Physics Colloquium | A 20th Century Perspective on Summer Antarctic Pressure Change and Variability and Contributions from Tropical SSTs and Ozone Depletion, Jan. 26

The Physics & Astronomy Colloquium Series presents Ryan Fogt, of Ohio University,  on “A 20th Century Perspective on Summer Antarctic Pressure Change and Variability and Contributions from Tropical SSTs and Ozone Depletion” on Friday, Jan. 26, at 4:10 p.m. in Walter 245.

Ryan Fogt

Abstract: During the late 20th Century, the Antarctic atmospheric circulation has changed and significantly influenced the overall Antarctic climate, through processes including a poleward shift of the circumpolar westerlies. However, little is known about the full spatial pattern of atmospheric pressure over the Antarctic continent prior to 1979.

This presentation investigates surface pressure changes across the entire Antarctic continent back to 1905 from a newly developed summer pressure reconstruction poleward of 60°S. It will be shown that only across East Antarctica are the recent pressures significantly lower than pressures in the early 20th century, partly because of periods of significant positive pressure trends in the early 20th century across the coastal South Atlantic sector of Antarctica. Climate model simulations reveal that both tropical sea surface temperature variability and other radiative forcing mechanisms, in addition to ozone depletion, have played an important role in forcing the recent observed negative trends.