SUMMER TEMPERATURE SINCE 1600 FOR THE UPPER KOLYMA REGION, NORTHEASTERN RUSSIA, RECONSTRUCTED FROM TREE-RINGS

Dahurian larch (Larix gmelini) growing in the Upper Kolyma region of northeastern Siberia provide the first tree-ring chronology from this area. Ring widths in this long-lived species are highly correlated (r = 0.33 to 0.62) with average daily maximum temperatures for summer months and weakly correlated with other monthly climate variables. The correlation with summer temperature was sufficiently strong to reconstruct a long (1545-1989) temperature record for a nearby meteorological station at Atka. This reconstruction indicates that temperature during the 20th century has been generally less variable than during much of the past 400 yr. A period of warming from 1910 to 1965 has ended and a cooling trend has prevailed since 1977. Comparison with a Siberian larch (Larix siberica) chronology from the polar Urals reveals decades-long periods of agreement and of disagreement between the two chronologies. These suggest the presence of occasional persistent anomalies in the atmospheric circulation of arctic Asia, which warrant exploration by further dendroclimatic studies in this region.