A Climatological Interpretation of Precipitation δ18O across Siberia and Central Asia

Abstract

Siberia and Central Asia are located at middle to high latitudes, encompassing a large landlocked area of the Eurasian continent and vast tracts of permafrost, which are sensitive to global climate change. Here, we investigated the data from 15 Global Network of Isotopes in Precipitation (GNIP) stations to clarify the relationship between precipitation δ18O (δ18OP) and the local temperature and precipitation amount on the monthly, seasonal, and annual timescales. Three main conclusions as following: (1) On the monthly time scale, the variation in δ18OP is mainly controlled by the “temperature effect”. (2) The weighted average value of precipitation δ18O (δ18Ow) exhibited “temperature effect” over 60° N–70° N. However, δ18Ow was dominated by multiple factors from 40° N to 60° N (e.g., the North Atlantic Oscillation (NAO) and water vapor source changes). (3) The variations of δ18OW can be attributed to the changes in pathway of the westerly dominated by the NAO at annual timescale. Therefore, it is possible to reconstruct the histories of past atmospheric circulations and water vapor sources in this region via δ18O in geologic archives, e.g., speleothem and ice core records.