Published data were used to analyse the long-term annual temperature trends at 13 locations located in the Siberia region of Russia (this is the region to the East of the Ural Mountains). Similarities in the trends for individual stations enabled a comprehensive trend to be established for the whole region.
The data used were all from the website of KNMI (the Royal Netherlands Meteorological Institute). Only raw data were used (ie as originally recorded, without any adjustments). Data were only used from stations located in rural areas or in small towns so as to avoid the possible influence of urbanisation on the temperatures.
The periods of the data were all over at least a century (the earliest record, at Nercinskij Zavod, commencing in 1839). Shorter records at rural stations were also available on the KNMI website but these were not used.
The plots shown below are of the annual mean temperatures at each of the 13 locations. On each plot a polynomial “best fit” trendline has been added. It should be noted that the trendlines near each extremity (ie near the start and end of the records) are quite sensitive to individual data points, whereas trendlines within the main body of the record are much more stable and reliable.
COMPARISON OF TRENDLINES
Annual Mean Temperature Trends
[ The basis of these trendlines can be seen from the analyses for the 13 individual stations – see next section ]
Annual Mean Temperature Residual Trends
[ The individual trend-lines have been adjusted by constant amounts to be approximately zero at around 1940 ]
ANNUAL MEAN TEMPERATURE TRENDS FOR INDIVIDUAL STATIONS
Salehard (Russia) 1882-2015
Hanty-Mansijs (Russia) 1892-2015
Ostrov Dikson (Russia) 1916-2015
Turuhansk (Russia) 1881-2015
Enisejsk (Russia) 1871-2015
Kirensk (Russia) 1892-2015
Verhojansk (Russia) 1885-2015
Viljujsk (Russia) 1898-2015
Nercinskij Zavod (Russia) 1839-2015
Anadyr (Russia) 1898-2015
Ohotsk (Russia) 1890-2015
Nikol’skoe (Russia) 1899-2015
Nikolayevsk-na-Amure (Russia) 1854-2015
DISCUSSION AND COMMENTS
- The data analysed was limited to that which were available on the KNMI website.
- The annual mean temperature trend-lines for the 13 stations are remarkably similar, with four exceptions: Nercinskij Zavod, Nikolayevsk-na-Amure, Nikol’skoe and Ostrov Dikson.
- A well-defined cyclical pattern in the trend-line is apparent at nine of the stations. A Low occurred in around 1970, and Highs occurred in around 1940 and 2010, indicating a cyclical wavelength of about 70 years.
- The ~2010 peak was generally about 0.8-1.2 deg C higher that that in ~1940.
- The ~1970 trough was generally about 0.3-0.7 deg C less than the peak in ~1940.
- Three stations (Nercinskij Zavod, Nikolayevsk-na-Amure and Nikol’skoe), all located on or near the Pacific coast, did not show any trough around 1970.
- At Ostrov Dikson (located on the northern coast) there was a very marked trough around 1970, about 1.8 deg C less than around 1940. However, by 2010 the trend has risen to about 1 deg C above the 1940 temperature.
- The consistency of the annual mean temperature trend-line at the 13 widely separated stations provides support for the good quality of the data and the conclusions drawn from the analysis.
- The well-defined cyclical pattern of the trendlines over such a wide area raises the question (un-answered by me) of the causes of this pattern.
- The cyclical pattern of the trendlines were not evident at three stations located in the south-east corner of Siberia and this apparent inconsistency needs to be investigated further.
- There is no evidence of alarmingly increasing temperatures in recent years. Conversely, there is strong evidence that a peak in the temperature cycle was reached in about 2010 and a decrease in the annual mean temperature of around 0.5 deg C could be anticipated to occur in the next 30-40 years.
This article was written by Brian Gunter of Narooma, NSW. In his previous life Brian was an engineering hydrologist involved over many years in the analysis of rainfall and river flow data for the planning of water resources projects in Australia, Asia and Africa. In recent years he has been one of the Marine Rescue NSW (previously Royal Volunteer Coastal Patrol) volunteer weather observers who operate the Narooma station for the Bureau of Meteorology.