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albedo.F90 in branches/2011/dev_NEMO_MERGE_2011/NEMOGCM/NEMO/OPA_SRC/SBC – NEMO

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source: branches/2011/dev_NEMO_MERGE_2011/NEMOGCM/NEMO/OPA_SRC/SBC/albedo.F90 @ 3152

Last change on this file since 3152 was 3152, checked in by smasson, 12 years ago
dev_NEMO_MERGE_2011: new dynamical allocation in IOM and SBC
Property svn:keywords set to `Id`
File size: 11.6 KB

Rev	Line
[152]	1	MODULE albedo
	2	!!======================================================================
	3	!! * MODULE albedo *
	4	!! Ocean forcing: bulk thermohaline forcing of the ocean (or ice)
	5	!!=====================================================================
[1601]	6	!! History : 8.0 ! 2001-04 (LIM 1.0)
	7	!! NEMO 1.0 ! 2003-07 (C. Ethe, G. Madec) Optimization (old name:shine)
	8	!! - ! 2004-11 (C. Talandier) add albedo_init
	9	!! - ! 2001-06 (M. Vancoppenolle) LIM 3.0
	10	!! - ! 2006-08 (G. Madec) cleaning for surface module
[152]	11	!!----------------------------------------------------------------------
[1601]	12
	13	!!----------------------------------------------------------------------
[888]	14	!! albedo_ice : albedo for ice (clear and overcast skies)
	15	!! albedo_oce : albedo for ocean (clear and overcast skies)
	16	!! albedo_init : initialisation of albedo computation
[152]	17	!!----------------------------------------------------------------------
	18	USE phycst ! physical constants
[888]	19	USE in_out_manager ! I/O manager
[2715]	20	USE lib_mpp ! MPP library
[3152]	21	USE wrk_nemo_2 ! work arrays
[152]	22
	23	IMPLICIT NONE
	24	PRIVATE
	25
[1601]	26	PUBLIC albedo_ice ! routine called sbcice_lim.F90
	27	PUBLIC albedo_oce ! routine called by ???
[165]	28
[888]	29	INTEGER :: albd_init = 0 !: control flag for initialization
	30	REAL(wp) :: zzero = 0.e0 ! constant values
	31	REAL(wp) :: zone = 1.e0 ! " "
[152]	32
[888]	33	REAL(wp) :: c1 = 0.05 ! constants values
	34	REAL(wp) :: c2 = 0.10 ! " "
	35	REAL(wp) :: rmue = 0.40 ! cosine of local solar altitude
	36
[1601]	37	! !!* namelist namsbc_alb
	38	REAL(wp) :: rn_cloud = 0.06 ! cloudiness effect on snow or ice albedo (Grenfell & Perovich, 1984)
[833]	39	#if defined key_lim3
[1601]	40	REAL(wp) :: rn_albice = 0.53 ! albedo of melting ice in the arctic and antarctic (Shine & Hendersson-Sellers)
[833]	41	#else
[1601]	42	REAL(wp) :: rn_albice = 0.50 ! albedo of melting ice in the arctic and antarctic (Shine & Hendersson-Sellers)
[833]	43	#endif
[1601]	44	REAL(wp) :: rn_alphd = 0.80 ! coefficients for linear interpolation used to compute
	45	REAL(wp) :: rn_alphdi = 0.72 ! albedo between two extremes values (Pyane, 1972)
	46	REAL(wp) :: rn_alphc = 0.65 !
[152]	47
	48	!!----------------------------------------------------------------------
[2528]	49	!! NEMO/OPA 3.3 , NEMO Consortium (2010)
[888]	50	!! $Id$
[2715]	51	!! Software governed by the CeCILL licence (NEMOGCM/NEMO_CeCILL.txt)
[152]	52	!!----------------------------------------------------------------------
	53	CONTAINS
	54
[888]	55	SUBROUTINE albedo_ice( pt_ice, ph_ice, ph_snw, pa_ice_cs, pa_ice_os )
[152]	56	!!----------------------------------------------------------------------
[888]	57	!! * ROUTINE albedo_ice *
[152]	58	!!
	59	!! ** Purpose : Computation of the albedo of the snow/ice system
[888]	60	!! as well as the ocean one
[152]	61	!!
	62	!! ** Method : - Computation of the albedo of snow or ice (choose the
[888]	63	!! rignt one by a large number of tests
[152]	64	!! - Computation of the albedo of the ocean
	65	!!
[888]	66	!! References : Shine and Hendersson-Sellers 1985, JGR, 90(D1), 2243-2250.
	67	!!----------------------------------------------------------------------
[1463]	68	REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: pt_ice ! ice surface temperature (Kelvin)
[888]	69	REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: ph_ice ! sea-ice thickness
	70	REAL(wp), INTENT(in ), DIMENSION(:,:,:) :: ph_snw ! snow thickness
	71	REAL(wp), INTENT( out), DIMENSION(:,:,:) :: pa_ice_cs ! albedo of ice under clear sky
	72	REAL(wp), INTENT( out), DIMENSION(:,:,:) :: pa_ice_os ! albedo of ice under overcast sky
[719]	73	!!
[888]	74	INTEGER :: ji, jj, jl ! dummy loop indices
	75	INTEGER :: ijpl ! number of ice categories (3rd dim of ice input arrays)
	76	REAL(wp) :: zalbpsnm ! albedo of ice under clear sky when snow is melting
	77	REAL(wp) :: zalbpsnf ! albedo of ice under clear sky when snow is freezing
	78	REAL(wp) :: zalbpsn ! albedo of snow/ice system when ice is coverd by snow
	79	REAL(wp) :: zalbpic ! albedo of snow/ice system when ice is free of snow
	80	REAL(wp) :: zithsn ! = 1 for hsn >= 0 ( ice is cov. by snow ) ; = 0 otherwise (ice is free of snow)
	81	REAL(wp) :: zitmlsn ! = 1 freezinz snow (pt_ice >=rt0_snow) ; = 0 melting snow (pt_ice<rt0_snow)
	82	REAL(wp) :: zihsc1 ! = 1 hsn <= c1 ; = 0 hsn > c1
	83	REAL(wp) :: zihsc2 ! = 1 hsn >= c2 ; = 0 hsn < c2
	84	!!
[2715]	85	REAL(wp), POINTER, DIMENSION(:,:,:) :: zalbfz ! = rn_alphdi for freezing ice ; = rn_albice for melting ice
	86	REAL(wp), POINTER, DIMENSION(:,:,:) :: zficeth ! function of ice thickness
[152]	87	!!---------------------------------------------------------------------
	88
[888]	89	ijpl = SIZE( pt_ice, 3 ) ! number of ice categories
[165]	90
[3152]	91	CALL wrk_alloc( jpi,jpj,ijpl, zalbfz, zficeth )
[2715]	92
[888]	93	IF( albd_init == 0 ) CALL albedo_init ! initialization
	94
	95	!---------------------------
[152]	96	! Computation of zficeth
[888]	97	!---------------------------
	98	! ice free of snow and melts
[2715]	99	WHERE ( ph_snw == 0._wp .AND. pt_ice >= rt0_ice ) ; zalbfz(:,:,:) = rn_albice
	100	ELSE WHERE ; zalbfz(:,:,:) = rn_alphdi
	101	END WHERE
	102
	103	WHERE ( 1.5 < ph_ice ) ; zficeth = zalbfz
	104	ELSE WHERE( 1.0 < ph_ice .AND. ph_ice <= 1.5 ) ; zficeth = 0.472 + 2.0 * ( zalbfz - 0.472 ) * ( ph_ice - 1.0 )
	105	ELSE WHERE( 0.05 < ph_ice .AND. ph_ice <= 1.0 ) ; zficeth = 0.2467 + 0.7049 * ph_ice &
	106	& - 0.8608 * ph_ice * ph_ice &
	107	& + 0.3812 * ph_ice * ph_ice * ph_ice
	108	ELSE WHERE ; zficeth = 0.1 + 3.6 * ph_ice
[152]	109	END WHERE
[888]	110
[2715]	111	!!gm old code
	112	! DO jl = 1, ijpl
	113	! DO jj = 1, jpj
	114	! DO ji = 1, jpi
	115	! IF( ph_ice(ji,jj,jl) > 1.5 ) THEN
	116	! zficeth(ji,jj,jl) = zalbfz(ji,jj,jl)
	117	! ELSEIF( ph_ice(ji,jj,jl) > 1.0 .AND. ph_ice(ji,jj,jl) <= 1.5 ) THEN
	118	! zficeth(ji,jj,jl) = 0.472 + 2.0 * ( zalbfz(ji,jj,jl) - 0.472 ) * ( ph_ice(ji,jj,jl) - 1.0 )
	119	! ELSEIF( ph_ice(ji,jj,jl) > 0.05 .AND. ph_ice(ji,jj,jl) <= 1.0 ) THEN
	120	! zficeth(ji,jj,jl) = 0.2467 + 0.7049 * ph_ice(ji,jj,jl) &
	121	! & - 0.8608 * ph_ice(ji,jj,jl) * ph_ice(ji,jj,jl) &
	122	! & + 0.3812 * ph_ice(ji,jj,jl) * ph_ice(ji,jj,jl) * ph_ice (ji,jj,jl)
	123	! ELSE
	124	! zficeth(ji,jj,jl) = 0.1 + 3.6 * ph_ice(ji,jj,jl)
	125	! ENDIF
	126	! END DO
	127	! END DO
	128	! END DO
	129	!!gm end old code
[152]	130
	131	!-----------------------------------------------
	132	! Computation of the snow/ice albedo system
	133	!-------------------------- ---------------------
	134
	135	! Albedo of snow-ice for clear sky.
	136	!-----------------------------------------------
[888]	137	DO jl = 1, ijpl
[833]	138	DO jj = 1, jpj
	139	DO ji = 1, jpi
	140	! Case of ice covered by snow.
[888]	141	! ! freezing snow
	142	zihsc1 = 1.0 - MAX( zzero , SIGN( zone , - ( ph_snw(ji,jj,jl) - c1 ) ) )
[1601]	143	zalbpsnf = ( 1.0 - zihsc1 ) * ( zficeth(ji,jj,jl) &
	144	& + ph_snw(ji,jj,jl) * ( rn_alphd - zficeth(ji,jj,jl) ) / c1 ) &
	145	& + zihsc1 * rn_alphd
[888]	146	! ! melting snow
	147	zihsc2 = MAX( zzero , SIGN( zone , ph_snw(ji,jj,jl) - c2 ) )
[1601]	148	zalbpsnm = ( 1.0 - zihsc2 ) * ( rn_albice + ph_snw(ji,jj,jl) * ( rn_alphc - rn_albice ) / c2 ) &
	149	& + zihsc2 * rn_alphc
[888]	150	!
	151	zitmlsn = MAX( zzero , SIGN( zone , pt_ice(ji,jj,jl) - rt0_snow ) )
	152	zalbpsn = zitmlsn * zalbpsnm + ( 1.0 - zitmlsn ) * zalbpsnf
[833]	153
	154	! Case of ice free of snow.
[888]	155	zalbpic = zficeth(ji,jj,jl)
[833]	156
	157	! albedo of the system
[888]	158	zithsn = 1.0 - MAX( zzero , SIGN( zone , - ph_snw(ji,jj,jl) ) )
	159	pa_ice_cs(ji,jj,jl) = zithsn * zalbpsn + ( 1.0 - zithsn ) * zalbpic
[833]	160	END DO
	161	END DO
	162	END DO
	163
	164	! Albedo of snow-ice for overcast sky.
	165	!----------------------------------------------
[1601]	166	pa_ice_os(:,:,:) = pa_ice_cs(:,:,:) + rn_cloud ! Oberhuber correction
[888]	167	!
[3152]	168	CALL wrk_dealloc( jpi,jpj,ijpl, zalbfz, zficeth )
[2715]	169	!
[888]	170	END SUBROUTINE albedo_ice
[833]	171
	172
[888]	173	SUBROUTINE albedo_oce( pa_oce_os , pa_oce_cs )
[152]	174	!!----------------------------------------------------------------------
[888]	175	!! * ROUTINE albedo_oce *
[152]	176	!!
[888]	177	!! ** Purpose : Computation of the albedo of the ocean
	178	!!----------------------------------------------------------------------
[2715]	179	REAL(wp), DIMENSION(:,:), INTENT(out) :: pa_oce_os ! albedo of ocean under overcast sky
	180	REAL(wp), DIMENSION(:,:), INTENT(out) :: pa_oce_cs ! albedo of ocean under clear sky
[152]	181	!!
[2715]	182	REAL(wp) :: zcoef ! local scalar
[152]	183	!!----------------------------------------------------------------------
[888]	184	!
	185	zcoef = 0.05 / ( 1.1 * rmue**1.4 + 0.15 ) ! Parameterization of Briegled and Ramanathan, 1982
	186	pa_oce_cs(:,:) = zcoef
	187	pa_oce_os(:,:) = 0.06 ! Parameterization of Kondratyev, 1969 and Payne, 1972
	188	!
	189	END SUBROUTINE albedo_oce
[152]	190
	191
[165]	192	SUBROUTINE albedo_init
	193	!!----------------------------------------------------------------------
	194	!! * ROUTINE albedo_init *
	195	!!
	196	!! ** Purpose : initializations for the albedo parameters
	197	!!
[1601]	198	!! ** Method : Read the namelist namsbc_alb
[165]	199	!!----------------------------------------------------------------------
[1601]	200	NAMELIST/namsbc_alb/ rn_cloud, rn_albice, rn_alphd, rn_alphdi, rn_alphc
[719]	201	!!----------------------------------------------------------------------
[1601]	202	!
	203	albd_init = 1 ! indicate that the initialization has been done
	204	!
	205	REWIND( numnam ) ! Read Namelist namsbc_alb : albedo parameters
	206	READ ( numnam, namsbc_alb )
	207	!
	208	IF(lwp) THEN ! Control print
[165]	209	WRITE(numout,*)
[1601]	210	WRITE(numout,*) 'albedo : set albedo parameters'
	211	WRITE(numout,*) '~~~~~~~'
	212	WRITE(numout,*) ' Namelist namsbc_alb : albedo '
	213	WRITE(numout,*) ' correction for snow and ice albedo rn_cloud = ', rn_cloud
	214	WRITE(numout,*) ' albedo of melting ice in the arctic and antarctic rn_albice = ', rn_albice
	215	WRITE(numout,*) ' coefficients for linear rn_alphd = ', rn_alphd
	216	WRITE(numout,*) ' interpolation used to compute albedo rn_alphdi = ', rn_alphdi
	217	WRITE(numout,*) ' between two extremes values (Pyane, 1972) rn_alphc = ', rn_alphc
[165]	218	ENDIF
[888]	219	!
	220	END SUBROUTINE albedo_init
[719]	221
[152]	222	!!======================================================================
	223	END MODULE albedo

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