마이크로네시아에서 얻어진 산호중 표층수온 온도 와 기계적 관측: 최근기후변화와의 비교 및 의의

Abstract

It is usually recognized that oxygen isotope of the coral skeleton can provide information on variations of the past sea surface temperature (SST), therefore climatic changes, for the several hundreds year (Gagan et al., 2000; Charles et al., 2003). For these reason, there has been numerous pioneering studies for reconstructing past multi-decadal climatic sensitivity and tracking the relationship between coral records and paleoclimatological records. About 90 cm long coral skeleton was collected from Chuuk Island of Micronesia to reconstructing past SST variation in July, 2007. X-radiograph of the hard coral skeleton showed distinctive density layer showing cyclic occurrence of annual band. Assuming that the growth rate is constant from the coral, total growth rate of the coral of these areas reaches about 1.5 cm /year with irregular growth rate. Oxygen isotope of the coral skeleton collected from the tropical Micronesian sea clearly showed clear cyclic variations. Assuming that the past sea surface temperature variation tightly associated with oxygen isotope variation (Grottoli et al., 2007), this high resolution cyclic variation of oxygen isotope excursion implying the annual variation of sea surface temperature. Oxygen isotopic value ranges from -6.10 to -5.21 which suggesting winter and summer time SST proxies. Comparison between oxygen isotope of coral and instrumental SST variation shows strong association suggesting that the oxygen isotope of coral signal can be used for the reconstructing the past SST.