大连地区GPS反演大气可降水量的变化特征

Variation Characteristics of Precipitable Water Vapor Inversed by GPS in Dalian

利用GPS反演的大气可降水量(PWV)分析了2010-2012年大连地区水汽的时空变化特征,结果表明,GPS/PWV资料能够反映大气中水汽的变化。大连地区PWV空间分布比较均匀;PWV最大的月份为7-8月,月平均值为43 mm左右;PWV最小的月份为1月,月平均值在4 mm以下。大连地区春、冬季PWV日平均变化幅度在0.5 mm以下,夏、秋季PWV日平均变化幅度在1 mm以上;夏、秋季PWV日平均变化呈单峰型,春、冬季PWV日平均变化呈多峰型。主汛期(7-8月),日平均PWV与气温有较好的负相关,与相对湿度有较好的正相关;06:00(北京时,下同)-15:00,气温逐渐升高,水汽输送造成PWV的下降大于蒸发所造成PWV的上升,大气水汽总量减小,相对湿度减小;15:00-次日06:00,气温逐渐下降,水汽输送造成PWV的下降小于蒸发造成PWV的上升,大气水汽总量增加,相对湿度增加。

The temporal and spatial characteristics of vapor in Dalian by using the PWV inversed by GPS during2010-2012 were analyzed. The results showed that the data of GPS / PWV can reflect the change of vapor in atmosphere. The spatial distribution of PWV was the evenly in Dalian area. The monthly mean PWV was maximum in July or August( 43 mm),the minimum in January( 4 mm). The range of daily variation of PWV in Dalian was less than 0. 5 mm in spring and winter,but more than 1 mm in summer and autumn. Daily variation of PWV showed single peak type in summer and autumn,but multi-peak in the other seasons. In flood season( from July to August),daily variation of PWV was significant negatively correlated with temperature,but positively correlated with relative humidity. During 06: 00( Beijing Time,hereafter the same) to 15: 00,temperature was increased gradually,while the atmospheric water vapor and relative humidity were decrease,and the decreased of PWV caused by water vapor transport was higher than the increased of PWV caused by evaporation.During 15: 00 to 06: 00 in next day,the result is opposite.