[ecco-support] [EXTERNAL] What is the definition of mixed layer depth for the ECCO2 data

[Zhang, Hong (US 398K)]

On Jul 16, 2024, at 7:59 AM, Joe Smith <jxh207256 at gmail.com> wrote:

Dear professors,
    I am a doctoral student. And I want to download ECCO2 mixed layer depth data (https://ecco.jpl.nasa.gov/drive/files/ECCO2/cube92_latlon_quart_90S90N/daily/MXLDEPTH )  and compare it with my MODEL.
    My question is,
    1. What is the definition of mixed layer depth for the ECCO2 data ?
    2. Which variable is used to calculate the mixed layer depth ? potential temperature? potential density? or in-situ density?
    3. What is the criteria of the mixed layer depth ? e.g., if potential density is used to calculated mixed layer depth, and I suppose the reference depth is 10 meters, and what is the criteria of density difference between the density at the mixed layer depth and the density at the reference depth (10 meters)?
    Looking forward to hearing from you soon.
Hi Joe,
For ECCO, we use the default criterion for calculating MLD
that is, Kara et al  method.
See source code here
<https://github.com/MITgcm/MITgcm/blob/e37161e05a79673e8b0591373a2708cda402eaca/model/src/calc_oce_mxlayer.F#L104>
[MITgcm.png]
MITgcm/model/src/calc_oce_mxlayer.F at e37161e05a79673e8b0591373a2708cda402eaca · MITgcm/MITgcm<https://github.com/MITgcm/MITgcm/blob/e37161e05a79673e8b0591373a2708cda402eaca/model/src/calc_oce_mxlayer.F#L104>
github.com<https://github.com/MITgcm/MITgcm/blob/e37161e05a79673e8b0591373a2708cda402eaca/model/src/calc_oce_mxlayer.F#L104>
It involves potential temperature and salinity,

Hope it helps
Hong

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