Thanks Bob. I am not a climate scientist so I probably should not venture into the area of answering if correlations, perhaps even phase shifted, have been found for the PDO and solar cycles. It's a darn good question.

As far as urban vs rural data, you might be interested in this volunteer survey of US surface stations.

http://www.surfacestations.org/

I don't know enough about the project to comment, but they claim that inly about 4% of the surface stations are relatively unbiased with repeated measures over time due to urbanization.

Sorry to toot the horn again, but I have examined other surface stations. Though I have not spent as much time modeling those data as I have with the Wichita data set, since it is quite robust with no missing points.

The essay starts here and on the right are the other surface stations examined.

http://www.well.com/user/pdeep/pages/warm07/20071019.shtml

To my eye, and as far as the models, it looks like the PDO phenomenon might influence temperature over larger areas of the US. The exception might tbe coastal areas that are altered by local currents. Though I really don't know that for sure.

Hope that helps,

Paolo