MASS Seminar - Adam Sobel (Columbia)
Date Time Location
October 28th, 2013 12:00pm-1:00pm 54-915
Title: "Dynamics of the Madden-Julian oscillation"

Abstract: The Madden-Julian oscillation (MJO) is the dominant mode of variability in the tropics on the intraseasonal time scale (~20-90 day periods) and one of the most important
coherent, quasi-periodic modes of natural variability in the global climate system
altogether. Though it was discovered over 40 years ago, we still do not understand the
MJO, in the sense of being able to state a simple mathematical model that explains its
basic features.

I will present evidence that the MJO is what some of us now call a "moisture mode", best
analyzed by examining the budget of moist static energy or moist entropy. I will argue
that cloud-radiative feedbacks are important to the maintenance of the MJO, while
advection of moist static energy - both horizontal and vertical - is important to its
eastward propagation. I will present evidence from observations, theory, general
circulation models, and cloud-resolving models to this effect.

Speaker's website: http://www.columbia.edu/~ahs129/home.html