[SQM] [walnutpointobservatory] Re: a "ground albedo influence" night

[Joseph Mayer]

Jan Hollan !!
 
Hi, Jan.  I'm Joe Mayer, the observatory director of the Chicago Astronomical Society and I've investigated this problem with an illumination engineer from Portland, Oregon.  I can't put my hands on the papers right now; nor can I remember the engineer's name.  However, he is a former board member of the IDA.
 
His calculations and measurements produced the following results:  Given a fully shielded illumination source such as a street light, from a dry asphalt surface, 8% of the incident light is reflected into the atmosphere.  From a dry concrete surface 25% of the incident light is reflected into the atmosphere.  From a wet surface it's no problem:  It's raining.