In a 2000 paper submitted to JGR-Atmospheres GISS lead authors and several other leading US experts in the field of temperature data history include two very simple diagrams which illustrate major truths about how how urban influences impact on temperature station data.
They go to the issue of what temperature trends may have been if cities had not been built.
Does anybody believe that global trends reflect the "undisturbed temperature" as drawn on these figures ?
Sorry for the lack of fresh posts this month.
San Juan was studied in the 1980’s by C.E Duchon who published in 1986, "Temperature Trends at San Juan, Puerto Rico, Bull.Amer.Met.Soc. 67, 1370-1377. A downloadable pdf file of this paper is available through BAMS. Click on Print Version for Duchon, Claude E.
My 20th Anniversary Review of Jones et al 1986 explores how San Juan was specifically mentioned in Wood’s 1988 critique of Jones et al 1986. The issue of San Juan was elucidated in the Wigley & Jones reply to Wood 1988 see point (5) in my Table listing the sparring between Wood and Wigley & Jones.
Do you know that GISS sometimes correct temperature data for supposed urban cooling? Let us look at examples from southern Sweden.
The three towns Karlstad, Jönköping, and Visby all have small airports. Of these towns, Visby is located on Gotland, the largest island in the Baltic Sea. Karlstad lies on the northern shores of the largest lake of Sweden, while Jönköping lies on the southern shores of the second largest lake. These two lakes are nearby to each other, and it seems unlikely that there could be any climate change at one of them not affecting the other.