海上动态GPS大气可降水量信息反演

Retrieval method of marine kinematic GPS precipitable water vapor

基于精密单点定位(PPP)技术,对海洋上空大气可降水量(PWV)信息反演方法进行研究。采用随机游走过程估计方法,动态模拟船载GPS接收机天顶对流层湿延迟(ZWD)在时间和空间尺度上的随机变化。利用渤海湾船载动态GPS测量数据和同步气象观测数据,结合海洋动态环境,以渤海湾MM5模式积分水汽为参考值,详细分析不同随机过程噪声约束和卫星截至高度角等因素对PWV提取精度的影响。结果表明,选取槡2～5mm/h的随机过程噪声约束以及7°～10°的卫星截至高度角,海上船载动态PWV反演结果与MM5模式积分水汽基本一致,其偏差的绝对值均小于3 mm,均方根误差优于1.2 mm。

The retrieval method of marine kinematic GPS precipitable water vapor （PWV） was researched using precise point positioning （PPP） technique. The random variation of GPS zenith wet dalay in the time and spatial scales was simulated by the evaluation method of random walk process. The ship-borne GPS data and simultaneous meteorological observation in Bohai sea were processed. Then the integral water vapor for MM5 model was used as reference, and the influence of PWV retrieval precision for different random process noise constraint and cut-off elevation angle was analyzed. The results show that the absolute differences of marine kinematic GPS/PWV are all less than 3 mm and the root mean square error is 1.2 mm, using random process noise constraint of 2-5 mm/√h and cut-off elevation angle of 7°-10°. The ship-borne kinematic GPS/ PWV agrees well with the integral water vapor for MM5 model.