We have talked about finding Waldo for a while. Here are a few interesting graphics showing the Adjusters in Peru. Here are 4 stations where temperatures in the mid-20th century have been lowered by around 3 deg C. These are all reverse UHI effects.
For all of the above graphics, I’ve plotted original monthly data without taking an annual average. The annual variation in monthly temperatures is only a few degrees. Given this very placid temperature variation, how can Hansen simply assume that something happened that threw the measurements off by 3 deg C?
In order to make adjustments of this magnitude, Hansen should have written to the Peruvian meteorological service and asked them for an explanation or interpretation of any results that didn’t appear to make sense. If he were unsatisfied with the explanation, maybe he could decide not to use the data. In order to make adjustments of this magnitude, he should have to prepare a detailed technical report on Peruvian station histories showing how the problems originated.
As I’ve noted before, I increasingly wonder whether it makes any sense for academic scientists like Hansen (or Jones) to be reporting temperature statistics. They don’t appear to have the faintest interest in the gritty details. So turn the calculations over to professional data analysts.