/[MITgcm]/MITgcm/pkg/land/land_albedo.F
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Contents of /MITgcm/pkg/land/land_albedo.F

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Revision 1.1 - (show annotations) (download)
Thu Mar 11 14:41:59 2004 UTC (20 years, 2 months ago) by jmc
Branch: MAIN
CVS Tags: checkpoint58l_post, checkpoint57t_post, checkpoint57o_post, checkpoint58e_post, checkpoint57v_post, checkpoint52n_post, checkpoint53d_post, checkpoint58u_post, checkpoint54a_pre, checkpoint57m_post, checkpoint55c_post, checkpoint54e_post, checkpoint57s_post, checkpoint54a_post, checkpoint53c_post, checkpoint57k_post, checkpoint55d_pre, checkpoint57d_post, checkpoint57g_post, checkpoint57b_post, checkpoint57c_pre, checkpoint58r_post, checkpoint55j_post, checkpoint56b_post, checkpoint57i_post, checkpoint57y_post, checkpoint57e_post, checkpoint52l_post, checkpoint55h_post, checkpoint58n_post, checkpoint57g_pre, checkpoint54b_post, checkpoint53b_pre, checkpoint55b_post, checkpoint58t_post, checkpoint58h_post, checkpoint54d_post, checkpoint56c_post, checkpoint52m_post, checkpoint57y_pre, checkpoint55, checkpoint53a_post, checkpoint57f_pre, checkpoint57a_post, checkpoint54, checkpoint58q_post, checkpoint54f_post, checkpoint53b_post, checkpoint55g_post, checkpoint58j_post, checkpoint55f_post, checkpoint57r_post, checkpoint58, checkpoint57a_pre, checkpoint55i_post, checkpoint57, checkpoint56, checkpoint53, eckpoint57e_pre, checkpoint57h_done, checkpoint58f_post, checkpoint53g_post, checkpoint57x_post, checkpoint57n_post, checkpoint58d_post, checkpoint58c_post, checkpoint57w_post, checkpoint57p_post, checkpint57u_post, checkpoint57f_post, checkpoint58a_post, checkpoint58i_post, checkpoint57q_post, checkpoint58g_post, checkpoint58o_post, checkpoint57z_post, checkpoint57c_post, checkpoint55e_post, checkpoint58k_post, checkpoint53f_post, checkpoint55a_post, checkpoint53d_pre, checkpoint54c_post, checkpoint58s_post, checkpoint58p_post, checkpoint57j_post, checkpoint58b_post, checkpoint57h_pre, checkpoint58m_post, checkpoint57l_post, checkpoint57h_post, checkpoint56a_post, checkpoint55d_post 
new land formulation:
a) use ground enthalpy as prognostic variable to ensure exact
   energy conservation.
b) account for water temperature and for latent heat of freezing
   in all processes (rain, run-off, ground storage)
c) compute surface and ground temperature implicitly.
1 C $Header: $
2 C $Name: $
3
4 #include "LAND_OPTIONS.h"
5
6 CBOP
7 C !ROUTINE: LAND_DIAGNOSTICS
8 C !INTERFACE:
9 SUBROUTINE LAND_ALBEDO(
10 I land_frc, grnd_alb,
11 O alb_land,
12 I bi,bj, myTime, myIter, myThid )
13
14 C !DESCRIPTION: \bv
15 C *==========================================================*
16 C | S/R LAND_ALBEDO
17 C | o Calculate snow albedo over land
18 C *==========================================================*
19 C \ev
20
21 C !USES:
22 IMPLICIT NONE
23
24 C == Global variables ===
25 C-- size for MITgcm & Land package :
26 #include "LAND_SIZE.h"
27
28 #include "EEPARAMS.h"
29 #include "PARAMS.h"
30 #include "LAND_PARAMS.h"
31 #include "LAND_VARS.h"
32
33 C !INPUT/OUTPUT PARAMETERS:
34 C == Routine arguments ==
35 C land_frc :: land fraction [0-1]
36 C grnd_alb :: ground albedo [0-1]
37 C alb_land :: albedo of land (including snow effect) [0-1]
38 C bi,bj :: Tile index
39 C myTime :: Current time of simulation ( s )
40 C myIter :: Current iteration number in simulation
41 C myThid :: Number of this instance of the routine
42 _RS land_frc(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
43 _RS grnd_alb(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
44 _RL alb_land(sNx,sNy)
45 INTEGER bi, bj, myIter, myThid
46 _RL myTime
47 CEOP
48
49 #ifdef ALLOW_LAND
50
51 C == Local Variables ==
52 C i,j :: Loop counters
53 C albSnow :: albedo of snow
54 C ageSnow :: age of snow [days]
55 INTEGER i,j
56 _RL albSnow, ageSnow, hSnow, Tsf
57
58 C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
59 C- Compute albedo of snow and then albedo of land.
60
61 DO j=1,sNy
62 DO i=1,sNx
63 alb_land(i,j) = grnd_alb(i,j,bi,bj)
64 IF ( land_frc(i,j,bi,bj).GT.0. ) THEN
65 Tsf = land_skinT(i,j,bi,bj)
66 C snow age (units = days):
67 ageSnow = land_snowAge(i,j,bi,bj)/86400. _d 0
68 hSnow = land_hSnow(i,j,bi,bj)
69
70 C--------------------------------------------
71 C--- taken from thsice/thsice_albedo.F :
72 C- New snow: (linear) transition between -10.oC and 0.oC
73 C from cold/dry snow albedo to warm/wet snow albedo
74 albSnow = albColdSnow
75 & + (albWarmSnow - albColdSnow)
76 & *MAX( 0. _d 0, 1. _d 0 + MIN(Tsf/10. _d 0, 0. _d 0) )
77 C- albedo of snow is function of snow-age
78 albSnow = albOldSnow
79 & +(albSnow-albOldSnow)*exp(-0.2 _d 0*ageSnow)
80
81 C- layer of snow over the ground:
82 alb_land(i,j) = albSnow
83 & +(alb_land(i,j)-albSnow)*exp(-hSnow/hAlbSnow)
84 C--------------------------------------------
85 ENDIF
86 ENDDO
87 ENDDO
88
89 C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
90
91 #endif /* ALLOW_LAND */
92
93 RETURN
94 END
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