Environmental Science and Engineering Seminar

Wednesday April 27, 2016 4:00 PM

The dynamics of changing winter temperature extremes

Speaker: Andrew Rhines, Department of Atmosphere, Ocean and Climate Dynamics, Harvard University
Location: South Mudd 365

There is considerable interest in determining how surface temperature variability is influenced by mean warming. Model ensembles project that variability will decrease in the future, consistent with physical arguments related to polar amplification. However, observational studies have thus far come to conflicting conclusions. Several analytical pitfalls in interpreting observational records lead to these discrepancies, and highlight the importance of accounting for non-normality and the effects of filtering, time-averaging, gridding, and smoothing. Applying a set of methods designed to overcome these challenges, I will show that a decrease in temperature variability is already robustly detectable in the extratropics during winter. The effects of polar amplification on synoptic-scale advection explain much of the decreased variability, though a substantial residual signal suggests that additional mechanisms are of similar importance.

Series Environmental Science and Engineering Seminar

Contact: Kathy Young at 626-395-8732 katyoung@gps.caltech.edu