Reference SSH field

[Laura Braby]

Hello,

I hope you are well.

I am downloading the GOFS3.1 analysis data and was wondering if the steric_ssh variable listed is the same as a reference field for the ssh? I am looking to calculate the SSH bias relative to satellite data and wanted to subtract the reference field. 

Thank you very much.

Laura Braby

---

https://www.nrf.ac.za/email-legal-notice

[Alan Wallcraft]

We are using a 4-year mean from GOFS 3.5, which is 1/25 degree HYCOM+CICE with data assimilation and the precursor to ESPC-D.  See https://data.hycom.org/datasets/ESPC-D-V02/relax/SSH/

COAPS 123> cat relax_montg_216_2017-2020.b
montgomery pot.sm mean: 2017.00-2020.99 [21.6H] : -5.2907395E+00  1.8357203E+00
sea surf. height  mean: 2017.00-2020.99 [21.6H] : -1.8834080E+00  2.5513208E+00
## interp from GOFS3.5/GLBc0.04 (216); SSH is mean Steric 2017-2020; uses Air Pressure

You can use HYCOM-tools to convert to netcdf:

hycom_extract relax_montg_216_2017-2020.a 4500 4251 1 2 1 1 relax_ssh_216_2017-2020.a > ! relax_ssh_216_2017-2020.b

env CDF_CNAME=SSH CDF_PNAME="Mean SSH 2017-2020" CDF_UNAME=m CDF_DAY1=-1.0 hycom2nc relax_ssh_216_2017-2020.a 4500 4251 0 relax_ssh_216_2017-2020.nc

Alan.

[Laura Braby]

Hi Alan, 

Thank you very much for your response!

Could you please confirm that I should use this same file for GOFS3.1? I am looking at data over the time period of 2015-2022. Presumably then I would regrid it to a lower resolution?

Thank you.

Laura

---

https://www.nrf.ac.za/email-legal-notice

[Alan Wallcraft]

For GOFS 3.1 I would use the reanalysis mean GLBv0.08_53X_archMN.1994_01_2015_12_ssh.nc

Note that long term means from the Navy systems tend to look like steric SSH from T&S climatology because altimetry is assimilated via synthetic T&S profiles.

Alan.