UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
               Office of Air Quality Planning and Standards
               Research Triangle Park, North Carolina 27711

                             November 8, 1988




MEMORANDUM

SUBJECT:  State of Indiana Meteorological Preprocessor Program

FROM:     Joseph A. Tikvart, Chief /s/
          Source Receptor Analysis Branch, TSD (MD-14)

TO:       Michael Koerber, Regional Meteorologist
          Region V

     As follow-up to my January 27, 1988, memorandum to you, the On-site
Meteorological Data Work Group has now reached a consensus regarding which
surface temperature data is appropriate for use in calculating hourly
mixing heights from NWS sounding data.  Their recommendation, which is
attached, is that the temperature data should be taken from the station
where the sounding is taken.

     The Model Clearinghouse agrees with the Work Group position and thus
recommends that, both for Indiana and for your other States, the
temperature data be taken from the radiosonde site, if possible.  By copy
of this memorandum we are informing all other Regions of this decision and
recommend that for all future analyses this procedure be followed.

Attachments

cc:  R. Brode (MD-14)
     J. Dicke (MD-14)
     D. Grano (MD-14)
     R. Lee (MD-14)
     S. Reinders (MD-14)
     D. Wilson (MD-14)
     Regional Modeling Contact, Regions I-IV, VI-X (w/attachment,
       Copy of the January 27, 1988 memo, and list of FY-89
       Clearinghouse Memoranda)