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Webinar: Regional mechanisms for extratropical-tropical climate interactions

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Tuesday, 31 March 2020, 1:00

Tuesday, March 31, 2020.  1:00 PM Eastern Time. Webinar: Regional mechanisms for extratropical-tropical climate interactions. Dillon Amaya, University of Colorado. Sponsored by NCAR-CGD. More information here. Join via Zoom.

Meeting ID: 310 841 4069.

Recent studies have made great strides in diagnosing the pathways by which extratropical temperature perturbations can teleconnect into the deep tropics and influence climate. However, this research has historically focused on the zonal mean energy balance with little consideration for the regional mechanisms that lead to these changes. In this talk, we explore the physical mechanisms that govern regional extratropical-tropical interactions in a variety of modeling frameworks. 

In particular, we utilize a new SST pacemaker simulation to show that North Pacific SST variability can teleconnect to the equatorial region and influence the timing and magnitude of ENSO events in the historical record. The connection between the North and tropical Pacific arises from two physical pathways: 1. A Wind-Evaporation-SST (WES) propagating mechanism, and 2. A Gill-like atmospheric response associated with anomalous deep convection in boreal summer and fall, which we refer to as the Summer Deep Convection (SDC) response. On an event-by-event basis, our pacemaker experiment most closely reproduces the 2014-2015 and 2015-2016 El Niños. We further show that the 2015 Pacific Meridional Mode event increased wind forcing along the equator by 20%, potentially contributing to the extreme nature of the 2015-2016 El Niño.

Location  Join via Zoom. Meeting ID: 310 841 4069.