Calculating point solar radiation from 1 meter DEM

Discussion created by chaf0081 on Apr 17, 2014

I am trying to accurately calculate daily and total summer (JJA) solar radiation for about 100 points in northern Minnesota using LiDAR derived 1 meter DEMs as the input rasters.  The topography of the area is moderately complex.  Two questions: 

How many viewshed calculations should I use?  The default is 32, which ESRI states is quite adequate for 30m DEMs, but they also say that the number of calculations should increase when using finer-scale DEMs.  I'd like to find that happy medium between processing time and accuracy.

And what sky size should I use given my 1 day interval requirement?  The default is 200, which ESRI says is fine for whole DEMs and day intervals > 14 days.  But, ESRI suggests a sky size of 2800 or more when calculating solar radiation for a location at the equator with a 1 day interval.  How about a 1 day interval in northern Minnesota?   

I've never used the solar radiation tool before so any wisdom you can send my way would be much appreciated.