What is a typical Sun radiance?

radiance-general
1

Dear List,

what would be sort of "ball park" figures for the radiance of the Sun and of a clear blue sky?

I have found sources that indicate the irradiance from the Sun to be on the order of 1400 W/m^2, across all wavelengths, with probably around half being within the visible spectrum.

I am primarily interested in the visible spectrum, and would like to know the RGB radiances of the Sun, say at noon at the Equator.

I have contemplated stealing this information from the output of gensky, but if someone has this information (or a link) please let me know

Best,
Claus

2

Claus,
Here's a handy list of typical luminance values courtesy of 'schorsch':
http://www.schorsch.com/kbase/glossary/luminance.html
-John

···

-----------------------------------------------
Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
The Gateway
Leicester
LE1 9BH, UK
+44 (0) 116 257 7972
+44 (0) 116 257 7981 (fax)

[email protected]
http://www.iesd.dmu.ac.uk/~jm

3

You can download weather data files that contain information like direct normal,
diffuse and global horizontal radiation in Wh/m^2 here:

http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm

This data is for the EnergyPlus program. You can download the 'stat' files
which are readable text files with average values for wetware ('brain') processing.

There is also the Satel-Light website but I don't think it covers areas outside of Europe:

http://www.satel-light.com/core.htm

Regards,
Thomas

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On 10 Sep 2008, at 08:11, Claus B. Madsen wrote:

what would be sort of "ball park" figures for the radiance of the Sun and of a clear blue sky?