STABLE ISOTOPES IN TREE RINGS AS PROXIES FOR WINTER PRECIPITATION CHANGES IN THE RUSSIAN ARCTIC OVER THE PAST 150 YEARS

Abstract: We present results from an analysis of tree ring width and stable carbon and oxygen iso-topes in tree ring cellulose of Siberian Spruce collected from remote forest islands in the northwestern Russian tundra. Ring width is often considered a proxy for summer temperatures. The aim of this pi-lot study was to test whether stable isotopes can provide additional information about climate during the growth of trees in this extreme environment. Comparison of δ13C and δ18O with observed mete-orological data shows that there is a link between stable isotopes and winter precipitation. This may be explained by the strong influence that snow exerts on the isotopic composition of soil moisture during spring and early summer, when the new cellulose is formed. Our results show that winter pre-cipitation in the study area was increasing from 1865-1900, and thereafter decreasing until ~1930. The 1960-1980 period was again rather humid, followed by a drying trend until 1990. The study high-lights the potential of stable carbon and oxygen isotopes in tree rings as proxies for winter precipita-tion