MASS Seminar- Karen Smith (LDEO)
Date Time Location
April 1st, 2013 12:00pm-1:00pm 54-915
Title:

What can natural variability tell us about the Antarctic's response to climate change?

Abstract:

The dominant driver of recent multi-decadal change in Antarctic climate has been the depletion of stratospheric ozone. The associated changes in the extratropical Southern Hemisphere atmospheric circulation are characterized by a positive trend in the Southern Annular Mode (SAM). In this seminar, the extent to which interannual relationships between the SAM and the Antarctic climate system can be extrapolated to interpret the multi-decadal response to anthropogenic forcing in this region will be examined. This question is addressed in two recent studies about the effect of stratospheric ozone changes on the Antarctic climate. In the first study, the effect of stratospheric ozone recovery on Antarctic sea ice in the next half-century is investigated, by comparing two ensembles of WACCM4 (The Whole Atmosphere Community Climate Model, Version 4) integrations, from 2001 to 2065. Second, the effect of past ozone depletion and future recovery on the energy budget of the Antarctic atmosphere is examined using satellite data, reanalyses and WACCM4. In both cases, the sea ice and horizontal energy transport respond differently to SAM anomalies on interannual and multi-decadal time scales. Reasons for this behaviour will be discussed.