Atmosphere Ocean Science Colloquium

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Sampling and studying rare events (mostly) in AOS

Speaker: Jonathan Weare & Justin Finkel, Courant & U of Chicago

Location: Warren Weaver Hall 1302

Date: Wednesday, October 13, 2021, 3:30 p.m.

Synopsis:

This talk will cover recent work in our group developing and applying algorithms to simulate and analyze rare events in AOS and other areas. In a first part of the talk, I will review a rare event simulation scheme that biases model simulations toward the rare event of interest by preferentially duplicating simulations making progress toward the event and removing others. I will describe applications of this approach to rapid intensification of tropical cyclones and instability of Mercury's orbit. In a second part of the talk, Justin will describe his use of Transition Path Theory (TPT) to study sudden stratospheric warming events. TPT provides a detailed statistical description of rare transition events using key forecast functions (both forward and backward-in-time) as inputs. We compute these inputs on both an idealized model and, preliminarily, on ECMWF hindcast data. Crucially, our approach relies only on short forecast ensembles, allowing us to utilize a vast store of data previously untapped for this purpose.