Cloudiness regime shift during 1946-1992 recorded by coral in the South China Sea

1 IntroductionCorals from the tropical oceans are the well-known paleoclimate proxies that offer both the high-resolution and multi-century record length needed forquantification of seasonal to centennial variations.Most corals build skeletons of aragonite (CaCO3) andgrow at rates of millimeters to centimeters per year(Sun et al., 2002). During growth, annual densitybands are produced in the skeleton that shows timemarkers for the development of chronologies (seeFig.1). Coral skeletons may p…

Cloudiness regime shift during 1946-1992 recorded by coral in the South China Sea

By extracting and comparing long-term trend components of coral gray value, sea surface temperature, cloudiness, and net heat flux for the period of 1946-1992, the relationships among them are addressed. There exists a prominent regime shift in the cloudiness associated with the corresponding variabilities of sea surface temperature and net heat flux occurred in the mid-1960s, which can be successfully recorded by coral gray value, a climatic proxy. Long-term cloudiness variations in the South China Sea are completely opposite to the equatorial western Pacific in the past five decades, whereas they share a similar trend to that over Asian monsoon prevailing waters. The fact that the coral gray value is highly correlated to cloudiness provides a unique perspective on utilizing this coral to study cloudiness variations in the pre-instrumental period.