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Climatic change and Asian monsoon variation for the last 300 years recorded in coral skeleton of the South China Sea.

南海珊瑚骨架记录的近300年气候变化和亚洲季风变化.

基本信息

批准号：
11691114
负责人：
OBA Tadamichi
金额：
$ 7.3万
依托单位：
HOKKAIDO UNVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11691114/
关键词：
Coral skeleton Hainan Island Oxygen isotope Carbon isotope Asian monsoon Mg Ca Sr 東アジアモンスーン Ca比サンゴ微量元素古気候エルニーニョモンスーン

项目摘要

We collected one coral drilling core of 2.2 m length in Octorber 1999 from the east coast of Hainan Island, China. The following conclusions were obtained by comparing the in situ temperature-salinity record and the high-resolution oxygen carbon isotopic record (ca 200 samples) of a Hainan Island coral (Porites lutea) for the same one-year period (1999-2000).1. The oxygen isotopic ratios of the coral are clearly affected by both SST and the oxygen isotopic composition of the seawater.2. Minimum oxygen isotopic ratios occurred in December when surface temperatures were the coldest and the maximum peak occurred in September when surface salinities at the coral site in the South China Sea were the lowest.3. Using the correlation between the measured oxygen isotopic curve and the estimated curve from the temperature and salinity changes in seawater the following temperature equation for Porites lutea is derived. T=-5.617x(δc-δw)+0.6934. The growth rate of the coral was slow (0.24 mm/day) in summer from June to September and fast (0.44 mm/day) in winter from December to March.5. The carbon isotopic ratios of the coral decrease from April and coincide with the start of the rainy season at Hainan Island. This suggests that solar radiation may be the most important factor determining the carbon isotopic ratios in the corals.6. The maximum peak in carbon isotopic ratios occurred between January and March when SST increased rapidly and the minimum peak occurred in September-October when the annual cycle of turbidity is at a maximum due to the increased outflow

我们于1999年10月在中国海南岛东海岸采集了一颗长2.2m的珊瑚钻芯。通过比较海南岛珊瑚（Porites utea）一年（1999-2000年）的原位温度盐度记录和高分辨率氧碳同位素记录（约200个样本），得出以下结论。 1．珊瑚的氧同位素比值明显受到海温和海水氧同位素组成的影响。2．氧同位素比值最小出现在12月，此时表面温度最冷；最大峰值出现在9月，此时南海珊瑚礁表面盐度最低。3．利用测量的氧同位素曲线与海水温度和盐度变化的估计曲线之间的相关性，推导出以下黄滨滨珊瑚的温度方程。 T=-5.617x(δc-δw)+0.6934。夏季6-9月珊瑚生长速度较慢（0.24毫米/天），冬季12月-3月5日生长速度较快（0.44毫米/天）。珊瑚的碳同位素比率从四月份开始下降，恰逢海南岛雨季开始。这表明太阳辐射可能是决定珊瑚碳同位素比率的最重要因素。6．碳同位素比值的最大峰值出现在海温快速上升的1月至3月，最小峰值出现在9月至10月，由于出水量增加，浑浊度年循环最大。