RESUME / ABSTRACT  


Comparisons of GPS derived precipitable water with radiosonde observations and operational analyses


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Stephen MacPherson







The presence of atmospheric water vapour causes a delay in radio signals broadcast from satellites of the global positioning system (GPS). Estimates of this delay using GPS data from a network of ground-based GPS receivers can be used to derive estimates of integrated water vapour (IWV) for meteorological applications such as data assimilation. MSC/MRB is collaborating with Natural Resources Canada (NRCan) on a project to evaluate the quality and usefulness of GPS derived IWV. NRCan provided MRB with GPS delay data for a network of GPS sites in Canada. GPS IWV derived from these data were compared with IWV from radiosondes and operational analyses and trial fields of the global GEM model. An introduction to GPS meteorology will be presented followed by the IWV inter-comparison results.