Up to now, all analysis of the distribution of water vapor over the Taklimakan desert area only depends on limited ground measurements and radio soundings setting mostly on the outer margin area. This paper establishes an approach to retrieve the water vapor over the desert at high temporal and spatial resolutions by the use of FY2C geostationary satellite split-window channels in cooperation with ground-based GPS water vapor measurement. Results show that the water vapor distribution over the Taklimakan desert is affected highly by topography and surface properties. The outer margin area has generally more water vapor than the inner area. Over the outer margin area, the western part has more water vapor than the eastern part, and the northern part has more than the southern part. The driest area lies to the south of Tazhong, east of Hotan River, and extended to the south boundary of the desert. Similar to elsewhere, water vapor over the desert area shows diurnal, monthly, seasonal and annual variations even at the driest inner area of the desert. In summer, the water vapor is transported from west to east over a long distance along the westerlies at a height between 700-400 hPa and with the average speed of 50 km h-1.
LIU XlaoYangMAO JieTaiZHANG FanCUI CaiXiaLIU DianLI JunZHAO Ling
利用2007-2010年的中国探空资料评估GPS掩星探测系统COSMIC（constellation observing system for meteorology,ionosphere，and climate）反演产品，对比数据在空间上限定掩星事件发生地和探空站的水平距离在100km以内，在时间上相差不超过1小时，对比高度范围为925～10hPa。对比结果表明，COSMIC反演大气温度略低于探空仪测量值，平均绝对偏差为-0．08K，标准差为1．67K。两者水汽资料在200hPa以上高度有系统性偏差；在200hPa以下，比湿的平均偏差约为＋0．080g／kg，标准差为0．692g／kg，水汽压平均相对误差约为＋69．6％，标准差为160．O％，水汽压存在极端低值的异常情况。通过对全球不同区域6种探空仪的对比，COSMIC反演产品在700hPa以下高度显著受背景场影响，由于背景场误差随区域改变，因此，只有在精度要求不高的情况下，COSMIC反演产品才适合用于评估其他资料。
