85th AMS Annual Meeting

Tuesday, 11 January 2005: 2:45 PM
CPTEC GCM and Eta Model verifications against Rond˘nia Reference site in Brazil
S.C. Chou, INPE, Cachoeira Paulista, SP, Brazil; and P. Waldheim and C. P. Dereczynski
Poster PDF (1.6 MB)
CPTEC runs global spectral model at T126L28 and the regional Eta model at 40km and 38 layers. Forecasts from these two models are are evaluated with respect to surface observations collected at Rebio-Jaru, in Rondonia, included as part of the CEOP reference sites. The site is located in a protected tropical forest area, at about 8.5S. The evaluation was based on the diurnal cycle of the 24-h and 48-h forecasts of temperature, winds, precipitation and surface fluxes for the period from July to September 2001. The results show that the global model temperature forecasts for Rondonia agree better when there is model production of precipitation. In the absence of precipitation, the near surface temperature and the sensible heat fluxes are generally higher than observations, while the latent heat fluxes are underestimated and the net radiation is well represented. The frequency and intensity of precipitation are better forecast by the Eta model. The errors of the Eta model forecast do not seem to be directly related to the model rain production. The temperature and sensible heat flux is also overestimated by the regional model. Both models use same initial soil moisture conditions. The global model uses SSiB surface scheme, whereas the Eta uses the OSU scheme. While the errors of the latent and sensible heat fluxes in the global model tend to increase from 24-h to 48-h forecasts, in the Eta model the errors tend to decrease from 24-h to 48-h forecast. The winds agree reasonably with the forecasts. The diurnal cycle was generally well captured by both models. The Pantanal and Brasilia reference sites will be included in the analysis.

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