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 distrubuted 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:

 majordomo "at" environ "dot" org

Put the words "subscribe CAMxusers" in the body of the message.  When you
subscribe, Majordomo will send you a reply that provides details on how to use
this list-serve.

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 DOCUMENTATION FIRST **

Please direct specific comments or questions about problems or bugs with CAMx or
its support software to:

 ask-camx "at" environ "dot" org

which comes directly to the developers.


3. UPGRADING TO CAMx V6 FROM PREVIOUS VERSIONS
----------------------------------------------

V6.x is a major update from previous releases (v5.x).  Version 6 introduces
a consistent I/O file format for all large gridded arrays, which is similar to 
the CAMx/UAM binary Fortran file structure used previously for emissions, output
concentrations, etc.  The file header records now hold more information about 
grid configuration, time zone, and some variable-specific flags.  Otherwise the
file structures are unchanged.  Note that the meteorological input fields are 
now in the updated CAMx/UAM format. Met variables are grouped as follows:

2-D time-invariant: 26-cat landuse, topography, LAI (optional)
2-D time-variant: surface temperature, snow cover
3-D time-variant: height grid, pressure, temperature, humidity, U/V winds
3-D diffusivity
3-D cloud/rain

Pre-existing software that reads CAMx/UAM format will continue to be
able to read these files, including the new meteorologial files, but will ignore
the new header variables unless otherwise modified to explicitly read them.  
The meteorological pre-processors (WRFCAMx, MM5CAMx, RAMSCAMx) have been 
revised to generate the new met files.  See the User's Guide for more 
information on file formats.

**      CAMx WILL BE ABLE TO READ OLDER EMISSIONS AND IC/BC FILES.       **
** CAMx WILL ONLY READ THE NEW MET FORMATS, SO YOU MUST REGENERATE THOSE **
**    FILES USING THE NEW PRE-PROCESSORS, OR CONVERT OLD FILES USING     **
**                     THE NEW "METCONVERT" PROGRAM.                     **

V6 also introduces a revised manner in which photolysis rates are generated
and used in CAMx.  The albedo/haze/ozone column file now only contains
ozone column.  Albedo and haze patterns are determined by CAMx automatically.
Snow cover is moved to the CAMx 2-D met file.  Land/ocean mask has been removed
and now the CAMx Landuse file must make the distinction between salt water
(landuse index 1) and fresh water (landuse index 3).  The AHOMAP pre-processor
has been modified accordingly and is now called O3MAP.  The TUV photolysis
pre-processor has been revised to read the ozone column file and generates a
lookup table as a function of solar zenith, altitude, ozone column, albedo, and
terrain height (new).  Photolysis rates are generated for a default haze
optical depth profile.  CAMx interpolateis lookup table values to cell-specific
values of these variables.  All cloud and haze adjustments are made using the
in-line TUV.

**               CAMx WILL NOT READ OLD AHO AND TUV FILES                **
**            YOU MUST RUN O3MAP AND TUV TO GENERATE NEW FILES           **

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 test case is provided to help new CAMx User's get started and permit
performance benchmarking.  The test case is for the Midwest U.S. on June 3-4
2002.  The test case has 1 nested fine grid and requires about 650 MBytes of
memory.  The test case includes inputs and outputs for 2 days of simulation,
and is 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.
