Reconstruction of southeast Tibetan Plateau summer climate using tree ring δ18O: moisture variability over the past two centuries
- 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- 2Laboratoire des Sciences du Climat et de l'Environnement, UMR8212, IPSL/CEA/CNRS/UVSQ Bat 701, L'Orme des Merisiers, CEA Saclay, 91 191 Gif sur Yvette Cedex, France
- 3CIRES, University of Colorado, 80309 Boulder CO, USA
- 4Key Laboratory for Coast and Island Development, Ministry of Education, School of Geographic and Oceanographic Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093, China
- 5Research center For Eco-Environment Change, Chinese Academy of Sciences, Beijing 100085, China
- 6Graduate School of Chinese Academy of Sciences, Beijing 100049, China
Abstract. A tree-ring δ18O chronology of Linzhi spruce, spanning from AD 1781 to 2005, was developed in Bomi, Southeast Tibetan Plateau (TP). During the period with instrumental data (AD 1961–2005), this record is strongly correlated with regional CRU (Climate Research Unit) summer cloud data, which is supported by a precipitation δ18O simulation conducted with the isotope-enabled atmospheric general circulation model LMDZiso. A reconstruction of a regional summer cloud index, based upon the empirical relationship between cloud and diurnal temperature range, was therefore achieved. This index reflects regional moisture variability in the past 225 yr. The climate appears drier and more stable in the 20th century than previously. The drying trend in late 19th century of our reconstruction is consistent with a decrease in the TP glacier accumulation recorded in ice cores. An exceptional dry decade is documented in the 1810s, possibly related to the impact of repeated volcanic eruptions on monsoon flow.