Variational assimilation of slant-path wet delay measurements from a hypothetical ground-based GPS network. Part I: Comparison with precipitable water assimilation

The derivation of ZWD and PW can greatly reduce the uncertainties associated with each SWD measurement by averaging over many epochs and satellites, but it also loses valuable information on the three-dimensional moisture structure around the receiver site. [...]the assumption of azimuthal homogeneity limits the accuracy and spatial resolution of GPS-sensed water vapor (Davis et al. 1993; Elosegui et al. 1998). [...]of slant wet delay assimilation, the squall line in the model develops at a time and location very close to the ''perfect'' initial condition run.