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albedo.F90 in branches/dev_002_LIM/NEMO/OPA_SRC/SBC – NEMO

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source: branches/dev_002_LIM/NEMO/OPA_SRC/SBC/albedo.F90 @ 826

Last change on this file since 826 was 826, checked in by ctlod, 16 years ago
dev_002_LIM: change remaining cpp key key_ice_lim into key_lim3, see ticket:#71
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 12.2 KB

Rev	Line
[152]	1	MODULE albedo
	2	!!======================================================================
	3	!! * MODULE albedo *
	4	!! Ocean forcing: bulk thermohaline forcing of the ocean (or ice)
	5	!!=====================================================================
	6	!!----------------------------------------------------------------------
[719]	7	!! flx_blk_albedo : albedo for ocean and ice (clear and overcast skies)
[152]	8	!!----------------------------------------------------------------------
[719]	9	!! * Modules used
[152]	10	USE oce ! ocean dynamics and tracers
[719]	11	USE dom_oce ! ocean space and time domain
	12	USE cpl_oce ! ???
[152]	13	USE phycst ! physical constants
[719]	14	USE daymod
	15	USE blk_oce ! bulk variables
	16	USE flx_oce ! forcings variables
	17	USE ocfzpt ! ???
[152]	18	USE in_out_manager
[719]	19	USE lbclnk
[152]	20
	21	IMPLICIT NONE
	22	PRIVATE
	23
[719]	24	!! * Accessibility
	25	PUBLIC flx_blk_albedo ! routine called by limflx.F90 in coupled
	26	! and in flxblk.F90 in forced
	27	!! * Module variables
	28	INTEGER :: & !: nameos : ocean physical parameters
	29	albd_init = 0 !: control flag for initialization
[165]	30
[719]	31	REAL(wp) :: & ! constant values
	32	zzero = 0.e0 , &
	33	zone = 1.0
[152]	34
[719]	35	!! * constants for albedo computation (flx_blk_albedo)
[152]	36	REAL(wp) :: &
[719]	37	c1 = 0.05 , & ! constants values
	38	c2 = 0.10 , &
	39	albice = 0.50 , & ! albedo of melting ice in the arctic and antarctic (Shine & Hendersson-Sellers)
[703]	40	cgren = 0.06 , & ! correction of the snow or ice albedo to take into account
[719]	41	! effects of cloudiness (Grenfell & Perovich, 1984)
[152]	42	alphd = 0.80 , & ! coefficients for linear interpolation used to compute
	43	alphdi = 0.72 , & ! albedo between two extremes values (Pyane, 1972)
[719]	44	alphc = 0.65 , &
	45	zmue = 0.40 ! cosine of local solar altitude
[152]	46
	47	!!----------------------------------------------------------------------
[719]	48	!! OPA 9.0 , LOCEAN-IPSL (2005)
	49	!! $Header$
	50	!! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt
[152]	51	!!----------------------------------------------------------------------
	52
	53	CONTAINS
	54
[826]	55	#if defined key_lim3
[152]	56	!!----------------------------------------------------------------------
[826]	57	!! 'key_lim3' LIM ice model
[152]	58	!!----------------------------------------------------------------------
	59
[719]	60	SUBROUTINE flx_blk_albedo( palb , palcn , palbp , palcnp )
[152]	61	!!----------------------------------------------------------------------
[719]	62	!! * ROUTINE flx_blk_albedo *
[152]	63	!!
	64	!! ** Purpose : Computation of the albedo of the snow/ice system
[719]	65	!! as well as the ocean one
[152]	66	!!
	67	!! ** Method : - Computation of the albedo of snow or ice (choose the
[719]	68	!! rignt one by a large number of tests
[152]	69	!! - Computation of the albedo of the ocean
	70	!!
[719]	71	!! References :
	72	!! Shine and Hendersson-Sellers 1985, JGR, 90(D1), 2243-2250.
	73	!!
	74	!! History :
	75	!! 8.0 ! 01-04 (LIM 1.0)
	76	!! 8.5 ! 03-07 (C. Ethe, G. Madec) Optimization (old name:shine)
[703]	77	!!----------------------------------------------------------------------
[719]	78	!! * Modules used
	79	USE ice ! ???
	80
	81	!! * Arguments
	82	REAL(wp), DIMENSION(jpi,jpj), INTENT(out) :: &
	83	palb , & ! albedo of ice under overcast sky
	84	palcn , & ! albedo of ocean under overcast sky
	85	palbp , & ! albedo of ice under clear sky
	86	palcnp ! albedo of ocean under clear sky
	87
	88	!! * Local variables
	89	INTEGER :: &
	90	ji, jj ! dummy loop indices
	91	REAL(wp) :: &
	92	zmue14 , & ! zmue**1.4
[152]	93	zalbpsnm , & ! albedo of ice under clear sky when snow is melting
	94	zalbpsnf , & ! albedo of ice under clear sky when snow is freezing
	95	zalbpsn , & ! albedo of snow/ice system when ice is coverd by snow
	96	zalbpic , & ! albedo of snow/ice system when ice is free of snow
	97	zithsn , & ! = 1 for hsn >= 0 ( ice is cov. by snow ) ; = 0 otherwise (ice is free of snow)
	98	zitmlsn , & ! = 1 freezinz snow (sist >=rt0_snow) ; = 0 melting snow (sist<rt0_snow)
	99	zihsc1 , & ! = 1 hsn <= c1 ; = 0 hsn > c1
	100	zihsc2 ! = 1 hsn >= c2 ; = 0 hsn < c2
[719]	101	REAL(wp), DIMENSION(jpi,jpj) :: &
	102	zalbfz , & ! ( = alphdi for freezing ice ; = albice for melting ice )
	103	zficeth ! function of ice thickness
	104	LOGICAL , DIMENSION(jpi,jpj) :: &
	105	llmask
[152]	106	!!---------------------------------------------------------------------
	107
[719]	108	! initialization
	109	IF( albd_init == 0 ) CALL albedo_init
[165]	110
[719]	111	!-------------------------
[152]	112	! Computation of zficeth
[719]	113	!--------------------------
[152]	114
	115	llmask = (hsnif == 0.e0) .AND. ( sist >= rt0_ice )
	116	WHERE ( llmask ) ! ice free of snow and melts
	117	zalbfz = albice
	118	ELSEWHERE
	119	zalbfz = alphdi
	120	END WHERE
	121
	122	DO jj = 1, jpj
	123	DO ji = 1, jpi
	124	IF( hicif(ji,jj) > 1.5 ) THEN
	125	zficeth(ji,jj) = zalbfz(ji,jj)
	126	ELSEIF( hicif(ji,jj) > 1.0 .AND. hicif(ji,jj) <= 1.5 ) THEN
	127	zficeth(ji,jj) = 0.472 + 2.0 * ( zalbfz(ji,jj) - 0.472 ) * ( hicif(ji,jj) - 1.0 )
	128	ELSEIF( hicif(ji,jj) > 0.05 .AND. hicif(ji,jj) <= 1.0 ) THEN
	129	zficeth(ji,jj) = 0.2467 + 0.7049 * hicif(ji,jj) &
	130	& - 0.8608 * hicif(ji,jj) * hicif(ji,jj) &
	131	& + 0.3812 * hicif(ji,jj) * hicif(ji,jj) * hicif (ji,jj)
	132	ELSE
	133	zficeth(ji,jj) = 0.1 + 3.6 * hicif(ji,jj)
	134	ENDIF
	135	END DO
	136	END DO
	137
	138	!-----------------------------------------------
	139	! Computation of the snow/ice albedo system
	140	!-------------------------- ---------------------
	141
	142	! Albedo of snow-ice for clear sky.
	143	!-----------------------------------------------
	144	DO jj = 1, jpj
	145	DO ji = 1, jpi
	146	! Case of ice covered by snow.
	147
	148	! melting snow
	149	zihsc1 = 1.0 - MAX ( zzero , SIGN ( zone , - ( hsnif(ji,jj) - c1 ) ) )
	150	zalbpsnm = ( 1.0 - zihsc1 ) * ( zficeth(ji,jj) + hsnif(ji,jj) * ( alphd - zficeth(ji,jj) ) / c1 ) &
	151	& + zihsc1 * alphd
	152	! freezing snow
	153	zihsc2 = MAX ( zzero , SIGN ( zone , hsnif(ji,jj) - c2 ) )
	154	zalbpsnf = ( 1.0 - zihsc2 ) * ( albice + hsnif(ji,jj) * ( alphc - albice ) / c2 ) &
	155	& + zihsc2 * alphc
	156
	157	zitmlsn = MAX ( zzero , SIGN ( zone , sist(ji,jj) - rt0_snow ) )
	158	zalbpsn = zitmlsn * zalbpsnf + ( 1.0 - zitmlsn ) * zalbpsnm
	159
	160	! Case of ice free of snow.
	161	zalbpic = zficeth(ji,jj)
	162
	163	! albedo of the system
	164	zithsn = 1.0 - MAX ( zzero , SIGN ( zone , - hsnif(ji,jj) ) )
	165	palbp(ji,jj) = zithsn * zalbpsn + ( 1.0 - zithsn ) * zalbpic
	166	END DO
	167	END DO
	168
	169	! Albedo of snow-ice for overcast sky.
	170	!----------------------------------------------
	171	palb(:,:) = palbp(:,:) + cgren
	172
	173	!--------------------------------------------
	174	! Computation of the albedo of the ocean
	175	!-------------------------- -----------------
	176
[719]	177	! Parameterization of Briegled and Ramanathan, 1982
	178	zmue14 = zmue**1.4
	179	palcnp(:,:) = 0.05 / ( 1.1 * zmue14 + 0.15 )
	180
	181	! Parameterization of Kondratyev, 1969 and Payne, 1972
	182	palcn(:,:) = 0.06
	183
	184	END SUBROUTINE flx_blk_albedo
[152]	185
	186	# else
	187	!!----------------------------------------------------------------------
	188	!! Default option : NO sea-ice model
	189	!!----------------------------------------------------------------------
	190
[719]	191	SUBROUTINE flx_blk_albedo( palb , palcn , palbp , palcnp )
[152]	192	!!----------------------------------------------------------------------
[719]	193	!! * ROUTINE flx_blk_albedo *
[152]	194	!!
[719]	195	!! ** Purpose : Computation of the albedo of the snow/ice system
	196	!! as well as the ocean one
[152]	197	!!
[719]	198	!! ** Method : Computation of the albedo of snow or ice (choose the
	199	!! wright one by a large number of tests Computation of the albedo
	200	!! of the ocean
[152]	201	!!
[719]	202	!! History :
	203	!! 8.0 ! 01-04 (LIM 1.0)
	204	!! 8.5 ! 03-07 (C. Ethe, G. Madec) Optimization (old name:shine)
[152]	205	!!----------------------------------------------------------------------
[719]	206	!! * Arguments
	207	REAL(wp), DIMENSION(jpi,jpj), INTENT(out) :: &
	208	palb , & ! albedo of ice under overcast sky
	209	palcn , & ! albedo of ocean under overcast sky
	210	palbp , & ! albedo of ice under clear sky
	211	palcnp ! albedo of ocean under clear sky
[152]	212
[719]	213	REAL(wp) :: &
	214	zmue14 ! zmue**1.4
	215	!!----------------------------------------------------------------------
[152]	216
[719]	217	!--------------------------------------------
	218	! Computation of the albedo of the ocean
	219	!-------------------------- -----------------
[152]	220
[719]	221	! Parameterization of Briegled and Ramanathan, 1982
	222	zmue14 = zmue**1.4
	223	palcnp(:,:) = 0.05 / ( 1.1 * zmue14 + 0.15 )
	224
	225	! Parameterization of Kondratyev, 1969 and Payne, 1972
	226	palcn(:,:) = 0.06
	227
	228	palb (:,:) = palcn(:,:)
	229	palbp(:,:) = palcnp(:,:)
	230
	231	END SUBROUTINE flx_blk_albedo
	232
[152]	233	#endif
[165]	234
	235	SUBROUTINE albedo_init
	236	!!----------------------------------------------------------------------
	237	!! * ROUTINE albedo_init *
	238	!!
	239	!! ** Purpose : initializations for the albedo parameters
	240	!!
	241	!! ** Method : Read the namelist namalb
[719]	242	!!
	243	!! ** Action :
	244	!!
	245	!!
	246	!! History :
	247	!! 9.0 ! 04-11 (C. Talandier) Original code
[165]	248	!!----------------------------------------------------------------------
[719]	249	NAMELIST/namalb/ cgren, albice, alphd, alphdi, alphc
	250	!!----------------------------------------------------------------------
	251	!! OPA 9.0, LODYC-IPSL (2004)
	252	!!----------------------------------------------------------------------
[165]	253
[719]	254	! set the initialization flag to 1
	255	albd_init = 1 ! indicate that the initialization has been done
	256
	257	! Read Namelist namalb : albedo parameters
	258	REWIND( numnam )
[165]	259	READ ( numnam, namalb )
	260
[719]	261	! Control print
	262	IF(lwp) THEN
[165]	263	WRITE(numout,*)
[719]	264	WRITE(numout,*) 'albedo_init : albedo '
[165]	265	WRITE(numout,*) '~~~~~~~~~~~'
[719]	266	WRITE(numout,*) ' Namelist namalb : set albedo parameters'
	267	WRITE(numout,*)
	268	WRITE(numout,*) ' correction of the snow or ice albedo to take into account cgren = ', cgren
	269	WRITE(numout,*) ' albedo of melting ice in the arctic and antarctic albice = ', albice
	270	WRITE(numout,*) ' coefficients for linear alphd = ', alphd
	271	WRITE(numout,*) ' interpolation used to compute albedo alphdi = ', alphdi
	272	WRITE(numout,*) ' between two extremes values (Pyane, 1972) alphc = ', alphc
	273	WRITE(numout,*)
[165]	274	ENDIF
[719]	275
[703]	276	END SUBROUTINE albedo_init
[152]	277	!!======================================================================
	278	END MODULE albedo

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