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2020WP/KERNEL-06_techene_better_e3_management – NEMO
wiki:2020WP/KERNEL-06_techene_better_e3_management

Version 7 (modified by techene, 5 years ago) (diff)

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  1. Summary
  2. Preview
  3. Tests
  4. Review

Summary

Action optimisation of the vertical scale factor e3 computation
PI(S) Techene, Madec
Digest compute e3 on the fly from e3_0(:,:,:,Ktl) * ( 1 + ssh(:,:,Ktl) / h_0( :,: ) * mask( :,:,: ) instead of storing e3t/u/v/w/f...
Dependencies If any
Branch source:/NEMO/branches/2020/dev_r12377_KERNEL-06_techene_e3
Previewer(s) Madec, Chanut, Masson
Reviewer(s) Madec
Ticket #2385

Description

The current e3[P] at P-point computation uses interpolation of the r3t 4D table at P = {u-, v-, w-, f-, uw-, vw-} points. This means 7 4D tables stored in memory. The proposed optimisation consists in computing e3[P](ji,jj,jk,Ktl) on the fly using the r3[P] = ssh[P] / h_0 and the e3[P]_0. r3[P] is a 2D table, then this means only 4 2D tables stored in memory. z-tilde management is done through e3[P]_0 that may varies with time in the z-tilde case. Asselin filter management is done recomputing r3[P] directly with the filtered ssh.

Implementation

Error: Failed to load processor box
No macro or processor named 'box' found

Step 1 : Check the error for e3t, e3w between the current way to compute e3 at T-, W-point and the proposed way to compute e3 at T-, W-point.

Because this change is likely to induce changes in the code we need to insure and because we need backward compatibility, we will duplicate the modules that will be modified and implement changes gradually.

Step 2 : First we change only the core routine in domvvl which should be changed into domQE.

  • add new variables, duplicate step into steplf and domvvl into domQE
  • change interpolation routines into scaling routines in domQE

Step 3 : Then we change the Asselin filtering routine indeed because water forcing are applied locally.

  • change Asselin routines (maybe not required since e3 scale with vertical with JC modif)

Step 4 : Finally we remove the interpol routine in the whole code

  • remove interpolating routine in all the code (AGRIF, OFF,...)
  • use a SUBSTITUTE when there are e3 CALL
  • make some changes in step and domQE to have the whole thing consistent

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Documentation updates

Error: Failed to load processor box
No macro or processor named 'box' found

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Preview

Error: Failed to load processor box
No macro or processor named 'box' found

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Tests

Error: Failed to load processor box
No macro or processor named 'box' found

... We want to track and maybe explain the differences observed at every steps. Reference set up : For that we produce a reference data set with the trunk -r 12377 using the GYRE_PISCES configuration where top cpp_key has been removed. We run it on 120 time steps. The drag coefficient is zero. We XIOS output an averaged field every 5 days.

Review

Error: Failed to load processor box
No macro or processor named 'box' found

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