Within the polynya, large heat loss to the air causes surface water to become cold and sink to the bottom via open -
ocean deep convection.
Southern
Ocean deep convection as a driver of Antarctic warming events, Geophysical Research Letters, 43, p. 2192 - 2199.
Not exact matches
During a postdoctoral fellowship at MIT, Cambridge USA, his research interest focused on the interaction between
ocean eddies and
deep convection regions and their respective heat and density transports.
(In real life I understand that mixing is the main agent of
deeper warming in the
ocean due to winds, currents, etc.) Only the top skin of water heats up and therefore lower warming must be by diffusion, or are
convection cells within the water inevitable?
Evaporation from the
ocean surface both cools and salinifies the
ocean surface and thereby bringing about the
deep convection.
Consenquently, the associated SST pattern is slightly cooler in the
deep convection upwelling regions of the Equitorial Pacific and the Indian
Ocean, strongly cooler in the nearest
deep convection source region of the South Atlantic near Africa and the Equator, warm over the bulk of the North Atlantic, strongly warmer where the gulf stream loses the largest portion of its heat near 50N 25W, and strongly cooler near 45N 45W, which turns out to be a back - eddy of the Gulf Stream with increased transport of cold water from the north whenever the Gulf Stream is running quickly.
For a rough estimate, downwelling water to the
deep ocean in
convection zones is about 40 Sv (10 ^ 6 m3 / s), assuming that comes in with say 2 deg C, and leaves (through upwelling, isopycnal and diapycnal diffusion), that is a heat flux of 320 TW, thus at least an order of magnitude larger than the geothermal fluxes.
If we call the
deep ocean the bottom 3 km, then, were it not for
convection carrying the heat to the surface, the total geothermal heat flux of about 20TW would raise the temperature of the
deep ocean by 1K every 4000 years or so.
The vertically integrated inventory of human emitted CO2 in the
oceans is (not surprisingly) much greater in areas of cold
deep convection, especially in the northern Atlantic (the falling leg of the thermohaline circulation), and much less in the tropics where the
ocean is strongly stratified; absorption in the tropics really is more in the near - surface waters.
The idea is that Arctic sea ice decline would expose the
ocean to anomalous surface heat and freshwater fluxes, resulting in positive buoyancy anomalies that can propagate downstream to the North Atlantic, in due time suppressing
deep convection and weakening the AMOC.
Another factor is
convection currents in water allow heat to move into the depths and
oceans are very
deep.
Too much precip in the Pacific makes the
ocean overall fresher and more difficult to initiate
deep convection in the
ocean.
Martinson, D. G. in
Deep Convection and
Deep Water Formation in the
Oceans (eds Chu, P. C. & Gascard, J. C.) 37 — 52 (Elsevier Oceanography Series, 1991).
The latter determines the intensity of
convection in the
ocean and the timescale of
deep -
ocean processes affecting CO2 uptake and storage.
Therefore about 60 % of the «hook profile» must come from
convection because the remaining energy makes its way back out of the
ocean from
deeper.
It says nothing about
deep - sea temperatures, although it does reference increased warm water and
convection (i.e. tropical cyclones) in the Indian
Ocean, which might, in turn, be involved with the 0 - 2000 meter trend in the Indian
Ocean mentioned above (originally from Bob Tisdale).
Canuto, V.M., Y. Cheng, and A.M. Howard, 2007: Non-local
ocean mixing model and a new plume model for
deep convection.
``... among the present generation of global climate models,
deep convection is common in the Southern
Ocean under pre-industrial conditions, but weakens and ceases under a climate change scenario owing to surface freshening.
[b] Cessation of
deep convection in the open Southern
Ocean under anthropogenic climate change [/ b]
The study: Cessation of
deep convection in the open Southern
Ocean under anthropogenic climate change doi: 10.1038 / nclimate2132
The warm water evaporates from the
ocean surface, and the light, warm and humid air rises, leading to
deep convection in the form of towering cumulonimbus clouds and heavy precipitation.
In that case, persistent
deep convection did not occur in the central Pacific, and the usual strong interaction between the atmosphere and the
ocean there failed to play its normal role in anchoring the
convection and heat transfer.
This statement is made in a paragraph discussing the
deep ocean convection in the Southern O
ocean convection in the Southern
OceanOcean.
TheWeddell Sea polynya is a large opening in the open -
ocean sea ice cover associated with intense
deep convection in the
ocean.
Without winds or a high vertical diffusivity, the
ocean does not support
deep convection.