AIRS反演中国区域上对流层水汽分布特征研究

上对流层水汽分布对于全球能量和水循环具有非常重要的影响。利用美国Aqua卫星红外高光谱仪器（AIRS）反演的湿度廓线资料对中国上对流层水汽时空分布特征进行了分析。为了保证卫星反演湿度廓线产品精度可以满足气候特征分析的需求，首先利用JICA野外加密探空试验观测数据对卫星反演湿度廓线进行了真实性检验，分析表明，Aqua卫星搭载的AIRS反演的湿度廓线与探空加密观测数据总体具有较好的相关性，在200 hPa高度相对湿度偏差在5%以内，其精度可以用于上对流层水汽气候特征的分析。通过趋势分析以及EOF分解等方法，分析了2003年1月-2013年12月的中国区域上对流层水汽时空分布特征，结果表明，受夏季风影响，中国区域上对流层水汽具有明显的季节变化规律和年周期特征，中国大部分地区上对流层冬季偏干、夏季偏湿，夏季高湿区可以北移到35°N以北。而在新疆地区冬季偏湿、夏季偏干。总体来说，全年夏季水汽含量最高，秋季次之，冬季最小。2003年以来新疆地区及南部海域上对流层水汽呈显著增加趋势，华南、华北、内蒙古中西部水汽也有所增加，在高原地区及东北区域上对流层水汽稍有减少，但变化均不显著。上对流层水汽的增加，将有可能放大温室效应，在气候变化研究中应给予重视。

A Spatial-Temporal Distribution Characteristics Study on the Water Vapor of Upper Troposphere over China Using AIRS Data

The Upper Troposphere (UT) water vapor distribution has a very important influence on global energy and water cycle. The spatial-temporal distribution of water vapor in UT has been analyzed using humidity profile data retrieved from AIRS (Atmospheric Infrared Sounder) which is on board of Aqua satellite. In order to make sure that the accuracy of the humidity profile data meets the needs of the climate characteristics analyses, we run a validation on the relative humidity against the sounding observation data in JICA field campaign in 2008. The result shows that the two data sets have a good correlation, and the absolute error is within 5% in 200 hPa. Therefore, the AIRS relative humidity data in 200 hPa can be used for the climate characteristics analysis. Our analysis on the spatial-temporal characteristics of the relative humidity during the period of January 2003 through December 2013 prove that, with the impact of the summer monsoon, the relative humidity in China has significant seasonal and yearly variation characteristics. The relative humidity in UT is more in summer than that in winter in China, the high relative humidity area can move northward to 35°N in summer. There is a opposite distribution in Xinjiang province that more humidity in winter and less in summer. Over all, the relative humidity in UT over China is the highest in summer, lower in fall, and the lowest in winter. From 2003, the relative humidity has shown a significant elevating trend in South China Sea and Xinjiang province. In South China, North China, central and western of Inner Mongolia, relative humidity in UT also increased, but did not change significantly, and in the Tibetan Plateau and the Northeast China, water vapor in UT decreased slightly, but the changes were not significant. The increase of water vapor in the UT will have the potential to amplify the greenhouse effect, which should be paid more attention in the study of climate change.