[MITgcm-support] add stochastic forcing in surface fluxes

[Olivier Arzel]

Hi Martin,
Thank you for your response.
I have modified model/src/external_forcing_surf.F among other routines to be able to read in input the spatial structure of the noise, its variance etc, and it works perfectly.
Best,
Olivier


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Message: 3
Date: Mon, 8 Jan 2018 17:29:18 +0100
From: Martin Losch <Martin.Losch at awi.de>
To: MITgcm Support <mitgcm-support at mitgcm.org>
Subject: Re: [MITgcm-support] add stochastic forcing in surface fluxes
Message-ID: <7E07975E-BA9B-4E9F-977E-E6B337297ADE at awi.de>
Content-Type: text/plain; charset="us-ascii"

Hi Olivier,

I would try the end of model/src/external_forcing_surf.F where the fields surfaceForcingT and surfaceForcingS are computed from various input fields (including restoring). At the end you can add your stochastic forcing.

Alternatively you can modify the forcing fields (Qnet and EmPmR, different units that surfaceForcingT/S) at the beginning of the routine.

Martin


> On 26. Dec 2017, at 17:05, Olivier Arzel <Olivier.Arzel at univ-brest.fr> wrote:
>
> Hello all
>
> I would like to add stochastic forcing to prescribed surface fluxes.
>
> The stochastic forcing is build here from white noise using random numbers picked up from a normal distribution and a specified autocorrelation timescale.
>
> The easiest way to do it in the model would be to read the forcing files (which contain both the prescribed and stochastic parts) (for example surfQFile for the heat flux) every n timesteps (n small). Unfortunately, the size of these forcing files in this case is too big for simulations of typically > 100 years.
>
> The other possibility would be to first read the prescribed part using 'surfQFile', then compute the stochastic part online, and finally add it to the prescribed flux. What is the routine I need to modify to do this, and has this been attempted before ?
>
> Thank you,
>
> Olivier