* rr_diff_tz.F * * Rick Romea * Jan. 24, 2000 * * Zonal momentum diffusive term : [Az T_z]_z * Units : oC/s * MOM2 Grid : T * ******************************************************************* SUBROUTINE RR_diff_tz_init(id) IMPLICIT NONE INCLUDE 'ferret_cmn/EF_Util.cmn' INTEGER id CALL ef_set_desc (id, .'d(Az dT/dz)/dz momentum diffusive term (oC/s);MOM2 T Grid') CALL ef_set_num_args (id, 5) CALL ef_set_axis_inheritance (id, IMPLIED_BY_ARGS, . IMPLIED_BY_ARGS, . IMPLIED_BY_ARGS, . IMPLIED_BY_ARGS) CALL ef_set_piecemeal_ok (id, NO, NO, NO, NO) CALL ef_set_arg_name (id, ARG1, 'U') CALL ef_set_arg_desc (id, ARG1, . 'Zonal velocity, on the MOM2 U Grid. ') CALL ef_set_arg_unit (id, ARG1, 'cm/sec') CALL ef_set_arg_type (id, ARG1, FLOAT_ARG) CALL ef_set_axis_influence (id, ARG1, YES, YES, YES, YES) CALL ef_set_axis_extend (id, ARG1, X_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG1, Y_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG1, Z_AXIS,0,+1) CALL ef_set_arg_name (id, ARG2, 'V') CALL ef_set_arg_desc (id, ARG2, . 'Meridional velocity, on the MOM2 U Grid. ') CALL ef_set_arg_unit (id, ARG2, 'cm/sec') CALL ef_set_arg_type (id, ARG2, FLOAT_ARG) CALL ef_set_axis_influence (id, ARG2,YES,YES,YES,YES) CALL ef_set_axis_extend (id, ARG2, X_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG2, Y_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG2, Z_AXIS,0,+1) CALL ef_set_arg_name (id, ARG3, 'TEMP') CALL ef_set_arg_desc (id, ARG3, . 'Potential temperature, on MOM2 T Grid. ') CALL ef_set_arg_unit (id, ARG3, 'deg-C') CALL ef_set_arg_type (id, ARG3, FLOAT_ARG) CALL ef_set_axis_influence (id, ARG3, NO, NO,YES,YES) CALL ef_set_axis_extend (id, ARG3, X_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG3, Y_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG3, Z_AXIS,0,+1) CALL ef_set_arg_name (id, ARG4, 'SALT') CALL ef_set_arg_desc (id, ARG4, . 'Salinity, on MOM2 T Grid. ') CALL ef_set_arg_unit (id, ARG4, '(ppt-35)/1000') CALL ef_set_arg_type (id, ARG4, FLOAT_ARG) CALL ef_set_axis_influence (id, ARG4, NO, NO,YES,YES) CALL ef_set_axis_extend (id, ARG4, X_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG4, Y_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG4, Z_AXIS,0,+1) CALL ef_set_arg_name (id, ARG5, 'HFLX') CALL ef_set_arg_desc (id, ARG5, . 'Surface heat flux.') CALL ef_set_arg_unit (id, ARG5, 'cal/cm^2/sec') CALL ef_set_arg_type (id, ARG5, FLOAT_ARG) CALL ef_set_axis_influence (id, ARG5, NO, NO, NO,YES) CALL ef_set_axis_extend (id, ARG5, X_AXIS,-1,+1) CALL ef_set_axis_extend (id, ARG5, Y_AXIS,-1,+1) END SUBROUTINE RR_diff_tz_compute(id, . arg_1,arg_2,arg_3,arg_4,arg_5,result) IMPLICIT NONE INCLUDE 'ferret_cmn/EF_Util.cmn' INCLUDE 'ferret_cmn/EF_mem_subsc.cmn' INTEGER id REAL bad_flag(EF_MAX_ARGS) REAL bad_flag_result REAL arg_1 (mem1lox:mem1hix, mem1loy:mem1hiy, . mem1loz:mem1hiz, mem1lot:mem1hit) REAL arg_2 (mem2lox:mem2hix, mem2loy:mem2hiy, . mem2loz:mem2hiz, mem2lot:mem2hit) REAL arg_3 (mem3lox:mem3hix, mem3loy:mem3hiy, . mem3loz:mem3hiz, mem3lot:mem3hit) REAL arg_4 (mem4lox:mem4hix, mem4loy:mem4hiy, . mem4loz:mem4hiz, mem4lot:mem4hit) REAL arg_5 (mem5lox:mem5hix, mem5loy:mem5hiy, . mem5loz:mem5hiz, mem5lot:mem5hit) REAL result (memreslox:memreshix,memresloy:memreshiy, . memresloz:memreshiz,memreslot:memreshit) INTEGER res_lo_ss (4) INTEGER res_hi_ss (4) INTEGER res_incr (4) INTEGER arg_lo_ss (4,EF_MAX_ARGS) INTEGER arg_hi_ss (4,EF_MAX_ARGS) INTEGER arg_incr (4,EF_MAX_ARGS) INTEGER i, j, k, l INTEGER i1, j1, k1, l1 INTEGER i2, j2, k2, l2 INTEGER i3, j3, k3, l3 INTEGER i4, j4, k4, l4 INTEGER i5, j5, k5, l5 REAL*8 zT(1024) REAL*8 zU(1024) INTEGER iZ REAL get_dzw,diff_fb,diff_cbt REAL rhom1z,riu,Ri,Potential_density INCLUDE 'rr_parameters.h' c MOM2: diff_fb(i,k,j)=diff_cbt(i,k,j)/dzw(k)*(t(i,k,j)-t(i,k+1,j)) c diff_cbt = diffusion coefficient at bottom of "t" cells (cm**2/s) c dzw(k) = zT(k+1)-zT(k) diff_fb(i,j,k,l,iZ) = diff_cbt/get_dzw(iZ,zT) . *(arg_3(i,j,k,l)-arg_3(i,j,k+1,l)) ! arg_3 = T c MOM2: rhom1z(i,k,j) = ro(i,k,j) - ro(i,k+1,j) rhom1z(i3,j3,k3,l3,i4,j4,k4,l4) = . Potential_density(arg_3(i3,j3,k3 ,l3), ! arg_3 = T . arg_4(i4,j4,k4 ,l4)) ! arg_4 = S . - Potential_density(arg_3(i3,j3,k3+1,l3), . arg_4(i4,j4,k4+1,l4)) c MOM2: grav = gravity (cm/sec**2) c MOM2: epsln = small value: 1.e-25 ! rr_parameters.h : ! REAL gravity = 980.6 cm/sec**2 ! REAL epsln = 1.e-25 c MOM2: c riu(i,k,j) = -grav/4.*dzw(k)*(rhom1z(i,k,j+1) + rhom1z(i+1,k,j+1) + c & rhom1z(i,k,j) + rhom1z(i+1,k,j)) / c & ((u(i,k,j,1)-u(i,k+1,j,1))**2+(u(i,k,j,2)-u(i,k+1,j,2))**2 + epsln) riu (i1,j1,k1,l1, . i2,j2,k2,l2, . i3,j3,k3,l3, . i4,j4,k4,l4, iZ) = - gravity/4. * get_dzw(iZ,zT) * ( . rhom1z(i3 ,j3+1,k3,l3,i4 ,j4+1,k4,l4) + . rhom1z(i3+1,j3+1,k3,l3,i4+1,j4+1,k4,l4) + . rhom1z(i3 ,j3 ,k3,l3,i4 ,j4 ,k4,l4) + . rhom1z(i3+1,j3 ,k3,l3,i4+1,j4 ,k4,l4) ) / . ( (arg_1(i1,j1,k1,l1)-arg_1(i1,j1,k1+1,l1))**2 + !arg_1=U . (arg_2(i2,j2,k2,l2)-arg_2(i2,j2,k2+1,l2))**2 !arg_2=V . + epsln ) CALL ef_get_res_subscripts (id, res_lo_ss, res_hi_ss, res_incr) CALL ef_get_arg_subscripts (id, arg_lo_ss, arg_hi_ss, arg_incr) CALL ef_get_bad_flags (id, bad_flag, bad_flag_result) CALL ef_get_coordinates (id, ARG1, Z_AXIS, . arg_lo_ss(Z_AXIS,ARG1), . arg_hi_ss(Z_AXIS,ARG1), zU) CALL ef_get_coordinates (id, ARG3, Z_AXIS, . arg_lo_ss(Z_AXIS,ARG3), . arg_hi_ss(Z_AXIS,ARG3), zT) l1 = arg_lo_ss(T_AXIS,ARG1) l2 = arg_lo_ss(T_AXIS,ARG2) l3 = arg_lo_ss(T_AXIS,ARG3) l4 = arg_lo_ss(T_AXIS,ARG4) l5 = arg_lo_ss(T_AXIS,ARG5) DO l = res_lo_ss(T_AXIS), res_hi_ss(T_AXIS) j1 = arg_lo_ss(Y_AXIS,ARG1) + 1 j2 = arg_lo_ss(Y_AXIS,ARG2) + 1 j3 = arg_lo_ss(Y_AXIS,ARG3) + 1 j4 = arg_lo_ss(Y_AXIS,ARG4) + 1 j5 = arg_lo_ss(Y_AXIS,ARG5) + 1 DO j = res_lo_ss(Y_AXIS), res_hi_ss(Y_AXIS) i1 = arg_lo_ss(X_AXIS,ARG1) + 1 i2 = arg_lo_ss(X_AXIS,ARG2) + 1 i3 = arg_lo_ss(X_AXIS,ARG3) + 1 i4 = arg_lo_ss(X_AXIS,ARG4) + 1 i5 = arg_lo_ss(X_AXIS,ARG5) + 1 DO i = res_lo_ss(X_AXIS), res_hi_ss(X_AXIS) iZ = 1 k1 = arg_lo_ss(Z_AXIS,ARG1) k2 = arg_lo_ss(Z_AXIS,ARG2) k3 = arg_lo_ss(Z_AXIS,ARG3) k4 = arg_lo_ss(Z_AXIS,ARG4) k5 = arg_lo_ss(Z_AXIS,ARG5) DO k = res_lo_ss(Z_AXIS), res_hi_ss(Z_AXIS) IF (arg_1(i1, j1, k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1, j1,k1+1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1+1,j1, k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1-1,j1, k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1, j1+1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1+1,j1+1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1-1,j1+1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1, j1-1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1+1,j1-1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_1(i1-1,j1-1,k1,l1) .EQ. bad_flag(ARG1) .OR. . arg_2(i2, j2, k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2+1,j2, k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2-1,j2, k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2, j2+1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2+1,j2+1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2-1,j2+1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2, j2-1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2+1,j2-1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_2(i2-1,j2-1,k2,l2) .EQ. bad_flag(ARG2) .OR. . arg_3(i3, j3, k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3+1,j3, k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3-1,j3, k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3, j3+1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3+1,j3+1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3-1,j3+1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3, j3-1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3+1,j3-1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_3(i3-1,j3-1,k3,l3) .EQ. bad_flag(ARG3) .OR. . arg_4(i4, j4, k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4+1,j4, k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4-1,j4, k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4, j4+1,k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4+1,j4+1,k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4-1,j4+1,k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4, j4-1,k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4+1,j4-1,k4,l4) .EQ. bad_flag(ARG4) .OR. . arg_4(i4-1,j4-1,k4,l4) .EQ. bad_flag(ARG4) .OR. . (iZ .EQ. 1 .AND. . arg_5(i5,j5,k5,l5).EQ. bad_flag(ARG5)) . )THEN result(i,j,k,l) = bad_flag_result ELSE c MOM2: rit(i,k,j)=(riu(i,k,j)+riu(i-1,k,j)+riu(i,k,j-1)+riu(i-1,k,j-1))/4 Ri = (Riu(i1, j1, k1,l1, i2, j2, k2,l2, . i3, j3, k3,l3, i4, j4, k4,l4,iZ) . + Riu(i1-1,j1, k1,l1, i2-1,j2, k2,l2, . i3-1,j3, k3,l3, i4-1,j4, k4,l4,iZ) . + Riu(i1, j1-1,k1,l1, i2, j2-1,k2,l2, . i3, j3-1,k3,l3, i4, j4-1,k4,l4,iZ) . + Riu(i1-1,j1-1,k1,l1, i2-1,j2-1,k2,l2, . i3-1,j3-1,k3,l3, i4-1,j4-1,k4,l4,iZ) . )/4. ! Compute diffusion coefficient ! REAL fricmx=maximum diffusion coefficient=50 cm**2/s ! REAL diff_cbt_limit=largest diffusion coefficient=50 cm**2/sec ! REAL diff_cbt_back=background diffusion coefficient=0.1 cm**2/s ! REAL wndmix = min value for diffusion coefficient at surface to ! simulate high freq wind mixing = 10 cm**2/sec ! REAL Meters_to_cm = Convert: m --> cm = 100. ! REAL sec_per_month = Time conversion : Convert: month --> sec ! NOTE: sec_per_month currently set = 1, ! so the function returns ! oC/s, not oC/month c MOM2: check stability: if(rit(i,k,j).lt.0.)diff_cbt(i,k,j,1)=diff_cbt_limit c diff_cbt(i,k,j,1) = fricmx*t2**3 + diff_cbt_back c t2 = 1/(1 + 5*rit(i,k,j)) c surface effect at top grid point: c if(diff_cbt(i,1,j,1).lt.wndmix)diff_cbt(i,1,j,1)=wndmix IF(Ri.lt.0.)THEN ! PRINT*,'WARNING::Ri<0.-->unstable' diff_cbt = diff_cbt_limit ! unstable ELSE diff_cbt = fricmx/(1.+5.*Ri)**3 . + diff_cbt_back IF(iZ.EQ.1.AND.diff_cbt.lt.wndmix)THEN !PRINT*,'surface flux pegged at wndmix' diff_cbt=wndmix ! surface ENDIF ENDIF c MOM2: c DIFF_Tz(i,k,j) = (diff_fb(i,k-1,j) - diff_fb(i,k,j)) / dzt(k) c diff_fb(i,0,j) = stf(i,j,n) c dzt = thickness of "t" grid cells (cm) c dzw(0) = zT(1) c stf = surface heat flux (cal/cm2/sec) c Note: units: result(i,j,k,l) c stf = Heat Flux/rho/Cp =(cal/cm2/sec)/(1 g/cm3)/(1. cal/g/oC) c = oC-cm/sec IF (iZ.EQ.1) THEN ! Top term is wind stress term result(i,j,k,l) = ( arg_5(i5,j5,k5,l5) ! arg_5 = HFLX . - diff_fb(i1,j1,k1,l1,iZ) ) . /(SNGL(zT(1)+zT(2))/2.*Meters_to_cm) . * sec_per_month ELSE result(i,j,k,l) = ( diff_fb(i1,j1,k1-1,l1,iZ-1) . - diff_fb(i1,j1,k1,l1,iZ) ) . /(SNGL(zT(iZ+1)-zT(iZ-1))/2. * Meters_to_cm) . * sec_per_month ENDIF ! GOTO 1009 PRINT* PRINT* PRINT*,'i,j,k,l = ', i,j,k,l PRINT*,'i1,j1,k1,l1 = ', i1,j1,k1,l1 PRINT*,'i2,j2,k2,l2 = ', i2,j2,k2,l2 PRINT*,'i3,j3,k3,l3 = ', i3,j3,k3,l3 PRINT*,'i4,j4,k4,l4 = ', i4,j4,k4,l4 PRINT*,'i5,j5,k5,l5 = ', i5,j5,k5,l5 PRINT*,'iZ = ',iZ PRINT*,'zT(iZ) = ',zT(iZ) PRINT*,'get_dzw(iZ,zT) = ',get_dzw(iZ,zT) PRINT*,'T(i3,j3,k3 ,l3) = ', arg_3(i3,j3,k3 ,l3) PRINT*,'S(i4,j4,k4 ,l4) = ', arg_4(i4,j4,k4 ,l4) PRINT*,'T(i3,j3,k3+1,l3) = ', arg_3(i3,j3,k3+1,l3) PRINT*,'S(i4,j4,k4+1,l4) = ', arg_4(i4,j4,k4+1,l4) PRINT*,'T(i3+1,j3,k3 ,l3) = ', arg_3(i3+1,j3,k3 ,l3) PRINT*,'S(i4+1,j4,k4 ,l4) = ', arg_4(i4+1,j4,k4 ,l4) PRINT*,'T(i3+1,j3,k3+1,l3) = ', arg_3(i3+1,j3,k3+1,l3) PRINT*,'S(i4+1,j4,k4+1,l4) = ', arg_4(i4+1,j4,k4+1,l4) PRINT*,'T(i3,j3+1,k3 ,l3) = ', arg_3(i3,j3+1,k3 ,l3) PRINT*,'S(i4,j4+1,k4 ,l4) = ', arg_4(i4,j4+1,k4 ,l4) PRINT*,'T(i3,j3+1,k3+1,l3) = ', arg_3(i3,j3+1,k3+1,l3) PRINT*,'S(i4,j4+1,k4+1,l4) = ', arg_4(i4,j4+1,k4+1,l4) PRINT*,'T(i3+1,j3+1,k3 ,l3) = ', arg_3(i3+1,j3+1,k3 ,l3) PRINT*,'S(i4+1,j4+1,k4 ,l4) = ', arg_4(i4+1,j4+1,k4 ,l4) PRINT*,'T(i3+1,j3+1,k3+1,l3) = ', arg_3(i3+1,j3+1,k3+1,l3) PRINT*,'S(i4+1,j4+1,k4+1,l4) = ', arg_4(i4+1,j4+1,k4+1,l4) PRINT*,'Potential_density(1) = ', . Potential_density(arg_3(i3,j3,k3 ,l3), ! arg_3 = T . arg_4(i4,j4,k4 ,l4)) ! arg_4 = S PRINT*,'Potential_density(2) = ', . Potential_density(arg_3(i3,j3,k3+1,l3), . arg_4(i4,j4,k4+1,l4)) PRINT*,'rhom1z(1) = ',rhom1z(i3 ,j3+1,k3,l3,i4 ,j4+1,k4,l4) PRINT*,'rhom1z(2) = ',rhom1z(i3+1,j3+1,k3,l3,i4+1,j4+1,k4,l4) PRINT*,'rhom1z(3) = ',rhom1z(i3 ,j3 ,k3,l3,i4 ,j4 ,k4,l4) PRINT*,'rhom1z(4) = ',rhom1z(i3+1,j3 ,k3,l3,i4+1,j4 ,k4,l4) PRINT*,'Riu(1) = ',Riu(i1, j1, k1,l1, i2, j2, k2,l2, . i3, j3, k3,l3, i4, j4, k4,l4,iZ) PRINT*,'Riu(2) = ',Riu(i1-1,j1, k1,l1, i2-1,j2, k2,l2, . i3-1,j3, k3,l3, i4-1,j4, k4,l4,iZ) PRINT*,'Riu(3) = ',Riu(i1, j1-1,k1,l1, i2, j2-1,k2,l2, . i3, j3-1,k3,l3, i4, j4-1,k4,l4,iZ) PRINT*,'Riu(4) = ',Riu(i1-1,j1-1,k1,l1, i2-1,j2-1,k2,l2, . i3-1,j3-1,k3,l3, i4-1,j4-1,k4,l4,iZ) PRINT*,'Ri = ',Ri PRINT*,'HFLX = ',arg_5(i5,j5,k5,l5) PRINT*,'diff_cbt = ',diff_cbt PRINT*,'diff_fb = ',diff_fb(i1,j1,k1,l1,iZ) PRINT*,'result = ',result(i,j,k,l) PRINT*,'SNGL(zT(1)+zT(2))/2.*Meters_to_cm', . SNGL(zT(1)+zT(2))/2.*Meters_to_cm PRINT* PRINT*,'*******************************************' PRINT* 1009 CONTINUE ENDIF iZ = iZ + 1 k1 = k1 + arg_incr(Z_AXIS,ARG1) k2 = k2 + arg_incr(Z_AXIS,ARG2) k3 = k3 + arg_incr(Z_AXIS,ARG3) k4 = k4 + arg_incr(Z_AXIS,ARG4) k5 = k5 + arg_incr(Z_AXIS,ARG5) ENDDO i1 = i1 + arg_incr(X_AXIS,ARG1) i2 = i2 + arg_incr(X_AXIS,ARG2) i3 = i3 + arg_incr(X_AXIS,ARG3) i4 = i4 + arg_incr(X_AXIS,ARG4) i5 = i5 + arg_incr(X_AXIS,ARG5) ENDDO j1 = j1 + arg_incr(Y_AXIS,ARG1) j2 = j2 + arg_incr(Y_AXIS,ARG2) j3 = j3 + arg_incr(Y_AXIS,ARG3) j4 = j4 + arg_incr(Y_AXIS,ARG4) j5 = j5 + arg_incr(Y_AXIS,ARG5) ENDDO l1 = l1 + arg_incr(T_AXIS,ARG1) l2 = l2 + arg_incr(T_AXIS,ARG2) l3 = l3 + arg_incr(T_AXIS,ARG3) l4 = l4 + arg_incr(T_AXIS,ARG4) l5 = l5 + arg_incr(T_AXIS,ARG5) ENDDO END REAL FUNCTION Potential_density(T,S) ! Density at one Bar IMPLICIT NONE REAL T ! Potential Temperature REAL S ! ( SALINITY(ppt) - 35) / 1000 REAL Pressure / 1.0 / ! Bar REAL Sppt ! Salinity (ppt) Sppt = 1.e3*S+35. ! Convert S: --> ppt CALL RR_unesco(T,Sppt,Pressure,Potential_density) Potential_density = Potential_density*1.e-3 ! Convert:kg/m^3-->g/cm^3 END REAL FUNCTION get_dzw(iZ,zT) IMPLICIT NONE INCLUDE 'rr_parameters.h' INTEGER iZ REAL*8 zT(iZ+1) IF(iZ.EQ.0)THEN get_dzw=SNGL(zT(1))*Meters_to_cm ELSE get_dzw=SNGL(zT(iZ+1)-zT(iZ))*Meters_to_cm ENDIF END