Development of Dynamical Tropical Cyclone Model

Presentation Type: 
Dong-Hyun Cha (Ulsan National Institute of Science and Technology)

Considerable progress has been made in numerical TC forecasts because of the advancements in observations and the rapid increase in computing resources. In general, the track forecasts of TC using dynamical model has been notalby progressed with the advancement of low-resolution global model to capture large-scale steering wind. However, the improvement of intensity forecast with dynamical model has been prominently slower than that of track forecast because of lower resolution of dynamical model, which cannot resolve TC core dynamics associated with TC intensity.

For the TC forecast we have developed dynamical TC models by applying some methods improving the TC forecast. The operational numerical weather prediction models of Korea Meteorological Administration (KMA) have about 12 km horizontal resolution, which is somewhat coarse to resolve TC core dynamics. Therefore, we increase the model horizontal resolution to 6 km for the TC forecast. To improve the initial TC vortex, a dynamical initialization (DI) scheme, which can construct realistic TC vortex through repetitive cycle runs, has been implemented into the new TC model. Physical parameterzation schemes in cumulus convection, cloud microphysics, and boundary latyer process, are optimized through sensitivity tests. Hindcast experiments for the typhoons in 2012 show that the developed model has improved performance in TC forecast because of increasing model resolution, implementation of DI scheme, and the optimization of physical parameterization schemes.

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