The impact of the use of high spatial resolution sea surface temperature data in a numerical weather prediction model / Impacto da utilização de dados de temperatura da superfície do mar de alta resolução espacial em um modelo de previsão numérica do tempo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Sea surface temperature (SST) is an important indicator of Earth´s climate. An accurate and global measurement of this parameter is of fundamental importance in applications related to climate studies, ocean-atmosphere interactions, marine ecosystem, etc. Special attention may be given to meteorological forecasts, where SST stands as an important boundary condition for numerical weather prediction (NWP) models. Presently, the regional NWP model operationally running at the Center for Weather Forecast and Climate Studies of the National Institute for Space Research (CPTEC/INPE) uses a SST field with a spatial resolution of 0,5° (SST database Real-Time, Global Sea Surface Temperature - RTG_SST). A question that arises is if this spatial resolution is enough to represent the SST variations in dynamic oceanic areas, such as the upwelling region in Cabo Frio or at the inshore thermal front of the Brazil Current, flowing at the shelf break. Studies in those places show average horizontal SST gradients of 1°C/km. The misrepresentation of SST variation may introduce errors and viéses to the boundary conditions, leading to the decrease of the skill of a model. This study intends to compare high-spatial resolution SST databases (Real-Time, Global Sea Surface Temperature, High Resolution - RTG_SST_HR e Operational Sea Surface Temperature and Sea Ice Analysis OSTIA) and to analyze the sensitivity of a NWP model to the insertion of the new high-resolution database. This goal was reached in two steps: first, two high spatial resolution SST databases (<0,1°) were compared and one was indicated as the most suitable to be inserted in a NWP model. The second step was the comparison between the values of the latent and sensible heat flows and the total precipitable water forecasted with the use of the original SST database (RTG_SST) and the values forecasted with the use of the SST database indicated as the most suitable in the first part of the study (OSTIA). A study is conducted for a specific case of a South Atlantic Convergence Zone (SACZ) case that occurred in January, 2008. Results indicate that OSTIA database represented better the mains oceanographic features in the southeast-south Brazilian coast. The insertion of the OSTIA SST field, as a boundary condition, affected the skillness of ETA model, resulting in better predictions for regions of the study area.

ASSUNTO(S)

rtg_sst_hr sensoriamento remoto sea surface temperature osita rtg_sst_hr temperatura da superfície do mar remote sensing ostia

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