Influence of upper ocean stratification interannual variability on tropical cyclones
Author(s)
Vincent, Emmanuel M.; Lengaigne, Matthieu; Madec, Gurvan; Emanuel, Kerry Andrew; Vialard, Jerome
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Climate modes, such as the El Niño Southern Oscillation (ENSO), influence Tropical Cyclones (TCs) interannual activity through their effect on large-scale atmospheric environment. These climate modes also induce interannual variations of subsurface oceanic stratification, which may also influence TCs. Changes in oceanic stratification indeed modulate the amplitude of TCs-induced cooling, and hence the negative feedback of air-sea interactions on the TC intensity. Here we use a dynamical downscaling approach that couples an axisymmetric TC model to a simple ocean model to quantify this interannual oceanic control on TC activity. We perform twin experiments with contrasted oceanic stratifications representative of interannual variability in each TC-prone region. While subsurface oceanic variations do not significantly affect the number of moderate (Category 3 or less) TCs, they do induce a 30% change of Category 5 TC-days globally, and a 70% change for TCs exceeding 85 m s[superscript −1]. TCs in the western Pacific and the southwestern Indian Ocean are most sensitive to oceanic interannual variability (with a ~10 m s[superscript −1] modulation of the intensity of strongest storms at low latitude), owing to large upper ocean variations in response to ENSO. These results imply that a representation of ocean stratification variability should benefit operational forecasts of intense TCs and the understanding of their climatic variability.
Date issued
2014-08Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate; Woods Hole Oceanographic InstitutionJournal
Journal of Advances in Modeling Earth Systems
Publisher
American Geophysical Union (AGU)
Citation
Vincent, Emmanuel M., Kerry A. Emanuel, Matthieu Lengaigne, Jérôme Vialard, and Gurvan Madec. “Influence of Upper Ocean Stratification Interannual Variability on Tropical Cyclones.” Journal of Advances in Modeling Earth Systems 6, no. 3 (August 5, 2014): 680–699.
Version: Final published version
ISSN
19422466