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source: branches/publications/ORCHIDEE_gmd-2018-261/src_stomate/lpj_gap.f90 @ 8692

Last change on this file since 8692 was 4333, checked in by josefine.ghattas, 8 years ago
Merge with trunk for revision r3623 - r3977 Some corrections for gfortran
Property svn:keywords set to `HeadURL Date Author Revision`
File size: 14.6 KB

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1	! =================================================================================================================================
2	! MODULE : lpj_gap
3	!
4	! CONTACT : orchidee-help _at_ ipsl.jussieu.fr
5	!
6	! LICENCE : IPSL (2006)
7	! This software is governed by the CeCILL licence see ORCHIDEE/ORCHIDEE_CeCILL.LIC
8	!
9	!>\BRIEF Simulate mortality of individuals and update biomass, litter and
10	!! stand density of the PFT
11	!!
12	!!\n DESCRIPTION : Simulate mortality of individuals and update biomass, litter and
13	!! stand density of the PFT. This module differs from lpj_kill.f90 in that this
14	!! module kills individuals within a PFT and lpj_kill.f90 removes a PFT from a
15	!! gridbox
16	!!
17	!! RECENT CHANGE(S): None
18	!!
19	!! REFERENCE(S) :
20	!! - Sitch, S., B. Smith, et al. (2003), Evaluation of ecosystem dynamics,
21	!! plant geography and terrestrial carbon cycling in the LPJ dynamic
22	!! global vegetation model, Global Change Biology, 9, 161-185.\n
23	!! - Waring, R. H. (1983). "Estimating forest growth and efficiency in relation
24	!! to canopy leaf area." Advances in Ecological Research 13: 327-354.\n
25	!!
26	!! SVN :
27	!! $HeadURL$
28	!! $Date$
29	!! $Revision$
30	!! \n
31	!_ ================================================================================================================================
32
33	MODULE lpj_gap
34
35	! modules used:
36	USE xios_orchidee
37	USE stomate_data
38	USE pft_parameters
39	USE ioipsl_para
40	USE constantes
41	USE function_library, ONLY: biomass_to_lai
42
43	IMPLICIT NONE
44
45	! private & public routines
46
47	PRIVATE
48	PUBLIC gap,gap_clear
49
50	! Variable declaration
51
52	LOGICAL, SAVE :: firstcall_gap = .TRUE. !! first call flag
53	!$OMP THREADPRIVATE(firstcall_gap)
54	REAL(r_std), PARAMETER :: frost_damage_limit = -3 + ZeroCelsius !! Spring frost-damage limitation (K)
55	REAL(r_std), PARAMETER :: coldness_mort = 0.04 !! Daily mortality induced by extreme coldness in winter
56	CONTAINS
57
58
59	!! ================================================================================================================================
60	!! SUBROUTINE : gap_clear
61	!!
62	!>\BRIEF Set the firstcall_gap flag back to .TRUE. to prepare for the next simulation.
63	!_ ================================================================================================================================
64
65	SUBROUTINE gap_clear
66	firstcall_gap = .TRUE.
67	END SUBROUTINE gap_clear
68
69
70	!! ================================================================================================================================
71	!! SUBROUTINE : gap
72	!!
73	!>\BRIEF Simulate tree and grass mortality, transfer dead biomass to litter and update stand density
74	!!
75	!! DESCRIPTION : Calculate mortality of trees and grasses, transfer the dead biomass to litter pool,
76	!! and update biomass pool and number of individuals. To get tree mortality, it's possible to choose either a
77	!! constant mortality rate; or to calculate the tree mortality rate based on it's growth efficiency, which is
78	!! defined as this year's net biomass increment per leaf area.\n
79	!!
80	!! When using growth efficiency mortality, first calculate the net biomass increment for the last year, then
81	!! calculate the growth efficiency and finally calculate the growth efficiency mortality.\n
82	!!
83	!! Eqation to calculate growth efficiency:
84	!! \latexonly
85	!! \input{gap1.tex}
86	!! \endlatexonly
87	!! Where $greff$ is growth efficiency, $\Delta$ is net biomass increment,
88	!! $C_{leaf} is last year's leaf biomass, and $SLA$ the specific leaf area.
89	!!
90	!!
91	!! Eqation to calculate growth efficiency mortality:
92	!! \latexonly
93	!! \input{gap2.tex}
94	!! \endlatexonly
95	!! Where $mort_{greff}$ is the growth efficiency mortality, $greff$ is growth
96	!! efficiency, $k_{mort1}$ is asymptotic maximum mortality rate.
97	!!
98	!! The name for variable ::availability is not well chosen. Actually the meaning of the variable is mortailty
99	!! rate derived from growth efficiency related mortality. ?? Suggestion: change the name "availability" to
100	!! "mortgref", which means "mortality caused by ".\n
101	!!
102	!! RECENT CHANGE(S): None
103	!!
104	!! MAIN OUTPUT VARIABLE(S): ::biomass; biomass, ::ind density of individuals, ::bm_to_litter biomass transfer
105	!! to litter and ::mortality mortality (fraction of trees that is dying per time step)
106	!!
107	!! REFERENCE(S) :
108	!! - Sitch, S., B. Smith, et al. (2003), Evaluation of ecosystem dynamics,
109	!! plant geography and terrestrial carbon cycling in the LPJ dynamic
110	!! global vegetation model, Global Change Biology, 9, 161-185.
111	!! - Waring, R. H. (1983). "Estimating forest growth and efficiency in relation
112	!! to canopy leaf area." Advances in Ecological Research 13: 327-354.
113	!!
114	!! FLOWCHART : None
115	!!\n
116	!_ ================================================================================================================================
117
118	SUBROUTINE gap (npts, dt, &
119	npp_longterm, turnover_longterm, lm_lastyearmax, &
120	PFTpresent, t2m_min_daily, Tmin_spring_time, &
121	biomass, ind, bm_to_litter, mortality )
122
123
124	!! 0. Variable and parameter declaration
125
126	!! 0.1 Input variables
127	INTEGER(i_std), INTENT(in) :: npts !! Domain size (-)
128	REAL(r_std), INTENT(in) :: dt !! Time step (days)
129	REAL(r_std), DIMENSION(npts,nvm), INTENT(in) :: npp_longterm !! "Long term" (default 3-year) net primary
130	!! productivity
131	!! @tex $(gC m^{-2} year^{-1})$ @endtex
132	REAL(r_std), DIMENSION(npts,nvm,nparts,nelements), INTENT(in) :: turnover_longterm !! "Long term" (default 3-year) turnover
133	!! rate @tex $(gC m^{-2} year^{-1})$ @endtex
134	REAL(r_std), DIMENSION(npts,nvm), INTENT(in) :: lm_lastyearmax !! Last year's maximum leaf mass, for each
135	!! PFT @tex $(gC m^{-2})$ @endtex
136	LOGICAL, DIMENSION(npts,nvm), INTENT(in) :: PFTpresent !! Is the pft present in the pixel
137	REAL(r_std), DIMENSION(npts), INTENT(in) :: t2m_min_daily !! Daily minimum 2 meter temperatures (K)
138	REAL(r_std), DIMENSION(npts,nvm), INTENT(in) :: Tmin_spring_time !! Number of days after begin_leaves (leaf onset)
139
140	!! 0.2 Output variables
141
142	REAL(r_std), DIMENSION(npts,nvm),INTENT(out) :: mortality !! Mortality (fraction of trees that is
143	!! dying per time step)
144
145	!! 0.3 Modified variables
146
147	REAL(r_std), DIMENSION(npts,nvm,nparts,nelements), INTENT(inout) :: biomass !! Biomass @tex $(gC m^{-2}) $@endtex
148	REAL(r_std), DIMENSION(npts,nvm), INTENT(inout) :: ind !! Number of individuals
149	!! @tex $(m^{-2})$ @endtex
150	REAL(r_std), DIMENSION(npts,nvm,nparts,nelements), INTENT(inout) :: bm_to_litter !! Biomass transfer to litter
151	!! @tex $(gC m^{-2})$ @endtex
152
153	!! 0.4 Local variables
154
155	REAL(r_std), DIMENSION(npts) :: delta_biomass !! Net biomass increase for the previous
156	!! year @tex $(gC m^{-2} year^{-1})$ @endtex
157	REAL(r_std), DIMENSION(npts) :: dmortality !! Dead biomass caused by mortality
158	!! @tex $(gC m^{-2}) $@endtex
159	REAL(r_std), DIMENSION(npts) :: vigour !! Growth efficiency, an indicator of tree
160	!! vitality, used to calculate mortality
161	REAL(r_std), DIMENSION(npts) :: availability !! Mortality rate derived by growth
162	!! efficiency @tex $(year^{-1})$ @endtex
163	INTEGER(i_std) :: i, j,k,m !! Indices
164
165	!_ ================================================================================================================================
166
167	IF ( firstcall_gap ) THEN
168
169	firstcall_gap = .FALSE.
170
171	ENDIF
172
173	IF (printlev>=3) WRITE(numout,*) 'Entering gap',lpj_gap_const_mort
174
175	mortality(:,:) = zero
176
177	! loop over #PFT
178	DO j = 2,nvm
179
180	!! 1. Tree mortality
181
182	IF ( is_tree(j) ) THEN
183
184	!! 1.1 Use growth efficiency or constant mortality?
185	IF ( .NOT. lpj_gap_const_mort ) THEN
186
187	!! 1.1.1 Estimate net biomass increment
188	! To calculate growth efficiency mortality, first estimate net biomass increment by
189	! subtracting turnover from last year's NPP.
190	WHERE ( PFTpresent(:,j) .AND. ( lm_lastyearmax(:,j) .GT. min_stomate ) )
191
192	!??! the following should be removed
193	! note that npp_longterm is now actually longterm growth efficiency (NPP/LAI)
194	! to be fair to deciduous trees
195	! calculate net biomass increment
196	delta_biomass(:) = MAX( npp_longterm(:,j) - ( turnover_longterm(:,j,ileaf,icarbon) + &
197	turnover_longterm(:,j,iroot,icarbon) + turnover_longterm(:,j,ifruit,icarbon) + &
198	turnover_longterm(:,j,isapabove,icarbon) + turnover_longterm(:,j,isapbelow,icarbon) ) ,zero)
199
200	!! 1.1.2 Calculate growth efficiency
201	! Calculate growth efficiency by dividing net biomass increment by last year's
202	! maximum LAI. (corresponding actually to the maximum LAI of the previous year)
203
204	vigour(:) = delta_biomass(:) / (biomass_to_lai(lm_lastyearmax(:,j),npts,j))
205
206	ELSEWHERE
207
208	vigour(:) = zero
209
210	ENDWHERE
211
212	!! 1.1.3 Calculate growth efficiency mortality rate
213	WHERE ( PFTpresent(:,j) )
214
215	availability(:) = availability_fact(j) / ( un + ref_greff * vigour(:) )
216	! Scale mortality by timesteps per year
217	mortality(:,j) = MAX(min_avail,availability(:)) * dt/one_year
218
219	ENDWHERE
220
221	ELSE ! .NOT. lpj_gap_const_mort
222
223	!! 1.2 Use constant mortality accounting for the residence time of each tree PFT
224	WHERE ( PFTpresent(:,j) )
225
226	mortality(:,j) = dt/(residence_time(j)*one_year)
227
228	ENDWHERE
229
230	ENDIF ! .NOT. lpj_gap_const_mort
231
232	!! 1.3 Mortality in DGVM
233	! If the long term NPP is zero, all trees are killed
234	!??! This is this only applied in the DGVM maybe in order to make the DGVM respond faster and thus make the vegetation dynamics more dynamic?
235	!??! the link here with lpj_kill.f90 is still not clear and so would leave to who especially working on this.
236	IF ( ok_dgvm ) THEN
237
238	WHERE ( PFTpresent(:,j) .AND. ( npp_longterm(:,j) .LE. min_stomate ) )
239
240	mortality(:,j) = un
241
242	ENDWHERE
243
244	ENDIF
245
246	IF ( ok_dgvm .AND. (tmin_crit(j) .NE. undef) ) THEN
247	! frost-sensitive PFTs
248	WHERE ( t2m_min_daily(:) .LT. tmin_crit(j) )
249	mortality(:,j) = MIN(un,(coldness_mort*(tmin_crit(j)-t2m_min_daily(:))+mortality(:,j) ) )
250	ENDWHERE
251	ENDIF
252
253	IF ( ok_dgvm .AND. leaf_tab(j)==1 .AND. pheno_type(j)==2) THEN
254	! Treat the spring frost for broadleaf and summergreen vegetations
255	! leaf_tab=broadleaf and pheno_typ=summergreen
256	DO i=1,npts
257	IF ( (Tmin_spring_time(i,j)>0) .AND. (Tmin_spring_time(i,j)<spring_days_max+1) ) THEN
258	IF ( t2m_min_daily(i) .LT. frost_damage_limit ) THEN
259	mortality(i,j) = MIN(un,(0.01(frost_damage_limit-t2m_min_daily(i)) &
260	Tmin_spring_time(i,j)/spring_days_max+mortality(i,j) ) )
261	END IF
262	END IF
263	END DO
264	END IF
265
266
267	!! 1.4 Update biomass and litter pools
268	! Update biomass and litter pool after dying and transfer recently died biomass to litter
269
270	DO m = 1,nelements
271	DO k = 1, nparts
272
273	WHERE ( PFTpresent(:,j) )
274
275	dmortality(:) = mortality(:,j) * biomass(:,j,k,m)
276	bm_to_litter(:,j,k,m) = bm_to_litter(:,j,k,m) + dmortality(:)
277	biomass(:,j,k,m) = biomass(:,j,k,m) - dmortality(:)
278
279	ENDWHERE
280
281	ENDDO
282	END DO
283
284	!! 1.5 In case of dynamic vegetation, update tree individual density
285	IF ( ok_dgvm ) THEN
286
287	WHERE ( PFTpresent(:,j) )
288
289	ind(:,j) = ind(:,j) * ( un - mortality(:,j) )
290
291	ENDWHERE
292
293	ENDIF
294	ELSE
295
296	!! 2. Grasses mortality
297
298	! For grasses, if last year's NPP is very small (less than 10 gCm^{-2}year{-1})
299	! the grasses completely die
300	IF ( .NOT.ok_dgvm .AND. .NOT.lpj_gap_const_mort) THEN
301
302	WHERE ( PFTpresent(:,j) .AND. ( npp_longterm(:,j) .LE. npp_longterm_init ) )
303
304	mortality(:,j) = un
305
306	ENDWHERE
307
308	! Update biomass and litter pools
309	DO m = 1,nelements
310	DO k = 1, nparts
311
312	WHERE ( PFTpresent(:,j) )
313
314	dmortality(:) = mortality(:,j) * biomass(:,j,k,m)
315
316	bm_to_litter(:,j,k,m) = bm_to_litter(:,j,k,m) + dmortality(:)
317
318	biomass(:,j,k,m) = biomass(:,j,k,m) - dmortality(:)
319
320	ENDWHERE
321
322	ENDDO
323	END DO
324
325	ENDIF
326
327	ENDIF !IF ( is_tree(j) )
328
329	ENDDO !loop over pfts
330
331	!! 3. Write to history files
332
333	! output in fraction of trees that dies/day.
334	mortality(:,:) = mortality(:,:) / dt
335
336	CALL xios_orchidee_send_field("mortality",mortality)
337
338	CALL histwrite_p (hist_id_stomate, 'MORTALITY', itime, &
339	mortality, npts*nvm, horipft_index)
340
341	IF (printlev>=4) WRITE(numout,*) 'Leaving gap'
342
343	END SUBROUTINE gap
344
345	END MODULE lpj_gap

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