Thursday, 15 January 2004: 1:45 PM
Assimilation of QuikSCAT surface winds observations for hurricane initialization and prediction
Room 618
Poster PDF
(173.9 kB)
Directly assimilating QuikSCAT surface winds has resulted in only
a marginal impact in hurricane initialization and prediction.
In order to maximize the impact of QuikSCAT observations
on hurricane prediction, a radial profile of sea level pressures
(SLP) is first derived from QuikSCAT surface winds, and
then a four-dimensional variational data assimilation procedure
is used to assimilate the QuikSCAT-derived SLP.
Specifically, radial profiles of QuikSCAT surface winds are
first calculated in the four quadrants of the hurricane
(north-east, south-east, south-west, and north-west).
Second, radial profiles of wind are corrected by Holland's formula.
Third, radial profiles of SLP are derived using the gradient wind relation.
Finally, the SLP is assimilated in a half hour window under the forecast model constraint,
which creates a realistic initial vortex in all model variables.
The fifth generation Pennsylvania
State University and National Center for
Atmospheric Research Mesoscale Model (MM5) and its adjoint modeling system are used
for this study.
The impact of QuikSCAT winds on hurricane initialization and forecasts
are examined for three hurricanes: Alberto (2000), Gordon (2000) and
Erin (2001). Numerical results will be presented at the conference.
Supplementary URL: