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The Bjerknes Centre is a collaboration on climate research, between the University of Bergen, Uni Research, the Institute of Marine Research, Nansen Environmental and Remote Sensing Centre.

Seminar: "Beyond cold and warm: An objective classification for maritime mid-latitude fronts"

Clemens Spensberger from the Geophysical Institute and the Bjerknes Centre will give a seminar talk on November 20.

Clemens Spensberger
Clemens Spensberger

Short biography:

I am currently in the final of three years of a mobility stipend concerned with front-orography interactions. During my PhD project at GFI, I worked on large-scale atmospheric dynamics, with a focus on blocking and jet streams.

Abstract:

This study introduces a detailed and objective classification for mid-latitude maritime fronts. The classification is based on a principal component analysis (PCA) to determine the dominant patterns of variability between fronts. Here, fronts are defined as three-dimensional frontal volumes, which are detected in the ERA-Interim data set for a large number of locations in the Atlantic, Pacific and Indian oceans during both winter and summer. In addition to the well-established distinction between warm and cold fronts, the PCA exposes several new dimensions of variability: (a) front intensity, (b) surface fluxes, and (c) along-front transports, linked to the intensity of the associated conveyor belts. These new dimensions of variability are regionally and seasonally robust, and a lagged composite analysis demonstrates that each of the new front types evolves in a dynamically characteristic way. Further, the new front types can be related to established ones like katafronts and anafronts. The new front types are finally redefined based on simple parameter thresholds to simplify their application in future studies.

Arranged date for the seminar talk: Nov 20, 2017