Let's put this "air resistance" issue in perspective.
Assume you start to get a sunburn at sea level in 60 minutes.
In Reno - about 1 mile elevation - you will burn in 30 minutes.
At Lake Tahoe - about 1-1/2 mile elevation - you will burn in 20 minutes.
The same applies for latitude. If a certain panel generates
100 watts at the equator, at 45 degrees latitude it will produce about 70 watts. At the Arctic circle, it will produce perhaps 50 watts ... all because the sunlight has to pass through more air to reach the panels.
