A dinâmica da camada de mistura oceânica da porção Abrolhos-Campos da costa brasileira
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Data
2015-12-21
Autores
Salviato, Júlia Tavares
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Universidade Federal do Espírito Santo
Resumo
The oceanic surface mixed layer is the link by which the ocean and atmosphere are coupled. The characteristics of the mixed layer determine the air-sea fluxes of heat and gases affecting this way the climate. Additionally, biogeochemical cycles and biological productivity are profoundly affected by the mixed layer depth, which controls the amount of nutrient input to the euphotic zone through vertical mixing and entrainment. Improved understanding of these processes depends in some measure on our understanding of mechanisms and dynamics of the mixed layer. Using temperature and salinity from WOA, heat fluxes from OAFlux Project (Objectively Analyzed air-sea Fluxes) and wind stresses from Comprehensive Ocean-Atmosphere Data Set (COADS) the spatial pattern of the seasonal variability of mixed layer in the Abrolhos-Campos region is investigated, as well as the importance relative of heat and momentum fluxes and Ekman pumping to the seasonal heat-budget of the mixed layer. To complement the above analysis and to investigate mixed layer dynamics at suprainertial scale, time series from October 2011 to October 2012of air-sea fluxes and upper ocean response, obtained from PIRATA mooring at 19oS and 34oW were also analyzed. The seasonal cooling and deepening of the mixed layer is driven primarily by heat fluxes with larger contribution from the short wave radiation. By the end of the winter and spring, strong wind stresses are important to maintain the mixed deep. Ekman pumping velocities play only a small role in the upper ocean evolution in the region of study. In general, the results of the analysis of PIRATA time series confirm those from the climatological data sets. Furthermore, spectral analysis of the mixed layer computed from the PIRATA time series revealed a sharp energy peak at about 12 and 24 hours, suggesting the contribution of internal tides to oceanic mixing.