Require e3t filtered through depth not just surface in tranxt/dynnxt for rivers distributed through depth

[deazer]

Context

Bug in Time Filtering with respect to Rivers specified through water column not just at the surface.

Problem code is in subroutine tra_nxt_vvl: here e3t only updated at surface:

301                   IF( jk == mikt(ji,jj) ) THEN           ! first level 
302                      ze3t_f = ze3t_f - zfact2 * ( (emp_b(ji,jj)    - emp(ji,jj)   )  &
'''303                             &                   - (rnf_b(ji,jj)    - rnf(ji,jj)   )  &'''
304                             &                   + (fwfisf_b(ji,jj) - fwfisf(ji,jj))  )
305                      ztc_f  = ztc_f  - zfact1 * ( psbc_tc(ji,jj,jn) - psbc_tc_b(ji,jj,jn) )
306                   ENDIF

Analysis

The code here only works if the rivers are specified at the surface. There needs to be a case

to deal with rivers specified through depth. Otherwise the tracer content will be inconsistent with the level volume.

Fix

Create cases based on if ln_rnf_depth is true or false. If it is false then the existing code can be used but

if it is true then the rnf needs to be distributed through all the levels for which the river is specified to enter into the ocean.

   jk <= nk_rnf(ji,jj)

possible similar fix also required in dynnxt where e3t is updated?

[clem]

done