Dept. of Geophysics Colloquium: Bridging Scales in the Midlatitude Climate

Zoom: https://tau-ac-il.zoom.us/j/83888751261?pwd=36z53wLKBh2swtqb0scG5UTUYs2g95.1

Abstract:

Midlatitude climate emerges from interactions between storms and atmospheric phenomena spanning scales from planetary jets to kilometer-scale clouds. Here, we combine Eulerian and Lagrangian approaches to reveal how these multiscale interactions shape the atmospheric circulation.

We first examine how the planetary-scale circulation shapes synoptic-scale storm growth, focusing on the paradox that Atlantic winter storms are stronger despite the stronger Pacific jet. Using a single-storm perspective, we show that the large-scale jet controls storm growth through both its strength and geometry. Stronger jets promote rapid intensification but shorten the time storms remain within favorable conditions, while jet orientation controls how closely storms remain aligned with the jet as they propagate. Together, these mechanisms explain how differences in the planetary-scale circulation produce the observed differences in synoptic-scale storm intensity.

Going a thousand-fold smaller, we next examine how midlatitude storms couple planet-wide climate to kilometer-scale clouds. We show that storms bridge hemispheric differences in surface conditions and cloud albedo, thereby reinforcing the observed albedo symmetry. We then demonstrate that storm-generated cloud fields feed back onto the circulation by reinforcing the meridional temperature gradients required for storm growth. Together, these results reveal a tight two-way coupling between storms and clouds that links kilometer-scale cloud processes to the large-scale climate.

Event Organizer: Dr. Leah Langer