[MITgcm-support] Diagnosed KPP diffusivities

[Ruan Xiaozhou]

Dear MITgcm users,

I diagnosed KPPdiffS and KPPdiffT in my model run and they look remarkably similar to my 3D diffusivity input field (except at the surface and a very thin layer near the bottom). I was wondering if these two fields are the total diffusivities used in the model or net contribution to the diffusivity from just the KPP package? Looking at the calcu_3d_diffusivity.F routine, it doesn’t seem like the KPP diffusivities are added to the input field (the code seems to output a new KappaRTr and thus overwrites the previous one). A related question is, if I only had KPP and the input diffusivity field, could I equate the total vertical heat/salt flux (explicit + implicit components) to the total diffusivity multiplied by the corresponding gradients? Thanks!

Best,
Xiaozhou

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Xiaozhou Ruan
Postdoctoral researcher
Department of Earth, Atmospheric and Planetary Sciences
Massachusetts Institute of Technology
54-1622
Cambridge, MA  02139

email: xruan at mit.edu
web:   http://www.mit.edu/~xruan