Program INTERPF is the fourth program in the suite of MM5 system programs. This program takes pressure-level meteorological fields produced either by REGRID or RAWINS/LITTLE_R, and the user's definition of model sigma levels, and interpolates pressure level data to sigma levels. You should not be here if you have not successfully run either the REGRID or RAWINS/LITTLE_R program.

To learn more about how the INTERPF program works, please read Chapter 7 of the Tutorial Notes.

Where to Start?

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

gunzip INTERPF.TAR.gz
tar -xvf INTERPF.TAR

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

cd INTERPF

and you should see the following files and subdirectories listed:

ls -l

-rwxr-xr-x   1 mesouser system      1452 Mar  8 10:35 CHANGES
drwxr-xr-x   2 mesouser system      8192 Mar  1 13:49 Diff
drwxr-xr-x   2 mesouser system      8192 Feb  8 10:01 Doc
-rwxr-xr-x   1 mesouser system      3786 Mar 12 17:32 Makefile
-rwxr-xr-x   1 mesouser system      3182 Sep 25  1999 README
-rw-r--r--   1 mesouser system       418 Jun  7 10:01 configure.rules
-rw-r--r--   1 mesouser system      7319 Feb  8 10:01 interpf.deck.cray
-rw-r--r--   1 mesouser system        90 Jun  7 10:01 macros_interpf
-rwxr-xr-x   1 mesouser system      2059 Feb  8 10:01 namelist.input
-rw-r--r--   1 mesouser system       760 Feb  8 10:01 namelist.input.SOC
drwxr-xr-x   2 mesouser system      8192 Feb  8 10:01 src

Read the README file in the directory.

Now you are ready to work with INTERPF.

How to Run INTERPF?

1. Compile INTERPF:

INTERPF 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 interpf in the directory:

./interpf -> src/interpf
 

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:

interpf >& log &

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

-rw-r--r--   1 mesouser system   1825164 Mar 23 19:16 BDYOUT_DOMAIN1
-rw-r--r--   1 mesouser system    129472 Mar 23 19:16 LOWBDY_DOMAIN1
-rw-r--r--   1 mesouser system   1041428 Mar 23 19:16 MMINPUT_DOMAIN1
-rw-r--r--   1 mesouser system      4915 Mar 23 19:16 log

where log is a log file of all print statements generated by INTERPF 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:

-------------------------------------------------
FINISHED INTERPF FOR DOMAIN ID #1
-------------------------------------------------
STOP 99999

MMINPUT_DOMAIN1 is the binary initial condition file for MM5, and it contains 3-D wind, temperature, mixing ratio, vertical motion and perturbation pressure fields on model sigma levels. BDYOUT_DOMAIN1 is the binary lateral boundary condition file that contains rows and columns of fields in the MMINPUT_DOMAIN1 file in the boundary zone. LOWBDY_DOMAIN1 is the lower boundary condition file that contains either daily means of, or time-varying, ground temperature and sea-surface temperature, and (optionally) sea-ice and snow cover fields.

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

If everything checks out ok, then your attempt to run INTERPF should be a successful one. You are now ready to run the MM5 model.
 

Miscellanies:

INTERPF only produces input files for MM5 on one domain, normally it is the coarse domain. Depending on the application, you may use program NESTDOWN to create nest input files for MM5, or use nest TERRAIN files in MM5 directly. At the present, we recommend the use of program NESTDOWN to create input files for nest domains only if you want to use the OSU land-surface model option in MM5.

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

Trouble Shooting:

1. On machines like Linux, it may not like reading a namelist with comments in it. In this case, edit the namelist.input file and remove all comments after '!'.

2. To generate a single boundary condition file, you must have at least two time periods, so that a lateral boundary tendency may be computed. Even if you are not going to run a long forecast, it is recommended that you provide a full day for the lower boundary condition file, as this file contains daily mean values.

3. When INTERPF runs into an interpolation error that it did not expect (i.e., forced to do an extrapolation when none should be required), INTERPF will stop and print out the offending (I,J,K) and pressure values. If this is not simply a fix by amending the provided sigma or pressure surfaces, it is usually a bit more tricky and implies that the analysis data is possibly in error.

If you have run INTERPF successfully, move to the next program: MM5.

If you have questions, ask mesouser.