[ecco-support] Salt/salinity budget closure in ECCO V4r4

[Wang, Ou (US 321D)]

Hi Anthony,

SFLUX is appropriate for closing the salt budget. The global ocean surface area integral of SFLUX matches the time-derivative of total ocean salt content.

The two descriptions are intended to convey the same thing. We will revise one or both descriptions to improve clarity.

Best,
Ou

From: ecco-support <ecco-support-bounces at mit.edu> on behalf of Anthony Meza <ameza at mit.edu>
Date: Thursday, February 19, 2026 at 7:48 PM
To: ecco-support <ecco-support at mit.edu>
Subject: [EXTERNAL] [ecco-support] Salt/salinity budget closure in ECCO V4r4

Hi all,

I had a question about the salt/salinity budget closure in ECCO V4r4. The ECCO V4r4 tutorial says that "SFLUX" is total salt flux (match salt-content variations) (g/m^2/s)<https://urldefense.us/v3/__https://ecco-v4-python-tutorial.readthedocs.io/ECCO_v4_Salt_and_salinity_budget.html__;!!PvBDto6Hs4WbVuu7!PngytV6-_8w8tZqzSpmozFQZe5AR6MjXxwpSSJMa6n_3PJg2iWxuKWpT0Pr-LrUVO7oUcEgwofyNFY7Wfw$>. However, the corresponding diagnostics document says that SFLUX is "Rate of change of total ocean salinity per m^2 accounting for mass fluxes (g/(m^2 s)<https://urldefense.us/v3/__https://raw.githubusercontent.com/ECCO-GROUP/ECCO-ACCESS/refs/heads/main/varlist/v4r4/v4r4_nctiles_monthly_varlist.txt__;!!PvBDto6Hs4WbVuu7!PngytV6-_8w8tZqzSpmozFQZe5AR6MjXxwpSSJMa6n_3PJg2iWxuKWpT0Pr-LrUVO7oUcEgwofxiuofHIA$>)

These are quite different. Which is accurate? Is SFLUX still appropriate for closing the salt budget, or should it have the freshwater flux component removed?

Sincerely,
Anthony


————————————

Anthony Meza (he/him)

PhD Candidate

Physical Oceanography

MIT-WHOI Joint Program
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