青藏高原上空平流层水汽的时空演变特征

Temporal and Spatial Evolution Characteristics of Stratospheric Water Vapor over the Tibetan Plateau

为研究青藏高原上空平流层水汽的时空演变特征,利用ERA-Interim再分析数据,通过气候统计学方法,对青藏高原上空平流层水汽时空演变特征及长期变化趋势进行研究。结果显示,青藏高原上空不同高度平流层水汽分布不同。在平流层低层,夏季和秋季水汽由南向北递减,而冬季水汽由南向北逐渐递增。在平流层中层,夏季水汽含量的分布呈现明显的东西差异。在平流层上层,水汽呈现一致的由南向北方向逐渐增加的分布情况。在垂直方向上随高度增加水汽先迅速地减小后再增加,春季和冬季“<”型结构明显。青藏高原上空水汽含量在不同时段的变化趋势表现不同,1979-1991年及1997-2007年呈递减的趋势,1992-1996年及2007年以后呈增加的趋势。近10年以来平流层低层水汽含量显著增加,增长趋势约为每年0.4~0.5 ppmv。

In order to study the characteristics of the temporal and spatial evolution of stratospheric water vapor over the Tibetan Plateau,the ERA-Interim reanalysis data is used and the method of climate statistics is used to discuss the characteristics of the temporal and spatial evolution of stratospheric water vapor over the Tibetan Plateau and the long-term change trend were studied.The results show that the stratospheric water vapor distribution over the Tibetan Plateau is different at different altitudes.In the lower stratosphere,the water vapor decreases from south to north in summer and autumn;while in winter,the water vapor gradually increases from south to north.In the middle stratosphere,the distribution of water vapor content in summer shows obvious differences between east and west.In the upper stratosphere,water vapor presents a uniform distribution that gradually increases from south to north.In the vertical direction,with the increase of height,the water vapor first decreases rapidly and then increases,and the " <" structure is obvious in spring and winter.The variation trend of water vapor content over the Tibetan Plateau is different in different periods,showing a decreasing trend in 1979-1991 and 1997-2007,and an increasing trend in 1992-1996 and after 2007.In recent ten years,the water vapor content in the lower stratosphere has increased significantly,and the growth trend is about 0.4~0.5 ppmv per year.