Sack Lunch Seminar (SLS)

SLS - Xinfeng Liang (MIT) - Global Ocean Vertical Heat Flux and Its Bidecadal
Date Time Location
December 2nd, 2015 12:00pm-1:00pm 54-915
Using a dynamically consistent state estimate, the vertical redistribution of oceanic heat is investigated over a 20-year period (1992-2011). The 20-year mean vertical heat flux shows strong variations both horizontally and vertically, consistent with the ocean being a dynamically active and spatially complex heat exchanger. Between mixing and advection, the two processes determining the vertical heat transport in the deep ocean, advection plays a more important role in setting the spatial patterns of vertical heat exchange. The global integral of vertical heat flux shows an upward heat transport in the deep ocean, suggesting an abyssal cooling trend over 1992-2011.

The bidecadal change of the ocean vertical heat flux is also examined and provides dynamical insights into the global ocean heat content change. Preliminary results show that above 1500 m more heat is transported downward during 2002 2011 than 1992-2001. The spatial pattern of the vertical heat flux change shows consistent features with previous studies, such as more downward heat transport in the tropical Pacific and the North Atlantic during the last decade. Whereas the spatial pattern of vertical heat flux change is closely related to the advection change, its global integral is largely determined by the change in mixing, indicating a crucial role of ocean mixing in explaining the long-term change of ocean vertical heat exchange.