A case study of the role of surface latent and sensible heat fluxes in South America east coast cyclogenesis / Estudo de caso sobre o papel dos fluxos de calor latente e sensível em superfície em processos de ciclogênege de costa leste ocorrido na costa da América do Sul

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

A cyclogenesis case observed over South America coast is simulated with the aim of verifying the impact of the surface latent (FCL), sensible (FCS)and total (FCT)heat fluxes. The Brazil current role is also explored. The limited-area model of Japan Meteorological Agency (MAL-JAPA)adapted to South America region is used in this work. The data used to initial and boundary conditions are the NCEP/NCAR reanalysis. This case is an explosive cyclogenesis event developed during May 28-30, 1999. The results of the simulations show that the surface heat fluxes had large contribution to the development of the extratropical cyclone. The FCL had more contribution to the FCT than the FCS. Simulations without surface heat flux show that the static stability is larger and the availability of humidity is less than in the simulation with FCT. In the beginning the differences were small and localized over small regions, but during the evolution of the simulations the differences grew in their magnitude and extension. Based in these results, it is possible conclude that the surface heat fluxes are more important in the early development phase of the cyclone and they also contribute for the atmosphere to become unstable and humid over the ocean adjoining the continent. These conditions are favorable to the development of a system moving over this region. The results of the simulation with the climatological sea surface temperature suggest that the meanders associated with the Brazil and Malvinas currents do not have much impact in the studied cyclone development.

ASSUNTO(S)

atmospherical models latent heat ciclogênese correntes costeiras color latente tsm temperatura da superfície do mar américa do sul estudo do tempo fluxo de calor coastal currentes cyclogenesis sea surface temperature heat flux modelos atmosféricos

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