Narragansett Bay Campus, Corless Auditorium (Watkins Laboratory)

Title: A potential pathway for AMOC influence on sub-seasonal atmospheric variability



Speaker: Dr. Givo Alsepan, Postdoctoral Research Associate, Florida State University

Abstract: The importance of Gulf Stream (GS) variability for Northern Hemisphere weather and climate has received considerable support in recent years. Recent observational advances show that significant GS variability occurs on multiple timescales, including sub-seasonal. Recently, a high degree of sub-seasonal variability has also been observed in the Atlantic Meridional Overturning Circulation (AMOC), suggesting a potential connection between the sub-seasonal AMOC and mid-latitude atmosphere via the GS. Modeling studies, however, are yet to agree on the exact relationship between AMOC and GS variability, partly due to the lack of eddy-scale resolution. Here, a novel ensemble of eddy-rich model simulations is used to investigate the patterns of co-variability between AMOC and fine-scale sea surface temperature (SST) anomalies over the GS on sub-seasonal timescales as a function of time lag. Our results reveal that wintertime variability in GS SST and its meridional gradient is preceded by AMOC variability in the previous summer. These AMOC-induced SST gradient anomalies then drive air temperature gradient anomalies through changes in the differential air-sea sensible heat flux. The findings indicate a potential pathway through which deeper ocean circulation precedes atmospheric variability via the GS. The identification of this pathway may provide a potential source of untapped predictability in weather forecast and climate prediction systems.

Lectures / Presentations