Numerical Tests of a Method for Dynamic Analysis in Regions of Poor Data Coverage

This paper describes a series of numerical experiments which were done to test a theoretical method for dynamic analysis in regions of poor data coverage. Theoretically, if vorticity were conserved, the exact vorticity field in such a region could be determined by Lagrangian advection of vorticity from areas of known data. The technique was applied to a field of rather dense data where a “hole” was created by withholding all observations within a given area.

The first experiments, assuming the atmosphere to be purely barotropic, resulted in a field within the hole that closely approached, after a reasonable time, the field obtained by a barotropic forecast using all the data. The remaining experiments, under simulated operational conditions, tested the effects of: 1) baroclinic processes, 2) size of hole, 3) frequency of observation, and 4) allowing a single strip of data across the hole. The results were much as predicted by the theory and reasonably accurate analyses were obtained.