NORTH PACIFIC DECADAL CLIMATE VARIABILITY: COMPARISON OF TREE RING RECORDS AND CLIMATE RECONSTRUCTIONS FROM THE EASTERN AND WESTERN BASINS

There is a significant effort underway to characterize and understand the decadal climate variability of the North Pacific. One strategy to examine the decadal variability over centuries to millennia is to use coastal and near coastal tree-ring records as proxies of air-sea interactions by reconstructing climate (primarily temperature). Most of this work has been done from sites on the northeast Pacific coast. Recent collections from coastal sites bordering the Sea of Okhotsk on Sakhalin Island, the coast of Primorsky, the Kamchatkan Peninsula, and the Kurile Islands are providing tree-ring based climate reconstructions for the northwestern Pacific.

Well-verified reconstructions of temperature for the western Pacific have been developed. Initial comparison across the Pacific identifies the need to improve our understanding of the western Pacific ocean-atmosphere variability. Whereas in Alaska along the northeastern Pacific, shifts in the Pacific Decadal Variability (PDV) are readily identified in the instrumental and tree-ring reconstructions, in the western Pacific summer temperature reconstructions are more restricted to summer temperatures when PDV is more muted. Thus the western records are more a combination of local scale variability as well as large-scale dynamics.

Despite this recent progress in climate reconstruction in the western Pacfic challenges and opportunities to improve reconstructions remain. Anthropogenic disturbances in the western Pacific coastal regions dating back to the early 18^th century through the present make it difficult to locate old growth forest and find sites that have not been disturbed. Additionally, changes in sea ice in winter months and variations in the production of sea fog in the Sea of Okhotsk can influence tree growth and potentially complicate the climate signal. Improved reconstructions seek to better utilize the growing network of tree-ring records from multiple species, longer records, and an appreciation of local and regional scale influences.