For water isotopes in version 1.0.0b

(should apply to 1.0 release and following in 1.0.x).

To have a pristine start for water isotopes: the "no restart option"

  • Set clio/sources/ parameter isoocn_restart = 0. The water isotopes in the ocean are initialized with a constant RSMOW value.
  • Set isoatm/sources/isoatm_mod.f90 parameter isoatm_restart = 0. The atmospheric isotopes are set to -12 per mil for d18O and no excess for deuterium and 17O.
  • Set isoatm/sources/isoatm_mod.f90 parameter isolbm_restart = 0. The land surface isotopic content are set to a fixed value (-30 per mil) for 18O and no excess for the other isotopes.

Obtaining the standard version for water isotopes

Water isotopes are very sensitive to the conditions for evaporation at the oceanic surface. In ECBilt -- CLIO, there is evaporation from the oceanic surface THROUGH the sea-ice. My guess is that it was implemented as a counteracting effect to the precipitation over-estimation in the Arctic, later compensated by a flux correction.
With regards to the water isotopes, this parameterization causes a strong increase of d18O at high latitude, found to be unrealistic. To obtain a better agreement with observed data, I therefore suggest to suppress the evaporation through sea-ice. The EVAPSI key switch in choixcomposantes.h is there for the purpose.
Action: set EVAPSI to 1 for standard version of water isotopes.

Combination of FLAGS

  • Combination that works
    • ISOATM == 2 / ISOOCN = 2 / ISOLBM = 1 (Full interactive, this is the default)
    • ISOATM == 2 / ISOOCN = 1 / ISOLBM = 1 (No land surface water interactive isotopic content, oceanic content calculated but not updated)
  • Combination that does not work
  • Untested
    • All the rest
Last modified 9 years ago Last modified on 02/12/13 15:02:18