THE DETECTION OF CLIMATE-CHANGE IN THE ARCTIC - AN UPDATED REPORT

An air mass-based synoptic climatological approach is used to determin e if the frequency of occurrence of the coldest and mildest air masses at seven stations in the Russian Arctic has changed and if the physic al character of these air masses have shown signs of modification over the past 40 years. It has been suggested that a detected increase in surface temperatures over the past 40 years within the coldest air mas ses in the western North American Arctic may be attributed to the shor ter residence time of these air masses through the time period. A re-e valuation of the data at two of the stations in the Alaskan and Yukon Arctic indicates that a long-term warming is, in fact, taking place ev en when residence time is kept constant. Results for seven additional Russian stations are less conclusive, and they do not exhibit a consis tent statistically significant warming. It is possible that changes in the physical character of these very cold air masses are due to facto rs other than residence time, such as anthropogenic influences.