Premium
Essential Role of the Midlatitude South Atlantic Variability in Altering the Southern Hemisphere Summer Storm Tracks
Author(s) -
Zhang Li,
Gan Bolan,
Wang Hong,
Wu Lixin,
Cai Wenju
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 - 10.1029/2020gl087910
Subject(s) - extratropical cyclone , climatology , middle latitudes , storm track , storm , sea surface temperature , baroclinity , southern hemisphere , northern hemisphere , front (military) , geology , environmental science , oceanography
Storm tracks are a pivotal component in extratropical weather and climate. The sea surface temperature (SST) front in the midlatitude South Indian Ocean has been found to anchor the climatological core of the Southern Hemisphere (SH) storm tracks. However, on interannual‐to‐decadal timescales, observational and modeling evidence is presented here that the strengthened SST front in the midlatitude western South Atlantic (SA) can intensify the SH summer storm tracks by supplying more baroclinic energy, which overwhelms contributions from other oceanic frontal zones. Idealized experiments suggest that such a predominant impact on synoptic storms lies in the strengthened SA SST front acting in concert with the favorable thermal background produced in the presence of the Andes (i.e., enhancements of downstream low‐level temperature gradients and synoptic temperature variability). Our findings imply that oceanic variability in the western SA frontal zone could be a remote regulator of the SH extratropical summer climate variability.