From d5faef039451bb17c61a32fb8245e379ccbfc5f5 Mon Sep 17 00:00:00 2001
From: Clement Rousset <clement.rousset@locean.ipsl.fr>
Date: Wed, 5 Apr 2023 09:26:31 +0000
Subject: [PATCH] Resolve "SI3 problem with supercooling"
---
src/ICE/icesbc.F90 | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/src/ICE/icesbc.F90 b/src/ICE/icesbc.F90
index 81915405..404236de 100644
--- a/src/ICE/icesbc.F90
+++ b/src/ICE/icesbc.F90
@@ -322,23 +322,21 @@ CONTAINS
! qlead is the energy received from the atm. in the leads.
! If warming (zqld >= 0), then the energy in the leads is used to melt ice (bottom melting) => fhld (W/m2)
! If cooling (zqld < 0), then the energy in the leads is used to grow ice in open water => qlead (J.m-2)
- IF( zqld >= 0._wp .AND. at_i(ji,jj) > 0._wp ) THEN
- ! upper bound for fhld: fhld should be equal to zqld
- ! but we have to make sure that this heat will not make the sst drop below the freezing point
- ! so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr_pos
- ! The following formulation is ok for both normal conditions and supercooling
- fhld (ji,jj) = rswitch * MAX( 0._wp, ( zqld - zqfr_pos ) * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) & ! divided by at_i since this is (re)multiplied by a_i in icethd_dh.F90
- & - qsb_ice_bot(ji,jj) )
- qlead(ji,jj) = 0._wp
- ELSE
+ IF( ( zqld - zqfr ) < 0._wp .OR. at_i(ji,jj) < epsi10 ) THEN
fhld (ji,jj) = 0._wp
! upper bound for qlead: qlead should be equal to zqld
! but before using this heat for ice formation, we suppose that the ocean cools down till the freezing point.
- ! The energy for this cooling down is zqfr. Also some heat will be removed from the ocean from turbulent fluxes (qsb)
- ! and freezing point is reached if zqfr = zqld - qsb*a/dt
- ! so the max heat that can be pulled out of the ocean is zqld - qsb - zqfr
+ ! The energy for this cooling down is zqfr and freezing point is reached if zqfr = zqld
+ ! so the max heat that can be pulled out of the ocean is zqld - zqfr
+ ! The following formulation is ok for both normal conditions and supercooling
+ qlead(ji,jj) = MIN( 0._wp , zqld - zqfr )
+ ELSE
+ ! upper bound for fhld: fhld should be equal to zqld
+ ! but we have to make sure that this heat will not make the sst drop below the freezing point
+ ! so the max heat that can be pulled out of the ocean is zqld - zqfr_pos
! The following formulation is ok for both normal conditions and supercooling
- qlead(ji,jj) = MIN( 0._wp , zqld - ( qsb_ice_bot(ji,jj) * at_i(ji,jj) * rDt_ice ) - zqfr )
+ fhld (ji,jj) = rswitch * MAX( 0._wp, ( zqld - zqfr_pos ) * r1_Dt_ice / MAX( at_i(ji,jj), epsi10 ) ) ! divided by at_i since this is (re)multiplied by a_i in icethd_dh.F90
+ qlead(ji,jj) = 0._wp
ENDIF
!
! If ice is landfast and ice concentration reaches its max
--
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