Meridional heat transports in the ocean from an ECCO2 data synthesis

A global ocean data synthesis product at eddy-permitting resolution from
Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2)
project is used to estimate the oceanic heat transport and investigate
its mechanisms. Heat in the ocean is transported poleward by both the
overturning circulation (zonally integrated flow) and the horizontal
circulation (gyre transport). We demonstrate that the overturning
dominates in the subtropical gyres while the horizontal circulation is
responsible for most of the heat transport in the subpolar oceans. We
analyze contributions from the time-mean circulation and temperature
fields and from the correlation of the time-varying velocity and
temperature fields. We define the eddy heat transport as the deviation
of the zonally integrated heat transport from the heat transport due to
the 3-month average fields of velocity and temperature. The estimated
heat transport thus contains signals only with periods shorter than 3
months, which are mainly associated with the eddy variability. We show
that in a number of locations the time-mean eddy heat transport
constitutes a considerable portion of the total time-mean heat
transport, in particular, in the tropics, in the Southern Ocean and in
the Kuroshio Current. The variability of the eddy heat transport appears
to be a significant contributor to the variability of the total heat
transport and globally it explains about 1/3 of its variance. Eddies are
also found to explain a significant portion of the interannual heat
transport variance. Using the estimates of the meridional heat transport
we investigate the mechanisms of the recent sea level rise in the
Subpolar North Atlantic and the mechanisms of the heat transport in the
Southern Ocean.

Date

21.11.2008

Time

11:30 h

Place

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

Speaker

Denis L. Volkov, Jet Propulsion Laboratory, California Institute of Technology

Organizers


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