[MITgcm-support] using (zero-d) scalars as controls with state estimate/optimisation

[Daniel Goldberg]

Hello All

As in the subject, I am wondering if any MITgcm/adjoint users have ever used a (zero-dimensional) scalar (either static, or time dependent) as a control, and have any examples of doing so or any advice as to whether it is a good idea. As far as I know, it is only possible to use 2D and 3D static and time varying fields.

I know that it is possible to ensure that gradients of a genarr2d or gentim2d control are spatially constant e.g. by using a global sum of the control array and adding to a scalar -- but this does not reduce the size of the gradient passed to lsopt or m1qn3, so im not sure if the results would be similar to a case where we simply consider the gradient of a scalar. So Im not sure if this is a suitable replacement. Apologies if what Im saying is unclear.

Many thanks
Dan

--
Daniel Goldberg, PhD (he/him)
Reader in Glaciology
School of Geosciences, University of Edinburgh
Geography Building, Drummond Street, Edinburgh EH8 9XP


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