Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

IR refractive index of air

0 views
Skip to first unread message

Ken Ellis

unread,
Oct 12, 1992, 3:46:30 AM10/12/92
to

I am trying to determine the refractive index of air in the IR
(3-15 microns) as a function of temperature and pressure. Many
references that I have found have a relationship for the visible:

n-1=Ap/T(1+Be/Tp)x10E-6

where T is temperature, p is pressure, e is the water vapor pressure
and A and B are other parameters. Many authors imply that this
relation does not hold in the IR. People I have talked to say that the
gas molecule absorption in the IR makes this relationship invalid.

Is there a relationship valid in the IR? Is this one valid in
the atmospheric windows where the absorption is small? What does
LOWTRAN use for the atmospheric refraction calculations when computing
the apparent solar zenith angle in the IR?

Thanks in advance for your help.

-Ken


--
_____
\ | Opinions expressed here are solely
\ ERIM Ken Ellis | those of the author and do not
/ el...@erim.org | necessarily represent those of
/____| | his employer.

0 new messages