Temperature Adjustments At Ostrov Dikson
By Paul Homewood
I looked yesterday at the temperature adjustments made by GISS/GHCN to the temperature record for Ostrov Dikson, a small settlement on the edge of the Kara Sea in Siberia. As with many similar adjustments at Arctic stations, the effect has been to downgrade the warm spell of the 1940’s.
For instance, the actual data shows that 1943 was 1.08C warmer than 2007, yet after adjustment they are exactly the same.
It has been suggested that the sharp drop in temperature in the early 1940’s could be due to a change on equipment, rather than a genuine reflection of temperature. The drop referred to was between 1945 and 1946, when annual temperatures fell from –8.16C to –11.03C.
However, as the chart below shows, a year on year change of this order is not unusual in Ostrov Dikson.
Changes of 3.0C+, both up and down, have occurred on nine occasions since 1922.
Another clue is given by the monthly figures for 1945 and 1946. If there had been a step change between the two years, we should see it reflected in the monthly data. In fact, we don’t. Although 1945 was warmer as a whole, four months were actually colder.
The clincher, though , is that other stations in the region also showed a similarly sharp drop in temperature between the two years. For instance, Dudinka, 499km to the east:
And GMO, 801 km away:
Notice that both of these stations are to the east of Dikson, yet still show exactly the same warm 1940’s/cold 1960’s cyclical pattern as the stations much further to the west, such Archangel, Akureyri and Nuuk. As I reported last week, this cyclical pattern is closely related to the natural AMO.