Model Change Bulletin

                                    MCB#8                       04/10/2000

                             ISCST3 (dated 00101)


    This Model Change Bulletin documents changes made to the Industrial
Source Complex Short Term (ISCST3) Dispersion Model (see Code Changes below).
[NOTE:  New ISC3 users are urged to read ISC3 MCB#1, Amendment #1 for
important information.  In addition, this change to the ISCST3 model does
not address the anomalous behavior of the dry deposition algorithm described
in MCB#2 and MCB#5.]


CODE CHANGES

    Changes from ISCST3 (dated 99155) include the following:

1.  Modifications to METEXT.FOR, MESET.FOR and EVCALC.FOR to explicitly
    remove support for unformatted meteorological data (UNFORM option
    on the ME INPUTFIL card).  Proper error handling has been implemented
    to support this change.  Users with unformatted meteorological data
    should first convert the data to an ASCII format using the BINTOASC
    utility program available on the SCRAM website.

2.  Modification of the variable emission factor feature (SO EMISFACT) to
    include an option to specify emission factors that vary by season,
    hour-of-day, and day-of-week.  The day-of-week variability allows
    for different emission factors to be specified for Weekdays
    (Monday-Friday), Saturdays, and Sundays.  The option is selected by
    including the SHRDOW secondary keyword on the SO EMISFACT card (see
    the Addendum to Volume I of the ISC3 Model User's Guide for more
    information).


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                           *   IMPORTANT   *
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    This program will henceforth be identified by its name and a Julian date,
i.e.: ISCST3 (dated 00101).  Future changes to this model will be identified
by an updated Julian date found at the beginning of the model source code
and followed by a reference to a SCRAM Model Change Bulletin (MCB#n)
which will explain the nature and content of the changes.  All Model Change
Bulletins for this program will always be available for back reference on
this website.  In the future, notification of changes (MCBs) to this program
will be made in the SCRAM ALERTS section of this website.