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Estudo da camada limite atmosférica na região de Angra dos Reis através do modelo de mesoescala MM5 e dados observacionais

2009; Brazilian Society of Geophysics; Volume: 27; Issue: 1 Linguagem: Inglês

10.1590/s0102-261x2009000100013

1809-4511

José Francisco de Oliveira‐Júnior,

Tropical and Extratropical Cyclones Research

RESUMO Motivados pela fenomenologia existente no Complexo Nuclear Almirante Alvaro Alberto (CNAAA), Angra dos Reis - Rio de Janeiro, foram feitas avaliacoes climatologicas, sazonais, mensais e diarias da direcao e velocidade do vento, estabilidade atmosferica, dos sistemas sinoticos num periodo de 26 anos e das forcantes na CNAAA. A estabilidade foi estimada por Pasquill-Gifford (P-G) e pelo Numero de Richardson Bulk (Ri). O Numero de Froude (Fr) foi usado na caracterizacao do escoamento na regiao. As maiores frequencias da Passagem de Sistemas Frontais (PSF) foram em maio e setembro, enquanto o Sistema de Alta Pressao (SAP) em julho, setembro e novembro. Atraves das torres identificou-se a predominância de calmaria e ventos fracos, sendo a media de 2 m.s -1 . As predominâncias nas torres A10 e B foram devido as forcantes termicas e em A60, A100, C e D foram o vento de encosta, as brisas maritima-terrestre e a canalizacao forcada pelo terreno. O P-G e Ri mostrou que a condicao estaticamente estavel prevaleceu em relacao as demais. O Fr mostrou que o regime e fraco, estavel e ar estagnado. O modelo conceitual de Whiteman & Doran (1993) e os dados de reanalise foram utilizados na identificacao de alguns padroes relacionais entre o vento sinotico versus observado (A60 e C). Foram realizados dois experimentos com o MM5 para avaliar o seu desempenho num estudo de caso sob a atuacao da SAP. As simulacoes utilizaram as parametrizacoes Eta/NOAH e GS/MULTI-LAYER. Ocorreram discrepâncias entre os resultados das parametrizacoes, e de um modo geral, a Eta/NOAH apresentou resultados mais concordantes com o observado que a GS/MULTI-LAYER. ABSTRACT Motivated by the existence phenomenology of the Almirante Alvaro Alberto Nuclear Complex (CNAAA), Angra dos Reis - Rio de Janeiro, climatological evaluations were made during a period of 26 years, including: seasonal, monthly and daily analyses of wind speed and direction, atmospheric stability, synoptic systems, and forcing mechanisms of the CNAAA. The stability was estimated considering Pasquill-Gifford (P-G) and Bulk Richardson's number (Ri). Froude's number (F) was used to characterize inlets/outlets flowing in the region. The highest transition Frequencies of Frontal Systems (FFS) were in May and September, while High Pressure System (HPS) occurred in July, September and November. Through towers calm and weak winds predominance were identified, with mean less than 2 m.s -1 . Prevailing directions in A10 and B towers were due to thermal forcing. Through towers A60, A100, C and D it was identified as main forcing: wind slopes, sea and terrestrial breezes and channeling forced by ground. P-G criteria and Ri showed that statically stable conditions prevailed in comparison to others. F showed that the regime is weak, stable and stagnant air in CNAAA. The conceptual model proposed by Whiteman & Doran (1993) and reanalysis of data were used to identify some relational patterns between synoptic wind versus observed (A60 and C). Two numerical experiments were carried out using MM5 to analyze their performance in a case study during on the SAP. Simulation settings with Eta/NOAH scheme GS/MULTI-LAYER parameterizations were used. Discrepancies were observed between parameterization and, in a general way, the Eta/NOAH presented results which are more consistent with observational as it was expected for a GS / MULTI-LAYER.