correct air pressure

[Chris Alston <alstonc@odrge.odr.georgetown.edu>]

>Date:         Wed, 25 Mar 1998 23:45:27 EST
>Reply-To: Medical Physics Mailing List <MEDPHYS@LISTS.WAYNE.EDU>
>Sender: Medical Physics Listserver <medphys@lists.wayne.edu>
>From: Physics92 <Physics92@AOL.COM>
>Subject:      correct air pressure
>To: Multiple recipients of list MEDPHYS <MEDPHYS@LISTS.WAYNE.EDU>
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>Dear Medical Physics subscribers,
>
>Any comments and/or references on how to correct for altitude and latitute on
>a barometer calibrated at the sea level would be appreciated. I am interested
>(for beam calibration) in corrections required by both a mercury and non-
>mercury barometer. I made an audit at a radiation therapy department and there
>was a discrepancy of 20 Hg mm between the readings of the barometer and the
>air pressure given by the weather service. The "local" physicist says that it
>is because he made the "corrections" while the weather service gives the sea
>level pressure; the weather man says that this is the pressure measured in
>their yard (close to the hospital; so I take it as being the "real" or
>absolute pressure, the one which I need for Cpt). How do I solve the problem?
>
>Thank you in advance for your comments.
>
>George Capatina, Ph.D.
>physics92@aol.com
>