#725 closed task (fixed)

leaf_longevity vs leaf_age_crit

Reported by: luyssaert Owned by: luyssaert
Priority: blocker Milestone: ORCHIDEE 4.1
Component: Biogeochemical processes Version: trunc
Keywords: Cc:


Several issues related to leaf_age_crit and longevity_leaf were observed:

(1) The trunk has two parameters (leaf_age_crit and longevity_leaf) which basically describe the same.
(2) Observed leaf longevity differs a lot within the boreal zone. It is a fixed parameter in ORCHIDEE.
(3) The ORCHIDEE approach to calculate leaf turnover for evergreens seems in line with plant ecology/physiology but there is some confusion for deciduous species. The point of confusion is whether there is a real difference between leaf turnover (due to ageing) and senescence (now triggered by climate). If turnover starts too early in the season, unrealistic amounts of leaves will have to be replaced during the growing season.

(1) remove the duplication
(2) make leaf_age_crit a function of temperature as is the case for grasses
(3) study the impact of leaf turnover on the deciduous PFTs to confirm whether this is a real problem or not.

Change History (3)

comment:1 Changed 23 months ago by luyssaert

  • Owner changed from somebody to luyssaert
  • Status changed from new to assigned

comment:2 Changed 23 months ago by luyssaert

(1) remove the duplication
Done in r6886 for modeles/ORCHIDEE (code has been reviewed by Chao Yue)
Bug fix in r6901 (in stomate_vmax.f90 and stromate_lpj.f90)

(2) make leaf_age_crit of PFT7 a function of temperature
Done in r6887 for config/ORCHIDEE_OL

(3) study the impact of leaf turnover on the deciduous PFTs to confirm whether this is a real problem or not.

While testing It was noted that fruits accumulated in grasslands. This bug was fixed in r6908.

The impact of within-season leaf turnover (thus the turnover between plant_status = icanopy and isenescent) can be monitored by two variables: LEAF_TURN_AGEING_c and LEAF_M_MAX_c. When expressed as percentage the within season turnover (thus due to ageing) varies between 0 and 30% for trees and reaches 100-150% for grasses. This seems to be acceptable. See the documentation on the wiki for some additional background on this issue.

Last edited 22 months ago by luyssaert (previous) (diff)

comment:3 Changed 22 months ago by luyssaert

  • Resolution set to fixed
  • Status changed from assigned to closed
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