Definition of angle[edit source]

Effects of snow on photovoltaic performance#16 panel solar array says:

  • "There are 8 panels each of Nexpower amorphous silicon framed 100W and 8 panels of Bosch unframed micro-morph silicon 100W panels positioned at angles from 0 to 70 degrees in 10 degree increments."

Does "degrees" mean "degrees from horizontal" or "degrees from vertical"? I guess it would be degrees from horizontal but the article should clarify that. --Teratornis 11:38, 25 February 2011 (PST)

Critical angle[edit source]

Effects of snow on photovoltaic performance#Applications says:

  • "The data ... will (determine) the following parameters: ... "critical" angles for snow shedding as a function of temperature"

See wikipedia:Angle of repose and follow the links therefrom for some possibly related work. "Critical angle" sounds like a synonym for "angle of repose", probably the more widely used term among earth scientists and civil engineers. The literature on avalanchesW may give insights on the behavior of snow on (large) slopes. I don't know how the physics would scale down from a mountain to a solar panel, but it may be worth a mention. --Teratornis 11:47, 25 February 2011 (PST)