The use of ERS scatterometer data to investigate the surface circulation of Antarctic mesocyclones

The value of ERS-1 scatterometer data as a tool for studying the wind fields of Antarctic mesocyclones is assessed by using one year's observations of these systems derived from satellite imagery. The scatterometer processing scheme utilized can affect the resultant wind fields, particularly the accuracy of the external forecast winds used for meteorological ambiguity removal. Very few of the mesocyclones (9%) were captured by the scatterometer data because (1) -60% of the vortices did not form over the open ocean (25% of those that did were included in the scatterometer data) and (2) the narrow scatterometer swath results in a poor temporal resolution. Most systems had a surface circulation, varying from a slight deviation from the geostrophic flow to a closed circulation; however, 25% of mesocyclones did not exhibit a surface circulation. Derived maximum cyclonic relative vorticity varied between ∼-100 and ∼-400 x 10 -6 s -1 .