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High‐Resolution Ensemble Simulations of Intense Tropical Cyclones and Their Internal Variability During the El Niños of 1997 and 2015
Author(s) -
Yamada Y.,
Kodama C.,
Satoh M.,
Nakano M.,
Nasuno T.,
Sugi M.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl082086
Subject(s) - tropical cyclone , climatology , anomaly (physics) , trough (economics) , sea surface temperature , environmental science , monsoon trough , atmospheric sciences , meteorology , geology , physics , economics , macroeconomics , condensed matter physics
Extreme El Niño events affect the number of intense tropical cyclones (ITCs) over the western North Pacific (WNP). In 1997 and 2015, both extreme El Niño years, ITC numbers were above normal in the WNP. In order to clarify how, and to what extent, sea surface temperature anomaly (SSTA) distributions control the ITCs genesis, the authors conducted 50‐member ensemble simulations using a high‐resolution global nonhydrostatic model that explicitly simulates ITCs. The ensemble simulations showed a clear relationship between the number of ITCs and their genesis locations in the WNP. However, the authors found that the simulated numbers of ITCs in the WNP were also closely related to the strength of the monsoon trough, which varies under given SSTA conditions. This indicates that reliable seasonal forecasting of ITCs depends on our ability to accurately reproduce the monsoon trough, whose strength is modulated mainly by internal atmospheric variability but also by SSTA.