This post will extend the study of the relationship between CET and temperature in the eastern US to cover the western US (Nevada and Washington State) and the Plains States (South Dakota), and I will do another graph for Barrow on the Alaska North Slope, although I did not calculate a correlation coefficient because reliable temperature data for the North Slope go back only to the middle 1920s, when land clearing in Australia was well under way and aluminum and titanium metallurgy which have produced a significant part of the greenhouse pollution emitted since then.
We saw in the previous post that winter CET was:
- positively correlated (even excluding Australian greenhouse gas emissions) with winter temperature in Florida and the Ohio Valley division
- marginally positively correlated (excluding Australian greenhouse gas emissions) with winter temperatures in Texas (south-central US)
- not correlated with winter temperatures in Maine
If we look at the warmest CET winters between 1881 and 1974 – excluding 1898/1899 and 1948/1949 which I have discussed in earlier posts – the warmest (1934/1935) is quite exceptional in following most of the opposite patterns to those very cold CET winters woudl imply to occur in exceptionally mild CET winters:
- warm over the Lake Baikal region
- warm over Alaska and Western Canada
- cold over the northeastern United States
- warm over most of Greenland (although not on a 1921 to 1974 base period):
|Global temperature anomalies for December 1942. This was the coldest December over Alaska since 1917, but began a very mild winter over the UK.|
South Dakota (Great Plains)
One does see a cluster of dark red diamonds in the upper right, which suggests a definite alteration from the virgin patter, and indeed the dark red diamonds do show an absence in the upper left. Oddly, however, for those who want to believe the relationship has been altered by Australian greenhouse gas emissions, there does not exist a white diamond anywhere close to the upper left of the graph, as if a natural limit to this possibility exists. The same is true of the light red diamonds, and seems to beg some sort of explanation.
The case of South Dakota, unlike those of the eastern and southern United States, does suggest a possible alteration in relationships due to Australian-made greenhouse gas emissions. However, a peculiarity in the blanks in the upper left (warmer than normal over South Dakota, colder over the United Kingdom à la 1941/1942 or 1986/1987) suggests that a case for relationships altering remains unproven.
Nevada (Southwestern United States)
- they are highly negative so that when Nevada is cold during the winter, the UK tends to be mild
- much more distinctly different than in other plots
- because the Spearman coefficient is less sensitive than the Pearson to outliers, this suggests that the natural correlation coefficient in winter temperatures is more strongly negative than the raw values
|This map coincides with the record cold European winter and spring of 1916/1917. Note that, contrary to the correlations we have seen in earlier scatter plots, the record cool was in the West and North rather than the Southeast.|
Washington State (Northwestern Conterminous United States)
|Contiguous US temperature anomalies for February 1984 in ˚C. Observe the cold over the Great Basin in contrast to abnormal warmth over the northern and eastern regions|
Barrow (Alaska North Slope)As a final post in this second installment (I am unsure whether I will do a third to look at extratropical Asia where temperature records are not as long but are less well-known), I will look at the station of Barrow, Alaska, on the Arctic Ocean 510 kilometres north of the Arctic Circle. Data for Barrow – easily the oldest station on the North Slope – go only to 1923/1924, but given that in the previous post Alaska stood out for its conspicuous warm anomalies during cold UK winters, I was interested to do what graph I could.
The top right and bottom left are almost empty apart from a few recent winters as the impact of man-made global warming intensifies, whereas dots are dense in the top left and bottom right. Likely the correlation coefficients between Barrow and CET winter temperature are more negative than those for Nevada, but I have not bothered to calculate them. The isolated white diamond is the winter of 1934/1935, whose full graph is given at the beginning of this post. Between 1922 and 1974 it was the warmest CET winter and the second-warmest in Barrow behind only 1941/1942. The evolution and cause of this anomaly will be examined from Barrow’s temperature graph shown below, although it might be noted that Barrow’s mean temperature troughs out at the tail end of February – indeed its warmest March, that of 2002, is as much as 11.4˚F or 6.3˚C colder than its record-warm February 1989 (during which Barrow was amazingly 0.02 inch wetter than superhumid Yakutat which had easily its driest month on record).
The winter of 1934/1935 is extremely famous in Alaska for Fairbanks’ only ever “brown Christmas” due to a powerful chinook wind melting all the snow cover during the second week of the month when temperatures rose to a phenomenal 58˚F or 14˚C for several days, followed when the weather turned seasonably cold by conditions too dry for snow. As we can see above, temperatures in Barrow did not reach such record-breaking levels (in fact, no day in December 1934 is record-warm in Barrow) but did average around 20˚F or 11.1˚C above normals for those dates, resulting in, as shown below, substantially above-normal temperatures:
In the UK, December 1934 was notorious for the frequency of rain, the mildness and lack of sunshine. Princetown in Dartmoor recorded 307 hours of rain during the month – in other words it rained for 41.26 percent of the time there, much more even than the long-term mean of such notorious wet places as Ketchikan (26 percent). January 1935 was cooler – though still above average – and dry in the UK, and as the graph above showed only marginally warm in Alaska, besides being exceptionally cold and snowy in Canada and cold throughout southwestern Eurasia due to easterly flow from the European block:
February 1935 is a month I noticed a great deal looking at temperature tables for the northern hemisphere because in huge areas of Siberia, Central Asia, and Canada it was an exceptionally mild month due to enhanced westerly flow and in Canada, chinook winds. The global anomaly of +0.27˚C above the 1880 to 1974 mean is not striking (January 1926 had a figure of +0.38˚C) but this figure is certainly higher for the northern hemisphere alone.
This fast westerly flow, of course, explains the temperature anomaly very well, the only surprising thing being how well the warm air entered Alaska. However, the pattern is consistent with a split jet stream, seen classically during the winters of 1943/1944 and 1991/1992, with heavy rainfall over southern Alaska and the southwestern United States and dry conditions over the Pacific Northwest:
The winter of 1946/1947 may appear to be an outlier, but in fact the cold occurred at different times – in Barrow during December and January, in England during late January and February. Barrow did not get below -47˚F or -43.9˚C on the day Snag, Yukon recorded the coldest temperature in North America away from the Greenland Ice Sheet, but whilst the UK was in a deep freeze, temperatures from 8 to 28 February in Barrow were near normal.
The winter of 2006/2007 shows the complete dominance of Australian-made pollution on the global climate – the only cooler than normal areas being in the Sahara where an expanded Hadley cell allowed more radiational cooling, typical of highly positive NAO episodes. The weakening of polar highs meant that hotter-than-normal air covered all the rest of the globe. This was the winter when loss of sea ice reached its most critical level – without a sign of sanctions against the worst (per capita) culprit nations who are too important to the global economy for the rest of the world to dare make them pay the vast costs of increasingly runaway climate change.
Despite severe and increasingly rapid alterations to the climate from fossil fuel use and land clearing in a small number of oil- or mineral rich and largely arid nations around the Indian Ocean (Australia, the Gulf States and South Africa being the important culprits), most natural temperature correlations and anticorrelations do not seem to have disappeared. In most cases, if one subdivides into pre-1974, 1974 to 1997 and post-1997 using coloured diamonds, it is possible to see something approaching the same relationship in each colour of diamond.