北京地区单双频地基GPS大气水汽遥测试验与研究

Atmospheric Water Vapor Experiment with the Mixed Single-and Dual-frequency Ground-based GPS-met Network in Beijing

该文对北京地区单双频地基GPS大气水汽监测网布网依据、单频与双频地基GPS测量数据解算技术应用、GAMIT和Bernese地基GPS数据分析处理软件应用、远程遥控GPS数据采集与通讯系统、资料分析与数值同化应用等方面的工作进展进行简要介绍,重点讨论了单双频地基GPS大气水汽资料的解算技术及其应用效果。结果表明:在北京天气敏感区通过单双频地基GPS接收机合理组网布局,可构建并利用高分辨率电离层延迟订正技术将单频接收机的大气水汽监测精度提高到实用水平,为强降水天气预报提供有价值的产品。

In the summer of 2000, a joint GPS-met experiment with 10 dual-frequency ground-based GPS receivers is successfully carried out by close collaboration among Institute of Meteorological Science of Beijing Municipal Meteorological Bureau （Institute of Urban Meteorology, CMA）, Peking University and the National Satellite Meteorological Center. Due to the fact that single-frequency GPS receivers are much cheaper than those of dual-frequency, and that the mixed single- and dual-frequency ground-based GPS-met network would be more economical, Beijing Municipal Meteorological Bureau established collaboration on this field with National Center for Atmospheric Research, U. S. A on the basis of the previous 2000 summer GPS-met experiment. And then for monitoring and investigating the atmospheric water vapor space-time evolution on the fine-resolution scale, Institute of Urban Meteorology sets up a GPS-met network over the severe weather events sensitive area within Beijing using the mixed single- and dual-frequency ground-based receivers following the principle efficient complementarily with the constructing network supported by Beijing municipal government. The progress in the mixed single- and dual-frequency ground-based GPS-met network in Beijing is briefly summarized, especially on network design, application techniques of the mixed single- and dual-frequency network, data process method with Bernese and GAMIT software, and remote automatic transfer/control system for data collection, and impacts of retrieved atmospheric water vapor on weather forecasts and short-rang NWP. Comparing experiment results from the mixed single- and dual-frequency GPS receivers with those of the whole dual-frequency network, it shows that under the mixed GPS-met network spaced 5- 10 km over the severe weather events sensitive area within Beijing, the retrieval accuracy of the single-frequency GPS observations can meet the practical requirement after correcting the ionosphere-delay error with the high resolution correction model, and it also clearly shows that the fine resolution construction distribution and timely evolution information on the atmospheric water vapor can be captured efficiently with this mesoscale ground-based GPS-met network, and that valuable products for severe precipitation forecasts can be provided. Compared with dual-frequency ground-based GPS-met application technique, it is preponderant for single-frequency GPS-met observation because it can significantly reduce the construction costs. The study provides a useful example of how to establish regional ground-based GPS-met network, and how to apply GPS-met data into weather forecasts.