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

[Christopher L. P. Wolfe]

Thanks!

Christopher


> On Jun 4, 2021, at 2:41 PM, Wang, Ou (US 329B) <ou.wang at jpl.nasa.gov> wrote:
> 
> 
> Hi Christopher,
>  
> One correction to the alternative way I mentioned;
> Alternatively, you can calculate it by summing up the first guess of a constant 1e-5 m^2/s (not total_diffkr_r009bit11.bin) and xx_diffkr.dim.0000000129.data.
>  
> See Forget et al. (2015; doi:10.5194/gmd-8-3071-2015), Table 1 for the first guess of the mixing parameters.
>  
> Ou
>  
>  
> From: <ecco-support-bounces at mit.edu> on behalf of "Wang, Ou (US 329B)" <ou.wang at jpl.nasa.gov>
> Reply-To: "ECCO support list, wider membership" <ecco-support at mit.edu>
> Date: Friday, June 4, 2021 at 9:17 AM
> To: "ECCO support list, wider membership" <ecco-support at mit.edu>
> Subject: Re: [ecco-support] [EXTERNAL] How to get the total diffusivity in ECCOv4
>  
> 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) 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) 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             631-632-3152
> ----------------------------------------------------------------------------
> 
> 
> 
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