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<p class="MsoNormal">Hi Christopher,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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
<a href="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">
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</a>. The variable is called “DIFFKR” in the NetCDF file. Alternatively, you can calculate
it by summing up <span style="color:black">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
<a href="https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/other/adjustments/xx_diffkr.dim.0000000129.data">
https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/other/adjustments/xx_diffkr.dim.0000000129.data</a>.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:black">The description about </span>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
<span style="color:red">1</span>, not the adjusted Redi parameter from Release 4.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ou<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black"><ecco-support-bounces@mit.edu> on behalf of Christopher Wolfe <christopher.wolfe@stonybrook.edu><br>
<b>Reply-To: </b>"ECCO support list, wider membership" <ecco-support@mit.edu><br>
<b>Date: </b>Friday, June 4, 2021 at 6:44 AM<br>
<b>To: </b>"ecco-support@mit.edu" <ecco-support@mit.edu><br>
<b>Subject: </b>[EXTERNAL] [ecco-support] How to get the total diffusivity in ECCOv4<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi all: <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">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. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The ECCOv4 python tutorial (at <a href="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$">
https://ecco-v4-python-tutorial.readthedocs.io/ECCO_v4_Loading_LLC_compact_binary_files.html#Example-3:-Load-a-3D-'compact'-llc-binary-file-with-3rd-dimension-=-Depth</a>) says that total_kapredi_r009bit11.bin is the "adjusted GM redi parameter (first guess
+ adjustments)”, which implies that total_diffkr_r009bit11.bin should be the adjusted diffusivity. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On the other hand, the README at <a href="https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/input_init/README">https://ecco.jpl.nasa.gov/drive/files/Version4/Release4/input_init/README</a> says that <span style="color:black"> total_diffkr_r009bit11.bin
is the </span>"vert. diff. of release 1 (this field plus xx is the total)”, which means that I should add xx_diffkr.0000000129.data to this to get the full diffusivity. However, the values in this file are order 1, so adding it to <span style="color:black">total_diffkr_r009bit11
would produce diffusivities far outside the expected range.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black"><br>
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<p class="MsoNormal"><span style="color:black">The gencost documentation of the ctrl package (<a href="https://urldefense.us/v3/__https:/mitgcm.readthedocs.io/en/latest/ocean_state_est/ocean_state_est.html*ctrl-model-parameter-adjustment-capability__;Iw!!PvBDto6Hs4WbVuu7!eGOlWbFIVdKaXoIQQEcSSqRPb2UW2kabBqJXw8Hdg5AizGFceCu2pSW1rdXfrjEs71w$">https://mitgcm.readthedocs.io/en/latest/ocean_state_est/ocean_state_est.html#ctrl-model-parameter-adjustment-capability</a>)
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?</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black"><br>
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<p class="MsoNormal"><span style="color:black">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.</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black">Thanks in advance for your advise,</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black">Christopher</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="color:black">----------------------------------------------------------------------------<br>
Christopher L. Pitt Wolfe<br>
Associate Professor (Physical Oceanography)<br>
School of Marine and Atmospheric Sciences<br>
Stony Brook University<br>
</span><a href="mailto:christopher.wolfe@stonybrook.edu">christopher.wolfe@stonybrook.edu</a><span style="color:black"> 631-632-3152<br>
----------------------------------------------------------------------------</span><o:p></o:p></p>
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