CGD Seminar Series - Darryn Waugh, Revisiting trends in southern hemisphere westerlies and their impact on the oceans

Title: Revisiting trends in southern hemisphere westerlies and their impact on the oceans

Speaker: Darryn Waugh, Johns Hopkins University

Date: Tuesday, 6 October 2020

Time: 11 am - 12 pm

For Zoom viewing access contact Tracy Baker, tbaker@ucar.edu

Abstract: It is widely understood that there has been a trend towards a more positive phase of the southern annular mode (SAM), with an associated strengthening and poleward shift of southern near-surface westerlies, over the last few decades.  However, as will be shown in this talk, there has been a recent pause in some of these trends together with substantial longitudinal variations in the wind trends.  Specifically there has been a large strengthening and a statistically insignificant equatorward shift of peak annual-mean near-surface winds over the Pacific, in contrast to a weaker strengthening and significant poleward shift over the Atlantic and Indian Ocean sectors.   Analysis of ensembles of climate model simulations indicate that while the summer trends and pause are a forced response, the differential movement of the peak westerlies is a manifestation of internal variability.   Implications of these asymmetries in wind trends for the ocean response will also be discussed, with a focus on the inter-basin differences in the ventilation of mode and intermediate waters, and possible impact on ocean uptake of carbon and heat.

For more information contact Tracy Baker, tbaker@ucar.edu, 303-497-1366

Type of event:

Will this event be webcast to the public by NCAR|UCAR?: 
No
Announcement Timing: 
Monday, October 5, 2020 to Tuesday, October 6, 2020
Calendar Timing: 
Tuesday, October 6, 2020 - 11:00am to 12:00pm MDT

Posted by Tracy Baker at ext. 1366, tbaker@ucar.edu

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