Published data were used to analyse the long-term annual temperature trends at ten locations located in the Arctic region. Stations, all at latitudes of greater than 75 deg N, were located in Canada, Greenland, Norway and Russia. 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). All of the stations were located in small settlements or at arctic research stations.
The periods of the data ranged from 35 years to 73 years(the earliest record, at Isfjord Radio, commencing in 1912).
The plots shown below are of the annual mean temperatures at each of the ten 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 ten 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 the perceived trend peaks around 1950-1960 ]
ANNUAL MEAN TEMPERATURE TRENDS FOR INDIVIDUAL STATIONS
Eureka (Canada) 1947-2015
Alert (Canada) 1950-2004
Nord (Greenland) 1952-2015
Danmarkshavn (Canada) 1951-2015
Isfjord Radio (Norway) 1912-1980
Svalbard (Norway) 1977-2015
Krenkelja (Russia) 1957-2015
Ostrov Vize (Russia) 1951-2015
Fedorova (Russia) 1932-2015
Ostrov Kotel’nyj (Russia) 1933-2015
DISCUSSION AND COMMENTS
- The data analysed was limited to that which were available on the KNMI website.
- The annual mean temperature trend-lines for ten stations are remarkably similar, although the period of records are relatively short for trend analysis.
- A cyclical pattern in the trend-line is apparent at the ten stations, although the short records limit this observation. A Low occurred in around 1980, and Highs occurred in around 1950 and 2010, indicating a cyclical wavelength of about 60 years.
- The ~2010 peak was generally about 1.0-2.0 deg C higher that that in ~1950.
- The ~1980 trough was generally about 0.5-1.2 deg C less than the peak in ~1950.
- Although the analysis is limited by the short period of records, the consistency of the annual mean temperature trend-lines of the ten widely separated stations provides support for the good quality of the data and the conclusions drawn from the analysis.
- The increase in the annual temperature trend since around 1980 is typically around 2.0 deg C which is higher than that recorded at lower latitudes. However, there is no evidence of alarmingly increasing temperatures in recent years (except, perhaps, at Krenkelja and Ostrov Kotel’nyj which have very incomplete data in recent years). Conversely, there is some evidence that a peak in the temperature cycle may have been reached in about 2010 and a decrease in the annual mean temperature of around 1.0 deg C could 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.