Remove lavg_N_or_Nsqr option

After discussion with Bill Large, the unresolved shear computation really needs
the buoyancy frequency to be at the bottom interface of the cell so I removed
the option to interpolate it to the cell center.

reg_tests/kpp/input.nl

@@ -38,7 +38,6 @@ mix_type = 'kpp'
   hmix5          = 17.0d0
   ! Parameter settings to match LMD94 (linear interp, average Nsqr)
   interp_type_t5 = "linear"
-  lavg_N_or_Nsqr = .true.
 /
 
 ! Test 6 params

src/drivers/cvmix_kpp_drv.F90

@@ -66,15 +66,13 @@ Subroutine cvmix_kpp_driver()
   ! True => run specified test
   logical :: ltest1, ltest2, ltest3, ltest4, ltest5, ltest6
   logical :: lnoDGat1 ! True => G'(1) = 0 (in test 4)
-  logical :: lavg_N_or_Nsqr ! True => N_cntr = avg(N_iface[above,below])
 
   namelist/kpp_col1_nml/ltest1, nlev1, layer_thick1, interp_type_t1, hmix1,   &
                         ri_crit
   namelist/kpp_col2_nml/ltest2
   namelist/kpp_col3_nml/ltest3, nlev3
   namelist/kpp_col4_nml/ltest4, interp_type_t4, OBL_levid4, lnoDGat1
-  namelist/kpp_col5_nml/ltest5, nlev5, layer_thick5, hmix5, interp_type_t5,   &
-                        lavg_N_or_Nsqr
+  namelist/kpp_col5_nml/ltest5, nlev5, layer_thick5, hmix5, interp_type_t5
   namelist/kpp_col6_nml/ltest6, vonkarman6, tao, rho0, grav, alpha, Qnonpen,  &
                         Cp0, OBL_depth6
 
@@ -107,7 +105,6 @@ Subroutine cvmix_kpp_driver()
   layer_thick5   = real(5,  cvmix_r8)
   hmix5          = real(17, cvmix_r8)
   interp_type_t5 = "linear"
-  lavg_N_or_Nsqr = .true.
 
   ! Defaults for test 6
   ltest6     = .false.
@@ -403,8 +400,7 @@ Subroutine cvmix_kpp_driver()
 
     ! using linear interpolation, averaging Nsqr, and setting Cv = 1.5  to
     ! match LMD result
-    call cvmix_init_kpp(Cv = 1.5_cvmix_r8, interp_type=interp_type_t5,        &
-                        lavg_N_or_Nsqr = lavg_N_or_Nsqr)
+    call cvmix_init_kpp(Cv = 1.5_cvmix_r8, interp_type=interp_type_t5)
 
     ! Set up vertical levels (centers and interfaces) and compute bulk
     ! Richardson number

src/shared/cvmix_kpp.F90

@@ -167,12 +167,6 @@ module cvmix_kpp
       logical        :: lMonOb         ! True => compute Monin-Obukhov limit
       logical        :: lnoDGat1       ! True => G'(1) = 0 (shape function)
                                        ! False => compute G'(1) as in LMD94
-      logical        :: lavg_N_or_Nsqr ! True => N (or Nsqr) at cell center is
-                                       !  average of values at interfaces above
-                                       !  and below.
-                                       ! False => N (or Nsqr) at cell center is
-                                       !  set to value at interface below
-                                       ! (only used in compute_unresolved_shear)
       logical        :: lenhanced_diff ! True => enhance diffusivity at OBL
   end type cvmix_kpp_params_type
 
@@ -191,8 +185,8 @@ subroutine cvmix_init_kpp(ri_crit, minOBLdepth, maxOBLdepth, minVtsqr,      &
                             vonkarman, Cstar, zeta_m, zeta_s, surf_layer_ext, &
                             Cv, interp_type, interp_type2, MatchTechnique,    &
                             old_vals, lEkman, lMonOb, lnoDGat1,               &
-                            lavg_N_or_Nsqr, lenhanced_diff,                   &
-                            lnonzero_surf_nonlocal, CVmix_kpp_params_user)
+                            lenhanced_diff, lnonzero_surf_nonlocal,           &
+                            CVmix_kpp_params_user)
 
 ! !DESCRIPTION:
 !  Initialization routine for KPP mixing.
@@ -220,7 +214,6 @@ subroutine cvmix_init_kpp(ri_crit, minOBLdepth, maxOBLdepth, minVtsqr,      &
     logical,          optional, intent(in) :: lEkman,                         &
                                               lMonOb,                         &
                                               lnoDGat1,                       &
-                                              lavg_N_or_Nsqr,                 &
                                               lenhanced_diff,                 &
                                               lnonzero_surf_nonlocal
 
@@ -464,13 +457,6 @@ subroutine cvmix_init_kpp(ri_crit, minOBLdepth, maxOBLdepth, minVtsqr,      &
       call cvmix_put_kpp('lnoDGat1', .true., CVmix_kpp_params_user)
     end if
 
-    if (present(lavg_N_or_Nsqr)) then
-      call cvmix_put_kpp('lavg_N_or_Nsqr', lavg_N_or_Nsqr,                    &
-                         CVmix_kpp_params_user)
-    else
-      call cvmix_put_kpp('lavg_N_or_Nsqr', .true., CVmix_kpp_params_user)
-    end if
-
     if (present(lenhanced_diff)) then
       call cvmix_put_kpp('lenhanced_diff', lenhanced_diff,                    &
                          CVmix_kpp_params_user)
@@ -1138,8 +1124,6 @@ subroutine cvmix_put_kpp_logical(varname, val, CVmix_kpp_params_user)
         CVmix_kpp_params_out%lMonOb = val
       case ('lnoDGat1')
         CVmix_kpp_params_out%lnoDGat1 = val
-      case ('lavg_N_or_Nsqr')
-        CVmix_kpp_params_out%lavg_N_or_Nsqr = val
       case ('lenhanced_diff')
         CVmix_kpp_params_out%lenhanced_diff = val
       case DEFAULT
@@ -2105,11 +2089,7 @@ function cvmix_kpp_compute_unresolved_shear(zt_cntr, ws_cntr, N_iface,      &
         stop 1
       end if
       do kt=1,nlev
-        if (CVmix_kpp_params_in%lavg_N_or_Nsqr) then
-          N_cntr(kt) = 0.5_cvmix_r8*(N_iface(kt)+N_iface(kt+1))
-        else
-          N_cntr(kt) = N_iface(kt+1)
-        end if
+        N_cntr(kt) = N_iface(kt+1)
       end do
     else
       if (present(Nsqr_iface)) then
@@ -2118,12 +2098,7 @@ function cvmix_kpp_compute_unresolved_shear(zt_cntr, ws_cntr, N_iface,      &
           stop 1
         end if
         do kt=1,nlev
-          if (CVmix_kpp_params_in%lavg_N_or_Nsqr) then
-            N_cntr(kt)=0.5_cvmix_r8*(sqrt(max(Nsqr_iface(kt),cvmix_zero)) +   &
-                                     sqrt(max(Nsqr_iface(kt+1),cvmix_zero)))
-          else
-            N_cntr(kt)=sqrt(max(Nsqr_iface(kt+1),cvmix_zero))
-          end if
+          N_cntr(kt)=sqrt(max(Nsqr_iface(kt+1),cvmix_zero))
         end do
       else
         print*, "ERROR: you must provide N_iface OR Nsqr_iface"