Opened 10 years ago

Closed 10 years ago

#502 closed help (fixed)

Sea-ice ancillary qrice_pcmdi

Reported by: dstevens Owned by: jeff
Component: UM Model Keywords: Sea-ice ancillary qrice_pcmdi
Cc: iamack@… Platform:
UM Version: 4.5


I checked the sea-ice fractions in these (frequently used?) ancillary files, and found they often fall outside the expected 0-1 range. Is this well known/understood? They look a bit dodgy to me.

e.g. this file on Hector:


(compare with, which seems OK)

Change History (2)

comment:1 Changed 10 years ago by jeff

  • Owner changed from um_support to jeff
  • Status changed from new to accepted

Hi Dave

This is how the data was created by PCMDI, I'm sure there was a reason but it was so long ago I can't find out what it is. In the UM (RPANCA1A) there is this code to handle the data

             IF (LAMIPII) THEN                                             GRS2F404.159   
! linear uncontrolled time interpolation                                   GRS2F404.160   
              CALL T_INT (ICE_EXTENT,TIME1,ANCIL2,TIME2,ANCIL_DATA,        GRS2F404.161   
     &             TIME,P_FIELD)                                           GRS2F404.162   
! For AMIP II strictly ice concentrations should range between             GRS2F404.164   
! 0.0 and 1.0 but because of assumptions on T* made by the boundary        GRS2F404.165   
! layer and radiation schemes ice concentrations are restricted to         GRS2F404.166   
! 0.3 to 1.0. This will allow SSTs in areas of less than 30% ice to        GRS2F404.167   
! be used rather than TFS=-1.8C.                                           GRS2F404.168   
              DO I=1,P_FIELD                                               RPANCA1A.932   
                IF (ANCIL_DATA(I).lt.0.3) ANCIL_DATA(I)=0.0                GRS2F404.170   
                IF (ANCIL_DATA(I).gt.1.0) ANCIL_DATA(I)=1.0                GRS2F404.171   
              ENDDO                                                        GRS2F404.172   
             ELSE       ! non AMIPII option                                GRS2F404.174   


comment:2 Changed 10 years ago by jeff

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