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source: palm/trunk/SOURCE/land_surface_model.f90 @ 1497

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1	MODULE land_surface_model_mod
2
3	!--------------------------------------------------------------------------------!
4	! This file is part of PALM.
5	!
6	! PALM is free software: you can redistribute it and/or modify it under the terms
7	! of the GNU General Public License as published by the Free Software Foundation,
8	! either version 3 of the License, or (at your option) any later version.
9	!
10	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
11	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13	!
14	! You should have received a copy of the GNU General Public License along with
15	! PALM. If not, see <http://www.gnu.org/licenses/>.
16	!
17	! Copyright 1997-2014 Leibniz Universitaet Hannover
18	!--------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	!
23	!
24	! Former revisions:
25	! -----------------
26	! $Id: land_surface_model.f90 1497 2014-12-02 17:28:07Z maronga $
27	!
28	! 1496 2014-12-02 17:25:50Z maronga
29	! Initial revision
30	!
31	!
32	! Description:
33	! ------------
34	! Land surface model, consisting of a solver for the energy balance at the
35	! surface and a four layer soil scheme. The scheme is similar to the TESSEL
36	! scheme implemented in the ECMWF IFS model, with modifications according to
37	! H-TESSEL. The implementation is based on the formulation implemented in the
38	! DALES model.
39	!------------------------------------------------------------------------------!
40	USE arrays_3d, &
41	ONLY: pt, pt_p, q, q_p, qsws, rif, shf, ts, us, z0, z0h
42
43	USE cloud_parameters, &
44	ONLY: cp, l_d_r, l_v, rho_l, r_d, r_v
45
46	USE control_parameters, &
47	ONLY: dt_3d, humidity, intermediate_timestep_count, &
48	intermediate_timestep_count_max, pt_surface, rho_surface, &
49	surface_pressure, timestep_scheme, tsc
50
51	USE indices, &
52	ONLY: nxlg, nxrg, nyng, nysg, nzb_s_inner
53
54	USE kinds
55
56	USE radiation_model_mod, &
57	ONLY: Rn, SW_in, sigma_SB
58
59
60	IMPLICIT NONE
61
62	!
63	!-- LSM model constants
64	INTEGER(iwp), PARAMETER :: soil_layers = 4 !: number of soil layers (fixed for now)
65
66	REAL(wp), PARAMETER :: &
67	b_CH = 6.04_wp, & ! Clapp & Hornberger exponent
68	lambda_h_dry = 0.19_wp, & ! heat conductivity for dry soil
69	lambda_h_sm = 3.44_wp, & ! heat conductivity of the soil matrix
70	lambda_h_water = 0.57_wp, & ! heat conductivity of water
71	psi_sat = -0.388_wp, & ! soil matrix potential at saturation
72	rhoC_soil = 2.19E6_wp, & ! volumetric heat capacity of soil
73	rhoC_water = 4.20E6_wp, & ! volumetric heat capacity of water
74	m_max_depth = 0.0002_wp ! Maximum capacity of the water reservoir (m)
75
76
77	!
78	!-- LSM variables
79	INTEGER(iwp) :: veg_type = 2, & !: vegetation type, 0: user-defined, 1-19: generic (see list)
80	soil_type = 3 !: soil type, 0: user-defined, 1-6: generic (see list)
81
82	LOGICAL :: conserve_water_content = .TRUE., & !: open or closed bottom surface for the soil model
83	land_surface = .FALSE. !: flag parameter indicating wheather the lsm is used
84
85	! value 9999999.9_wp -> generic available or user-defined value must be set
86	! otherwise -> no generic variable and user setting is optional
87	REAL(wp) :: alpha_VanGenuchten = 0.0_wp, & !: NAMELIST alpha_VG
88	canopy_resistance_coefficient = 0.0_wp, & !: NAMELIST gD
89	C_skin = 20000.0_wp, & !: Skin heat capacity
90	drho_l_lv, & !: (rho_l * l_v)**-1
91	exn, & !: value of the Exner function
92	e_s = 0.0_wp, & !: saturation water vapour pressure
93	field_capacity = 0.0_wp, & !: NAMELIST m_fc
94	f_shortwave_incoming = 9999999.9_wp, & !: NAMELIST f_SW_in
95	hydraulic_conductivity = 0.0_wp, & !: NAMELIST gamma_w_sat
96	Ke = 0.0_wp, & !: Kersten number
97	lambda_skin_stable = 9999999.9_wp, & !: NAMELIST lambda_skin_s
98	lambda_skin_unstable = 9999999.9_wp, & !: NAMELIST lambda_skin_u
99	leaf_area_index = 9999999.9_wp, & !: NAMELIST LAI
100	l_VanGenuchten = 0.0_WP, & !: NAMELIST l_VG
101	min_canopy_resistance = 110.0_wp, & !: NAMELIST r_s_min
102	m_total = 0.0_wp, & !: weighed total water content of the soil (m3/m3)
103	n_VanGenuchten = 0.0_WP, & !: NAMELIST n_VG
104	q_s = 0.0_wp, & !: saturation specific humidity
105	residual_moisture = 0.0_wp, & !: NAMELIST m_res
106	rho_cp, & !: rho_surface * cp
107	rho_lv, & !: rho * l_v
108	rd_d_rv, & !: r_d / r_v
109	saturation_moisture = 0.0_wp, & !: NAMELIST m_sat
110	vegetation_coverage = 9999999.9_wp, & !: NAMELIST c_veg
111	wilting_point = 0.0_wp !: NAMELIST m_wilt
112
113	REAL(wp), DIMENSION(0:soil_layers-1) :: &
114	ddz_soil, & !: 1/dz_soil
115	ddz_soil_stag, & !: 1/dz_soil_stag
116	dz_soil, & !: soil grid spacing (center-center)
117	dz_soil_stag, & !: soil grid spacing (edge-edge)
118	root_extr = 0.0_wp, & !: root extraction
119	root_fraction = (/0.35_wp, 0.38_wp, 0.23_wp, 0.04_wp/), & !: distribution of root surface area to the individual soil layers
120	soil_level = (/0.07_wp, 0.28_wp, 1.00_wp, 2.89_wp/), & !: soil layer depths (m)
121	soil_moisture = 0.0_wp !: soil moisture content (m3/m3)
122
123	REAL(wp), DIMENSION(0:soil_layers) :: &
124	soil_temperature = 9999999.9_wp !: soil temperature (K)
125
126	#if defined( __nopointer )
127	REAL(wp), DIMENSION(:,:), ALLOCATABLE, TARGET :: T_0, & !: skin temperature (K)
128	T_0_p, & !: progn. skin temperature (K)
129	m_liq, & !: liquid water reservoir (m)
130	m_liq_p !: progn. liquid water reservoir (m)
131	#else
132	REAL(wp), DIMENSION(:,:), POINTER :: T_0, &
133	T_0_p, &
134	m_liq, &
135	m_liq_p
136
137	REAL(wp), DIMENSION(:,:), ALLOCATABLE, TARGET :: T_0_1, T_0_2, &
138	m_liq_1, m_liq_2
139	#endif
140
141	!
142	!-- Temporal tendencies for time stepping
143	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: tT_0_m, & !: skin temperature tendency (K)
144	tm_liq_m !: liquid water reservoir tendency (m)
145
146	!
147	!-- Energy balance variables
148	REAL(wp), DIMENSION(:,:), ALLOCATABLE :: &
149	alpha_VG, & !: coef. of Van Genuchten
150	c_liq, & !: liquid water coverage (of vegetated area)
151	c_veg, & !: vegetation coverage
152	f_SW_in, & !: ?
153	G, & !: surface soil heat flux
154	H, & !: surface flux of sensible heat
155	gamma_w_sat, & !: hydraulic conductivity at saturation
156	gD, & !: coefficient for dependence of r_canopy on water vapour pressure deficit
157	LAI, & !: leaf area index
158	LE, & !: surface flux of latent heat (total)
159	LE_veg, & !: surface flux of latent heat (vegetation portion)
160	LE_soil, & !: surface flux of latent heat (soil portion)
161	LE_liq, & !: surface flux of latent heat (liquid water portion)
162	lambda_h_sat, & !: heat conductivity for dry soil
163	lambda_skin_s, & !: coupling between skin and soil (depends on vegetation type)
164	lambda_skin_u, & !: coupling between skin and soil (depends on vegetation type)
165	l_VG, & !: coef. of Van Genuchten
166	m_fc, & !: soil moisture at field capacity (m3/m3)
167	m_res, & !: residual soil moisture
168	m_sat, & !: saturation soil moisture (m3/m3)
169	m_wilt, & !: soil moisture at permanent wilting point (m3/m3)
170	n_VG, & !: coef. Van Genuchten
171	r_a, & !: aerodynamic resistance
172	r_canopy, & !: canopy resistance
173	r_soil, & !: soil resitance
174	r_soil_min, & !: minimum soil resistance
175	r_s, & !: total surface resistance (combination of r_soil and r_canopy)
176	r_s_min !: minimum canopy resistance
177
178	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: &
179	lambda_h, & !: heat conductivity of soil (?)
180	lambda_w, & !: hydraulic diffusivity of soil (?)
181	gamma_w, & !: hydraulic conductivity of soil (?)
182	rhoC_total !: volumetric heat capacity of the actual soil matrix (?)
183
184	#if defined( __nopointer )
185	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE, TARGET :: &
186	T_soil, & !: Soil temperature (K)
187	T_soil_p, & !: Prog. soil temperature (K)
188	m_soil, & !: Soil moisture (m3/m3)
189	m_soil_p !: Prog. soil moisture (m3/m3)
190	#else
191	REAL(wp), DIMENSION(:,:,:), POINTER :: &
192	T_soil, T_soil_p, &
193	m_soil, m_soil_p
194
195	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE, TARGET :: &
196	T_soil_1, T_soil_2, &
197	m_soil_1, m_soil_2
198
199
200	#endif
201
202
203	REAL(wp), DIMENSION(:,:,:), ALLOCATABLE :: &
204	tT_soil_m, & !: T_soil storage array
205	tm_soil_m, & !: m_soil storage array
206	root_fr !: root fraction (sum=1)
207
208	!
209	!-- Land surface parameters according to the following classes (veg_type)
210	!-- (0 user defined)
211	!-- 1 crops, mixed farming
212	!-- 2 short grass
213	!-- 3 evergreen needleleaf trees
214	!-- 4 deciduous needleleaf trees
215	!-- 5 evergreen broadleaf trees
216	!-- 6 deciduous broadleaf trees
217	!-- 7 tall grass
218	!-- 8 desert
219	!-- 9 tundra
220	!-- 10 irrigated crops
221	!-- 11 semidesert
222	!-- 12 ice caps and glaciers
223	!-- 13 bogs and marshes
224	!-- 14 inland water
225	!-- 15 ocean
226	!-- 16 evergreen shrubs
227	!-- 17 deciduous shrubs
228	!-- 18 mixed forest/woodland
229	!-- 19 interrupted forest
230
231	!
232	!-- Land surface parameters I r_s_min, LAI, c_veg, gD
233	REAL(wp), DIMENSION(0:3,1:19) :: veg_pars = RESHAPE( (/ &
234	180.0_wp, 3.00_wp, 0.90_wp, 0.00_wp, & ! 1
235	110.0_wp, 2.00_wp, 0.85_wp, 0.00_wp, & ! 2
236	500.0_wp, 5.00_wp, 0.90_wp, 0.03_wp, & ! 3
237	500.0_wp, 5.00_wp, 0.90_wp, 0.03_wp, & ! 4
238	175.0_wp, 5.00_wp, 0.90_wp, 0.03_wp, & ! 5
239	240.0_wp, 6.00_wp, 0.99_wp, 0.13_wp, & ! 6
240	100.0_wp, 2.00_wp, 0.70_wp, 0.00_wp, & ! 7
241	250.0_wp, 0.50_wp, 0.00_wp, 0.00_wp, & ! 8
242	80.0_wp, 1.00_wp, 0.50_wp, 0.00_wp, & ! 9
243	180.0_wp, 3.00_wp, 0.90_wp, 0.00_wp, & ! 10
244	150.0_wp, 0.50_wp, 0.10_wp, 0.00_wp, & ! 11
245	0.0_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 12
246	240.0_wp, 4.00_wp, 0.60_wp, 0.00_wp, & ! 13
247	0.0_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 14
248	0.0_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 15
249	225.0_wp, 3.00_wp, 0.50_wp, 0.00_wp, & ! 16
250	225.0_wp, 1.50_wp, 0.50_wp, 0.00_wp, & ! 17
251	250.0_wp, 5.00_wp, 0.90_wp, 0.03_wp, & ! 18
252	175.0_wp, 2.50_wp, 0.90_wp, 0.03_wp & ! 19
253	/), (/ 4, 19 /) )
254
255	!
256	!-- Land surface parameters II z0, z0h
257	REAL(wp), DIMENSION(0:1,1:19) :: roughness_par = RESHAPE( (/ &
258	0.25_wp, 0.25E-2_wp, & ! 1
259	0.20_wp, 0.20E-2_wp, & ! 2
260	2.00_wp, 2.00_wp, & ! 3
261	2.00_wp, 2.00_wp, & ! 4
262	2.00_wp, 2.00_wp, & ! 5
263	2.00_wp, 2.00_wp, & ! 6
264	0.47_wp, 0.47E-2_wp, & ! 7
265	0.013_wp, 0.013E-2_wp, & ! 8
266	0.034_wp, 0.034E-2_wp, & ! 9
267	0.5_wp, 0.50E-2_wp, & ! 10
268	0.17_wp, 0.17E-2_wp, & ! 11
269	1.3E-3_wp, 1.3E-4_wp, & ! 12
270	0.83_wp, 0.83E-2_wp, & ! 13
271	0.00_wp, 0.00E-2_wp, & ! 14
272	0.00_wp, 0.00E-2_wp, & ! 15
273	0.10_wp, 0.10E-2_wp, & ! 16
274	0.25_wp, 0.25E-2_wp, & ! 17
275	2.00_wp, 2.00E-2_wp, & ! 18
276	1.10_wp, 1.10E-2_wp & ! 19
277	/), (/ 2, 19 /) )
278
279	!
280	!-- Land surface parameters III lambda_skin_s, lambda_skin_u, f_SW_in
281	REAL(wp), DIMENSION(0:2,1:19) :: skin_pars = RESHAPE( (/ &
282	10.0_wp, 10.0_wp, 0.05_wp, & ! 1
283	10.0_wp, 10.0_wp, 0.05_wp, & ! 2
284	20.0_wp, 15.0_wp, 0.03_wp, & ! 3
285	20.0_wp, 15.0_wp, 0.03_wp, & ! 4
286	20.0_wp, 15.0_wp, 0.03_wp, & ! 5
287	20.0_wp, 15.0_wp, 0.03_wp, & ! 6
288	10.0_wp, 10.0_wp, 0.05_wp, & ! 7
289	15.0_wp, 15.0_wp, 0.00_wp, & ! 8
290	10.0_wp, 10.0_wp, 0.05_wp, & ! 9
291	10.0_wp, 10.0_wp, 0.05_wp, & ! 10
292	10.0_wp, 10.0_wp, 0.05_wp, & ! 11
293	58.0_wp, 58.0_wp, 0.00_wp, & ! 12
294	10.0_wp, 10.0_wp, 0.05_wp, & ! 13
295	1.0E20_wp, 1.0E20_wp, 0.00_wp, & ! 14
296	1.0E20_wp, 1.0E20_wp, 0.00_wp, & ! 15
297	10.0_wp, 10.0_wp, 0.05_wp, & ! 16
298	10.0_wp, 10.0_wp, 0.05_wp, & ! 17
299	20.0_wp, 15.0_wp, 0.03_wp, & ! 18
300	20.0_wp, 15.0_wp, 0.03_wp & ! 19
301	/), (/ 3, 19 /) )
302
303	!
304	!-- Root distribution (sum = 1) level 1, level 2, level 3, level 4,
305	REAL(wp), DIMENSION(0:3,1:19) :: root_distribution = RESHAPE( (/ &
306	0.24_wp, 0.41_wp, 0.31_wp, 0.04_wp, & ! 1
307	0.35_wp, 0.38_wp, 0.23_wp, 0.04_wp, & ! 2
308	0.26_wp, 0.39_wp, 0.29_wp, 0.06_wp, & ! 3
309	0.26_wp, 0.38_wp, 0.29_wp, 0.07_wp, & ! 4
310	0.24_wp, 0.38_wp, 0.31_wp, 0.07_wp, & ! 5
311	0.25_wp, 0.34_wp, 0.27_wp, 0.14_wp, & ! 6
312	0.27_wp, 0.27_wp, 0.27_wp, 0.09_wp, & ! 7
313	1.00_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 8
314	0.47_wp, 0.45_wp, 0.08_wp, 0.00_wp, & ! 9
315	0.24_wp, 0.41_wp, 0.31_wp, 0.04_wp, & ! 10
316	0.17_wp, 0.31_wp, 0.33_wp, 0.19_wp, & ! 11
317	0.00_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 12
318	0.25_wp, 0.34_wp, 0.27_wp, 0.11_wp, & ! 13
319	0.00_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 14
320	0.00_wp, 0.00_wp, 0.00_wp, 0.00_wp, & ! 15
321	0.23_wp, 0.36_wp, 0.30_wp, 0.11_wp, & ! 16
322	0.23_wp, 0.36_wp, 0.30_wp, 0.11_wp, & ! 17
323	0.19_wp, 0.35_wp, 0.36_wp, 0.10_wp, & ! 18
324	0.19_wp, 0.35_wp, 0.36_wp, 0.10_wp & ! 19
325	/), (/ 4, 19 /) )
326
327	!
328	!-- Soil parameters according to the following porosity classes (soil_type)
329	!-- (0 user defined)
330	!-- 1 coarse
331	!-- 2 medium
332	!-- 3 medium-fine
333	!-- 4 fine
334	!-- 5 very fine
335	!-- 6 organic
336	!
337	!-- Soil parameters I alpha_VG, l_VG, n_VG, gamma_w_sat
338	REAL(wp), DIMENSION(0:3,1:6) :: soil_pars = RESHAPE( (/ &
339	3.83_wp, 1.250_wp, 1.38_wp, 6.94E-6_wp, & ! 1
340	3.14_wp, -2.342_wp, 1.28_wp, 1.16E-6_wp, & ! 2
341	0.83_wp, -0.588_wp, 1.25_wp, 0.26E-6_wp, & ! 3
342	3.67_wp, -1.977_wp, 1.10_wp, 2.87E-6_wp, & ! 4
343	2.65_wp, 2.500_wp, 1.10_wp, 1.74E-6_wp, & ! 5
344	1.30_wp, 0.400_wp, 1.20_wp, 0.93E-6_wp & ! 6
345	/), (/ 4, 6 /) )
346
347	!
348	!-- Soil parameters II m_sat, m_fc, m_wilt, m_res
349	REAL(wp), DIMENSION(0:3,1:6) :: m_soil_pars = RESHAPE( (/ &
350	0.403_wp, 0.244_wp, 0.059_wp, 0.025_wp, & ! 1
351	0.439_wp, 0.347_wp, 0.151_wp, 0.010_wp, & ! 2
352	0.430_wp, 0.383_wp, 0.133_wp, 0.010_wp, & ! 3
353	0.520_wp, 0.448_wp, 0.279_wp, 0.010_wp, & ! 4
354	0.614_wp, 0.541_wp, 0.335_wp, 0.010_wp, & ! 5
355	0.766_wp, 0.663_wp, 0.267_wp, 0.010_wp & ! 6
356	/), (/ 4, 6 /) )
357
358
359	SAVE
360
361
362	PRIVATE
363
364
365	PUBLIC alpha_VanGenuchten, C_skin, canopy_resistance_coefficient, &
366	conserve_water_content, field_capacity, f_shortwave_incoming, &
367	hydraulic_conductivity, init_lsm, lambda_skin_stable, &
368	lambda_skin_unstable, land_surface, leaf_area_index, &
369	lsm_energy_balance, lsm_soil_model, l_VanGenuchten, &
370	min_canopy_resistance, n_VanGenuchten, residual_moisture, &
371	root_fraction, saturation_moisture, soil_level, soil_moisture, &
372	soil_temperature, soil_type, vegetation_coverage, veg_type, &
373	wilting_point
374
375	#if defined( __nopointer )
376	PUBLIC m_liq, m_liq_p, m_soil, m_soil_p, T_0, T_0_p, T_soil, T_soil_p
377	#else
378	PUBLIC m_liq, m_liq_1, m_liq_2, m_liq_p, m_soil, m_soil_1, m_soil_2, &
379	m_soil_p, T_0, T_0_1, T_0_2, T_0_p, T_soil, T_soil_1, T_soil_2, &
380	T_soil_p
381	#endif
382
383
384	INTERFACE init_lsm
385	MODULE PROCEDURE init_lsm
386	END INTERFACE init_lsm
387
388	INTERFACE lsm_energy_balance
389	MODULE PROCEDURE lsm_energy_balance
390	END INTERFACE lsm_energy_balance
391
392	INTERFACE lsm_soil_model
393	MODULE PROCEDURE lsm_soil_model
394	END INTERFACE lsm_soil_model
395
396
397	CONTAINS
398
399
400	!------------------------------------------------------------------------------!
401	! Description:
402	! ------------
403	!-- Initialization of the land surface model
404	!------------------------------------------------------------------------------!
405	SUBROUTINE init_lsm
406
407
408	IMPLICIT NONE
409
410	INTEGER(iwp) :: i !: running index
411	INTEGER(iwp) :: j !: running index
412	INTEGER(iwp) :: k !: running index
413
414
415	!
416	!-- Calculate frequently used parameters
417	rho_cp = cp * rho_surface
418	rd_d_rv = r_d / r_v
419	rho_lv = rho_surface * l_v
420	drho_l_lv = 1.0 / (rho_l * l_v)
421
422	!
423	!-- Allocate skin and soil temperature / humidity
424	#if defined( __nopointer )
425	ALLOCATE ( T_0(nysg:nyng,nxlg:nxrg) )
426	ALLOCATE ( T_0_p(nysg:nyng,nxlg:nxrg) )
427	#else
428	ALLOCATE ( T_0_1(nysg:nyng,nxlg:nxrg) )
429	ALLOCATE ( T_0_2(nysg:nyng,nxlg:nxrg) )
430	#endif
431
432	ALLOCATE ( tT_0_m(nysg:nyng,nxlg:nxrg) )
433
434	#if defined( __nopointer )
435	ALLOCATE ( T_soil(0:soil_layers,nysg:nyng,nxlg:nxrg) )
436	ALLOCATE ( T_soil_p(0:soil_layers,nysg:nyng,nxlg:nxrg) )
437	#else
438	ALLOCATE ( T_soil_1(0:soil_layers,nysg:nyng,nxlg:nxrg) )
439	ALLOCATE ( T_soil_2(0:soil_layers,nysg:nyng,nxlg:nxrg) )
440	#endif
441
442	ALLOCATE ( tT_soil_m(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
443
444	#if defined( __nopointer )
445	ALLOCATE ( m_liq(nysg:nyng,nxlg:nxrg) )
446	ALLOCATE ( m_liq_p(nysg:nyng,nxlg:nxrg) )
447	#else
448	ALLOCATE ( m_liq_1(nysg:nyng,nxlg:nxrg) )
449	ALLOCATE ( m_liq_2(nysg:nyng,nxlg:nxrg) )
450	#endif
451
452	ALLOCATE ( tm_liq_m(nysg:nyng,nxlg:nxrg) )
453
454	#if defined( __nopointer )
455	ALLOCATE ( m_soil(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
456	ALLOCATE ( m_soil_p(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
457	#else
458	ALLOCATE ( m_soil_1(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
459	ALLOCATE ( m_soil_2(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
460	#endif
461
462	ALLOCATE ( tm_soil_m(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
463
464
465	#if ! defined( __nopointer )
466	!
467	!-- Initial assignment of the pointers
468	T_soil => T_soil_1; T_soil_p => T_soil_2
469	T_0 => T_0_1; T_0_p => T_0_2
470	m_soil => m_soil_1; m_soil_p => m_soil_2
471	m_liq => m_liq_1; m_liq_p => m_liq_2
472	#endif
473
474	T_0 = 0.0_wp
475	T_0_p = 0.0_wp
476	tT_0_m = 0.0_wp
477
478	T_soil = 0.0_wp
479	T_soil_p = 0.0_wp
480	tT_soil_m = 0.0_wp
481
482	m_liq = 0.0_wp
483	m_liq_p = 0.0_wp
484	tm_liq_m = 0.0_wp
485
486	m_soil = 0.0_wp
487	m_soil_p = 0.0_wp
488	tm_soil_m = 0.0_wp
489
490	!
491	!-- Allocate 2D vegetation model arrays
492	ALLOCATE ( alpha_VG(nysg:nyng,nxlg:nxrg) )
493	ALLOCATE ( c_liq(nysg:nyng,nxlg:nxrg) )
494	ALLOCATE ( c_veg(nysg:nyng,nxlg:nxrg) )
495	ALLOCATE ( f_SW_in(nysg:nyng,nxlg:nxrg) )
496	ALLOCATE ( G(nysg:nyng,nxlg:nxrg) )
497	ALLOCATE ( H(nysg:nyng,nxlg:nxrg) )
498	ALLOCATE ( gamma_w_sat(nysg:nyng,nxlg:nxrg) )
499	ALLOCATE ( gD(nysg:nyng,nxlg:nxrg) )
500	ALLOCATE ( LAI(nysg:nyng,nxlg:nxrg) )
501	ALLOCATE ( LE(nysg:nyng,nxlg:nxrg) )
502	ALLOCATE ( LE_veg(nysg:nyng,nxlg:nxrg) )
503	ALLOCATE ( LE_soil(nysg:nyng,nxlg:nxrg) )
504	ALLOCATE ( LE_liq(nysg:nyng,nxlg:nxrg) )
505	ALLOCATE ( l_VG(nysg:nyng,nxlg:nxrg) )
506	ALLOCATE ( lambda_h_sat(nysg:nyng,nxlg:nxrg) )
507	ALLOCATE ( lambda_skin_u(nysg:nyng,nxlg:nxrg) )
508	ALLOCATE ( lambda_skin_s(nysg:nyng,nxlg:nxrg) )
509	ALLOCATE ( m_fc(nysg:nyng,nxlg:nxrg) )
510	ALLOCATE ( m_res(nysg:nyng,nxlg:nxrg) )
511	ALLOCATE ( m_sat(nysg:nyng,nxlg:nxrg) )
512	ALLOCATE ( m_wilt(nysg:nyng,nxlg:nxrg) )
513	ALLOCATE ( n_VG(nysg:nyng,nxlg:nxrg) )
514	ALLOCATE ( r_a(nysg:nyng,nxlg:nxrg) )
515	ALLOCATE ( r_canopy(nysg:nyng,nxlg:nxrg) )
516	ALLOCATE ( r_soil(nysg:nyng,nxlg:nxrg) )
517	ALLOCATE ( r_soil_min(nysg:nyng,nxlg:nxrg) )
518	ALLOCATE ( r_s(nysg:nyng,nxlg:nxrg) )
519	ALLOCATE ( r_s_min(nysg:nyng,nxlg:nxrg) )
520
521	!
522	!-- Set initial and default values
523	c_liq = 0.0_wp
524	c_veg = 0.0_wp
525	f_SW_in = 0.05_wp
526	gD = 0.0_wp
527	LAI = 0.0_wp
528	lambda_skin_u = 10.0_wp
529	lambda_skin_s = 10.0_wp
530
531
532	G = 0.0_wp
533	H = rho_cp * shf
534	LE = rho_l * l_v * qsws
535	LE_veg = 0.0_wp
536	LE_soil = LE
537	LE_liq = 0.0_wp
538
539	r_a = 50.0_wp
540	r_canopy = 0.0_wp
541	r_soil = 0.0_wp
542	r_soil_min = 50.0_wp
543	r_s = 110.0_wp
544	r_s_min = min_canopy_resistance
545
546	!
547	!-- Allocate 3D soil model arrays
548	ALLOCATE ( root_fr(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
549	ALLOCATE ( lambda_h(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
550	ALLOCATE ( rhoC_total(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
551
552	lambda_h = 0.0_wp
553	!
554	!-- If required, allocate humidity-related variables for the soil model
555	IF ( humidity ) THEN
556	ALLOCATE ( lambda_w(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
557	ALLOCATE ( gamma_w(0:soil_layers-1,nysg:nyng,nxlg:nxrg) )
558
559	lambda_w = 0.0_wp
560	ENDIF
561
562	!
563	!-- Calculate grid spacings. Temperature and moisture are defined at
564	!-- the center of the soil layers, whereas gradients/fluxes are defined
565	!-- at the edges (_stag)
566	dz_soil_stag(0) = soil_level(0)
567
568	DO k = 1, soil_layers-1
569	dz_soil_stag(k) = soil_level(k) - soil_level(k-1)
570	ENDDO
571
572	DO k = 0, soil_layers-2
573	dz_soil(k) = 0.5 * (dz_soil_stag(k+1) + dz_soil_stag(k))
574	ENDDO
575	dz_soil(soil_layers-1) = dz_soil_stag(soil_layers-1)
576
577	ddz_soil = 1.0 / dz_soil
578	ddz_soil_stag = 1.0 / dz_soil_stag
579	!
580	!-- Initialize soil
581	IF ( soil_type .NE. 0 ) THEN
582	alpha_VG = soil_pars(0,soil_type)
583	l_VG = soil_pars(1,soil_type)
584	n_VG = soil_pars(2,soil_type)
585	gamma_w_sat = soil_pars(3,soil_type)
586	m_sat = m_soil_pars(0,soil_type)
587	m_fc = m_soil_pars(1,soil_type)
588	m_wilt = m_soil_pars(2,soil_type)
589	m_res = m_soil_pars(3,soil_type)
590	ELSE
591	alpha_VG = alpha_VanGenuchten
592	l_VG = l_VanGenuchten
593	n_VG = n_VanGenuchten
594	gamma_w_sat = hydraulic_conductivity
595	m_sat = saturation_moisture
596	m_fc = field_capacity
597	m_wilt = wilting_point
598	m_res = residual_moisture
599	ENDIF
600
601	!
602	!-- Map user settings of T and q for each soil layer
603	!-- (make sure that the soil moisture does not drop below the permanent
604	!-- wilting point) -> problems with devision by zero)
605	DO k = 0, soil_layers-1
606	T_soil(k,:,:) = soil_temperature(k)
607	m_soil(k,:,:) = MAX(soil_moisture(k),m_wilt(:,:))
608	ENDDO
609	T_soil(soil_layers,:,:) = soil_temperature(soil_layers)
610
611
612	exn = ( surface_pressure / 1000.0_wp )**0.286_wp
613	T_0 = pt_surface * exn
614
615	T_soil_p = T_soil
616	m_soil_p = m_soil
617
618	!
619	!-- Calculate saturation soil heat conductivity
620	lambda_h_sat(:,:) = lambda_h_sm ** (1.0_wp - m_sat(:,:)) * &
621	lambda_h_water ** m_sat(:,:)
622
623	!
624	!-- Initialize vegetation
625	IF ( veg_type .NE. 0 ) THEN
626
627	r_s_min = veg_pars(0,veg_type)
628	LAI = veg_pars(1,veg_type)
629	c_veg = veg_pars(2,veg_type)
630	gD = veg_pars(3,veg_type)
631	lambda_skin_s = skin_pars(0,veg_type)
632	lambda_skin_u = skin_pars(1,veg_type)
633	f_SW_in = skin_pars(2,veg_type)
634	z0 = roughness_par(0,veg_type)
635	z0h = roughness_par(1,veg_type)
636
637
638	DO k = 0, soil_layers-1
639	root_fr(k,:,:) = root_distribution(k,veg_type)
640	ENDDO
641
642	ELSE
643
644	DO k = 0, soil_layers-1
645	root_fr(k,:,:) = root_fraction(k)
646	ENDDO
647
648	ENDIF
649
650	!
651	!-- Possibly do user-defined actions (e.g. define heterogeneous land surface)
652	CALL user_init_land_surface
653
654	!
655	!-- Set artifical values for ts and us so that r_a has its initial value for
656	!-- the first time step
657	DO i = nxlg, nxrg
658	DO j = nysg, nyng
659	k = nzb_s_inner(j,i)
660	us(j,i) = 0.1_wp
661	ts(j,i) = (pt(k+1,j,i) - pt(k,j,i)) / r_a(j,i)
662	shf(j,i) = - us(j,i) * ts(j,i)
663	ENDDO
664	ENDDO
665
666	!
667	!-- Calculate humidity at the surface
668	IF ( humidity ) THEN
669	CALL calc_q0
670	ENDIF
671
672	RETURN
673
674	END SUBROUTINE init_lsm
675
676
677
678	!------------------------------------------------------------------------------!
679	! Description:
680	! ------------
681	!
682	!------------------------------------------------------------------------------!
683	SUBROUTINE lsm_energy_balance
684
685
686	IMPLICIT NONE
687
688	INTEGER(iwp) :: i !: running index
689	INTEGER(iwp) :: j !: running index
690	INTEGER(iwp) :: k, ks !: running index
691
692	REAL(wp) :: f1, & !: resistance correction term 1
693	f2, & !: resistance correction term 2
694	f3, & !: resistance correction term 3
695	m_min, & !: minimum soil moisture
696	T_1, & !: actual temperature at first grid point
697	e, & !: water vapour pressure
698	e_s, & !: water vapour saturation pressure
699	e_s_dT, & !: derivate of e_s with respect to T
700	tend, & !: tendency
701	dq_s_dT, & !: derivate of q_s with respect to T
702	coef_1, & !: coef. for prognostic equation
703	coef_2, & !: coef. for prognostic equation
704	f_LE, & !: factor for LE
705	f_LE_veg, & !: factor for LE_veg
706	f_LE_soil, & !: factor for LE_soil
707	f_LE_liq, & !: factor for LE_liq
708	f_H, & !: factor for H
709	lambda_skin, & !: Current value of lambda_skin
710	m_liq_max !: maxmimum value of the liquid water reservoir
711
712	!
713	!-- Calculate the exner function for the current time step
714	exn = ( surface_pressure / 1000.0_wp )**0.286_wp
715
716
717	DO i = nxlg, nxrg
718	DO j = nysg, nyng
719
720
721	!
722	!-- Set lambda_skin according to stratification
723	IF ( rif(j,i) >= 0.0_wp ) THEN
724	lambda_skin = lambda_skin_s(j,i)
725	ELSE
726	lambda_skin = lambda_skin_u(j,i)
727	ENDIF
728	!
729	!-- First step: calculate aerodyamic resistance. As pt(0), us, ts
730	!-- are not available for the current time step, data from the last
731	!-- time step is used here.
732	k = nzb_s_inner(j,i)
733
734	! r_a(j,i) = (pt(k+1,j,i) - pt(k,j,i)) / (ts(j,i) * us(j,i) + 1.0E-20)
735	r_a(j,i) = (pt(k+1,j,i) - pt(k,j,i)) / - (shf(j,i) + 1.0E-20)
736
737	!
738	!-- Second step: calculate canopy resistance r_canopy
739	!-- f1-f3 here are defined as 1/f1-f3 as in ECMWF documentation
740
741	!-- f1: correction for incoming shortwave radiation
742	f1 = MIN(1.0_wp, ( 0.004_wp * SW_in(j,i) + 0.05_wp ) / &
743	(0.81_wp * (0.004_wp * SW_in(j,i) + 1.0_wp) ) )
744
745	!
746	!-- f2: correction for soil moisture f2=0 for very dry soil
747	m_total = 0.0_wp
748	DO ks = 0, soil_layers-1
749	m_total = m_total + root_fr(ks,j,i) * m_soil(ks,j,i)
750	ENDDO
751
752	IF ( m_total .GT. m_wilt(j,i) .AND. m_total .LE. m_fc(j,i) ) THEN
753	f2 = ( m_total - m_wilt(j,i) ) / (m_fc(j,i) - m_wilt(j,i) )
754	ELSE
755	f2 = 1.0E-20_wp
756	ENDIF
757
758	!
759	!-- Calculate water vapour pressure at saturation
760	!-- (T_0 should be replaced by liquid water temp?!)
761	e_s = 0.01 * 610.78_wp * EXP( 17.269_wp * ( T_0(j,i) - 273.16_wp )&
762	/ ( T_0(j,i) - 35.86_wp ) )
763
764	!
765	!-- f3: correction for vapour pressure deficit
766	IF ( gD(j,i) .NE. 0.0_wp ) THEN
767	!
768	!-- Calculate vapour pressure
769	e = q_p(k+1,j,i) * surface_pressure / 0.622
770	f3 = EXP ( -gD(j,i) * (e_s - e) )
771	ELSE
772	f3 = 1.0_wp
773	ENDIF
774
775	!
776	!-- To do: check for very dry soil -> r_canopy goes to infinity
777	r_canopy(j,i) = r_s_min(j,i) / (LAI(j,i) * f1 * f2 * f3 + 1.0E-20)
778
779	!
780	!-- Third step: calculate bare soil resistance r_soil
781	m_min = c_veg(j,i) * m_wilt(j,i) + (1.0_wp - c_veg(j,i)) * &
782	m_res(j,i)
783
784	f2 = ( m_soil(0,j,i) - m_min ) / ( m_fc(j,i) - m_min )
785	f2 = MAX(f2,1.0E-20)
786
787	r_soil(j,i) = r_soil_min(j,i) / f2
788
789	!
790	!-- Calculate fraction of liquid water reservoir
791	m_liq_max = m_max_depth * LAI(j,i)
792	c_liq(j,i) = MIN(1.0, m_liq(j,i)/m_liq_max)
793
794	q_s = 0.622_wp * e_s / surface_pressure
795	IF ( q_s .LE. q_p(k+1,j,i)) THEN
796	! PRINT*, "dew fall at (before)", time_since_reference_point
797	r_canopy(j,i) = 0.0_wp
798	r_soil(j,i) = 0.0_wp
799	ENDIF
800
801
802	!
803	!-- Calculate coefficients for the total evapotranspiration
804	f_LE_veg = rho_lv * c_veg(j,i) * (1.0 - c_liq(j,i)) / (r_a(j,i) &
805	+ r_canopy(j,i))
806	f_LE_soil = rho_lv * (1.0 - c_veg(j,i)) / (r_a(j,i) + r_soil(j,i))
807	f_LE_liq = rho_lv * c_veg(j,i) * c_liq(j,i) / r_a(j,i)
808
809
810	! Plant cannot transpirate below wilting point. here, r_canopy
811	! should go to infinity
812	! IF ( m_soil(k,j,i) .LT. m_wilt(j,i) ) THEN
813	! f_LE_veg(j,i) = 0.0
814	! ENDIF
815
816	f_H = rho_cp / r_a(j,i)
817	f_LE = f_LE_veg + f_LE_soil + f_LE_liq
818
819	!
820	!-- Calculate derivative of q_s for Taylor series expansion
821	e_s_dT = e_s * ( 17.269_wp / (T_0(j,i) - 35.86_wp) - &
822	17.269_wp*(T_0(j,i) - 273.16_wp) / (T_0(j,i) &
823	- 35.86_wp)**2 )
824
825	dq_s_dT = 0.622_wp * e_s_dT / surface_pressure
826
827	T_1 = pt_p(k+1,j,i) * exn
828
829	!
830	!-- Add LW up so that it can be removed in prognostic equation
831	Rn(j,i) = Rn(j,i) + sigma_SB * T_0(j,i) ** 4
832
833	!
834	!-- Numerator of the prognostic equation
835	coef_1 = Rn(j,i) + 3.0_wp * sigma_SB * T_0(j,i) ** 4 + f_H / exn &
836	* T_1 + f_LE * ( q_p(k+1,j,i) - q_s + dq_s_dT * T_0(j,i) &
837	) + lambda_skin * T_soil(0,j,i)
838
839	!
840	!-- Denominator of the prognostic equation
841	coef_2 = 4.0_wp * sigma_SB * T_0(j,i) ** 3 + f_LE * dq_s_dT + &
842	lambda_skin + f_H / exn
843
844	tend = 0.0_wp
845
846	!
847	!-- Implicit solution when the skin layer has no heat capacity,
848	!-- otherwise use RK3 scheme.
849	T_0_p(j,i) = ( coef_1 * dt_3d * tsc(2) + C_skin * T_0(j,i) ) / &
850	( C_skin + coef_2 * dt_3d * tsc(2) )
851
852	!
853	!-- Add RK3 term
854	T_0_p(j,i) = T_0_p(j,i) + dt_3d * tsc(3) * tT_soil_m(0,j,i)
855
856	!
857	!-- Calculate true tendency
858	tend = (T_0_p(j,i) - T_0(j,i) - tsc(3) * tT_0_m(j,i)) / (dt_3d &
859	* tsc(2))
860
861	!
862	!-- Calculate T_0 tendencies for the next Runge-Kutta step
863	IF ( timestep_scheme(1:5) == 'runge' ) THEN
864	IF ( intermediate_timestep_count == 1 ) THEN
865	tT_0_m(j,i) = tend
866	ELSEIF ( intermediate_timestep_count < &
867	intermediate_timestep_count_max ) THEN
868	tT_0_m(j,i) = -9.5625_wp * tend + 5.3125_wp * tT_0_m(j,i)
869	ENDIF
870	ENDIF
871
872	pt_p(k,j,i) = T_0_p(j,i) / exn
873	!
874	!-- Calculate fluxes
875	Rn(j,i) = Rn(j,i) + 3.0_wp * sigma_SB * T_0(j,i)**4 &
876	- 4.0_wp * sigma_SB * T_0(j,i)*3 T_0_p(j,i)
877	G(j,i) = lambda_skin * (T_0_p(j,i) - T_soil(0,j,i))
878	H(j,i) = - f_H * ( pt_p(k+1,j,i) - pt_p(k,j,i) )
879	LE(j,i) = - f_LE * ( q_p(k+1,j,i) - q_s + dq_s_dT * &
880	T_0(j,i) - dq_s_dT * T_0_p(j,i) )
881
882	LE_veg(j,i) = - f_LE_veg * ( q_p(k+1,j,i) - q_s + dq_s_dT * &
883	T_0(j,i) - dq_s_dT * T_0_p(j,i) )
884	LE_soil(j,i) = - f_LE_soil * ( q_p(k+1,j,i) - q_s + dq_s_dT * &
885	T_0(j,i) - dq_s_dT * T_0_p(j,i) )
886	LE_liq(j,i) = - f_LE_liq * ( q_p(k+1,j,i) - q_s + dq_s_dT * &
887	T_0(j,i) - dq_s_dT * T_0_p(j,i) )
888
889
890	! IF ( i == 1 .AND. j == 1 ) THEN
891	! PRINT*, "Rn", Rn(j,i)
892	! PRINT*, "H", H(j,i)
893	! PRINT*, "LE", LE(j,i)
894	! PRINT*, "LE_liq", LE_liq(j,i)
895	! PRINT*, "LE_veg", LE_veg(j,i)
896	! PRINT*, "LE_soil", LE_soil(j,i)
897	! PRINT*, "G", G(j,i)
898	! ENDIF
899
900
901	IF ( LE(j,i) .EQ. 0.0 ) THEN
902	! PRINT*, "+++ Evapotranspiration -> 0"
903	r_s(j,i) = 1.0E10
904	ELSE
905	r_s(j,i) = - rho_lv * ( q_p(k+1,j,i) - q_s + dq_s_dT * T_0(j,i)&
906	- dq_s_dT * T_0_p(j,i) ) / LE(j,i) - r_a(j,i)
907	ENDIF
908
909	!
910	!-- Calculate change in liquid water reservoir due to dew fall or
911	!-- evaporation of liquid water (to do: add interception from rainfall)
912	IF ( q_s .LE. q_p(k+1,j,i)) THEN
913	!
914	!-- Check if reservoir is full (avoid values > m_liq_max)
915	!-- In that case, LE_liq goes to LE_soil. In this case
916	!-- LE_veg is zero anyway (because c_liq = 1), so that tend is
917	!-- zero and no further check is needed
918	IF ( m_liq(j,i) .EQ. m_liq_max ) THEN
919	LE_soil(j,i) = LE_soil(j,i) + LE_liq(j,i)
920	LE_liq(j,i) = 0.0_wp
921	ENDIF
922
923	!
924	!-- In case LE_veg becomes negative (unphysical behavior), let
925	!-- the water enter the liquid water reservoir as dew on the
926	!-- plant
927	IF ( LE_veg(j,i) .LT. 0.0_wp ) THEN
928	LE_liq(j,i) = LE_liq(j,i) + LE_veg(j,i)
929	LE_veg(j,i) = 0.0_wp
930	ENDIF
931	ENDIF
932
933	tend = - LE_liq(j,i) * drho_l_lv
934
935
936	m_liq_p(j,i) = m_liq(j,i) + dt_3d * ( tsc(2) * tend &
937	+ tsc(3) * tm_liq_m(j,i) )
938
939	!
940	!-- Check if reservoir is overfull -> reduce to maximum
941	!-- (conservation of water is violated here)
942	m_liq_p(j,i) = MIN(m_liq_p(j,i),m_liq_max)
943
944	!
945	!-- Check if reservoir is empty (avoid values < 0.0)
946	!-- (conservation of water is violated here)
947	m_liq_p(j,i) = MAX(m_liq_p(j,i),0.0_wp)
948
949
950	!
951	!-- Calculate m_liq tendencies for the next Runge-Kutta step
952	IF ( timestep_scheme(1:5) == 'runge' ) THEN
953	IF ( intermediate_timestep_count == 1 ) THEN
954	tm_liq_m(j,i) = tend
955	ELSEIF ( intermediate_timestep_count < &
956	intermediate_timestep_count_max ) THEN
957	tm_liq_m(j,i) = -9.5625_wp * tend + 5.3125_wp * tm_liq_m(j,i)
958	ENDIF
959	ENDIF
960
961	!
962	!-- Calculate fluxes in the atmosphere
963	shf(j,i) = H(j,i) / rho_cp
964	qsws(j,i) = LE(j,i) / rho_lv
965
966	ENDDO
967	ENDDO
968
969
970
971	END SUBROUTINE lsm_energy_balance
972
973
974	!------------------------------------------------------------------------------!
975	! Description:
976	! ------------
977	!
978	!------------------------------------------------------------------------------!
979	SUBROUTINE lsm_soil_model
980
981
982	IMPLICIT NONE
983
984	INTEGER(iwp) :: i !: running index
985	INTEGER(iwp) :: j !: running index
986	INTEGER(iwp) :: k !: running index
987
988	REAL(wp) :: h_VG !: Van Genuchten coef. h
989
990	REAL(wp), DIMENSION(0:soil_layers-1) :: gamma_temp, & !: temp. gamma
991	lambda_temp, & !: temp. lambda
992	tend !: tendency
993
994	DO i = nxlg, nxrg
995	DO j = nysg, nyng
996	DO k = 0, soil_layers-1
997	!
998	!-- Calculate volumetric heat capacity of the soil, taking into
999	!-- account water content
1000	rhoC_total(k,j,i) = (rhoC_soil * (1.0 - m_sat(j,i)) &
1001	+ rhoC_water * m_soil(k,j,i))
1002
1003	!
1004	!-- Calculate soil heat conductivity at the center of the soil
1005	!-- layers
1006	Ke = 1.0 + LOG10(MAX(0.1,m_soil(k,j,i) / m_sat(j,i)))
1007	lambda_temp(k) = Ke * (lambda_h_sat(j,i) + lambda_h_dry) + &
1008	lambda_h_dry
1009
1010	ENDDO
1011
1012	!
1013	!-- Calculate soil heat conductivity (lambda_h) at the _stag level
1014	!-- using linear interpolation
1015	DO k = 0, soil_layers-2
1016
1017	lambda_h(k,j,i) = lambda_temp(k) + &
1018	( lambda_temp(k+1) - lambda_temp(k) ) &
1019	* 0.5 * dz_soil_stag(k) * ddz_soil(k+1)
1020
1021	ENDDO
1022	lambda_h(soil_layers-1,j,i) = lambda_temp(soil_layers-1)
1023
1024	!
1025	!-- Prognostic equation for soil temperature T_soil
1026	tend(:) = 0.0_wp
1027	tend(0) = (1.0/rhoC_total(0,j,i)) * &
1028	( lambda_h(0,j,i) * ( T_soil(1,j,i) - T_soil(0,j,i) ) &
1029	* ddz_soil(0) + G(j,i) ) * ddz_soil_stag(0)
1030
1031	DO k = 1, soil_layers-1
1032	tend(k) = (1.0/rhoC_total(k,j,i)) &
1033	* ( lambda_h(k,j,i) &
1034	* ( T_soil(k+1,j,i) - T_soil(k,j,i) ) &
1035	* ddz_soil(k) &
1036	- lambda_h(k-1,j,i) &
1037	* ( T_soil(k,j,i) - T_soil(k-1,j,i) ) &
1038	* ddz_soil(k-1) &
1039	) * ddz_soil_stag(k)
1040	ENDDO
1041
1042	T_soil_p(0:soil_layers-1,j,i) = T_soil(0:soil_layers-1,j,i) &
1043	+ dt_3d * ( tsc(2) &
1044	* tend(:) + tsc(3) &
1045	* tT_soil_m(:,j,i) )
1046
1047	!
1048	!-- Calculate T_soil tendencies for the next Runge-Kutta step
1049	IF ( timestep_scheme(1:5) == 'runge' ) THEN
1050	IF ( intermediate_timestep_count == 1 ) THEN
1051	DO k = 0, soil_layers-1
1052	tT_soil_m(k,j,i) = tend(k)
1053	ENDDO
1054	ELSEIF ( intermediate_timestep_count < &
1055	intermediate_timestep_count_max ) THEN
1056	DO k = 0, soil_layers-1
1057	tT_soil_m(k,j,i) = -9.5625_wp * tend(k) + 5.3125_wp &
1058	* tT_soil_m(k,j,i)
1059	ENDDO
1060	ENDIF
1061	ENDIF
1062
1063
1064	DO k = 0, soil_layers-1
1065	!
1066	!-- Calculate soil diffusivity at the center of the soil layers
1067	lambda_temp(k) = (- b_CH * gamma_w_sat(j,i) * psi_sat &
1068	/ m_sat(j,i) ) * ( MAX(m_soil(k,j,i), &
1069	m_wilt(j,i)) / m_sat(j,i) )**(b_CH + 2.0_wp)
1070
1071	!
1072	!-- Calculate the hydraulic conductivity after Van Genuchten (1980)
1073	h_VG = ( ( (m_res(j,i) - m_sat(j,i)) / ( m_res(j,i) - &
1074	MAX(m_soil(k,j,i),m_wilt(j,i)) ) )**(n_VG(j,i) &
1075	/ (n_VG(j,i)-1.0_wp)) - 1.0_wp &
1076	)**(1.0_wp/n_VG(j,i)) / alpha_VG(j,i)
1077
1078	gamma_temp(k) = gamma_w_sat(j,i) * ( ( (1.0_wp + &
1079	(alpha_VG(j,i)h_VG)n_VG(j,i))*(1.0_wp &
1080	-1.0_wp/n_VG(j,i)) - (alpha_VG(j,i)*h_VG &
1081	)(n_VG(j,i)-1.0_wp))2 ) &
1082	/ ( (1.0_wp + (alpha_VG(j,i)h_VG)*n_VG(j,i) &
1083	)*((1.0_wp - 1.0_wp/n_VG(j,i))(l_VG(j,i) &
1084	+ 2.0)) )
1085
1086	ENDDO
1087
1088
1089	IF ( humidity ) THEN
1090	!
1091	!-- Calculate soil diffusivity (lambda_w) at the _stag level
1092	!-- using linear interpolation
1093	DO k = 0, soil_layers-2
1094
1095	lambda_w(k,j,i) = lambda_temp(k) + &
1096	( lambda_temp(k+1) - lambda_temp(k) ) &
1097	* 0.5 * dz_soil_stag(k) * ddz_soil(k+1)
1098	gamma_w(k,j,i) = gamma_temp(k) + &
1099	( gamma_temp(k+1) - gamma_temp(k) ) &
1100	* 0.5 * dz_soil_stag(k) * ddz_soil(k+1)
1101
1102	ENDDO
1103
1104	!
1105	!
1106	!-- In case of a closed bottom (= water content is conserved), set
1107	!-- hydraulic conductivity to zero to that no water will be lost
1108	!-- in the bottom layer.
1109	IF ( conserve_water_content ) THEN
1110	gamma_w(soil_layers-1,j,i) = 0.0_wp
1111	ELSE
1112	gamma_w(soil_layers-1,j,i) = lambda_temp(soil_layers-1)
1113	ENDIF
1114
1115	!-- The root extraction (= root_extr * LE_veg / (rho_l * l_v))
1116	!-- ensures the mass conservation for water. The transpiration of
1117	!-- plants equals the cumulative withdrawals by the roots in the
1118	!-- soil. The scheme takes into account the availability of water
1119	!-- in the soil layers as well as the root fraction in the
1120	!-- respective layer
1121
1122	!
1123	!-- Calculate the root extraction (ECMWF 7.69, with some
1124	!-- modifications)
1125	m_total = 0.0_wp
1126	DO k = 0, soil_layers-1
1127	m_total = m_total + root_fr(k,j,i) * m_soil(k,j,i) * &
1128	dz_soil_stag(k)
1129
1130	ENDDO
1131
1132	!
1133	!-- For conservation of mass, the sum of root_extr must be 1
1134	DO k = 0, soil_layers-1
1135	root_extr(k) = root_fr(k,j,i) * m_soil(k,j,i) &
1136	* dz_soil_stag(k) / m_total
1137	ENDDO
1138
1139
1140	!
1141	!-- Prognostic equation for soil water content m_soil
1142	tend(:) = 0.0_wp
1143	tend(0) = ( lambda_w(0,j,i) * ( m_soil(1,j,i) - m_soil(0,j,i) )&
1144	* ddz_soil(0) - gamma_w(0,j,i) - ( root_extr(0) &
1145	* LE_veg(j,i) + LE_soil(j,i) ) * drho_l_lv &
1146	) * ddz_soil_stag(0)
1147
1148	DO k = 1, soil_layers-2
1149	tend(k) = ( lambda_w(k,j,i) * ( m_soil(k+1,j,i) &
1150	- m_soil(k,j,i) ) * ddz_soil(k) - gamma_w(k,j,i)&
1151	- lambda_w(k-1,j,i) * (m_soil(k,j,i) - &
1152	m_soil(k-1,j,i)) * ddz_soil(k-1) &
1153	+ gamma_w(k-1,j,i) - (root_extr(k) * LE_veg(j,i)&
1154	* drho_l_lv) &
1155	) * ddz_soil_stag(k)
1156
1157	ENDDO
1158	tend(soil_layers-1) = ( - gamma_w(soil_layers-1,j,i) &
1159	- lambda_w(soil_layers-2,j,i) &
1160	* (m_soil(soil_layers-1,j,i) &
1161	- m_soil(soil_layers-2,j,i)) &
1162	* ddz_soil(soil_layers-2) &
1163	+ gamma_w(soil_layers-2,j,i) - ( &
1164	root_extr(soil_layers-1) &
1165	* LE_veg(j,i) * drho_l_lv ) &
1166	) * ddz_soil_stag(soil_layers-1)
1167
1168	m_soil_p(0:soil_layers-1,j,i) = m_soil(0:soil_layers-1,j,i) &
1169	+ dt_3d * ( tsc(2) * tend(:) &
1170	+ tsc(3) * tm_soil_m(:,j,i) )
1171
1172	!
1173	!-- Account for dry soils (find a better solution here!)
1174	m_soil_p(:,j,i) = MAX(m_soil_p(:,j,i),0.0_wp)
1175
1176	!
1177	!-- Calculate m_soil tendencies for the next Runge-Kutta step
1178	IF ( timestep_scheme(1:5) == 'runge' ) THEN
1179	IF ( intermediate_timestep_count == 1 ) THEN
1180	DO k = 0, soil_layers-1
1181	tm_soil_m(k,j,i) = tend(k)
1182	ENDDO
1183	ELSEIF ( intermediate_timestep_count < &
1184	intermediate_timestep_count_max ) THEN
1185	DO k = 0, soil_layers-1
1186	tm_soil_m(k,j,i) = -9.5625_wp * tend(k) + 5.3125_wp &
1187	* tm_soil_m(k,j,i)
1188	ENDDO
1189	ENDIF
1190	ENDIF
1191
1192	ENDIF
1193
1194	ENDDO
1195	ENDDO
1196
1197	!
1198	!-- Calculate surface specific humidity
1199	IF ( humidity ) THEN
1200	CALL calc_q0
1201	ENDIF
1202
1203
1204	END SUBROUTINE lsm_soil_model
1205
1206
1207	!------------------------------------------------------------------------------!
1208	! Description:
1209	! ------------
1210	!
1211	!------------------------------------------------------------------------------!
1212	SUBROUTINE calc_q0
1213
1214	IMPLICIT NONE
1215
1216	INTEGER :: i !: running index
1217	INTEGER :: j !: running index
1218	INTEGER :: k !: running index
1219	REAL(wp) :: resistance !: aerodynamic and soil resistance term
1220
1221	DO i = nxlg, nxrg
1222	DO j = nysg, nyng
1223
1224	k = nzb_s_inner(j,i)
1225	!
1226	!-- Temporary solution as long as T_0 is prescribed
1227
1228	pt_p(k,j,i) = T_0(j,i) / exn
1229	!
1230	!-- Calculate water vapour pressure at saturation
1231	e_s = 0.01_wp * 610.78_wp * EXP( 17.269_wp * ( T_0(j,i) - &
1232	273.16_wp ) / ( T_0(j,i) - &
1233	35.86_wp ) )
1234
1235	!
1236	!-- Calculate specific humidity at saturation
1237	q_s = 0.622_wp * e_s / surface_pressure
1238
1239
1240	resistance = r_a(j,i) / (r_a(j,i) + r_s(j,i))
1241
1242	!
1243	!-- Calculate specific humidity at surface
1244	q_p(k,j,i) = resistance * q_s + (1.0_wp - resistance) &
1245	* q_p(k+1,j,i)
1246
1247	ENDDO
1248	ENDDO
1249
1250	END SUBROUTINE calc_q0
1251
1252
1253	END MODULE land_surface_model_mod

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