Name: Helen Johnson
Affiliation: University of Oxford/University of Bergen
Short biography:
I am an Assistant Professor in the Earth Sciences Department at the University of Oxford. I also hold a 10% adjunct professorship at the University of Bergen. I work to improve our understanding of ocean circulation and the role it plays in the climate system, using fluid dynamics theory, simple and state-of-the-art numerical models and ocean observations. I am particularly interested in the dynamics of the Atlantic and Arctic Oceans.
Abstract:
Changes in Arctic Ocean circulation and freshwater content have the potential to significantly influence regional and global climate. This talk will focus on how quickly the Arctic Ocean responds to a change in sea-ice cover or wind forcing at the ocean surface, and the mechanisms determining the response timescale. I will present evidence from a hierarchy of studies recently carried out in Oxford, from a 1.5 layer reduced gravity model, through idealised numerical ocean model simulations, to analysis of a state-of-the-art coupled climate model control run, showing that (a) the Arctic Ocean and its fresh water content respond to changes in surface forcing on timescales of about a decade, and (b) ocean eddies likely determine this timescale.
Arranged date for the seminar talk: Mar 20, 2017