This is interesting, especially since Solar Cycle 23 was quite long.
The Hockey Schtick writes:
A paper published by the Danish Meteorological Institute finds a remarkable correlation of Arctic sea ice observations over the past 500 years to “the solar cycle length, which is a measure of solar activity. A close correlation (R=0.67) of high significance (0.5 % probability of a chance occurrence) is found between the two patterns, suggesting a link from solar activity to the Arctic Ocean climate.” The paper adds to several others demonstrating that Arctic sea ice extent and climate is controlled by natural variations in solar activity, ocean & atmospheric oscillations, winds & storm activity, not man-made CO2.
Multi-decadal variation of the East Greenland Sea-Ice Extent: AD 1500-2000
Knud Lassen and Peter Thejll
Abstract:
The extent of ice in the North Atlantic varies in time with time scales stretching to centennial, and the cause of these variations is discussed. We consider the Koch ice index which describes the amount of ice sighted from Iceland, in the period 1150 to 1983 AD. This measure of ice extent is a non-linear and curtailed measure of the amount of ice in the Greenland Sea, but gives an overall view of the amounts of ice there through more than 800 years. The length of the series allows insight into the natural variability of ice extent and this understanding can be used to evaluate modern-day variations. Thus we find that the recently reported retreat of the ice in the Greenland Sea may be related to the termination of the so-called Little Ice Age in the early twentieth century. We also look at the approximately 80 year variability of the Koch [sea ice] index and compare it to the similar periodicity found in the solar cycle length, which is a measure of solar activity. A close correlation (R=0.67) of high significance (0.5 % probability of a chance occurrence) is found between the two patterns, suggesting a link from solar activity to the Arctic Ocean climate.
…
Conclusion:
In view of the large significance observed we suggest that the correlation of 0.67, between
multi-decadal modes in the Koch ice index and the solar cycle length, is indicative of a relationship not due to chance. The multi-decadal modes still represent only a small fraction of the total variance in the ice series, which illustrates that while the kind of solar activity characterised by the variable length of the solar cycle may cause some of the variability seen in the ice series, the majority is caused by other factors.
Whereas the multi-decal mode may be a result of varying solar activity, the cause of the slowly varying mode is not directly seen from the data presented here. Obviously, it must be due to a natural variation of the climate. A variation of similar shape may be recognised in the solar cycle length (Figure 1.5), but it has not been possible from the present data to deduce a correlation that is significant. Nevertheless, the similarity of the variation of the ice export through the Fram Strait and the smoothed variation of the solar cycle length shown in Figure 1.7 speaks in favour of the assumption that the solar cycle variation may include both natural modes. This conclusion is in accordance with the finding by Bond et al., 2001 (their Figure 2) that a persistent series of solar influenced millennial-scale variations, which include the Medieval Warm Period and the Little Ice Age, reflect a baseline of the centennial-scale cycles.
values of solar cycle length (SCL121) (heavy curve).
The ’low frequency oscillation’ that dominated the ice export through the Fram Strait as well as the extension of the sea-ice in the Greenland Sea and Davis Strait in the twentieth century may therefore be regarded as part of a pattern that has existed through at least four centuries. The pattern is a natural feature, related to varying solar activity. The considerations of the impact of natural sources of variability on arctic ice extent are of relevance for concerns that the current withdrawal of ice may entirely be due to human activity. Apparently, a considerable fraction of the current withdrawal could be a natural occurrence.
Full paper is here (PDF)
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
80% of SST is this simple:
1+1 = 2
davidmhoffer says:
July 19, 2013 at 12:02 am
“Janice,
If you said 2 and 2 is 4 and I said it was 3, would you agree to saw it off at 3.5? Sorry, but in math and physics, there is little room for compromise.
For those still twisting the facts to fit their world view, see vuckevic’s comment above quoting Leif. When those two agree on something regarding solar physics that bluntly, I for one sit up and pay attention.”
As long as all of those demanding to see the data on the process ask for the same for popularly accepted scientific theories like dark matter, then they are not hypocrites. With dark matter we see only the effect but no one can come up with the cause, ie some actual dark matter. But this is accepted by many who demand to see the data on others’ correlations which may be “spurious” or, in fact, may not. Inventing a mental constuct which allows your numbers to work is no more scientifically rigorous than that of those whom you disdain. You reference Leif?
I gotta say, I’m unimpressed. They describe the procedure as follows:
This makes no sense to me. Here are the cycle lengths, based on one set of data, and it’s not the only set. One issue is how do you define the “start/end” of a cycle. In any case, this would be typical:
March 1755 – June 1766: 11.25 yrs
June 1766 – June 1775: 9 yrs
June 1775 – September 1784: 9.25 yrs
September 1784 – May 1798: 13.67 yrs
May 1798 – December 1810: 12.58 yrs
December 1810 – May 1823: 12.42 yrs
May 1823 – November 1833: 10.5 yrs
November 1833 – July 1843: 9.67 yrs
July 1843 – December 1855: 12.42 yrs
December 1855 – March 1867: 11.25 yrs
March 1867 – December 1878: 11.75 yrs
December 1878 – March 1890: 11.25 yrs
March 1890 – February 1902: 11.92 yrs
February 1902 – August 1913: 11.5 yrs
August 1913 – August 1923: 10 yrs
August 1923 – September 1933: 10.08 yrs
September 1933 – February 1944: 10.42 yrs
February 1944 – April 1954: 10.17 yrs
April 1954 – October 1964: 10.5 yrs
October 1964 – June 1976: 11.67 yrs
June 1976 – September 1986: 10.25 yrs
September 1986 – May 1996: 9.67 yrs
May 1996 – Jan 2008: 11.83 yrs
Immediately, we see problems. First, they explain that they are converting these cycle lengths to an “annual” value by interpolation … say what? That doesn’t make physical sense. Also, where do you place the values you are interpolating between? The first cycle in this data is March 1755 – June 1766: 11.25 yrs
So do we assign the value of 11.25 to the start, the end, or the middle of the cycle? And given that the value of the annual interpolation changes from year to year … then what are we measuring? Because it’s no longer the cycle length, that changes cycle to cycle, not year to year.
This kind of thing makes me extremely suspicious. You don’t just leave data out and say it was “ill-defined”. You leave it in, and discuss what you mean by “ill-defined”. In this case I suspect “ill-defined” means “didn’t agree with the ice data”.
You can’t use surrogate data that has “the same auto-correlative structure as one of the series” to test this by monte carlo. You have to build two surrogate datasets, one for ice, and one for cycle length, each with the same autocorrelation structure as what they are representing. The problem is, the autocorrelation on both will be horrible. In one case this is because of the interpolation. In the other case it is because we’re looking at principal components. And curiously, these are principle components numbers 6, 7, & 8 of the ice series, way down the line.
So I’d have to see a lot more than what they show to pay any attention to that. And in any case, they are not comparing it to the solar cycle length, but to an artificial steadily varying solar length index with free choice as to where the values are placed in the cycle.
Sorry, I wouldn’t pass the paper as written.
w.
Willis has made 2 mistakes interpreting.
Paul Vaughan says:
July 22, 2013 at 4:08 am
What is this, Paul, some kind of serial revelation where tomorrow you’ll tell us what “2 mistakes interpreting” I made?
As usual, you can’t bear anything I’ve written, but as usual, you can’t come up with a coherent argument against what I wrote. As a result, you just go up and down, like the song says,
My condolences, Paul, it must be frustrating …
w.
In the hunt for a real mechanism to connect solar activity to climate, this mechanism on the sun looks promising. This connection between magnetic field line re-connections and heat would not be limited to the solar case.
http://www.sciencedaily.com/releases/2013/07/130715164909.htm
Promising? Not til someone constructs indices and tries to correlate trends.
…and seeing as they’ve had 8 years to do so, but haven’t, maybe tells us something…?