18th Conference on Weather and Forecasting, 14th Conference on Numerical Weather Prediction, and Ninth Conference on Mesoscale Processes

Monday, 30 July 2001
Assimilation and forecast of Hurricane Floyd with the DAO Finite-Volume Data Assimilation System
Jiun-Dar Chern, NASA/GSFC, Greenbelt, MD; and S. J. Lin and A. M. da Silva
In recent years, a major effort has been undertaken at the Data Assimilation Office (DAO) at NASA/Goddard Space Flight Center to develop the next-generation data assimilation system -- Finite-Volume Data Assimilation System (FVDAS). The new system consists the NASA-NCAR General Circulation Model,the Statistical Quality Control System, and the Physical-space Statistical Analysis System (PSAS). The GCM is based on the finite-volume dynamical core developed at DAO with NCAR CCM3 physical parameterizations.

Hurricane Floyd first became a tropical depression on September 7, 1999. Later it became a Category 4 Hurricane and passed relatively close to the entire U.S. east coast. An estimated two million people were evacuated from the long stretch of coast due to the hurricane and it was blamed for 56 deaths and about $3-6 billion in total damage. In this study, a series of assimilation and 5-day forecast have been carried out from September 1 to September 18, 1999 to examine the hurricane forecast skills of this new data assimilation system. The results demonstrate the forecast capability of the system. We have also investigated the impacts of model horizontal resolution, cumulus parameterization, and the use of different observations on the overall prediction of hurricane track and intensity.

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