度资料和80个青藏高原气象观测站的降水、气温资料，对青藏高原土壤湿度时空演变、突变，及土壤湿度与降水、气温的关系进行了分析.结果表明：青藏高原土壤湿度呈自东南向西北递减的分布特征，土壤湿度与降水量在空间上有很好的对应关系，在时间上存在2~4个月的时滞相关.1980-2012年高原土壤湿度呈显著增多趋势，土壤湿度变化发生突变的年份为2003年.在土壤湿度变化过程中，降水和气温的作用明显，5-10月降水量和1-6月气温是影响高原土壤湿度变化的主要因素.5-10月降水量决定了多水期的土壤湿度，而多水期土壤湿度和1-6月气温共同决定了少水期的土壤湿度.

The temporal-spatial variations of soil moisture over the Tibetan Plateau during 1980-2012

Based on soil moisture dataset from US Climate Prediction Center and precipitation and temperature data from 80 meteorological stations over the Tibetan Plateau, in this study, the temporal-spatial variations and abrupt change of soil moisture were investigated along with the relationship between soil moisture and precipitation and temperature respectively. Result shows that soil moisture over the Tibetan Plateau decreases from southeast to northwest and it has a good corresponding correlation with precipitation in spatial distribution. But there is a time lag of 2-4 months between soil moisture and precipitation. The soil moisture over the Tibetan Plateau had presented significant increase during 1980-2012, and an abrupt change occurred in 2003. Precipitation and temperature, especially precipitation from May to October and temperature from January to June, have obvious effect on the process of soil moisture variation. Soil moisture during high water period is determined by precipitation while soil moisture during low water period is decided by both temperature from January to June and soil moisture during high water period.