OK, on the “Alaska Regime Change” posting here:
we ran into some “odd things” in some Canadian data that lead to this posting:
In comments, Boballab has raised objections to the data in Wolfram Alpha for Baker Lake, Canada. On two major counts. First, that the high record of 91 F or 92F was pretty darned hot for a place near the arctic circle. (Though Wunderground shows the same hot day in their data). Then that the “shape” of the graphs were quite different from W.A. but matched for Environment Canada vs GISS. There was also a minor point that the data in W.A. has a “dropout” in the ’70s that the GISS and Environment Canada data do not have.
OK, I’ve been off on my pursuit of geese….
But first, a point about GIStemp:
Remember that it will fill in missing data, sometimes from great distances and over reasonably sized spans of time, from other stations via “The Reference Station Method”. What you see in a GIStemp graph is NOT the original data. It has been highly processed and “filled in”. It has also had a “Q.A.” step done that suppresses extreme low temperatures via replacing them with an average of “nearby” airports that can be quite far away.
I do not know the E.C. methods, but if they are following GISS (and Canada seems to have a history of that, and of being more “advocates” for the Global Warming agenda); then they may well be doing similar “post processing” in a Post-Normal Science kind of way…. A speculative “Dig Here!”
First off, I went to GISS and clicked on the map for about where Baker Lake is located to get the list of stations
Then I picked another one “nearby” that had a long temperature history. There are many ‘fragmentary’ stations, so the closest one that had a very long record looked like Fort Smith. ( I tried “Cambridge Bay” in Wolfram Alpha but could not get it to stop sending me off to other Cambridges… probably THE most frustrating thing at the site… I’ve not figured out the incantation to force it to a specific station.)
Then I explored the Fort Smith data at other locations as well.
At Wunderground, the record for Fort Smith is given as 95 F (not out of line with the Baker Lake record). The data at Wunderground has a similar “dropout dip” in about 1966 (while GISS shows no such drop out). Checking for data at Wunderground for Fort Smith Canada and 1970 gave a ‘null record’, so they, too, are missing data then.
For comparison, here are the GISS graphs for Fort Smith and from Wolfram Alpha along with the metadata block for both the Wolfram Alpha Fort Smith and Baker Lake pages. The purpose? To show that there is some sort of “generic issue” and not just a data entry faux pas on Baker Lake. (And to cast suspicion that the “generic issue” is the filling in, adjusting, homogenizing, and who knows what else that is in the GIStemp product, so if E.C. matches it, they are likely doing something similar…)
So to me, it’s looking like a generic class of error, and not a “one off” bad data entry. Further, it’s looking like a “post processing” fill in the blanks and homogenize result, not a ‘wrong identity’ (for the simple reason that we KNOW GIStemp has done that, it’s in the code; and two matching random errors of the same type? That would be very unlikely…). I’ll leave it for others to try other sites and see if they can surface any more of these (where the base data looks to be “not there” but where E.C. and GISS both color it in, and find odd ‘trends’ to it). I leave it to others for the simple reason that I’m a bit too swamped at the moment to follow it up properly.
My “working hypothesis” is that Environment Canada has some sort of “fill in the missing data and homogenize” process similar to GIStemp. That Wunderground and Wolfram Alpha have less “improved” and more “undercooked” data (not quite raw…) That there is a significant ‘data drop out’ in the ’70s for that region of Canada for some stations, and that dropout is ‘colored in’ by the processing at E.C. and GIStemp. ( I know that GIStemp will do so as it’s in the code.)
That, then, likely results in the overall change of the nature of the graphs between the two sets. E.C. and GISS on one side; Wolfram Alpha on the other. Wunderground with the data, but declining to make the long term graph, that would match Wolfram Alpha.
It is possible that there is some other reasonable hypothesis (such as both Wunderground and W.A. getting a load of bogus data from the same place?) that could cause this as a legitimate bit of dirty data. That, too, would stand checking.
Yes, this could use a lot more detailed documentation (but I’m way behind on a lot of things already so) that will need to fall to others to provide. A very large “Dig Here!!”…