A numerical investigation of the atmosphere-ocean thermal contrast over the coastal upwelling region of Cabo Frio, Brazil


Autoria(s): DOURADAO, M.; OLIVEIRA, A. Pereira De
Contribuinte(s)

UNIVERSIDADE DE SÃO PAULO

Data(s)

19/10/2012

19/10/2012

2008

Resumo

An one-dimensional atmospheric second order closure model, coupled to an oceanic mixed layer model, is used to investigate the short term variation of the atmospheric and oceanic boundary layers in the coastal upwelling area of Cabo Frio, Brazil (23 degrees S, 42 degrees 08`W). The numerical simulations were carried out to evaluate the impact caused by the thermal contrast between atmosphere and ocean on the vertical extent and other properties of both atmospheric and oceanic boundary layers. The numerical simulations were designed taking as reference the observations carried out during the passage of a cold front that disrupted the upwelling regime in Cabo Frio in July of 1992. The simulations indicated that in 10 hours the mechanical mixing, sustained by a constant background flow of 10 in s(-1), increases the atmospheric boundary layer in 214 in when the atmosphere is initially 2 K warmer than the ocean (positive thermal contrast observed during upwelling regime). For an atmosphere initially -2 K colder than the ocean (negative thermal contrast observed during passage of the cold front), the incipient thermal convection intensifies the mechanical mixing increasing the vertical extent of the atmospheric boundary layer in 360 in. The vertical evolution of the atmospheric boundary layer is consistent with the observations carried out in Cabo Frio during upwelling condition. When the upwelling is disrupted, the discrepancy between the simulated and observed atmospheric boundary layer heights in Cabo Frio during July of 1992 increases considerably. During the period of 10 hours, the simulated oceanic mixed layer deepens 2 in and 5.4 in for positive and negative thermal contrasts of 2 K and -2 K, respectively. In the latter case, the larger vertical extent of the oceanic mixed layer is due to the presence of thermal convection in the atmospheric boundary layer, which in turn is associated to the absence of upwelling caused by the passage of cold fronts in Cabo Frio.

Identificador

ATMOSFERA, v.21, n.1, p.13-34, 2008

0187-6236

http://producao.usp.br/handle/BDPI/27005

http://apps.isiknowledge.com/InboundService.do?Func=Frame&product=WOS&action=retrieve&SrcApp=EndNote&UT=000252834300002&Init=Yes&SrcAuth=ResearchSoft&mode=FullRecord

Idioma(s)

eng

Publicador

CENTRO CIENCIAS ATMOSFERA UNAM

Relação

Atmosfera

Direitos

restrictedAccess

Copyright CENTRO CIENCIAS ATMOSFERA UNAM

Palavras-Chave #one-dimensional modelling #atmospheric boundary layer #air-sea interaction #upwelling #MIXED-LAYER MODEL #BOUNDARY-LAYER #VERTICAL STRUCTURE #WIND #FLUXES #HEAT #Meteorology & Atmospheric Sciences
Tipo

article

original article

publishedVersion