COMPARATIVE STUDIES OF RELATIVE VORTICITIES COMPUTED FROM GEOSTROPHIC AND OBSERVED WINDS

Abstract

Fixed networks of rawinsonde stations were used to compute geostrophic relative vorticity from reported heights and observed relative vorticity from components of reported winds at 500 mb. The geostrophic vorticity was computed on the two different scales of 600 km and 300 km ; the observed vorticity was computed on a 600 km scale. An analysis was made also of the vorticity variance produced by height errors, wind errors and small-scale wind fluctuations. Comparison of geostrophic vorticity on different scales indicates that grid size has a very important effect upon the computed value of geostrophic vorticity. Comparison of observed and geostrophic vorticity on the same scale shows some significant differences; many of these differences, however, can be explained by the effect of height and wind errors upon the computation of each vorticity.