Estimation and evaluation of real-time precipitable water vapor from GLONASS and GPS
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The revitalized Russian GLONASS system provides new potential for real-time retrieval of zenith tropospheric delays (ZTD) and precipitable water vapor (PWV) in order to support time-critical meteorological applications such as nowcasting or severe weather event monitoring. In this study, we develop a method of real-time ZTD/PWV retrieval based on GLONASS and/or GPS observations. The performance of ZTD and PWV derived from GLONASS data using real-time precise point positioning (PPP) technique is carefully investigated and evaluated. The potential of combining GLONASS and GPS data for ZTD/PWV retrieving is assessed as well. The GLONASS and GPS observations of about half a year for 80 globally distributed stations from the IGS (International GNSS Service) network are processed. The results show that the real-time GLONASS ZTD series agree quite well with the GPS ZTD series in general: the RMS of ZTD differences is about 8 mm (about 1.2 mm in PWV). Furthermore, for an inter-technique validation, the real-time ZTD estimated from GLONASS-only, GPS-only, and the GPS/GLONASS combined solutions are compared with those derived from very long baseline interferometry (VLBI) at colocated GNSS/VLBI stations. The comparison shows that GLONASS can contribute to real-time meteorological applications, with almost the same accuracy as GPS. More accurate and reliable water vapor values, about 1.5–2.3 mm in PWV, can be achieved when GLONASS observations are combined with the GPS ones in the real-time PPP data processing. The comparison with radiosonde data further confirms the performance of GLONASS-derived real-time PWV and the benefit of adding GLONASS to stand-alone GPS processing.
KeywordsGLONASS Zenith tropospheric delay Precipitable water vapor Real-time precise point positioning VLBI Radiosonde
We acknowledge IGS for providing the GPS and GLONASS data, IVS for providing the VLBI data, and NOAA for the online provision of radiosonde data. One of the authors (C. Lu) is supported by the China Scholarship Council, which is gratefully acknowledged.
- Böhm J, Böhm S, Nilsson T, Pany A, Plank L, Spicakova H, Teke K, Schuh H (2012) The new Vienna VLBI Software VieVS. Geodesy for planet earth. In: Proceedings of the 2009 IAG symposium, Buenos Aires, International Association of Geodesy Symposia Series, vol 136. pp 1007–1011Google Scholar
- Caissy M, Agrotis L, Weber G, Hernandez-Pajares M, Hugentobler U (2012) The international GNSS real-time service. GPS World 23(6):52–58Google Scholar
- Dach R, Schaer S, Hugentobler U (2006) Combined multi-system GNSS analysis for time and frequency transfer. Proc Eur Freq Time Forum 2006:530–537Google Scholar
- De Haan S (2006) National/regional operational procedures of GPS water vapour networks and agreed international procedures. Rep WMO/TD-No, 1340:20. KNMI, NetherlandsGoogle Scholar
- Dousa J (2010) Precise near real-time GNSS analyses at geodetic observatory Pecny-precise orbit determination and water vapour monitoring. Acta Geodyn Geomater 7(157):7–17Google Scholar
- Elgered G, Plag H, van der Marel H, Barlag S, Nash J (eds.) (2005) COST 716: exploitation of ground-based GPS for climate and numerical weather prediction applications, final report, European community, EUR 21639. ISBN 92-898-0012-7Google Scholar
- Kouba J (2009) A guide to using international GNSS service (IGS) products. http://igscb.jpl.nasa.gov/igscb/resource/pubs/UsingIGSProductsVer21.pdf
- Teke K, Boehm J, Nilsson T, Schuh H, Steigenberger P, Dach R, Heinkelmann R, Willis P, Haas R, Garcia-Espada S, Hobiger T, Ichikawa R, Shimizu S (2011) Multi-technique comparison of troposphere zenith delays and gradients during CONT08. J. Geod 85:395–413. doi: 10.1007/s00190-010-0434-y CrossRefGoogle Scholar