2002 Annual

Monday, 14 January 2002: 4:45 PM
Development of scatterometer-derived research-quality surface pressure fields for the Southern Ocean
Kyle A. Hilburn, COAPS, Florida State Univ., Tallahassee, FL; and M. A. Bourassa and J. J. O'Brien
Poster PDF (120.7 kB)
The SeaWinds scatterometer-derived wind fields can be used to estimate surface pressure fields. The method to be used has been developed and tested with Seasat-A and NSCAT wind measurements. The method involves blending two dynamically consistent values of vorticity. Geostrophic relative vorticity is calculated from an initial guess surface pressure field (NCEP reanalysis in this case). Relative vorticity is calculated from SeaWinds winds, adjusted to a geostrophic value, and then blended with the initial guess. The output field minimizes the differences between the initial guess field and scatterometer field subject to smoothing constraints. It is important to note that the new pressure field is modified not only where data are present but also outside the scatterometer swath.

This project will derive research-quality surface pressure fields from SeaWinds winds for the Southern Ocean from the Antarctic ice sheet to 30 deg S. The pressure fields will be validated in comparison to in situ observations from buoys and research vessels. The scatterometer pressure fields will have much finer resolution and better accuracy than pressure fields from current numerical weather prediction models. Previous investigations in the Southern Hemisphere using pressure fields computed from Seasat-A scatterometer winds have found important differences in storm position and structure. This project will also undertake meteorological analysis of the derived pressure fields both to study Southern Hemisphere meteorology and uncover artifacts in the pressure fields.

Supplementary URL: http://www.coaps.fsu.edu/~hilburn/18IIPS/index.html