Amy Butler (Reserach Scientist, NOAA Chemical Sciences Laboratory)

Variability in the circumpolar westerly winds of the winter polar stratosphere-- the stratospheric polar vortex-- has a known downward influence on the extratropical surface climate, including a broad spectrum of climate extremes, on timescales of weeks to months. However, the stratosphere also exerts influence on the surface climate and its predictability on decadal to centennial timescales. For example, using large-ensemble simulations, we find that decadal variability in stratosphere-troposphere coupling is associated with amplified decadal variability in regional surface temperatures. While the forced response of the polar vortex to climate change is unknown, with CMIP6 models showing robust disagreement on changes in the polar vortex strength in response to increased greenhouse gases, the uncertainty in the polar vortex response to climate change explains a significant fraction of the uncertainty in the extratropical surface climate response in some regions. These examples, and others, across a broad spectrum of timescales provide evidence for the important role that the stratosphere plays as a conduit for surface climate predictability.

Dr. Amy Butler is a research scientist at the NOAA Chemical Sciences Laboratory. She studies large-scale climate variability, teleconnections, atmospheric dynamics, stratospheric processes, and sub-seasonal to seasonal prediction. She is particularly interested in the stratospheric polar vortex and its influence on surface weather and extremes, and is a regular contributor to the NOAA Polar Vortex Blog