EARTH SYSTEM PHYSICS SEMINAR

[Pandora Malchose]

EARTH SYSTEM PHYSICS SEMINAR

Friday, 17 December 2010
Stasi Seminar Room, LB 1st Floor, 14:30 hrs

Neven S. Fuchkar
International Pacific Research Center, University of Hawaii, USA

ADAPTIVE SCALING MODEL OF THE MAIN PYCNOCLINE AND THE ASSOCIATED 
OVERTURNING CIRCULATION

The ocean plays an important role in climate dynamics. This study 
examines a number of factors and processes that control the large-scale 
structure of the main pycnocline and the associated overturning 
circulation that maintains the ocean stratification. We develop an 
adaptive scaling model that conceptually captures and incorporates the 
key water-mass conversion processes at the first order approximation. 
The constructed semi-empirical transformation balance equation, that 
linearly superimposes various transformation rate terms, is tested in a 
number of simplified single-basin configurations of a coarse-resolution 
ocean general circulation model.

The results provide us with further understanding of the ocean 
controlling mechanism and prediction of how the average depth of the 
main pycnocline, and the deep-water production and export rate, will 
change from one steady state to another. We show that wind-driven 
transformation processes can be decomposed into contributions from the 
mid-latitude westerly and the low-latitude easterly wind (also dependent 
on the mixed layer depth). This low-order model smoothly connects both 
classical limits (diffusive and advective). The proposed framework, that 
unifies wind-driven and thermohaline processes, give us more 
encompassing insight into the problem of the "Drake Passage effect 
without Drake Passage". The modification of different transformation 
pathways in the Southern Hemisphere can result in the equivalent net 
conversion changes.



Everyone is most welcome.