Inicialização física em modelos de previsão de tempo e estudo de seus efeitos na partição de energia em modos verticais e horizontais nos trópicos e na América do Sul / Physical initialization in weather prediction models and study of its effects on the energy partition the vertical and horizontal modes over the tropics and South Americar

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Physical initialization was developed at The Florida State University to improve rainfall forecast over tropical region by numerical weather prediction models. III this initialization procedure, observed rainfall rates are assimilated using reverse cumulus algorithms and nudging. At the end of the assimilation period - usually 24 hours - the model will be able to reproduce the proper rainfall rates. The ability of the FSU regional spectral model to assimilate high resolution rainfall data over Brazil will be focused in this work. Since the FSU global spectral model was used as a base field (i.e. boundary) for the regional model, the impact of initialization of the global model on the regional model s ability to assimilate rainfall is also examined. Physical initialization was also included in a version of the Center for Ocean-Land-Atmosphere Studies Global Spectral Model used by the Center for Weather Prediction and Climate Studies in Brazil. The 24-hour accumulated precipitation predicted fields from the physically initialized conditions show improved correlations with the Special Sensor Microwave/Imager-Outgoing Longwave Radiation estimates in FSU regional and CPTEC global models. A study of physical initialization effects on the normal mode vertical and horizontal structures showed that mixed Rossby-gravity mode, and eastward and westward propagating gravity modes with complex vertical structures, which have smaller equivalent depths, increase their total energy by the influence of physical initialization. On the other hand, the percentage of total energy in the vertical modes related to the convection - with larger equivalent depths - is decreased in the mixed Rossby-gravity mode, and in the two gravity modes due to physical initialization. During the Southern Hemisphere summer, westward gravity mode interaction with Rossby mode as well as Kelvin mode contribute positively to the total energy in the region of the South Atlantic Convergence Zone.

ASSUNTO(S)

trópicos modelos espectrais américa do sul inicialização física assimilação de precipitação previsão númerica de tempo

ACESSO AO ARTIGO

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