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From: awtron@strawber.Princeton.EDU (Andrew Tron D-313 x3749)
Newsgroups: sci.space
Subject: Re: Spy satellite coverage of the Gulf
Message-ID: <6010@idunno.Princeton.EDU>
Date: 6 Feb 91 21:56:46 GMT
References: <14230@ganymede.inmos.co.uk> <4409@syma.sussex.ac.uk>
Sender: news@idunno.Princeton.EDU
Reply-To: awtron@strawber.Princeton.EDU (Andrew Tron D-313 x3749)
Organization: Princeton University
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In article <4409@syma.sussex.ac.uk> nickw@syma.sussex.ac.uk (Nick Watkins) writes:
>From article <14230@ganymede.inmos.co.uk>, by conor@lion.inmos.co.uk (Conor O'Neill):
>> 5) Are they affected by the dark, or by cloud cover, or is much of the
>> sensing done in the Infra Red?
>Radar isn't, apparently, I think IR will be affected by cloud cover
>though. Maybe somebody who knows about weather satellites can help.
>
Water does a very good job of absorbing infra-red.  That's why you only
see infra-red telescopes at very high altitudes (to get above the water
vapour at lower altitudes) or in space.

Infra-red images are useful for weather satellites:  an infra-red image
can give you the temperatere of the highest layer of cloud, which can then
be translated to the height said cloud.  This is useful for predicting the
severity of thunderstorms (i.e high tops == severe thunderstorms).  I got
this info when I visited an FAA flight service station once.

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