[ecco-support] Artifacts in global meridional overturning circulation

[Wang, Ou (329B)]

Hello Tatsu,

NVELMASS and EVELMASS are not native model velocities and thus may not be suitable for studying integrated quantities or doing budget analysis. They are the northward and eastward geometry-weighted velocities that are converted from native model variables UVELMASS and VVELMASS; the latter two should be used instead to compute the meridional transport. The Matlab toolbox gcmfaces https://gcmfaces.readthedocs.io/en/latest/ has a built-in script to compute the meridional transport using UVELMASS and VVELMASS. The particular Matlab script is https://github.com/gaelforget/gcmfaces/blob/master/gcmfaces_calc/calc_MeridionalTransport.m.

Cheers,
Ou Wang

From: <ecco-support-bounces at mit.edu<mailto:ecco-support-bounces at mit.edu>> on behalf of Tatsu Monkman <tdmonkman at uchicago.edu<mailto:tdmonkman at uchicago.edu>>
Reply-To: "ECCO support list, wider membership" <ecco-support at mit.edu<mailto:ecco-support at mit.edu>>
Date: Monday, November 19, 2018 at 10:47 AM
To: "ecco-support at mit.edu<mailto:ecco-support at mit.edu>" <ecco-support at mit.edu<mailto:ecco-support at mit.edu>>
Subject: [ecco-support] Artifacts in global meridional overturning circulation

Hello,

I'm a current graduate student at the University of Chicago working with the latest ECCO v4r3 data output and am having some issues. When I do a global integration of NVELMASS tiles multiplied by DRF and DXG and then integrate by depth from the surface I see bright bands developing at several latitudes. This could be a simple calculation mistake on my end and I was wondering if this has been seen before and if there is a known solution. I suspect this may have to do with tiles near land-sea boundaries, but I assumed that NVELMASS was weighted for that, and have tried NVEL multiplied by hFacS with similar results. I am performing all of these calculations on NVEL and GRID data arrays extracted from Version4 Release3 on ftp://ecco.jpl.nasa.gov/ . I've attached a plot of my output for reference.

I am running ecco through the python 2.7 on OS Mojave 10.14.1

Thanks!
-Tatsu Monkman
University of Chicago
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