I thought I’d expand a bit more on why Svensmarks figure 4 is unacceptable (fig 4 of arXiv; fig 6 in Cosmoclimatology: a new theory emerges). Bear in mind that there is more wrong in the article than just this, though! The fig is:
I’m arguing about the lower line, which purports to be a 90-64S average. This is sourced to: http://data.giss.nasa.gov/gistemp/tabledata/ZonAnn.Ts+dSST.txt (90-64S zonal mean) and thats a perfectly reputable source. However, not one to be used blindly, as S does. You have to wonder about the data quality. And even a cursory think would lead you to wonder how much early data there is in there.
One hint is that the early data is more variable. If you look closely you can see this in S’s fig. If you draw the raw data its more obvious; and if you take the standard deviation its 1 oC before 1957 and 0.4 after. Which is because there are a whole pile of extra stations available after 1957 which smooths things out. The table referenced says it also uses HadISST1 for SSTs in the early period, and it says its a land-ocean mean. But that isn’t consistent with the change in variability (there is an other table, http://data.giss.nasa.gov/gistemp/tabledata/ZonAnn.Ts.txt, which only has the stations in. But the differences between that and the former, for 90-64S, is very small).
A good source of temperature data is the BAS READER project. A quick glance shows only Orcadas in the early years in the correct region (and even thats a bit wrong, since Orcadas is only 60 S; maybe GISS is taking 5 degree radius-of-influence to include it S of 64S?).
In fact, I can demonstrate that the early data *is* pure Orcadas by plotting it:
Black: GISS data. Blue: Orcadas station data. Note that GISS are anomalies so I’ve adjusted them vertically to fit (by 3.6 oC, if you care). The early fit is so good its clear that the GISS data *is* pure Orcadas. Which means the table description is odd? Anyway. I’ve also added 4th order polys a-la S. Amusingly, the poly fit is fine, so I would have no complaints if S just used the Orcadas data. But then the fit wouldn’t be so good after 1950; and he wouldn’t be able to call it “Antarctic” temperatures.
So: just to be clear: the early part of S’s data comes from Orcadas, an Island station at 60 S. it is *not* an average of 90-64S as he says: its data from a single station. Any competent Antarctic-type reviewer would have caught this glaring error. This is a teensy bit of a problem for him, as his “Antarctic theory” is most pronounced S of 75S; arguably, 60 S should actually be in rest-of-world as far as he is concerned. I’ve no doubt though that his theory will prove sufficiently pliable to account for this :-)
[Update: the data sparsity is a bit more obvious via a map: e.g. for 1910 (thanks G) -W]
[A read writes: Could you please be more clear? Write what is on the axes in different colors, what it is used by Svensmark for, and why you think that it’s wrong as opposed to some vague cliches that the data are not enough. I thought I had been. OK, my pic (the lower one) shows in black the raw data used in the lower line in S’s plot. They are the same, except I haven’t put a 12y filter through the data. Overplotted in blue is the raw Orcadas station data. From 1905 to 1950 the data overly so exactly that its hard to see the blue line unless you look closely, except for a few excursions (1945 is the most obvious) that are presumably caused by more data becomming transiently available for that year. This demonstrates that the data S is using from GISS really is the Orcadas data. Therefore it isn’t a mean for 90-64S or anything like it (that is obvious from the data from 1960 on, which disagrees. If anything there is an antiphase relation, especially from 1980 on. I hope thats clear now -W]