Monday, 21 January 2008
Hurricane Initialization Using TOMS Ozone Data
Exhibit Hall B (Ernest N. Morial Convention Center)
The total ozone from TOMS over the inner regions of tropical cyclones (TCs) is found to be usually lower than normal. However, the lowest center of total ozone is not always directly over the eye and the detailed structure of total ozone distribution varies. These characteristics found in TOMS ozone distributions are similar to tropopause topography within TCs, which is usually higher than normal over the inner regions of tropical cyclones, is not always highest directly over the eye, and has a case-dependent structure. High (either positive or negative) correlations between TOMS total ozone and tropopause height and several other meteorological variables in the upper troposphere and low stratosphere within TCs are found when the mean value of each variable in a circular domain of 650-km radius from the TC center is subtracted. Regression equations between TOMS ozone and these highly-correlated meteorological variables are developed. Through regression models, TOMS ozone data is used as additional upper-level constraints for a TC bogus scheme that imposes a bogus sea-level pressure. The structures of the initial vortices produced with and without TOMS ozone constraints are examined and compared with each other and with independent observations. Finally, forecast impacts initialized with two different initial vortices are assessed.
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