Effective Sky Temperature
Effective Sky Temperature
(OP)
I'm trying to calculate the effective Sky Temperature at a given point on the earth. All that I have been given so far is a rule of thumb for locations around the 30 to 45 deg N Latitude to be 10 to 20 deg C below that of ambient for a clear sky day. For a cloudy day, the effective sky temperature comes out to be 1 to 2 deg C below ambient.I'm looking for something a little more exact.
Any help would be greatly appreciated.
Any help would be greatly appreciated.





RE: Effective Sky Temperature
Since the sky radiance is a combination of many factors, there is no single "sky temperature". The photometric spectral sky temperature is something like 30,000 K, which reflects the fact that the sky is blue.
Sky temperature in the infrared is a function of elevation angle and can range from nearly ambient horizontally to 250 K at zenith.
TTFN
RE: Effective Sky Temperature
This may not be what you're looking for, since it won't help with radiation calculations, but I found a little program that calculates air properties (temperature, pressure, density, viscosity, sound speed) at any altitude up to 40,000 feet, for a given set of sea level conditions.
If you're interested and I can send you a copy.
ko
RE: Effective Sky Temperature
I think that the temperature that I looking for is actually an average temperature over which the high density of CO2 and H2O lie in the atmosphere (where the radiation is actually absorbed by the atmosphere).
I agree, with the above statement that this is a product of the elevation angle. I will be considering the “stow” position only. Zero degree look angle relative to the Azimuth Axis (looking directly up)
RE: Effective Sky Temperature
http://www.mathcad.com/library/LibraryContent/clearnigh...
TTFN
RE: Effective Sky Temperature
Cheers
RE: Effective Sky Temperature