Thread: Help with understanding humidity and dew point
View Single Post
  #2   Report Post  
Old November 27th 07, 04:15 PM posted to sci.geo.meteorology
I R A Darth Aggie[_2_] I R A Darth Aggie[_2_] is offline
external usenet poster
  
First recorded activity by Weather-Banter: Nov 2007
Posts: 65
Default Help with understanding humidity and dew point
On Mon, 26 Nov 2007 20:28:56 -0800 (PST),
, in
wrote:

+ Does it make sense for the weather channel to report a dew point below
+ freezing?

Yes. The value of the measure goes down as temperture drops further,
and becomes somewhat dubious at about -40. This where super-cooled
water vapor may exist, and it "condenses" directly to ice, and is one
source of aircraft icing.

+ If I want a more accurate method of measuring absolute humidity, can I
+ cool a plate and record the temperature when moisture condenses on the
+ plate and use that as dew point to calculate relative and absolute
+ humidity? (This is how they determine humidity in the chamber used to
+ house the Declaration of Independence without opening the chamber.)

That's one of the most accurate ways of measuring dewpoint. If you
know pressure, temperature and dewpoint, you can calculate any
relative or absolute humidity value you desire.

--
Consulting Minister for Consultants, DNRC
I can please only one person per day. Today is not your day. Tomorrow
isn't looking good, either.
I am BOFH. Resistance is futile. Your network will be assimilated.
Reply With QuoteReply With Quote