- Timestamp:
- 2020-12-02T14:55:21+01:00 (3 years ago)
- Location:
- NEMO/branches/2020/dev_r13327_KERNEL-06_2_techene_e3
- Files:
-
- 2 edited
-
. (modified) (1 prop)
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src/ICE/icethd_pnd.F90 (modified) (8 diffs)
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NEMO/branches/2020/dev_r13327_KERNEL-06_2_techene_e3
- Property svn:externals
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old new 8 8 9 9 # SETTE 10 ^/utils/CI/sette@13 292sette10 ^/utils/CI/sette@13559 sette
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- Property svn:externals
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NEMO/branches/2020/dev_r13327_KERNEL-06_2_techene_e3/src/ICE/icethd_pnd.F90
r12489 r13998 35 35 ! ! associated indices: 36 36 INTEGER, PARAMETER :: np_pndNO = 0 ! No pond scheme 37 INTEGER, PARAMETER :: np_pndCST = 1 ! Constant pond scheme38 INTEGER, PARAMETER :: np_pnd H12 = 2 ! Evolutive pond scheme (Holland et al. 2012)37 INTEGER, PARAMETER :: np_pndCST = 1 ! Constant ice pond scheme 38 INTEGER, PARAMETER :: np_pndLEV = 2 ! Level ice pond scheme 39 39 40 40 !!---------------------------------------------------------------------- … … 49 49 !! *** ROUTINE ice_thd_pnd *** 50 50 !! 51 !! ** Purpose : change melt pond fraction 51 !! ** Purpose : change melt pond fraction and thickness 52 52 !! 53 !! ** Method : brut force54 53 !!------------------------------------------------------------------- 55 54 ! … … 58 57 CASE (np_pndCST) ; CALL pnd_CST !== Constant melt ponds ==! 59 58 ! 60 CASE (np_pnd H12) ; CALL pnd_H12 !== Holland et al 2012melt ponds ==!59 CASE (np_pndLEV) ; CALL pnd_LEV !== Level ice melt ponds ==! 61 60 ! 62 61 END SELECT … … 86 85 ! 87 86 IF( a_i_1d(ji) > 0._wp .AND. t_su_1d(ji) >= rt0 ) THEN 88 a_ip_frac_1d(ji) = rn_apnd89 87 h_ip_1d(ji) = rn_hpnd 90 a_ip_1d(ji) = a_ip_frac_1d(ji) * a_i_1d(ji) 88 a_ip_1d(ji) = rn_apnd * a_i_1d(ji) 89 h_il_1d(ji) = 0._wp ! no pond lids whatsoever 91 90 ELSE 92 a_ip_frac_1d(ji) = 0._wp93 91 h_ip_1d(ji) = 0._wp 94 92 a_ip_1d(ji) = 0._wp 93 h_il_1d(ji) = 0._wp 95 94 ENDIF 96 95 ! … … 100 99 101 100 102 SUBROUTINE pnd_H12 103 !!------------------------------------------------------------------- 104 !! *** ROUTINE pnd_H12 *** 105 !! 106 !! ** Purpose : Compute melt pond evolution 107 !! 108 !! ** Method : Empirical method. A fraction of meltwater is accumulated in ponds 109 !! and sent to ocean when surface is freezing 110 !! 111 !! pond growth: Vp = Vp + dVmelt 112 !! with dVmelt = R/rhow * ( rhoi*dh_i + rhos*dh_s ) * a_i 113 !! pond contraction: Vp = Vp * exp(0.01*MAX(Tp-Tsu,0)/Tp) 114 !! with Tp = -2degC 115 !! 116 !! ** Tunable parameters : (no real expertise yet, ideas?) 101 SUBROUTINE pnd_LEV 102 !!------------------------------------------------------------------- 103 !! *** ROUTINE pnd_LEV *** 104 !! 105 !! ** Purpose : Compute melt pond evolution 106 !! 107 !! ** Method : A fraction of meltwater is accumulated in ponds and sent to ocean when surface is freezing 108 !! We work with volumes and then redistribute changes into thickness and concentration 109 !! assuming linear relationship between the two. 110 !! 111 !! ** Action : - pond growth: Vp = Vp + dVmelt --- from Holland et al 2012 --- 112 !! dVmelt = (1-r)/rhow * ( rhoi*dh_i + rhos*dh_s ) * a_i 113 !! dh_i = meltwater from ice surface melt 114 !! dh_s = meltwater from snow melt 115 !! (1-r) = fraction of melt water that is not flushed 116 !! 117 !! - limtations: a_ip must not exceed (1-r)*a_i 118 !! h_ip must not exceed 0.5*h_i 119 !! 120 !! - pond shrinking: 121 !! if lids: Vp = Vp -dH * a_ip 122 !! dH = lid thickness change. Retrieved from this eq.: --- from Flocco et al 2010 --- 123 !! 124 !! rhoi * Lf * dH/dt = ki * MAX(Tp-Tsu,0) / H 125 !! H = lid thickness 126 !! Lf = latent heat of fusion 127 !! Tp = -2C 128 !! 129 !! And solved implicitely as: 130 !! H(t+dt)**2 -H(t) * H(t+dt) -ki * (Tp-Tsu) * dt / (rhoi*Lf) = 0 131 !! 132 !! if no lids: Vp = Vp * exp(0.01*MAX(Tp-Tsu,0)/Tp) --- from Holland et al 2012 --- 133 !! 134 !! - Flushing: w = -perm/visc * rho_oce * grav * Hp / Hi --- from Flocco et al 2007 --- 135 !! perm = permability of sea-ice 136 !! visc = water viscosity 137 !! Hp = height of top of the pond above sea-level 138 !! Hi = ice thickness thru which there is flushing 139 !! 140 !! - Corrections: remove melt ponds when lid thickness is 10 times the pond thickness 141 !! 142 !! - pond thickness and area is retrieved from pond volume assuming a linear relationship between h_ip and a_ip: 143 !! a_ip/a_i = a_ip_frac = h_ip / zaspect 144 !! 145 !! ** Tunable parameters : ln_pnd_lids, rn_apnd_max, rn_apnd_min 117 146 !! 118 !! ** Note : Stolen from CICE for quick test of the melt pond 119 !! radiation and freshwater interfaces 120 !! Coupling can be radiative AND freshwater 121 !! Advection, ridging, rafting are called 122 !! 123 !! ** References : Holland, M. M. et al (J Clim 2012) 124 !!------------------------------------------------------------------- 125 REAL(wp), PARAMETER :: zrmin = 0.15_wp ! minimum fraction of available meltwater retained for melt ponding 126 REAL(wp), PARAMETER :: zrmax = 0.70_wp ! maximum - - - - - 127 REAL(wp), PARAMETER :: zpnd_aspect = 0.8_wp ! pond aspect ratio 128 REAL(wp), PARAMETER :: zTp = -2._wp ! reference temperature 129 ! 130 REAL(wp) :: zfr_mlt ! fraction of available meltwater retained for melt ponding 131 REAL(wp) :: zdv_mlt ! available meltwater for melt ponding 132 REAL(wp) :: z1_Tp ! inverse reference temperature 133 REAL(wp) :: z1_rhow ! inverse freshwater density 134 REAL(wp) :: z1_zpnd_aspect ! inverse pond aspect ratio 135 REAL(wp) :: zfac, zdum 136 ! 137 INTEGER :: ji ! loop indices 138 !!------------------------------------------------------------------- 139 z1_rhow = 1._wp / rhow 140 z1_zpnd_aspect = 1._wp / zpnd_aspect 141 z1_Tp = 1._wp / zTp 147 !! ** Note : mostly stolen from CICE 148 !! 149 !! ** References : Flocco and Feltham (JGR, 2007) 150 !! Flocco et al (JGR, 2010) 151 !! Holland et al (J. Clim, 2012) 152 !!------------------------------------------------------------------- 153 REAL(wp), DIMENSION(nlay_i) :: ztmp ! temporary array 154 !! 155 REAL(wp), PARAMETER :: zaspect = 0.8_wp ! pond aspect ratio 156 REAL(wp), PARAMETER :: zTp = -2._wp ! reference temperature 157 REAL(wp), PARAMETER :: zvisc = 1.79e-3_wp ! water viscosity 158 !! 159 REAL(wp) :: zfr_mlt, zdv_mlt ! fraction and volume of available meltwater retained for melt ponding 160 REAL(wp) :: zdv_frz, zdv_flush ! Amount of melt pond that freezes, flushes 161 REAL(wp) :: zhp ! heigh of top of pond lid wrt ssh 162 REAL(wp) :: zv_ip_max ! max pond volume allowed 163 REAL(wp) :: zdT ! zTp-t_su 164 REAL(wp) :: zsbr ! Brine salinity 165 REAL(wp) :: zperm ! permeability of sea ice 166 REAL(wp) :: zfac, zdum ! temporary arrays 167 REAL(wp) :: z1_rhow, z1_aspect, z1_Tp ! inverse 168 !! 169 INTEGER :: ji, jk ! loop indices 170 !!------------------------------------------------------------------- 171 z1_rhow = 1._wp / rhow 172 z1_aspect = 1._wp / zaspect 173 z1_Tp = 1._wp / zTp 142 174 143 175 DO ji = 1, npti 144 ! !--------------------------------!145 IF( h_i_1d(ji) < rn_himin ) THEN ! Case ice thickness < rn_himin!146 ! !--------------------------------!147 !--- Remove ponds on thin ice 176 ! !----------------------------------------------------! 177 IF( h_i_1d(ji) < rn_himin .OR. a_i_1d(ji) < epsi10 ) THEN ! Case ice thickness < rn_himin or tiny ice fraction ! 178 ! !----------------------------------------------------! 179 !--- Remove ponds on thin ice or tiny ice fractions 148 180 a_ip_1d(ji) = 0._wp 149 a_ip_frac_1d(ji) = 0._wp150 181 h_ip_1d(ji) = 0._wp 151 ! !--------------------------------! 152 ELSE ! Case ice thickness >= rn_himin ! 153 ! !--------------------------------! 154 v_ip_1d(ji) = h_ip_1d(ji) * a_ip_1d(ji) ! record pond volume at previous time step 155 ! 156 ! available meltwater for melt ponding [m, >0] and fraction 157 zdv_mlt = -( dh_i_sum(ji)*rhoi + dh_s_mlt(ji)*rhos ) * z1_rhow * a_i_1d(ji) 158 zfr_mlt = zrmin + ( zrmax - zrmin ) * a_i_1d(ji) ! from CICE doc 159 !zfr_mlt = zrmin + zrmax * a_i_1d(ji) ! from Holland paper 160 ! 161 !--- Pond gowth ---! 162 ! v_ip should never be negative, otherwise code crashes 163 v_ip_1d(ji) = MAX( 0._wp, v_ip_1d(ji) + zfr_mlt * zdv_mlt ) 164 ! 165 ! melt pond mass flux (<0) 182 h_il_1d(ji) = 0._wp 183 ! !--------------------------------! 184 ELSE ! Case ice thickness >= rn_himin ! 185 ! !--------------------------------! 186 v_ip_1d(ji) = h_ip_1d(ji) * a_ip_1d(ji) ! retrieve volume from thickness 187 v_il_1d(ji) = h_il_1d(ji) * a_ip_1d(ji) 188 ! 189 !------------------! 190 ! case ice melting ! 191 !------------------! 192 ! 193 !--- available meltwater for melt ponding ---! 194 zdum = -( dh_i_sum(ji)*rhoi + dh_s_mlt(ji)*rhos ) * z1_rhow * a_i_1d(ji) 195 zfr_mlt = rn_apnd_min + ( rn_apnd_max - rn_apnd_min ) * at_i_1d(ji) ! = ( 1 - r ) = fraction of melt water that is not flushed 196 zdv_mlt = MAX( 0._wp, zfr_mlt * zdum ) ! max for roundoff errors? 197 ! 198 !--- overflow ---! 199 ! If pond area exceeds zfr_mlt * a_i_1d(ji) then reduce the pond volume 200 ! a_ip_max = zfr_mlt * a_i 201 ! => from zaspect = h_ip / (a_ip / a_i), set v_ip_max as: 202 zv_ip_max = zfr_mlt**2 * a_i_1d(ji) * zaspect 203 zdv_mlt = MAX( 0._wp, MIN( zdv_mlt, zv_ip_max - v_ip_1d(ji) ) ) 204 205 ! If pond depth exceeds half the ice thickness then reduce the pond volume 206 ! h_ip_max = 0.5 * h_i 207 ! => from zaspect = h_ip / (a_ip / a_i), set v_ip_max as: 208 zv_ip_max = z1_aspect * a_i_1d(ji) * 0.25 * h_i_1d(ji) * h_i_1d(ji) 209 zdv_mlt = MAX( 0._wp, MIN( zdv_mlt, zv_ip_max - v_ip_1d(ji) ) ) 210 211 !--- Pond growing ---! 212 v_ip_1d(ji) = v_ip_1d(ji) + zdv_mlt 213 ! 214 !--- Lid melting ---! 215 IF( ln_pnd_lids ) v_il_1d(ji) = MAX( 0._wp, v_il_1d(ji) - zdv_mlt ) ! must be bounded by 0 216 ! 217 !--- mass flux ---! 166 218 IF( zdv_mlt > 0._wp ) THEN 167 zfac = z fr_mlt * zdv_mlt * rhow * r1_Dt_ice219 zfac = zdv_mlt * rhow * r1_Dt_ice ! melt pond mass flux < 0 [kg.m-2.s-1] 168 220 wfx_pnd_1d(ji) = wfx_pnd_1d(ji) - zfac 169 221 ! 170 ! adjust ice/snow melting flux to balance melt pond flux (>0) 171 zdum = zfac / ( wfx_snw_sum_1d(ji) + wfx_sum_1d(ji) ) 222 zdum = zfac / ( wfx_snw_sum_1d(ji) + wfx_sum_1d(ji) ) ! adjust ice/snow melting flux > 0 to balance melt pond flux 172 223 wfx_snw_sum_1d(ji) = wfx_snw_sum_1d(ji) * (1._wp + zdum) 173 224 wfx_sum_1d(ji) = wfx_sum_1d(ji) * (1._wp + zdum) 174 225 ENDIF 226 227 !-------------------! 228 ! case ice freezing ! i.e. t_su_1d(ji) < (zTp+rt0) 229 !-------------------! 230 ! 231 zdT = MAX( zTp+rt0 - t_su_1d(ji), 0._wp ) 175 232 ! 176 233 !--- Pond contraction (due to refreezing) ---! 177 v_ip_1d(ji) = v_ip_1d(ji) * EXP( 0.01_wp * MAX( zTp+rt0 - t_su_1d(ji), 0._wp ) * z1_Tp ) 178 ! 179 ! Set new pond area and depth assuming linear relation between h_ip and a_ip_frac 180 ! h_ip = zpnd_aspect * a_ip_frac = zpnd_aspect * a_ip/a_i 181 a_ip_1d(ji) = SQRT( v_ip_1d(ji) * z1_zpnd_aspect * a_i_1d(ji) ) 182 a_ip_frac_1d(ji) = a_ip_1d(ji) / a_i_1d(ji) 183 h_ip_1d(ji) = zpnd_aspect * a_ip_frac_1d(ji) 234 IF( ln_pnd_lids ) THEN 235 ! 236 !--- Lid growing and subsequent pond shrinking ---! 237 zdv_frz = 0.5_wp * MAX( 0._wp, -v_il_1d(ji) + & ! Flocco 2010 (eq. 5) solved implicitly as aH**2 + bH + c = 0 238 & SQRT( v_il_1d(ji)**2 + a_ip_1d(ji)**2 * 4._wp * rcnd_i * zdT * rdt_ice / (rLfus * rhow) ) ) ! max for roundoff errors 239 240 ! Lid growing 241 v_il_1d(ji) = MAX( 0._wp, v_il_1d(ji) + zdv_frz ) 242 243 ! Pond shrinking 244 v_ip_1d(ji) = MAX( 0._wp, v_ip_1d(ji) - zdv_frz ) 245 246 ELSE 247 ! Pond shrinking 248 v_ip_1d(ji) = v_ip_1d(ji) * EXP( 0.01_wp * zdT * z1_Tp ) ! Holland 2012 (eq. 6) 249 ENDIF 250 ! 251 !--- Set new pond area and depth ---! assuming linear relation between h_ip and a_ip_frac 252 ! v_ip = h_ip * a_ip 253 ! a_ip/a_i = a_ip_frac = h_ip / zaspect (cf Holland 2012, fitting SHEBA so that knowing v_ip we can distribute it to a_ip and h_ip) 254 a_ip_1d(ji) = MIN( a_i_1d(ji), SQRT( v_ip_1d(ji) * z1_aspect * a_i_1d(ji) ) ) ! make sure a_ip < a_i 255 h_ip_1d(ji) = zaspect * a_ip_1d(ji) / a_i_1d(ji) 256 257 !---------------! 258 ! Pond flushing ! 259 !---------------! 260 ! height of top of the pond above sea-level 261 zhp = ( h_i_1d(ji) * ( rho0 - rhoi ) + h_ip_1d(ji) * ( rho0 - rhow * a_ip_1d(ji) / a_i_1d(ji) ) ) * r1_rho0 262 263 ! Calculate the permeability of the ice (Assur 1958, see Flocco 2010) 264 DO jk = 1, nlay_i 265 zsbr = - 1.2_wp & 266 & - 21.8_wp * ( t_i_1d(ji,jk) - rt0 ) & 267 & - 0.919_wp * ( t_i_1d(ji,jk) - rt0 )**2 & 268 & - 0.0178_wp * ( t_i_1d(ji,jk) - rt0 )**3 269 ztmp(jk) = sz_i_1d(ji,jk) / zsbr 270 END DO 271 zperm = MAX( 0._wp, 3.e-08_wp * MINVAL(ztmp)**3 ) 272 273 ! Do the drainage using Darcy's law 274 zdv_flush = -zperm * rho0 * grav * zhp * rdt_ice / (zvisc * h_i_1d(ji)) * a_ip_1d(ji) 275 zdv_flush = MAX( zdv_flush, -v_ip_1d(ji) ) 276 v_ip_1d(ji) = v_ip_1d(ji) + zdv_flush 277 278 !--- Set new pond area and depth ---! assuming linear relation between h_ip and a_ip_frac 279 a_ip_1d(ji) = MIN( a_i_1d(ji), SQRT( v_ip_1d(ji) * z1_aspect * a_i_1d(ji) ) ) ! make sure a_ip < a_i 280 h_ip_1d(ji) = zaspect * a_ip_1d(ji) / a_i_1d(ji) 281 282 !--- Corrections and lid thickness ---! 283 IF( ln_pnd_lids ) THEN 284 !--- retrieve lid thickness from volume ---! 285 IF( a_ip_1d(ji) > epsi10 ) THEN ; h_il_1d(ji) = v_il_1d(ji) / a_ip_1d(ji) 286 ELSE ; h_il_1d(ji) = 0._wp 287 ENDIF 288 !--- remove ponds if lids are much larger than ponds ---! 289 IF ( h_il_1d(ji) > h_ip_1d(ji) * 10._wp ) THEN 290 a_ip_1d(ji) = 0._wp 291 h_ip_1d(ji) = 0._wp 292 h_il_1d(ji) = 0._wp 293 ENDIF 294 ENDIF 184 295 ! 185 296 ENDIF 297 186 298 END DO 187 299 ! 188 END SUBROUTINE pnd_ H12300 END SUBROUTINE pnd_LEV 189 301 190 302 … … 203 315 INTEGER :: ios, ioptio ! Local integer 204 316 !! 205 NAMELIST/namthd_pnd/ ln_pnd, ln_pnd_H12, ln_pnd_CST, rn_apnd, rn_hpnd, ln_pnd_alb 317 NAMELIST/namthd_pnd/ ln_pnd, ln_pnd_LEV , rn_apnd_min, rn_apnd_max, & 318 & ln_pnd_CST , rn_apnd, rn_hpnd, & 319 & ln_pnd_lids, ln_pnd_alb 206 320 !!------------------------------------------------------------------- 207 321 ! … … 217 331 WRITE(numout,*) '~~~~~~~~~~~~~~~~' 218 332 WRITE(numout,*) ' Namelist namicethd_pnd:' 219 WRITE(numout,*) ' Melt ponds activated or not ln_pnd = ', ln_pnd 220 WRITE(numout,*) ' Evolutive melt pond fraction and depth (Holland et al 2012) ln_pnd_H12 = ', ln_pnd_H12 221 WRITE(numout,*) ' Prescribed melt pond fraction and depth ln_pnd_CST = ', ln_pnd_CST 222 WRITE(numout,*) ' Prescribed pond fraction rn_apnd = ', rn_apnd 223 WRITE(numout,*) ' Prescribed pond depth rn_hpnd = ', rn_hpnd 224 WRITE(numout,*) ' Melt ponds affect albedo or not ln_pnd_alb = ', ln_pnd_alb 333 WRITE(numout,*) ' Melt ponds activated or not ln_pnd = ', ln_pnd 334 WRITE(numout,*) ' Level ice melt pond scheme ln_pnd_LEV = ', ln_pnd_LEV 335 WRITE(numout,*) ' Minimum ice fraction that contributes to melt ponds rn_apnd_min = ', rn_apnd_min 336 WRITE(numout,*) ' Maximum ice fraction that contributes to melt ponds rn_apnd_max = ', rn_apnd_max 337 WRITE(numout,*) ' Constant ice melt pond scheme ln_pnd_CST = ', ln_pnd_CST 338 WRITE(numout,*) ' Prescribed pond fraction rn_apnd = ', rn_apnd 339 WRITE(numout,*) ' Prescribed pond depth rn_hpnd = ', rn_hpnd 340 WRITE(numout,*) ' Frozen lids on top of melt ponds ln_pnd_lids = ', ln_pnd_lids 341 WRITE(numout,*) ' Melt ponds affect albedo or not ln_pnd_alb = ', ln_pnd_alb 225 342 ENDIF 226 343 ! … … 229 346 IF( .NOT.ln_pnd ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndNO ; ENDIF 230 347 IF( ln_pnd_CST ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndCST ; ENDIF 231 IF( ln_pnd_ H12 ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndH12; ENDIF348 IF( ln_pnd_LEV ) THEN ; ioptio = ioptio + 1 ; nice_pnd = np_pndLEV ; ENDIF 232 349 IF( ioptio /= 1 ) & 233 & CALL ctl_stop( 'ice_thd_pnd_init: choose either none (ln_pnd=F) or only one pond scheme (ln_pnd_ H12or ln_pnd_CST)' )350 & CALL ctl_stop( 'ice_thd_pnd_init: choose either none (ln_pnd=F) or only one pond scheme (ln_pnd_LEV or ln_pnd_CST)' ) 234 351 ! 235 352 SELECT CASE( nice_pnd ) 236 353 CASE( np_pndNO ) 237 IF( ln_pnd_alb ) THEN ; ln_pnd_alb = .FALSE. ; CALL ctl_warn( 'ln_pnd_alb=false when no ponds' ) ; ENDIF 354 IF( ln_pnd_alb ) THEN ; ln_pnd_alb = .FALSE. ; CALL ctl_warn( 'ln_pnd_alb=false when no ponds' ) ; ENDIF 355 IF( ln_pnd_lids ) THEN ; ln_pnd_lids = .FALSE. ; CALL ctl_warn( 'ln_pnd_lids=false when no ponds' ) ; ENDIF 356 CASE( np_pndCST ) 357 IF( ln_pnd_lids ) THEN ; ln_pnd_lids = .FALSE. ; CALL ctl_warn( 'ln_pnd_lids=false when constant ponds' ) ; ENDIF 238 358 END SELECT 239 359 !
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