地基北斗大气水汽反演及其精度分析

Retrieval of Atmospheric Water Vapor from Beidou System and Its Accuracy Analysis

摘要: 本文研究了基于北斗三号全球卫星导航系统(BDS-3)的大气水汽反演技术及其精度分析。大气水汽是气象演变中的重要参数，对降水、天气系统演变和全球气候变化等具有重要影响。传统的大气水汽探测方法存在成本高、时空分辨率低等问题。因此，本文利用北斗三号地球静止轨道(GEO)卫星播发的PPP-B2b信号，采用实时精密单点定位技术，实现了台站处分布式高时效、高精度对流层延迟解算和大气水汽含量反演。在上海、河池和海口三个地区进行了水汽试验，并利用同址探空和GPS水汽数据进行试验数据准确性比对评估分析。结果表明，实时水汽产品的平均RMS在3 mm左右，与目前准业务运行的GPS水汽产品精度相当。该研究为大气水汽含量反演、水汽业务建设提供了重要的参考依据，对于中小尺度极端强对流天气系统监测、台风监测和短临预报具有重要的应用价值。

Abstract: This paper investigates the atmospheric water vapor retrieval technology based on the BeiDou-3 Global Satellite Navigation System (BDS-3) and analyzes its accuracy. Atmospheric water vapor is a crucial parameter in meteorological evolution, significantly impacting precipitation, weather system evolution, and global climate change. Traditional methods for detecting atmospheric water vapor have issues such as high cost and low spatial and temporal resolution. Therefore, this paper utilizes the PPP-B2b signal broadcast by the BeiDou-3 Geostationary Orbit (GEO) satellite, adopting real-time precise point positioning technology to achieve distributed, high-efficiency, high-precision tropospheric delay resolution, and atmospheric water vapor content retrieval at stations. Water vapor experiments were conducted in Shanghai, Hechi, and Haikou, and the accuracy of the experimental data was compared and evaluated using collocated radiosonde and GPS water vapor data. The results show that the average RMS of real-time water vapor products is around 3 mm, which is comparable to the accuracy of currently quasi-operational GPS water vapor products. This study provides an important reference for atmospheric water vapor content retrieval and water vapor service construction, and has significant application value for monitoring small and medium-scale extreme severe convective weather systems, typhoon monitoring, and short-term forecasting.