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Laboratory simulation of the geothermal heating effects on ocean overturning circulation
Author(s) -
Wang Fei,
Huang ShiDi,
Zhou ShengQi,
Xia KeQing
Publication year - 2016
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2016jc012068
Subject(s) - thermocline , geothermal heating , geothermal gradient , stratification (seeds) , dissipation , heat flux , turbulence , mechanics , ocean current , environmental science , circulation (fluid dynamics) , geology , geophysics , atmospheric sciences , geothermal energy , heat transfer , climatology , thermodynamics , physics , seed dormancy , botany , germination , dormancy , biology
Motivated by a desire to understand the geothermal heating effects on ocean circulation, a large‐scale circulation generated and sustained by thermal forcing at the surface subject to a small amount of heating from the bottom boundary is investigated through laboratory experiments. Despite its idealization, our experiments demonstrate that the leading order effect of geothermal heating is to significantly enhance the abyssal overturning, in agreement with the findings in ocean circulation models. Our experiments also demonstrate that geothermal heating cannot influence the poleward heat transport due to the strong stratification in the thermocline. Our study further reveals that the ratio of geothermal‐flux‐induced turbulent dissipation to the dissipation due to other energies is the key parameter determining the dynamical importance of geothermal heating. This quantity explains why the impact of geothermal heating is sensitive to the deep stratification, the diapycnal mixing, and the amount of geothermal flux. Moreover, it is found that this dissipation ratio may be used to understand results from different studies in a consistent way.