NORTH PACIFIC CLIMATE AND THE C.E. 1741 VITUS BERING EXPEDITION TO ALASKA
Using a suite of tree-ring records from the Gulf of Alaska and Kamchatka, along with meteorological data from Kamchatka and Bering Island, we reconstruct the climate of the 1741-1742 expedition in the north Pacific and show that it had a role in condemning Bering’s voyage. Tree ring widths were measured from 190 Siberian larch cores in Kamchatka. These tree rings are representative of the years 1653 to 2014 and are shown to be positively correlated with land and sea surface temperature at meteorological stations in Petropavlovsk, Kamchatka and Nikol’skoe, Bering Island. A significant decrease in tree ring width is shown in the early 1740s, which is indicative of cooler average temperatures in late summer. A published 700-year tree-ring reconstruction of the El-Niño Southern Oscillation (ENSO) shows that this cooling coincided with the transition to a strong La Niña event in the tropical Pacific in 1742, which is also consistent with a negative phase of the Pacific Decadal Oscillation (PDO) suggested by our temperature tree-ring data from the Gulf of Alaska. These conditions both favor zonal flow of the Pacific Jet Stream through the Aleutians, which manifests itself as strong, continuous westerlies and storminess that Steller describes in his journal of the voyage.