INTRODUCTION
------------

This is the README file for the CAMx model that includes information about:
1) License agreement
2) CAMx e-mail contacts
3) Upgrading to the latest version of CAMx
4) The distributed test case

Further details about CAMx are provided in the Release Notes and in the CAMx
User's Guide, available from:

http://www.camx.com.


1. LICENSE AGREEMENT
--------------------

Read the "LICENSE" file included with the source code.
The LICENSE is also available from the CAMx download page at:
http://www.camx.com/download/agreement-form.aspx.
You agree to the CAMx license terms by downloading the source code and using
the CAMx model.


2. CAMx E-MAIL CONTACTS
-----------------------

Join the CAMx User's Group by sending an e-mail message to:

 camxdevel at gmail dot com

with the words “subscribe CAMxusers” in the BODY of the message.  You will
receive an invitation to join the Google Group along with additional
information on how to use this service.

The camxusers group is meant for broadcasting useful information about CAMx
and its pre- and post-processors to all users that subscribe to this group, or
to ask about available datasets or issues that other users may have come across.
It is not meant for asking how to run CAMx, how to prepare inputs, or why CAMx
arrived at a particular prediction.

         ** PLEASE REFER TO THE CAMx USER'S GUIDE FIRST **


3. UPGRADING TO CAMx V7 FROM PREVIOUS VERSIONS
----------------------------------------------

V7.x is a major update from previous releases (v6.x).  In general, all of the
inputs developed for CAMx prior to v7 can be used in v7+ versions, except for
O3MAP and TUV photolysis input files -- you must re-generate those.  Version 7
introduces netCDF input file formats for all large gridded arrays: meteorology,
landcover, initial/boundary/top concentrations, point sources, 2-D and 3-D
emissions.  Output concentration, deposition and Probing Tool files can also be
generated in netCDF format (since v6.5).  The Fortran binary I/O formats are
still allowed, but this option will be removed in the future. 

Multiple point, 2-D and 3-D emission files can be provided to CAMx and Probing
Tools, alleviating the need to merge component emissions into single input
files.  Except for the new 3-D emissions file, which must be in netCDF format,
multiple emission files can be netCDF or Fortran binary format, or any mix of
the two.

NOTE on Source Apportionment Technology (SAT): With this change, SAT input
      emission files are used to define emissions for BOTH the core model and
      the SAT application.  In earlier CAMx versions, separate sets of core
      and SAT files were listed and the model compared gridded and point
      emissions to core model inputs to ensure consistency.  ALL SAT point
      emissions are always used for BOTH SAT and the core model.  A
      "leftover" capability remains available for gridded emissions, based on
      differences between SAT emission inputs and core model emission inputs,
      but not for point emissions. It is no longer necessary to provide a
      consistent list of point sources among all of the SAT point source
      files.  The list of points to model are now an internal concatonation
      of point source lists from each input SAT point source file.

NOTE on DDM and RTRAC: With this change, DDM and RTRAC input point source
      emission files can include stack lists that are entirely unique to
      these Probing Tools.  Earlier CAMx versions required a consistent list
      of point sources among the core model, DDM and RTRAC, which was
      onerous.  This restriction is removed.

See the User's Guide for more information on file formats, requirements and
restrictions.

The CAMx namelist control file has changed significantly in this release; refer
to the namelist template provided with the source code and the User's Guide for
a full list of namelist variables.  Some namelist variables have been removed,
some new variables are added.

Visit www.camx.com to obtain the latest code, version-specific input files 
(e.g., chemistry parameters) and all test case I/O.


4. CAMx TEST CASE
-----------------

A new test case is provided to help new CAMx User's get started and permit
performance benchmarking.  The test case is based on the US EPA's 2016 Modeling
Platform, with a single nested domain covering the Eastern U.S.  The test case
includes inputs and outputs for 2 days of simulation over June 10-11, 2016,
which are available at www.camx.com.

You can compare your results to the test case benchmark by displaying
the concentration outputs using graphics programs.  You can perform a more
rigorous check by comparing the concentration outputs using the "AVGDIF" 
program. 

AVGDIF is on the CAMx web site in the download/support programs area.
We expect concentrations to agree within the limits of single precision
calculation, namely relative errors of about 1 in 100,000.
