Multidecadal Seesaw in Hadley Circulation Strength Between the Two Hemispheres Caused by the Atlantic Multidecadal Variability

Multidecadal variations in Hadley circulation (HC) strength have been observed during the historical period, which have significant implications for global and regional climate. However, the relationship between HC intensities in the two hemispheres remains unclear. In this study, we identify an int...

Full description

Bibliographic Details
Published in:Frontiers in Earth Science
Main Authors: Yusen Liu, Zhanqiu Gong, Cheng Sun, Jianping Li, Lin Wang
Format: Article in Journal/Newspaper
Language:English
Published: Frontiers Media S.A. 2020
Subjects:
Atlantic
multidecadal variability
Hadley circulation
monsoon precipitation
Indo-Pacific air–sea coupling
interhemispheric teleconnection
Science
Q
Pacific
North Atlantic
Online Access:https://doi.org/10.3389/feart.2020.580457
https://doaj.org/article/91d67e675d2c4c088cf1104a8b7d82f7
Description
Summary:Multidecadal variations in Hadley circulation (HC) strength have been observed during the historical period, which have significant implications for global and regional climate. However, the relationship between HC intensities in the two hemispheres remains unclear. In this study, we identify an interhemispheric seesaw in the annual HC strength at multidecadal timescales. This seesaw pattern physically corresponds to the meridional movement of the ascending branch of annual HC, leading to strengthened HC in one hemisphere and weakened HC in the other. The HC strength seesaw strongly correlates with the tropical land surface precipitation at multidecadal timescales, particularly for the monsoonal land regions. Further analyses link the HC strength seesaw to the Atlantic multidecadal variability (AMV). A suite of Atlantic Pacemaker experiments successfully reproduces the multidecadal HC strength seesaw and its relation to the AMV. The Northern Hemisphere SST warming associated with the positive AMV phase induces a northward shift of the upward branch of HC, and the Southern Hemispheric HC is strengthened in contrast to the weakened Northern Hemispheric HC. Comparisons of the North Atlantic SST forced HC changes between the coupled air–sea model and stand-alone atmospheric model suggest an important and non-negligible role of the SST footprint of AMV over the Indo-Pacific basins. The AMV and its Indo-Pacific SST footprint make a comparable contribution to the SST changes in the Northern Hemisphere, which control the movement of the HC ascending branch and thereby the interhemispheric seesaw in HC strength.

Similar Items