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Robust Enhancement of Tropical Convective Activity by the 2019 Antarctic Sudden Stratospheric Warming
Author(s) -
Noguchi S.,
Kuroda Y.,
Kodera K.,
Watanabe S.
Publication year - 2020
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 - 10.1029/2020gl088743
Subject(s) - downwelling , climatology , troposphere , upwelling , stratosphere , environmental science , atmospheric sciences , walker circulation , convection , hadley cell , lead (geology) , sea surface temperature , geology , climate change , general circulation model , meteorology , oceanography , geography , geomorphology
Tropical tropospheric responses to a sudden stratospheric warming (SSW) event that occurred over Antarctica in September 2019 have been investigated by conducting a series of ensemble forecast experiments. Comparative examinations between the normal forecast and the partially nudged forecast, whose stratospheric circulation is constrained to a reanalysis, reveal a significant enhancement/suppression in the convective activity (upwelling/downwelling) over the northern/southern part of the tropics. Such an acceleration of the Hadley circulation is set up by thermal structural changes in the upper troposphere and lower stratosphere. The tropical cooling caused by the enhanced Brewer‐Dobson circulation destabilizes the environment there and stimulates deep cumulus convections. In this case, the southern area of the Asian monsoon region is particularly sensitive. Although details of the triggered response depend on the adopted cumulus parameterization scheme, a boosting tendency of the convective upwelling via the SSW is robust.