Skip to main content


We’d like to understand how you use our websites in order to improve them. Register your interest.

GPS observations in Thailand for hydrological applications


We report the delineation of the onset of the Asian Monsoon based on GPS sensing of water vapor in Thailand. We conducted GPS observations at five sites in Thailand since March 1998 under the hydrological project called GAME-T. The objective of the project is to clarify the water and energy cycle system in the Asian Monsoon area. As a preliminary analysis, we used data from March to June 1998 and estimated the water vapor content in the zenith direction (PWV) every 30 minutes using GIPSY software (GPS-PWV). A comparison of the resultant PWV with those estimated from rawinsonde data (Sonde-PWV) suggested that, generally, the long term trends of both GPS-PWV and Sonde-PWV are consistent and a rapid increase of water vapor content is visible in May, which corresponds to the onset of the Monsoon. However, systematic differences between GPS-PWV and Sonde-PWV are eminent. The RMS of the difference (RMSD) between Sonde-PWV and GPS-PWV reaches about 8.7 mm. This large RMSD can be reduced to about 5 mm by removing some unreliable sonde data and making a linear correction to Sonde-PWV. In addition, a comparison of GPS-PWV with other meteorological data (temperature, humidity, and rainfall) showed that there is a strong correlation between a rapid increase of GPS-PWV and heavy rainfall in Bangkok and in Chiang Mai, which may be used to judge the onset of the Monsoon in the area accurately.


  1. Askne, J. and H. Nordius, Estimation of tropospheric delay for microwaves from surface weather data, Radio Sci., 22, 379–386, 1987.

  2. Bevis, M., S. Businger, T. A. Herring, C. Rocken, R. A. Anthes, and R. H. Ware, GPS Meteorology: Remote sensing of atmospheric water vapor using the Global Positioning System, J. Geophys. Res., 97, 15787–15801, 1992.

  3. Bevis, M., S. Businger, S. Chiswell, T. A. Herring, R. A. Anthes, C. Rocken, and R. H. Ware, GPS Meteorology: Mapping zenith wet delay onto precipitable water, J. Appl. Meteor., 33, 379–386, 1994.

  4. Boudouris, G., On the index of refraction of air, the absorption and dispersion of centimeter waves by gasses, J. Res. Natl. Bur. Stand., Sect., 67D, 631–684, 1963.

  5. Businger, S., S. R. Chiswell, M. Bevis, J. Duan, R. Anthes, C. Rocken, R. Ware, T. M. Exner, T. van Hove, and F. Solheim, The promise of GPS in atmospheric monitoring, Bull. Amer. Meteor. Soc., 77, 5–18, 1996.

  6. Curry, J. H. and P. J. Webster, Thermodynamics of Atmosphere and Oceans, 471 pp., Academic Press, 1999.

  7. Duan, J., M. Bevis, P. Fang, Y. Bock, S. Chiswell, S. Businger, C. Rocken, F. Solheim, T. Von Hove, R. Ware, S. McClusky, T. A. Herring, and R. W. King, GPS Meteorology: Direct estimation of the absolute value of precipitable water, J. Appl. Meteor., 35, 830–838, 1996.

  8. Kobayashi, H., Examination of precipitable water vapor from GPS tropospheric delay in the tropics, Ms.D. dissertation to the University of Tokyo, 69 pp., 1999 (in Japanese).

  9. Matsumoto, J., Seasonal transition of summer rainy season over Indochina and adjacent Monsoon region, Adv. in Atmos. Sci., 14(2), 231–245, 1997.

  10. Niell, A., Global mapping functions for the atmosphere delay at radio wavelengths, J. Geophys. Res., 101, 3227–3246, 1996.

  11. Ohtani, R., A study on the evaluation of GPS retrieved precipitable water vapor, Ph.D. dissertation to the University of Tokyo, 91 pp., 1999.

  12. Rocken, C., R. Ware, T. Van Hove, F. Solheim, C. Alber, J. Johnson, M. Bevis, and S. Businger, Sensing atmospheric water vapor with the Global Positioning System, Geophys. Res. Lett., 20, 2631–2634, 1993.

  13. Rocken, C., T. Van Hove, J. Johnson, F. Solheim, R. Ware, M. Bevis, S. Businger, and S. Chiswell, GPS storm—GPS sensing of atmospheric water vapor for meteorology, J. Ocean. Atmos. Tech., 12, 468–478, 1995.

  14. Rocken, C., T. Van Hove, and R. Ware, Near real-time GPS sensing of atmospheric water vapor, Geophys. Res. Lett., 24, 3221–3224, 1997.

  15. Ross, R. J. and S. Rosenfeld, Estimating mean weighted temperature of the atmosphere for GPS applications, J. Geophys. Res., 102, 21719–21730, 1997.

  16. Takagi, T., F. Kimura, and S. Kono, Diurnal variation of GPS precipitable water at Lhasa in premonsoon and monsoon periods, J. Meteor. Soc. Japan, 78(2), 175–180, 2000.

  17. Tregoning, P., R. Boers, D. O’Brien, and M. Hendy, Accuracy of absolute precipitable water vapor estimates from GPS observations, J. Geophys. Res., 103, 28701–28710, 1998.

  18. Ware, R., C. Alber, C. Rocken, and F. Solheim, Sensing integrated water vapor along GPS ray paths, Geophys. Res. Lett., 24, 417–420, 1997.

  19. Zumberge, J. F., M. B. Heflin, D. C. Jefferson, M. M. Watkins, and F. H. Webb, Precise point positioning for the efficient and robust analysis of GPS data from large networks, J. Geophys. Res., 102(B3), 5005–5017, 1997.

Download references

Author information



Corresponding author

Correspondence to Hiroshi Takiguchi.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Takiguchi, H., Kato, T., Kobayashi, H. et al. GPS observations in Thailand for hydrological applications. Earth Planet Sp 52, 913–919 (2000).

Download citation


  • Water Vapor Content
  • Atmospheric Water Vapor
  • Precipitable Water Vapor
  • Hydrological Application
  • Sonde Data