基于地基GPS遥感的大连地区大气水汽总量变化特征

Characteristics of precipitable water vapor based on ground-based GPS in Dalian

基于大连地区地基GPS综合观测网遥感反演了大气水汽总量(PWV),并利用2005—2011年大连本站探空资料拟合了大连地区地面温度和大气加权平均温度的关系,分析了大连地区PWV空间变化、逐月变化和日变化特征及PWV变化与降水的关系。结果表明:反演得到大连本站的PWV与探空积分的水汽含量的相关系数达0.988,均方根误差为2.5 mm。大连地区PWV南北分布较均匀;PWV最大的月为7—8月,最大月平均值约为40 mm;PWV最小的月为1月,最小月平均值小于4 mm;大连地区PWV春季和冬季日变化幅度约为0.5 mm,夏季和秋季日变化幅度约为1.3 mm。夏季和秋季的PWV日变化呈单峰型,春季和冬季的PWV日变化呈多峰型;在降水发生前8 h大气水汽总量有明显增加过程,对降水的发生有指示作用。

Based on the precipitable water vapor （PWV） retrieved from the ground-based GPS observation net- work in Dalian area, the characteristics of spatial distribution, diurnal variation, monthly variation and the relation- ship between the PWV and precipitation were analyzed. At the same time ,the relationship was fitted between sur- face temperature and weighted average temperature according to radiosonde data from 2005 to 2011 in Dalian. The results show that the correlation coefficient between the GPS PWV and radiosonde PWV is 0. 988 and the root- mean-square error is 2. 5 mm. The spatial distribution of the PWV in Dalian is homogeneous. The maximum values of the PWV occur from July to August and minimum values appear in January, and their corresponding monthly averages are 40 mm and 4 mm respectively. The daily variation of the PWV is in a multiple peaks shape with 0. 5 mm amplitude range in spring and winter in Dalian, while that in summer and autumn is in a single peak shape with 1.3 mm amplitude range. The PWV increases significantly 8 hours ahead of precipitation, which is of indica- tive role to the precipitation prediction.