View source for Creating Lateral Boundary Conditions

{{Pre UM10}}
{{Needs Update}}

'''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 <span style="font-family:monospace">Atmosphere->Control->Output Data Files}} panel in UMUI, selecting {{LBCs out}} and then pressing the {{NEXT</span> 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 [https://nf.nci.org.au/facilities/software/UM/7.8/umdoc_system/UM_docs/papers/html/F54/index.html | 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

<syntaxhighlight lang=fortran>
&DUMP2BOUND

! 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
NHOURS=1,
SUB_HR_INT=4,

! UM version to create the output for, multiplied by 100
UM_VERSN=706,

! Number of LAMs to create BCs for
NO_LAMS=1
/

</syntaxhighlight>

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

<syntaxhighlight lang=bash>
#!/bin/bash

export VN=7.6

# Directory for input files
DUMPS=$DATAOUTPUT/$USER/$JOBID

# Input filenames
F0=$DUMPS/dddnm.astart
F1=$DUMPS/dddnma_da001
F2=$DUMPS/dddnma_da002
F3=$DUMPS/dddnma_da003
F4=$DUMPS/dddnma_da004

# Namelist File
NAMELIST=$HOME/vn7.6/namel_0.25hr

# Output filename(s)
OUTPUT=$HOME/vn7.6/LBC_filename

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

[[Category:Unified Model]]