Oceanic eddy‑induced modifications to air–sea heat and CO2 fluxes in the Brazil‑Malvinas Confluence

Sea surface temperature (SST) anomalies caused by a warm core eddy (WCE) in the Southwestern Atlantic Ocean (SWA) rendered a crucial influence on modifying the marine atmospheric boundary layer (MABL). During the first cruise to support the Antarctic Modeling and Observation System (ATMOS) project, a WCE that was shed from the Brazil Current was sampled. Apart from traditional meteorological measurements, we used the Eddy Covariance method to directly measure the ocean–atmosphere sensible heat, latent heat, momentum, and carbon dioxide ( CO2) fluxes. The mechanisms of pressure adjustment and vertical mixing that can make the MABL unstable were both identified. The WCE also acted to increase the surface winds and heat fluxes from the ocean to the atmosphere. Oceanic regions at middle and high latitudes are expected to absorb atmospheric CO2, and are thereby considered as sinks, due to their cold waters. Instead, the presence of this WCE in midlatitudes, surrounded by predominantly cold waters, caused the ocean to locally act as a CO2 source. The contribution to the atmosphere was estimated as 0.3 ± 0.04 mmol m− 2 day− 1, averaged over the sampling period. The CO2 transfer velocity coefficient (K) was determined using a quadratic fit and showed an adequate representation of ocean–atmosphere fluxes. The ocean–atmosphere CO2, momentum, and heat fluxes were each closely correlated with the SST. The increase of SST inside the WCE clearly resulted in larger magnitudes of all of the ocean–atmosphere fluxes studied here. This study adds to our understanding of how oceanic mesoscale structures, such as this WCE, affect the overlying atmosphere

Diferenças na performance das previsões de variaveis simples e derivadas obtidas pelo modelo global do CPTEC/COLA para um caso de ciclogenese ocorrida a leste da região sul do Brasil

The statistical parameters normally used for the evaluation of the NWP models are the anomaly correlation coefficient and the standard error of the predicted field relatlve to the analysed flelds. It's attempted here to evaluate the CPTEC/COLA model using the statistics mentioned above for a case of cyclogenesis over the Atlantic Ocean east of the soulhern Brazil. The meteorological variables employed are the diagnostic fields vorticity advection, thermal advection, convergence of humidity and the vector Q. The performance of the model in terms of the derived fields is different from that in terms of simple model variables such as the geopotential and the wind components. Of all the important fields the convergence of humidity has the least reliability.Pages: 1073-107

Sobre interpretacao estatistica da saida do modelo numerico

A analysis of the statistical methods that used in the "Model Output Statistics" (MOS)and "Perfect Prog" (PP) was made and demonstrated difference among them. Development and application MOS and PP need in the operational works in the meteorological centers of Brazil was showed

Aplicacao "model output statistics" para previsao da temperatura minima no Sul e Sudeste do Brasil

There were made experiments for application "Model Output Statistics" (MOS) in the regions South and Southeast of Brazil. In the work it was used the data of the output of the model CPTEC/COLA and minimum temperature in the period April-September 1997 in the meteorological stations in the states São Paulo, Parana, Santa Catarina and Rio Grande do Sul of Brasil. The experiments show that main predictors is; minimum temperature of the previous day, absolute temperature in the levels 1000 and 850 hPa, precipitable water, specific humidity and zonal wind in the level 1000 hPa. But for 48 and 72 hours is influences the minimum temperature of the previous day it is not principal predictor. A statistical model was created to forecast the temperature minimum in the South and part Southeast of Brazil, and it was made evaluation the model in the independent data. The evaluation showed the possibility to apply MOS in the tropical and subtropical areas

Aplicacao do MOS para previsao da temperatura minima ate 72 horas no estado de Santa Catarina

The application was verified "Model Output Statistics" (MOS) in him area with complex relief as state Santa Catarina. To create the statistical model it was used the data of the exit of the global numeric model CPTEC/COLA and minimum temperature in the period April-September 1997 in them net meteorological stations EPAGRI. The experiments show that main predictors are; absolute temperature in them levels 1000 and 850 hPa, specific humidity at level 1000 hPa. The statistical model was evaluated in the independent data and the possibility application was shown it MOS in the state Santa Catarina