Program INTERPB handles the data transformation required to go from sigma coordinates back to pressure levels. INTERPB can use input fields produced by MM5, NESTDOWN or INTERPF. This program handles only vertical interpolation and a few diagnostics. The output from this program is suitable for input to REGRIDDER, RAWINS/LITTLE_R, INTERPF or GRAPH.  You should not be here if you have not successfully run MM5, NESTDOWN or INTERPF.

To learn more about how the INTERPB program works, please read Chapter 11 of the Tutorial Notes.

Where to Start?

First, go back to MM5V3 directory, and download the INTERPB program tar file from NCAR's ftp site. Once you have it on your machine, type the following to unzip and untar it:

gunzip INTERPB.TAR.gz
tar -xvf INTERPB.TAR

After this, you should see a program directory INTERPB/ created in your working directory. cd to this directory:

cd INTERPB

and you should see the following files and subdirectories listed:

ls -l

-rw-r--r--   1 mesouser users        739 Jan 23 16:32 CHANGES
drwxr-xr-x   2 mesouser users       8192 Feb 19 13:21 Diff
-rwxr-xr-x   1 mesouser users       8025 Mar  9  2001 Makefile
-rwxr-xr-x   1 mesouser users       4074 Dec  4 16:03 README
-rw-r--r--   1 mesouser users        418 Mar  9  2001 configure.rules
-rw-r--r--   1 mesouser users        371 Feb 19 13:28 macros_interpb
-rwxr-xr-x   1 mesouser users        820 Feb 19 13:31 namelist.input
drwxr-xr-x   2 mesouser users       8192 Feb 19 13:21 src

Read the README file in the directory.

Now you are ready to work with INTERPB.

How to Run INTERPB?

1. Compile INTERPB:

INTERPB is Fortran 90 program. Its memory allocation is done at the run time stage. You only need to compile it once unless you modify the code. There is no parameter statements to specify here. To compile, type:

make >& make.out &

This compiles the code on your machine, and writes output from "make" to file make.out. If it is successful, you should have created the executable called interpb in the directory:

./interpb -> src/interpb
 

2. Edit namelist.input file. It is already set up to run the SOC case, except for the input file location. Other highlighted namelist variables are the typical ones you need to modify when you work on a different case. Once you've changed it, type the following to run:

interpb >& log &

If you are successful, you should find these additional files generated in the directory:

-rw-r--r--   1 mesouser users     1492164 Mar  4 10:57 FILE_MMOUTP:1993-03-13_00
-rw-r--r--   1 mesouser users     1492164 Mar  4 10:57 FILE_MMOUTP:1993-03-13_06
-rw-r--r--   1 mesouser users     1492164 Mar  4 10:57 FILE_MMOUTP:1993-03-13_12
-rw-r--r--   1 mesouser users    12281744 Mar  4 10:57 MMOUTP_DOMAIN1
-rw-r--r--   1 mesouser users     4682544 Mar  4 10:57 REGRID_DOMAIN1
-rw-r--r--   1 mesouser users        1694 Mar  4 10:54 log

where log is a log file of all print statements generated by INTERPB program, and again if anything goes wrong, this is the first place to look for clues. Near the end of the log file, you should see the following line if the job is finished correctly:

    Completed all requested dates.  Exiting program.
    Successful completion 99999
 

FILE_MMOUTP:date, are pressure level files in the intermediate file format and are suitable for input to regridder.
MMOUTP_DOMAIN1, pressure level file containing all the fields that is written out to MMOUT_DOMAIN1, and a few diagnostic fields (such as sea-level pressure, geopotential height, and relative humidity).  This file may be used as input to RAWINS/LITTLE_R, INTERPF or GRAPH.
REGRID_DOMAIN1, this file contains only the meteorological fields, winds, temperature, relative humidity and geopotential height, on the pressure levels you specified, and a few 2D fields needs as input to RAWINS/LITTLE_R or INTERPF.

There is no plot file generated from INTERPB. To check whether input files are OK, you can run program GRAPH if you have NCAR Graphics on your machine.

Miscellanies:

The entries in record4 of the namelist are optional. Default values for each variable has been established to remain internally consistent with other interpolation assumptions made through out the modeling system. This record is not available from the standard namelist.input file in the INTERPB directory, but is located in the ./INTERPB/.hidden/namelist.input file. This record is to allow the user access to differing methods for the vertical interpolation and the extrapolation which are performed above or below the model half sigma levels.

For a brief  introduction to the INTERPB program, you can also view the lecture slides from the bi-annual tutorial.

Trouble Shooting:

If you have questions, ask mesouser.