顾及地形起伏的中国低纬度地区湿延迟与可降水量转换关系研究

On the Relation Between the Wet Delay and the Water Precipitable Vapor in Consideration of Topographic Relief in the Low-latitude Region of China

在地基GPS气象学中,湿延迟(zenith wet delay,ZWD)与可降水量(precipitable water vapor,PWV)的转换系数K是一个重要的参数。本文利用中国低纬度地区(20.03°N^28.2°N)20个探空站2008~2011年的探空数据,分析了K值随测站纬度和海拔的变化特征,并建立了一种无需站点气象数据,仅与站点纬度、年积日和海拔相关的区域转换系数K值模型。结果表明,各站平均K值分别随纬度、海拔的增大而减小,减小速率分别为0.0002/(°)和0.002/km;本文建立的区域模型的精度与单站模型或者通过加权平均温度(Tm)获得的转换系数K值的精度相当,可用于该区域无气象数据条件下GPS反演PWV。

The conversion coefgficient Kbetween the zenith wet delay and the precipitable water vapor is an important parameter in ground-based GPS meteorology.The data of 20 radiosonde stations from2008 to 2011in a low-latitude region of China（20.03°N^28.2°N）were used to analyze the change of K with respect to latitude and height.A regional conversion coefficient K model without any meteorological parameters was constructed by considering site latitude,day of the year,and site height.The results show that the mean values of Kat each site tend to reduce with increasing latitude and height at the rates of 0.000 2per degree and 0.002 per kilometer,respectively.The regional conversion coefficient K model has almost same accuracy as that of the site-specific model or as estimated by the weighted mean temperature,and can be used to obtain GPS PWV in the applied region without any meteorological parameters.