Linking AMOC Variations With the Multidecadal Seesaw in Tropical Cyclone Activity Between Eastern North Pacific and Atlantic

Abstract

AbstractTropical cyclone (TC) over the North Atlantic is an important extreme weather event, causing great social and economic damages to the American coastal regions. In this study, we find that the North Atlantic TC activity (genesis frequency and accumulated cyclone energy) has significant multidecadal variability, which exhibits an out‐of‐phase relationship with that over the eastern North Pacific, referring to as the inter‐basin seesaw in TC activity. By using five indicators of the Atlantic Meridional Overturning Circulation (AMOC) strength, we link this TC activity seesaw pattern to the AMOC and the associated North Atlantic sea surface temperature anomalies. Both observation and Atlantic pacemaker experiment indicate that the AMOC induces the North Atlantic sea surface temperature warming and eastern North Pacific cooling, which lead to contrasting backgrounds (vertical wind shear, maximum potential intensity, and humidity) for the TC formation and development, resulting in the seesaw pattern in TC activity. Our results provide additional evidence for the reversed relationship in TC activity between the two ocean basins and attribute this seesaw to the variations in the AMOC. More importantly, the atmospheric‐NAO‐based AMOC indicator shows a leading role in depicting the multidecadal seesaw, which has great potential in improving the decadal prediction of North Atlantic/eastern North Pacific TCs.