VERSION 3 NESTDOWN PROGRAM (release 3-7)
(Updated December 23, 2004)

This is the main directory of the NESTDOWN program in the MM5 modeling 
system Version 3. Everything a user needs to run the NESTDOWN program 
is contained in this directory.

For questions, please send emails to mesouser@ucar.edu

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What is in V3 NESTDOWN?

V3 NESTDOWN replicates the one-way nest Interp backend job in Version 2.

In V.35 release, vertical nesting is permitted.

V3 NESTDOWN can be used to create nest input file with MMINPUT file as
   input. It was recommended to use NESTDOWN to create nest input file
   when using OSU LSM (ISOIL=2) in pre-release-3-4 MM5.

   Since release-3-4, MM5 model can handle nest initialization with LSM
   and IOVERW=2 option. So there is no need to run NESTDOWN to generate 
   MMINPUT files for the nests any more.

V3 NESTDOWN is written in Fortran 90.

V3 NESTDOWN program uses V3 data format, which is different from
that in V2. For details on V3 data format, please see

http://www2.mmm.ucar.edu/mm5/mm5v3.html

NESTDOWN is a Fortran 90 program, and requires Fortran 90 compiler.

NESTDOWN is supported for Cray, Alpha, HP, IBM, SGI, SUN, and Fujitsu with
their native compilers, and PC running Linux using Portland Group Fortran
90 compiler. If your machine isn't one of the ones supported or the
compiler isn't the native one from the vendor, you need to edit the Makefile.

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***************************************************************
Also see the online self-tutorial at
http://www2.mmm.ucar.edu/mm5/mm5v3/tutorial/teachyourself.html
***************************************************************

To compile NESTDOWN:

- Type 'make' in the NESTDOWN directory to compile;

- When make is successful, executable nestdown will appear in this
  directory.

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To run NESTDOWN:

Edit namelist.input, and type ./nestdown to execute the program.

Required input file for NESTDOWN are:

MMOUT_DOMAINx (coarse domain MM5 output file)
LOWBDY_DOMAINx (coarse domain lower boundary file, if exsits, from INTERPF)
TERRAIN_DOMAIN(x+1) (nest terrain output from TERRAIN)

The directory and name of the input file are set in namelist.input.

The output files from NESTDOWN are

MMINPUT_DOMAIN(x+1)
BDYOUT_DOMAIN(x+1)
LOWBDY_DOMAIN(x+1)

Note, you will need to rename these files as if they are for domain 1 
when you run MM5.

Note: Like Interpf, Nestdown will also need a full-day data to properly
      calculate substrate temperature. If you don't have a full-day data
      from the coarse domain run, you must use the LOWBDY_DOMAINx file
      from the coarse domain. 

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Namelist:

On machines that do not support comments (Cray and SGI, for example),
you can use namelist.input.SOC as a template to build your namelist,
or simply delele all comments after the ! sign.

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What NESTDOWN does not do?

NESTDOWN doesn't yet work for creating LOWBDY file that contains 
time-varying SST, snow cover and sea ice fields (new in release-3-4 MM5).

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Files/directories in this directory:

Makefile:  	top-level makefile
README:    	general information about how to run NESTDOWN
namelist.input: namelist file requiring user modification
src:       	directory of NESTDOWN source code