Inflexible calendar year and approximate conversion in option 2 of the freshwater-budget adjustment mechanism

[smueller]

Context

The defect described in ticket #2487 is also present in the current trunk version of NEMO.

Analysis

See ticket #2487.

Recommendation

After substitution of rdt by rn_Dt and rau0 by rho0, the modifications recommended in ticket #2487 should be suitable for removing this defect from the current trunk version of NEMO.

[smueller]

The modification of source:/NEMO/trunk/src/OCE/SBC/sbcfwb.F90@13098​ which corresponds to the modification of source:/NEMO/releases/r4.0/r4.0-HEAD/src/OCE/SBC/sbcfwb.F90@13098​ presented in comment:1:ticket:2487 is:

src/OCE/SBC/sbcfwb.F90

@@ -123 +123 @@
             IF(lwp)WRITE(numout,*)'sbc_fwb : year = ',iyear  , ' freshwater budget correction = ', fwfold
             IF(lwp)WRITE(numout,*)'          year = ',iyear-1, ' freshwater budget read       = ', a_fwb
             IF(lwp)WRITE(numout,*)'          year = ',iyear-2, ' freshwater budget read       = ', a_fwb_b
-         ENDIF   
-         !                                         ! Update fwfold if new year start
-         ikty = 365 * 86400 / rn_Dt                  !!bug  use of 365 days leap year or 360d year !!!!!!!
-         IF( MOD( kt, ikty ) == 0 ) THEN
+         ELSEIF( ( nday_year == 1 ) .AND. ( nsec_day == NINT( 0.5_wp * rn_Dt ) ) ) THEN   ! Update fwfold at the start of 1 January
             a_fwb_b = a_fwb                           ! mean sea level taking into account the ice+snow
                                                       ! sum over the global domain
             a_fwb   = glob_sum( 'sbcfwb', e1e2t(:,:) * ( ssh(:,:,Kmm) + snwice_mass(:,:) * r1_rho0 ) )
-            a_fwb   = a_fwb * 1.e+3 / ( area * rday * 365. )     ! convert in Kg/m3/s = mm/s
-!!gm        !                                                      !!bug 365d year 
+            a_fwb   = a_fwb * rho0 / ( area * rday * nyear_len(1) )     ! convert into kg/m3/s
             fwfold =  a_fwb                           ! current year freshwater budget correction
             !                                         ! estimate from the previous year budget
          ENDIF

[smueller]

See ticket:2487#comment:2; it also applies to ticket #2488 after substitution of sshn, sshb, and r1_rau0 by ssh(:,:,Kmm), ssh(:,:,Kbb), and r1_rho0, respectively.

[smueller]

In 13170:

Error: Failed to load processor CommitTicketReference

No macro or processor named 'CommitTicketReference' found

[smueller]

See ticket:2487#comment:4, which also applies to ticket #2488 after substitution of e3t_n(:,:,jk), e3t_b(:,:,jk), sshn(:,:), and sshb(:,:) by e3t(:,:,jk,Kmm), e3t(:,:,jk,Kbb), ssh(:,:,Kmm), and ssh(:,:,Kbb), respectively.

[smueller]

The discussion with Gurvan and Seb in the context of tickets #2487 and #2488 also resulted in the recommendation to remove options nn_fwb = 1 and nn_fwb = 3 of the freshwater-budget adjustment mechanism from the trunk version of NEMO.