Interannual variations of bomb radiocarbon during 1977– 1998 recorded in coral from Daya Bay, South China Sea

22 annual layered samples of coral from 1977 to 1998 were collected from Daya Bay, South China Sea, their bomb- super(14)C (nuclear weapons testing super(14)C) concentrations were determined and studied, and the atmosphere-sea exchange rate and diffusion thickness were estimated and found to be 17 mol . m super(-2) . a super(-1) and 32 mu m, respectively. The interannual variation of coral Delta super(14)C is mainly controlled by oceanic factors. In ENSO years, the coastwise upwelling current of South China Sea gets intensified, hence the coral Delta super(14)C displays its bottom value. The coral Delta super(14)C does no respond vividly to the variation of the solar radiation energy. In the past 20 years or so, the genera situation and the oceanic thermal structure of South China Sea are still stable even though inter annual variation occurs in the atmosphere-sea interaction and the upwelling current driven by the tropical energy.