DETECTION OF CLIMATIC-CHANGE IN THE WESTERN NORTH-AMERICAN ARCTIC USING A SYNOPTIC CLIMATOLOGICAL APPROACH - REPLY

It has been suggested that previous results indicating an increase in surface temperatures over the past 40 years within the coldest air mas ses at four stations in the western North American Arctic may be attri buted to the shorter residence time of these air masses through the ti me period. If true, this contradicts the original contention that thes e air masses have undergone physical character changes, possibly attri buted to anthropogenic sources, during the period. A reevaluation of t he data at two of these stations indicates that a long-term warming is , in fact, taking place even when residence time is kept constant. Thu s, it is suggested that changes in the physical character of these ver y cold air masses are due to factors other than residence time.