Lookup NU author(s): Dr Nigel Penna
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We compare estimates of integrated water vapour derived from ground-based Global Positioning System (GPS) and nearby surface meteorological data, with estimates derived from radiosonde soundings and from two global numerical weather prediction systems over the Australian Region for the year 2000. The relative accuracies of GPS-based estimates for sites with co-located radiosondes are similar to those reported in previous studies for other regions of the world, with the exception of Antarctica. For eight GPS sites with nearby radiosonde launch sites, an average GPS-integrated water vapour estimation standard deviation error of 8.8 per cent over the year 2000 was obtained, relative to that of radiosonde estimates. Respective percentage errors of 10.7 and 18.0 obtained for integrated water vapour derived from analyses and six-hour forecasts of the Australian Bureau of Meteorology's operational global numerical weather prediction system for 2000, indicate the potential of GPS estimates, when comprehensively available for assimilation, to significantly reduce such errors. Marked precipitable water diurnal variations in the time series of GPS-based data were also detected. The variations, averaged over one year, were found to be very similar to variations in GPS-derived zenith wet delay at all GPS sites. The potential of using GPS estimates of precipitable water for monitoring the performance of numerical weather prediction system moisture variables is indicated.
Author(s): Glowacki TJ, Penna NT, Bourke WP
Publication type: Article
Publication status: Published
Journal: Australian Meteorological Magazine
ISSN (print): 0004-9743