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.