Late Holocene Asian summer monsoon variability reflected by δ18O in tree-rings from Tibetan junipers

Abstract

Recent warming in High Asia might have a strong impact on Asian summer monsoon variability with consequences for the hydrological cycle. Based on correlations between climate data, the tree-ring δ 18 O of high-elevation junipers is an indicator of August precipitation. Thus, our 800-year long annually resolved oxygen isotope series reflects long-term variations in summer monsoon activity on the southern Tibetan plateau. Summer precipitation was reduced during 13th-15th centuries and since the 19th century, whereas the Little Ice Age period (15th-19th century) was rather moist. The late 20th century was among the driest periods during the past 800 years, showing a tendency to slightly wetter conditions after AD 1990. Copyright © 2011 by the American Geophysical Union.