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  National Center for Atmospheric Research/Mesoscale and Microscale  
         Meteorology Division Public Domain Software Packages        

This document briefly describes several data analysis software packages
that are maintained by NCAR/MMM, are in the public domain, and are made 
available for non-commercial use.  Source code tarfiles are available 
along with documentation (usually postscript files), examples, and other 
relevant files.  All MMM-developed source code is free, but copyrighted 
and UCAR is the copyright holder.  In most subdirectories there are post-
script files (copyright.ps) containing the copyright statement.  These 
software packages use utilities that are within the NCAR Graphics package. 
You must obtain that package from NCAR/SCD if you do not already have it 
installed.  For information on the Graphics package, see SCD's website

	        http://ngwww.ucar.edu

For information on gbytes and sbytes (byte unpacking/packing routines),
see SCD's website

	http://www.scd.ucar.edu/dss/softlib/gbytes.html

1) ACCESSING MMM DATA ANALYSIS SOFTWARE PACKAGES:

For security purposes, UCAR/NCAR now has a firewall in place with all 
MMM divisional machines except our ftp server inside this firewall.  
Since the MMM server is not an anonymous ftp site, you must use a des-
ignated USERNAME and PASSWORD.  Contact L. Jay Miller (ljmill@ucar.edu) 
for instructions on accessing files on this restricted ftp server.

2) BRIEF DESCRIPTION OF MMM DATA ANALYSIS SOFTWARE PACKAGES:

PPI_MMM:
  PPI_MMM is a program to analyze radar measurements taken at spherical
  coordinates (range, azimuth, and elevation).  It accepts radar data 
  in any of the following formats: field formats (FF) from the NCAR/ATD 
  radar processors (RP-3 through 7), universal format (UF), the DORADE 
  (airborne and ground-based radars, including ATD/SOLO sweep files), 
  and the National Climate Data Center (NCDC) NEXRAD Level II format.  
  Data are processed by sweeps from PPI (surveillance or azimuth sector 
  at a constant elevation angle) or RHI (changing elevation angle at a 
  constant azimuth angle) scans.  Several options are available for 
  manipulating the data algebraically and displaying it.

SPRINT:
  SPRINT is a program to interpolate radar measurements taken at spher-
  ical coordinates (range, azimuth, and elevation) to regularly-spaced 
  Cartesian or longitude-latitude grids, in either constant height or
  constant elevation angle surfaces. It accepts radar data in any of 
  the ATD field, univeral, DORADE, or NEXRAD Level II formats.  SPRINT 
  outputs interpolated data in pure binary format readable by CEDRIC.  
  A description of the CEDRIC binary format can be found in Appendix D 
  of the SPRINT documentation.  Data from PPI scans can be interpolated
  to Cartesian or longitude-latitude grids, either at constant height
  or constant elevation angle surfaces.  Both airborne helical scans 
  and constant-azimuth (RHI) scans from ground-based radars are only
  interpolated to Cartesian grids (X, Y, and Z).

CEDRIC:
  CEDRIC is a mesoscale data analysis program that processes datasets 
  on regular Cartesian and longitude-latitude grids. The analysis op-
  tions include many numerical operations such as algebraic, filtering, 
  and Doppler radar wind synthesis, both ground-based and airborne,
  as well as graphical operations.  Several REMAPpings (interpolations)
  are possible: XYE --> XYZ, LLE--> LLZ, XYE <--> LLE, and XYZ <--> LLZ,
  where XY (LL) is a regular Cartesian (longitude-latitude) grid.  Z 
  (E) refers to a constant height (elevation angle) surface.  CEDRIC 
  uses its own self-describing, binary format as well as the network 
  Common Data Format (netCDF) that was developed by NASA and UCAR's 
  UNIDATA.  For information on netCDF, see UNIDATA's website 

		http://www.unidata.ucar.edu

CEDIO:
  CEDIO is a module consisting of input/output routines for the CEDRIC 
  pure binary format. These routines are useful for interfacing CEDRIC-
  generated gridded data with other software packages.  

CEDRIC Binary Format:
  The CEDRIC pure binary format is portable, very fast, and compact. 
  This format is recommended for general use and is described in Appen-
  dix D of the SPRINT and CEDRIC documentation files. An alternative is 
  the netCDF which is highly portable, and there are existing software 
  packages that can directly read this format. Thus, if you want to use 
  CEDRIC files in other software packages, it might be easier to create 
  them in this format. The pure binary format can also be used in your 
  own programs, but it would be harder to do.  Input and output to netCDF 
  files is slower and the files are bigger, so it is not recommended for 
  general, everyday use on the same platform type. Furthermore, only one
  volume can be written to netCDF files. With the pure format, up to 25 
  volumes can be placed in a single file. Writing out to a file that al-
  ready exists with the netCDF format option selected will cause the con-
  tents of the existing file to be overwritten. No appending takes place. 
  Users should exercise caution to avoid accidentally overwriting datasets.

If you need further assistance with these packages, contact either L. Jay
Miller (ljmill@ucar.edu) or Sherrie Fredrick (sherrie@ucar.edu) at NCAR/MMM.

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