A global empirical model for mapping zenith wet delays onto precipitable water vapor using GGOS Atmosphere data
The importance of water vapor in research of global climate change and weather forecast cannot be over emphasized; therefore substantial efforts have been made in exploring the optimal methods to measure water vapor. It is well-established that with a conversion factor, zenith wet delays can be mapped onto precipitable water vapor (PWV). However, the determination of the exact conversion factor depends heavily on the accurate calculation of a key variable, weighted mean temperature of the troposphere (Tm). As a critical parameter in Global Positioning System (GPS) meteorology, Tm has recently been modeled into a global grid known as GWMT. The GWMT model only requires the location and the day of year to calculate Tm. Despite the advantages that the GWMT model offers, anomalies still exist in oceanic areas due to low sampling resolution. In this study, we refine the GWMT model by incorporating the global Tm grid from Global Geodetic Observing System (GGOS) and obtain an improved model, GWMT-G. The results indicate that the GWMT-G model successfully addresses the anomaly in oceanic areas in the GWMT model and significantly improves the accuracy of Tm in other regions.
KeywordsGPS meteorology zenith wet delay GWMT model GWMT-G model GGOS
Unable to display preview. Download preview PDF.
- Chen J Y. 1998. On the error analysis for the remote sensing of atmospheric water vapor by ground based GPS. Acta Geod Cartogr Sin, 27: 113–118Google Scholar
- Ding J C. 2009. GPS Meteorology and Its Applications. Beijing: China Meteorological Press. 1–10Google Scholar
- Gu X P. 2004. Research on retrieval of GPS water vapor and method of rainfall forecast. Doctoral Dissertation. Beijing: China Agricultural University. 1–15Google Scholar
- Li J G, Mao J T, Li C C. 1999. The approach to remote sensing of water vapor based on GPS and linear regression T m in eastern region of China. Acta Meteorol Sin, 57: 283–292Google Scholar
- Saastamoinen J. 1972. Atmospheric correction for the troposphere and stratosphere in radio ranging satellites. In: Soren W. Henriksen, Armando Mancini, Bernard H. Chovitz, eds. The Use of Artificial Satellites for Geodesy, Geophysics Monograph Series, Vol. 15. Washington DC: American Geophysical Union. 247–251CrossRefGoogle Scholar
- Xu C Q, Shi J B, Guo J M, et al. 2011. Analysis of combining ground-based GPS network and space-based COSMIC occultation observation for precipitable water vapor application within China. Geomat Inf Sci Wuhan Univ, 36: 467–470Google Scholar
- Yu S J. 2011. Remote sensing of water vapor based on ground GPS observations. Doctoral Dissertation. Wuhan: Institute of Geodesy and Geophysics, Chinese Academy of Sciences. 37–50Google Scholar