TY - JOUR

T1 - The role of preconditioning in the evolution of open-ocean deep convection

AU - Noh, Yign

AU - Cheon, Woo Geun

AU - Raasch, Siegfried

N1 - Funding Information: This work was supported by Ko- rea/Japan Joint Research Project of KOSEF, the Climate Environment System Research Center sponsored by the SRC program of KOSEF, and the Ecotechnopia Project by KIEST.

PY - 2003/6/1

Y1 - 2003/6/1

N2 - Large-eddy simulation of open-ocean deep convection shows that the evolution of convection appears in a fundamentally different pattern, depending on the precondition of the ocean and the magnitude of the surface buoyancy flux. As the intensity of the cyclonic gyre in the ocean under the cooling increases, the pattern of convection is transformed from "distributed convection" to "localized convection." In localized convection the typical pattern of open-ocean deep convection appears, such as the generation of baroclinic instability and large lateral buoyancy transfer, secondary circulation, restratification, and the breakup of the original cyclonic gyre. On the other hand, in distributed convection small-scale convective plumes appear uniformly over the whole surface similarly to the convective boundary layer without generating the typical features of open-ocean deep convection. Hence, an enormous difference in the generated eddy kinetic energies exists between the two cases. It is also found that a stronger cooling at the sea surface suppresses the transition from distributed convection to localized convection. Dimensional analysis provides the parameters to characterize the pattern of convection, and the critical condition for the transition is estimated by analyzing the numerical results.

AB - Large-eddy simulation of open-ocean deep convection shows that the evolution of convection appears in a fundamentally different pattern, depending on the precondition of the ocean and the magnitude of the surface buoyancy flux. As the intensity of the cyclonic gyre in the ocean under the cooling increases, the pattern of convection is transformed from "distributed convection" to "localized convection." In localized convection the typical pattern of open-ocean deep convection appears, such as the generation of baroclinic instability and large lateral buoyancy transfer, secondary circulation, restratification, and the breakup of the original cyclonic gyre. On the other hand, in distributed convection small-scale convective plumes appear uniformly over the whole surface similarly to the convective boundary layer without generating the typical features of open-ocean deep convection. Hence, an enormous difference in the generated eddy kinetic energies exists between the two cases. It is also found that a stronger cooling at the sea surface suppresses the transition from distributed convection to localized convection. Dimensional analysis provides the parameters to characterize the pattern of convection, and the critical condition for the transition is estimated by analyzing the numerical results.

UR - http://www.scopus.com/inward/record.url?scp=0037669748&partnerID=8YFLogxK

U2 - 10.1175/1520-0485(2003)033<1145:TROPIT>2.0.CO;2

DO - 10.1175/1520-0485(2003)033<1145:TROPIT>2.0.CO;2

M3 - Article

AN - SCOPUS:0037669748

VL - 33

SP - 1145

EP - 1166

JO - Journal of physical oceanography

JF - Journal of physical oceanography

SN - 0022-3670

IS - 6

ER -