KlimaCampus Kolloquium: Hurricanes and Rossby waves: Dynamics and predictability in the middle latitudes

The midlatitude climate is characterized by the ever-changing weather associated with the alternation of high and low-pressure systems. These surface pressure systems are associated with undulations of the midlatitude jet stream, so-called Rossby waves. Understanding the dynamics of Rossby waves is therefore fundamental to understanding the midlatitude weather.

In this presentation, we will first focus on the weather timescale. It will be demonstrated that moist processes play an important role in the amplification of the Rossby wave pattern. Tropical cyclones that interact with the jet stream and move into the midlatitudes are showcase examples of such amplification. At the same time moist processes have limited predictability, which may severely affect the larger-scale wave pattern within a few days. Processes that govern this upscale error growth will be examined. In the context of moist processes, we will then discuss the low bias in Rossby-wave amplitude of current global weather prediction models.

In a concluding discussion, I will attempt to link the insights gained on the weather timescale to current discussions of extreme events related to large-amplitude Rossby waves in a warming climate.

Datum

08.12.2016

Uhrzeit

15:15 Uhr

Ort

Bundesstr. 53, room 022/023
Seminar Room 022/023, Ground Floor, Bundesstrasse 53, 20146 Hamburg, Hamburg

Referent

Michael Riemer, Johannes Gutenberg-Universität, Mainz

Chair

Stefan Bühler

Zur Übersicht