Oxygen isotope signatures preserved in tree ring cellulose as a proxy for April-September precipitation in Fujian, the subtropical region of southeast China

A tree ring cellulose oxygen isotope (O-18) chronology for the period 1870-2011 was established using samples from four Fokienia hodginsii trees with the aim of exploring the potential to use tree ring O-18 records to reconstruct climatic variations in Fujian, a subtropical region of southeast China. We believe that this is the first tree ring O-18 chronology from this area. Response analysis revealed that tree ring O-18 is significantly correlated with precipitation between April and September, relative humidity between August and October, and the Palmer drought severity index between April and October. Our O-18 chronology accounts for 37.4% (24.6%) of actual variation in precipitation between April and September during the period from 1951 to 2011 (1901 to 2011). Spatial correlation analysis revealed that tree ring cellulose O-18 is a suitable proxy for reconstructing April-September precipitation in Fujian, as well as in parts of Guangdong and Jiangxi, southeast China. In addition, significant correlations between O-18 chronology and the Indian summer monsoon index show that large-scale atmosphere circulation also influences tree ring O-18. Comparisons between the tropical Pacific sea surface temperature (SST) and tree ring O-18, during the period from 1895 to 2009, indicate that the tropical Pacific SST is positively correlated with tree ring O-18 in the study region over the last 110years, except between 1920 and 1960. Reduced El Nino-Southern Oscillation (ENSO) variance from 1920 to 1960 may result in collapsed relationship between tree ring O-18 in Fujian and tropical Pacific SST.