Possible link between decadal variability in precipitation in the South China Sea and the North Atlantic Oscillation during the 20th century: A perspective from coral geochemical records

Abstract

The South China Sea (SCS) is the major source of water vapor to China and East Asia. Modern observations, numerical simulations, and paleoclimate records suggest that on seasonal and annual timescales, variability in SCS precipitation is controlled mainly by the East Asian Monsoon and El Niño–Southern Oscillation (ENSO), respectively. Nevertheless, due to the lack of long-term observational records, our understanding of its decadal variability is limited. Because the understanding of decadal variability in SCS precipitation is fundamental in accurately predicting precipitation patterns in China and East Asia using climate models, it is necessary to obtain preinstrumental records of precipitation using climatic proxies in high resolution archives. We demonstrate the potential of coral Δδ18O, derived from Sr/Ca and δ18O measurements in the coral skeleton, as a proxy for precipitation in the SCS on different timescales. We then use this proxy to reconstruct decadal variability throughout the 20th century. The results suggest that the monsoon, Pacific Decadal Oscillation, ENSO, and Atlantic Multidecadal Oscillation are not significant forcings of decadal variability in precipitation over the SCS. In constrast, the North Atlantic Oscillation (NAO) might have modulated the number of tropical cyclones passing through the SCS and induced more (fewer) tropical cyclones and more (less) precipitation during its negative (positive) phases on decadal timescales during the past century. However, future numerical modeling studies are still required to improve our understanding of the underlying mechanism behind the relationship between the NAO and decadal variability in SCS precipitation.