Some Tests of the Pennsylvania State University Mesoscale Model with Tropical Cyclones.
NAVAL POSTGRADUATE SCHOOL MONTEREY CALIF
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A three-dimensional, primitive equation model by Anthes and Warner 1978 was used to predict five typhoon cases. The five-layer model on a 40X40 staggered grid with 120 km resolution included a moisture cycle, sensible and latent heat flux at the earths surface, and a bulk parameterization of the planetary boundary layer. The model is initialized using operational wind fields and two forms of a wind bogus. Due to the lack of a representative moisture analysis in the vicinity of tropical cyclones, simulated moisture fields were used to initialize the model. Initial experiments conducted with these fields produced widespread convection and heating which developed circulations in areas well removed from the actual storm. The associated modifications to the steering flow, and the overly intense storm circulations resulted in premature recurvature. Use of a second moisture bogus, which provided less available moisture especially at upper levels, reduced the amount of convection over the entire grid and the effect on the steering current. A second wind bogus was also tested. This technique resulted in a smaller and less intense initial storm, which also resulted in considerably less convection.