The Svalbard Airport Temperature Series

Abstract In the Isfjorden region of Spitsbergen in the Svalbard archipelago, the air temperature has been observed continuously at different sites since 1911 (except for a break during WW II). The thermal conditions at these various sites turned out to be different so that nesting the many series together in one composite time series would produce an inhomogenous long-term series. By using the SNHT (Standard Normal Homogeneity Test) the differences between the sites were assessed and the series adjusted accordingly. This resulted in an homogenised, composite series mainly from Green Harbour (Finneset in Grønfjorden), Barentsburg (also in Grønfjorden), Longyearbyen and the current observation site at Svalbard Airport. A striking feature in the series is a pronounced, abrupt change from cold temperature in the 1910s to warmth in the 1930s, when temperature reached a local maximum. This event is called the early 20th century warming. Thereafter the temperature decreased to a local minimum in the 1960s before the start of another increase that still seems to be ongoing. For the whole series, statistically significant positive trends were detected by the Mann-Kendall test for annual and seasonal values (except for winter). Quite often the Norwegian Meteorological Institute receives queries about long-term temperature series from Svalbard. Hopefully, the Svalbard Airport composite series will fulfil this demand for data. It may be downloaded free of charge from the Institute’s home page: http://sharki.oslo.dnmi.no and should be used with reference to this article.