[Ncep.list.emc.monsoondesk] Why Climatological Sea-Ice fraction send to GFS, but not the one computed by MOM-SIS

[Prajeesh A.G CAT]

In the subroutine flux_up_to_ atmos in flux_exchange.F90 of mom4, the following code sends the SST, fice _ atm (Sea-Ice fraction), hice _ atm (Sea-Ice depth) and hsno _ atm (snow depth) to coupler and which is then send to GFS as boundary conditions. 

!!--> cpl insertion 
Ice% fice = 1. 
Ice% fice (:,:,1)=0. 
Ice% hice _top(:,:,2:kice6)=Ice%h_ice(:,:,2:kice6) 
Ice% hsno _top(:,:,2:kice6)=Ice%h_snow(:,:,2:kice6) 
call put_to_ xgrid (Ice% fice , 'OCN' , ex_ fice , xmap _ sfc ) 
call put_to_ xgrid (Land% fice , 'LND' , ex_ fice , xmap _ sfc ) 
call put_to_ xgrid (Ice% hice _top, 'OCN' , ex_ hice , xmap _ sfc ) 
call put_to_ xgrid (Land% hice , 'LND' , ex_ hice , xmap _ sfc ) 
call put_to_ xgrid (Ice% hsno _top, 'OCN' , ex_ hsno , xmap _ sfc ) 
call put_to_ xgrid (Land% hsno , 'LND' , ex_ hsno , xmap _ sfc ) 
call put_to_ xgrid (Ice%t_surf, 'OCN' , ex_ tsurf , xmap _ sfc ) 
call put_to_ xgrid (Land%t_ sst , 'LND' , ex_ tsurf , xmap _ sfc ) 
! 
call get_from_ xgrid ( fice _ atm , 'ATM' , ex_ fice , xmap _ sfc ) 
call get_from_ xgrid ( hice _ atm , 'ATM' , ex_ hice , xmap _ sfc ) 
call get_from_ xgrid ( hsno _ atm , 'ATM' , ex_ hsno , xmap _ sfc ) 
call get_from_ xgrid ( tsurf _ atm , 'ATM' , ex_ tsurf , xmap _ sfc ) 
tsurf _ atm _ clim = Atmos %c_ sst 
! 
! mpi send 
call mpp _set_current_ pelist ( pesetnum = worldpeset , no_sync=no_sync) 
call mpp _send( tsurf _ atm ,size( tsurf _ atm ,1)*size( tsurf _ atm ,2), Atmos %coupler_rank) 
call mpp _send( tsurf _ atm _ clim ,size( tsurf _ atm _ clim ,1)*size( tsurf _ atm _ clim ,2), Atmos %coupler_rank) 
! call mpp _send( fice _ atm ,size( fice _ atm ,1)*size( fice _ atm ,2), Atmos %coupler_rank) 
call mpp _send( Atmos % fice ,size( fice _ atm ,1)*size( fice _ atm ,2), Atmos %coupler_rank) 
call mpp _send( hice _ atm ,size( hice _ atm ,1)*size( hice _ atm ,2), Atmos %coupler_rank) 
call mpp _send( hsno _ atm ,size( hsno _ atm ,1)*size( hsno _ atm ,2), Atmos %coupler_rank) 
if ( cice ) call mpp _send( Atmos % cice ,size( Atmos % cice ,1)*size( Atmos % cice ,2), Atmos %coupler_rank) 

call mpp _set_current_ pelist ( Atmos % pelist ) 
! 
!!<-- cpl insertion 


Here, fice _ atm is mapped from the exchange grid variable ex_ fice . ex_ fice gets data from Ice% fice and Land% fice . But we can see that Ice% fice is initialized to 0 and 1 every time. 

Now, Land% fice gets updated in the previous subroutine sfc _boundary_layer by these set of codes 

call data_override ( 'ATM' , 'fice' , Atm % fice , Time) ! line no: 953 of flux_exchange.F90 
call put_to_ xgrid ( Atm % fice , 'ATM' , ex_ fice , xmap _ sfc ) ! line no: 993 
call get_from_ xgrid (Land% fice , 'LND' , ex_ fice , xmap _ sfc ) !line no: 1000 

The data_override call is for overriding the data with specified values (Read from file or a constant, check data_table file of mom4). 

That means the Sea-Ice fraction which is being send to GFS is actually the climatological values not the computed Sea-Ice fraction. 

Can someone please clarify why climatological Sea-Ice fraction is send to the atmospheric model in place of the computed ones?? 

Thanks... 

Prajeesh A G 
Scientist 'B' 
CCCR, IITM 
Pune , India 


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