Creating Lateral Boundary Conditions

Template:Pre UM10 This information is only for versions of the UM before 10.0
Template:Needs Update This page needs updating

This page is still under construction, some information may be incorrect or unsuitable for the NCI machines

You can output lateral boundary conditions (LBCs) for a limited area model (LAM) from a larger run by going to the Atmosphere->Control->Output Data Files}} panel in UMUI, selecting Template:LBCs out and then pressing the {{NEXT button to see the output details. You will have to specify the output times and the location of the LAM.

Lateral boundary conditions for limited area simulations can also be manually constructed from a larger simulation using the MakeBC program. See its | documentation for more details, below is a condensed version.

To use MakeBC you require a namelist file, which can be produced by the UMUI by setting up the simulation you wish to run and then processing the job. You then need to go to the file ~/umui_runs/$JOBID/CNTLATM and copy everything from '&INTFCNSTA' to the next line containing only '/' to a new file. Add a new namelist to the top of the file called DUMP2BOUND, this defines when the BCs are output and will look similar to


! Number of input dumps
N_DUMPS = 5,

! Time spacing of the outputs, if < 1 hour set NHOURS to 1
! and SUB_HR_INT to the number of outputs in a 1 hour period

! UM version to create the output for, multiplied by 100

! Number of LAMs to create BCs for

You'll also need to create a run script for MakeBC, which will be similar to


export VN=7.6

# Directory for input files

# Input filenames

# Namelist File

# Output filename(s)

# Call MakeBC
~access/umdir/vn7.6/normal/utils/makebc -n $NAMELIST -i $F0 $F1 $F2 $F3 $F4 -o $OUTPUT