Open AccessInfluence of upper ocean stratification interannual variability on tropical cyclones
Author(s) -
Vincent Emmanuel M.,
Emanuel Kerry A.,
Lengaigne Matthieu,
Vialard Jérôme,
Madec Gurvan
Publication year - 2014
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1002/2014ms000327
Subject(s) - tropical cyclone , climatology , stratification (seeds) , environmental science , typhoon , el niño southern oscillation , sea surface temperature , ocean dynamics , ocean heat content , storm , latitude , atmospheric sciences , geology , oceanography , ocean current , seed dormancy , botany , germination , geodesy , dormancy , biology
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 −1 . TCs in the western Pacific and the southwestern Indian Ocean are most sensitive to oceanic interannual variability (with a ∼10 m s −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.