Bjerknessenterets mål er å forstå klima
til nytte for samfunnet.

Seminar talk: Changes in ocean water masses reveal excess heat distribution in the climate system

Jan Zika from UNSW, Australia, is the speaker on this seminar on October 22.

Jan Zika
Jan Zika

Short biography:

Jan is fascinated by the large scale physics of the ocean and the role of water in the climate. After completing a PhD at CSIRO in Hobart (for which he was awarded the AMOS Uwe Radock Prize) Jan has worked in Grenoble, Southampton and Imperial College London and has been awarded two National Environment Research Council Fellowships. In October 2016 Jan took up a lectureship in the School of Mathematics and Statistics at UNSW.



Accounting for 93% of the excess heat in the earth system, ocean warming is central to understanding climate change. The recent Argo observing program has revealed regional patterns of warming and cooling up to ten times the global average. So the regional distribution of excess heat is being obscured by large and compensating regional patterns of change. Regional ocean heat content changes occur either through the addition of excess heat at the ocean surface or through redistribution within the ocean of existing water masses. Here we present a novel diagnosis of the ‘excess’ and ‘redistributed’ contributions to regional heat content change between 2006 and 2017 based on water mass theory. A planetary scale southward redistribution of up to 0.1PW explains broad heat content changes in the Southern Ocean and North Atlantic. Meanwhile 0.4±0.08PW of excess heat is concentrating in tropical and subtropical regions with the largest reservoir in the North Atlantic.


Arranged date for the seminar talk: Oct 22, 2019 at 14:15, BCCR lecture room 4020; Jahnebakken 5.