[ecco-support] [EXTERNAL] How to get the total diffusivity in ECCOv4

[Wang, Ou (US 329B)]

Hi Christopher,

PO.DAAC is now hosting V4r4’s files. You can get V4r4’s dimensional vertical diffusivity field (first guess plus the control adjustment) from PO.DAAC at https://archive.podaac.earthdata.nasa.gov/podaac-ops-cumulus-protected/ECCO_L4_OCEAN_3D_MIX_COEFFS_LLC0090GRID_V4R4/OCEAN_3D_MIXING_COEFFS_ECCO_V4r4_native_llc0090.nc. The variable is called “DIFFKR” in the NetCDF file. Alternatively, you can calculate it by summing up total_diffkr_r009bit11.bin and xx_diffkr.dim.0000000129.data that are available on ECCO Drive at https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/input_init/total_diffkr_r009bit11.bin and https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/other/adjustments/xx_diffkr.dim.0000000129.data.

The description about total_kapredi_r009bit11.bin in the ECCOv4 Python tutorial is incorrect and will be corrected. The field in total_kapredi_r009bit11.bin is the Redi parameter from Release 1, not the adjusted Redi parameter from Release 4.

Ou

From: <ecco-support-bounces at mit.edu> on behalf of Christopher Wolfe <christopher.wolfe at stonybrook.edu>
Reply-To: "ECCO support list, wider membership" <ecco-support at mit.edu>
Date: Friday, June 4, 2021 at 6:44 AM
To: "ecco-support at mit.edu" <ecco-support at mit.edu>
Subject: [EXTERNAL] [ecco-support] How to get the total diffusivity in ECCOv4

Hi all:

I’m trying to figure out what the vertical diffusivity field in ECCOv4r4 is, but I’m a little confused about which input file actually contains this data.

The ECCOv4 python tutorial (at https://ecco-v4-python-tutorial.readthedocs.io/ECCO_v4_Loading_LLC_compact_binary_files.html#Example-3:-Load-a-3D-'compact'-llc-binary-file-with-3rd-dimension-=-Depth<https://urldefense.us/v3/__https:/ecco-v4-python-tutorial.readthedocs.io/ECCO_v4_Loading_LLC_compact_binary_files.html*Example-3:-Load-a-3D-'compact'-llc-binary-file-with-3rd-dimension-=-Depth__;Iw!!PvBDto6Hs4WbVuu7!eGOlWbFIVdKaXoIQQEcSSqRPb2UW2kabBqJXw8Hdg5AizGFceCu2pSW1rdXfRM0vvIA$>) says that total_kapredi_r009bit11.bin is the "adjusted GM redi parameter (first guess + adjustments)”, which implies that total_diffkr_r009bit11.bin should be the adjusted diffusivity.

On the other hand, the README at https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/input_init/README says that  total_diffkr_r009bit11.bin is the "vert. diff. of release 1 (this field plus xx is the total)”, which means that I should add xx_diffkr.0000000129.data to this to get the full diffusivity. However, the values in this file are order 1, so adding it to total_diffkr_r009bit11 would produce diffusivities far outside the expected range.


The gencost documentation of the ctrl package (https://mitgcm.readthedocs.io/en/latest/ocean_state_est/ocean_state_est.html#ctrl-model-parameter-adjustment-capability<https://urldefense.us/v3/__https:/mitgcm.readthedocs.io/en/latest/ocean_state_est/ocean_state_est.html*ctrl-model-parameter-adjustment-capability__;Iw!!PvBDto6Hs4WbVuu7!eGOlWbFIVdKaXoIQQEcSSqRPb2UW2kabBqJXw8Hdg5AizGFceCu2pSW1rdXfrjEs71w$>) says that the xx adjustments are non-dimensional and need to be scaled by one over the square root of the weights, which are in r2.wdiffkrFldv2.data. Using this produces adjustments on the order of 1e-6 to 1e-5, which seems about right. However, the data.ctrl namelist also specifies WC01 smoothing and some thresholding. Do these need to be applied as well?


Is the best way to get this data simply to run the model for a bit and have it dump diffkr? It would be convenient to be able to calculate these quantities without having to run the model, however.


Thanks in advance for your advise,
Christopher


----------------------------------------------------------------------------
Christopher L. Pitt Wolfe
Associate Professor (Physical Oceanography)
School of Marine and Atmospheric Sciences
Stony Brook University
christopher.wolfe at stonybrook.edu<mailto:christopher.wolfe at stonybrook.edu>             631-632-3152
----------------------------------------------------------------------------


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.mit.edu/pipermail/ecco-support/attachments/20210604/136ab1c8/attachment.html