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Significant Aerosol Influence on the Recent Decadal Decrease in Tropical Cyclone Activity Over the Western North Pacific
Author(s) -
Takahashi Chiharu,
Watanabe Masahiro,
Mori Masato
Publication year - 2017
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 - 10.1002/2017gl075369
Subject(s) - climatology , tropical cyclone , forcing (mathematics) , aerosol , environmental science , atmospheric sciences , wind shear , sea surface temperature , climate change , tropical cyclogenesis , oceanography , geology , cyclone (programming language) , wind speed , meteorology , geography , field programmable gate array , computer science , computer hardware
Over the past two decades, the number of tropical cyclones (TCs) has decreased markedly in the southeastern part of the western North Pacific (WNP) as a component of the interdecadal variation. This decrease has partially been explained by an internal low‐frequency variability of sea surface temperature (SST) in the Pacific, but influences of external forcing remain unclear. Here we show that past changes in sulfate aerosol emissions contributed approximately 60% of the observed decreasing trends in TC genesis frequency in the southeastern WNP for 1992–2011, using multiple simulations by a global climate model. This decrease was mainly attributed to the increased vertical wind shear and decreased low‐level vorticity, associated with a trans‐basin multidecadal SST change driven by aerosol forcing. The near‐future projection shows that the aerosol forcing still has some potential influence on decadal TC change, but the projected decreasing frequency is mainly due to increasing greenhouse gases forcing.