Mixed Layer Depth

[tylerrohr22]

1. Validating MLD will be key to looking at any BGC cycling. Some options for reanalysis products to compare to:

•    HYCOM.  Available on the OSU site (http://orca.science.oregonstate.edu/1080.by.2160.monthly.hdf.mld125.hycom.php)
  

•    bSOSE/SOSE (http://www.ecco.ucsd.edu/sose.html) 
  

2. Some metrics to look at

•    Winter mean/maximum; summer mean/maxima; timing for onset of shoal
  

[hrsdawson]

@lidefi87 is this something you've already explored?

[lidefi87]

Hi Hannah! Yes, I have done this here. For observations in the Southern Ocean, I used Sallee 2021.

[hrsdawson]

Cool, that looks great. Was this for cycle 4 with the BGC?

[lidefi87]

No, this was cycle 2, but @TamaraLSchlosser and I will be looking into updating this in the next week or so

[hrsdawson]

From meeting today - would be good to look at summertime MLDs. Are they shallower than expected and could this explain the lower productivity and lower iron uptake that we see?

[lidefi87]

Sorry I could not make it yesterday. I will likely need to do this for my second chapter anyway, but it will likely focus on the SO. @TamaraLSchlosser, could you confirm what was your source for observations?

[TamaraLSchlosser]

I have been looking at a gridded argo product (httpmixedlayer.ucsd.edu) and WOA18. Note these have different definitions of 'mld'. I've uploaded my initial monthly figures to the 'figures' folder but here is a Jan and July below.
Jan

July

[aekiss]

MLD comparisons are tricky due to differing definitions and averaging methods - see Treguier et al 2023. These issues were dealt with in this preprint, and ACCESS-OM2-01 shows a deep bias in MLD in both summer (top fig below) and winter (bottom fig; different scale) in most of the Southern Ocean and Antarctic shelf which looks consistent with what @TamaraLSchlosser has plotted. In the figs from the preprint below, "ACCESS-MOM" means ACCESS-OM2 at low resolution and ACCESS-OM2-01 at high resolution (IAF cycle 1).

[aekiss]

Treguier et al 2023 mostly use de Boyer Montégut (2022) as an observational reference

[aekiss]

Also see this forum post: https://forum.access-hive.org.au/t/bgc-validation-access-om2-1-10-degree-iaf/454/6