Changeset 10196 for branches/NERC/dev_r5518_GO6_under_ice_relax/NEMOGCM/NEMO/TOP_SRC/MEDUSA/detritus_fast_sink.F90

Timestamp:

2018-10-16T12:15:14+02:00 (6 years ago)

Author:

jpalmier

Message:

add DMS flux --

File:

• branches/NERC/dev_r5518_GO6_under_ice_relax/NEMOGCM/NEMO/TOP_SRC/MEDUSA/detritus_fast_sink.F90 (modified) (3 diffs)

branches/NERC/dev_r5518_GO6_under_ice_relax/NEMOGCM/NEMO/TOP_SRC/MEDUSA/detritus_fast_sink.F90

@@ -6 +6 @@
    !! History :
    !!   -   ! 2017-04 (M. Stringer)        Code taken from trcbio_medusa.F90
+   !!   -   ! 2018-19 (A. Yool)            Bugfix for excessive CaCO3 production
    !!----------------------------------------------------------------------
 #if defined key_medusa
@@ -63 +64 @@
 # if defined key_roam
                                    fifd_c, fofd_c, fregenfastc,            &
+               zdic, zalk,                             & 
 # endif
                                    idf, idfval,                            &
@@ -277 +279 @@
                !! factors to estimate the various elemental fractions (Si, Ca)
                ftempca(ji,jj) = ftempc(ji,jj) * fcaco3
+
+# if defined key_roam
+               !! AXY (12/10/18): while DIC and alkalinity typically occur at
+               !! high concentrations in the ocean relative to the fluxes that
+               !! affect them, there are occasions when fluxes are comparable
+               !! to local concentrations; for example, the "microboils" found
+               !! in UKESM1 produce very temporary (<< 1 day) T & S excursions
+               !! that also affect BGC tracers, moving them towards near-zero
+               !! concentrations; this causes carbonate chemistry deviations 
+               !! that, in turn, potentially support CaCO3 production that is
+               !! in excess of local availability of DIC and alkalinity; the
+               !! following code ensures that ftempca does not exceed the local
+               !! capacities of both tracers
+               fq0 = 0.1  ! threshold change limiter
+               fq1 = min(ftempca(ji,jj), (zdic(ji,jj) * fq0))        ! DIC
+               fq2 = min(ftempca(ji,jj) * 2.0, (zalk(ji,jj) * fq0))  ! ALK
+               fq3 = min(fq1, (fq2 / 2.0))  ! select smallest flux
+               ftempca(ji,jj) = fq3  ! reset CaCO3 production
+# endif               
 
 # if defined key_debug_medusa