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Impact of tropical cyclones on the heat budget of the south Pacific Ocean

DRS at CSIR-National Institute of Oceanography

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Title Impact of tropical cyclones on the heat budget of the south Pacific Ocean
 
Creator Jullien, S.
Menkes, C.E.
Marchesiello, P.
Jourdain, N.C.
Lengaigne, M.
Koch-Larrouy, A.
Lefevre, J.
Vincent, E.M.
Faure, V.
 
Subject heat budget
tropica depressions
air-sea interaction
mixed layer
 
Description The integrated ocean response to tropical cyclones (TCs) in the South Pacific convergence zone through a complete ocean heat budget was investigated. The TC impact analysis is based on the comparison between two long-term (1979-2003) oceanic simulations forced by a mesoscale atmospheric model solution in which extreme winds associated with cyclones are either maintained or filtered. The simulations provide a statistically robust experiment that fills a gap in the current modeling literature between coarse-resolution and short-term studies. The authors' results show a significant thermal response of the ocean to at least 500-m depth, driven by competing mixing and upwelling mechanisms. As suggested in previous studies, vertical mixing largely explains surface cooling induced by TCs. However, TC-induced upwelling of deeper waters plays an unexpected role as it partly balances the warming of subsurface waters induced by vertical mixing. Below 100 m, vertical advection results in cooling that persists long after the storm passes and has a signature in the ocean climatology. The heat lost through TC-induced vertical advection is exported outside the cyclogenesis area with strong interannual variability. In addition, 60 percent of the heat input below the surface during the cyclone season is released back to the oceanic mixed layer through winter entrainment and then to the atmosphere. Therefore, seasonal modulation reduces the mean surface heat flux due to TCs to about 3×10 sup(-3) PW in this region exposed to 10-15 percent of the world's cyclones. The resulting climatological anomaly is a warming of about 0.1 degrees C in the subsurface layer and cooling below the thermocline (less than 0.1 degrees C).
 
Date 2013-01-09T06:18:22Z
2013-01-09T06:18:22Z
2012
 
Type Journal Article
 
Identifier Journal of Physical Oceanography, vol.42; 2012; 1882-1906
http://drs.nio.org/drs/handle/2264/4220
 
Language en
 
Rights An edited version of this paper was published by American Meteorological Society. Copyright [2012] American Meteorological Society
 
Publisher American Meteorological Society