Tree-ring oxygen isotope across monsoon Asia: Common signal and local influence

[摘要] Tree-ring cellulose oxygen isotope (delta O-18) in monsoon Asia (MA) is affected collectively by local hydroclimate and remote oceanic-atmospheric variations. Variations of tree-ring delta O-18 have been widely used for quantitative reconstructions of monsoon-season precipitation, relative humidity and drought severity. However, local hydroclimate and remote large-scale circulation's influences on tree-ring delta O-18 has not been fully resolved. Here, we collected 24 tree-ring delta O-18 chronologies covering the period of 1884 - 1999 across a wide range of MA and investigated the common signals of these chronologies using principal component analysis. The first principal component (PC1) of the 24 tree-ring delta O-18 chronologies explained 25.2% of the total variances and showed significant positive correlations with the observed Asian summer monsoon oxygen isotope index (r = 0.69) during the period of 1978-1999, suggesting that a common signal of precipitation delta O-18 does exist in MA and that it is highly correlated with El Nino - Southern Oscillation (ENSO) (r = 0.72) and the South Asian summer monsoon precipitation (r = -0.66). South Asian summer monsoon precipitation and ENSO are the main factors controlling this common signal of tree-ring delta O-18 across MA. PC1 of tree-ring delta O-18 chronologies in MA also depicted a negative (positive) correlation with the Atlantic Multidecadal Oscillation (Pacific Decadal Oscillation), indicating the large-scale circulation influences. After removing the large-scale circulation influences on tree-ring delta O-18 chronologies, however, the residual tree-ring delta O-18 chronologies exhibit negative correlations with the regional hydroclimate, highlighting the role local hydroclimate on the individual tree-ring delta O-18 variations. Keywords: Tree-ring oxygen isotope Precipitation oxygen isotope Asian summer monsoon ENSO (C) 2021 Elsevier Ltd. All rights reserved.

[发布日期] 2021-10-01

[关键词] Tree-ring oxygen isotope;Precipitation oxygen isotope;Asian summer monsoon;ENSO