The implementation of the Local Ensemble Transform Kalman Filter Data
Assimilation with the CPTEC/INPE’s Global Circulation Model
José A. Aravéquia1, Solange Silva de Souza1, José Paulo Bonatti2 e Paulo
Kubota2
The Data Assimilation System is an important part to assure the quality of weather
forecasts, such analysis increments are applied to the short term forecasts (the first guess)
given by the atmospheric models, and the both together form the Weather Forecast System.
The Local Ensemble Transform Kalman Filter (LETKF) developed by the Chaos Group at
Department of Atmospheric and Ocean Science of the University of Maryland, is been
implemented at CPTEC/INPE to work together the CPTEC’s Global Circulation Model.
The analysis system consist of an 4D implementation of LETKF that assimilates all
conventional data plus satellite wind vectors and it uses the Community Radiative Transfer
Model (CRTM) forward model as Observation Operator to be able to assimilate satellite
radiances such as AIRS and AMSU-A from the Earth Observing System (Aqua-Terra
satellites). The system is going to be tested with the observational data to the period of
January and February 2004. The first results have showed to be able to ingest the available
data and showed subjective reasonable results. Furthers verifications are going to be done
with high resolution analysis from the NCEPs 3D Var analysis (Spectral Statistical
Interpolation).
Key words:
Data Assimilation, Kalman Filter, Numeric
Atmospheric Model, Ensemble Forecast.
Weather
Forecast,
1
Grupo de Assimilação de Dados/DMD/INPE. Rodovia Presidente Dutra, km 40, SP-RJ – 12630-000
Cachoeira Paulista – SP – Brasil. Fone: 55-12-3186-8462. Fax.: 55-12-3101-2835. Email:
jose.aravequia@cptec.inpe.br; solange.souza@cptec.inpe.br.
2
DMD/INPE. Rodovia Presidente Dutra, km 40, SP-RJ – 12630-000 Cachoeira Paulista – SP – Brasil. Fone:
55-12-3186-8421. Fax.: 55-12-3101-2835. Email: paulo.bonatti@cptec.inpe.br; pkubota@cptec.inpe.br.