CLIMATE VARIATIONS AND CHANGES IN MASS OF 3 GLACIERS IN WESTERN NORTH-AMERICA

Time series of net and seasonal mass balances for three glaciers in we stern North America, one in the Pacific Northwest and two in Alaska, s how various relationships to Pacific hemisphere climate indexes. Durin g the winter season the two coastal. maritime-regime glaciers, over 20 00 km apart, are affected almost identically, albeit inversely, by atm ospheric and oceanic conditions in both the tropical and North Pacific . The two Alaska glaciers, only 350 km apart, have almost no coherence . Lag correlations show that in winter the maritime glaciers are influ enced by concurrent conditions in the North Pacific, but by conditions in the tropical Pacific in August-September of the prior northern sum mer. The winter balance variations contain interannual Ei Nino-Souther n Oscillation variability superimposed on North Pacific interdecadal v ariability; the interdecadal 1976-77 climate regime shift is clearly e vident. The summer balances and the continental-regime glacier have a general lack of correlations, with no clear, strong, consistent patter ns, probably a result of being influenced more by local processes or b y circulation patterns outside the Pacific Ocean basin. The results sh ow the Pacific Northwest is strongly influenced by conditions in the t ropical Pacific, but that this teleconnection has broken down in recen t years, starting in 1989. During the seven years since then (1989-95) , all three glaciers have shown, for the first timer coherent signals, which were net mass loss at the highest rate in the entire record. Th e authors' results agree with those of other recent studies that sugge st these recent years are unusual and may be a signature of climate wa rming.