[MITgcm-support] Nudging SST data into MITgcm

[Martin Losch]

Hi Ruibin,

sounds good. In principle, the climsst/sss fields are forcing fields like any other and can controlled with startdate, and period. The “period” is the interval between data records (e.g. for daily data it’s 86400.) and the climsstTauRelax is the relaxation time scale i.e. dT/dt ~ (1/climsstTauRelax) * ( Trelax - T )

Martin

> On 16. Jan 2021, at 13:32, Ruibin Ding（丁睿彬） <kirkding at gmail.com> wrote:
> 
> Dear Martin,
> 
> I find an experiment in the Verification called "global_with_exf". In the data.exf namelist, I found that they use climatological SST and SSS to Relax the modeled SST and SSS towards monthly climatologies of observation. 
> The detailed configuration in this namelist is as follows:
> climsststartdate1 = 19920101,
> climsststartdate2 = 000000,
>  climsstperiod     = -12.,
> # 2 months restoring timescale for temperature
>  climsstTauRelax   = 5184000.,
> Instead of climatology, now I want to relax the modeled SST with real observed SST with some time interval (tau). Correct me if I am wrong, I just change the " climsststartdate1" and " climsststartdate2" the same as the observation period. The "  climsstperiod " should be changed accordingly. Then I make the observed SST as inputfocing file the same as other external forcing fields.
> Looking forward to hearing from you, thanks.
> 
> Best regards
> Ruibin
> 
> 
> Martin Losch <Martin.Losch at awi.de> 于2021年1月12日周二 下午8:21写道：
> Rubin,
> 
> there are plenty of different ways of relaxation (which is the same as nudging) to surface fields, and even to 3D fields, depending on what you want to do exactly. 
> 
> Please have a look at the tutorials in the documentation and at the verifications experiments, which have a lot of examples; with pkg/exf the relevant parameter names contain climsst, without pkg/exf the parameters are tauThetaClimRelax, thetaClimFile, etc. 
> 
> Martin
> 
> > On 12. Jan 2021, at 04:06, Ruibin Ding（丁睿彬） <kirkding at gmail.com> wrote:
> > 
> > Dear support of MITgcm,
> > 
> > I am a user of the MITgcm. I am writing this email to ask a question about how to nudge observed SST into modelled SST while the model is online.
> > I find a similar function of "relaxation of climatological SST" in the data.exf namelist. I am wondering if MITgcm contains this nudging option or I have to add one into
> > the temperature tendency equation or I can just modify the relaxation function mentioned above? 
> > 
> > Best regards
> > Ruibin
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