近2 000年南海北部海表温度变化特征及其对全球变暖的启示

(1.中国科学院 广州地球化学研究所,同位素地球化学国家重点实验室,广东 广州 510640; 2.中国科学院大学地球与行星科学学院,北京 100049)

海表温度变化; 南海北部; 近2 000年; 全球变暖

Changes of Sea Surface Temperature in the Northern South China Sea During the Past 2 000 Years and Its Enlightenment for Global Warming
XIAO Hangfang1,2,DENG Wenfeng1,WEI Gangjian1*

(1.State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China; 2.College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

sea surface temperature change; Northern South China Sea; past 2 000 years; global warming

DOI: 10.6043/j.issn.0438-0479.201804011

备注

近2 000年来的热带海洋高分辨率海表温度(sea surface temperature,SST)变化记录对了解晚全新世气候变化规律、评估当前全球变暖现象及未来气候趋势预测至关重要.南海北部海域具有较高的沉积速率,能够广泛发育珊瑚等能提供高分辨率气候记录的研究载体,是开展近2 000年高分辨率SST变化研究的理想区域.通过汇总并重新计算近年来南海北部高分辨率的SST重建记录,总结了近2 000年来该区域SST的演变特征,并探讨了其对当今全球变暖认识的启示.目前已有研究报道了10个时段共596年的高分辨率SST变化时间序列,其中包括41年的月分辨率记录和555年的年分辨率记录.这10个时段的SST异常值构成的SST变化趋势概况将南海北部近2 000年气候分成“暖期—冷期—暖期—冷期—暖期”5个阶段.影响SST变化的可能因素包括火山活动、东亚季风、厄尔尼诺-南方涛动、太阳活动和人类活动5个方面.与工业革命(18世纪60年代)前自然因素驱动的气候变化相比,当前的全球变暖是自然变化和人为干扰的共同结果.虽然强烈的人为干扰叠加并没有使现代暖期SST变化显著高出中世纪暖期,但却使SST变化的幅度加大、频率加快,很有可能给人类的生产生活带来影响.考虑到现有的重建结果不足以精细描述近2 000年来该区的SST变化,补充和完善南海北部高分辨率SST变化的资料库,精确划分南海北部近2 000年气候变化的特征时段,并建立起精细反演SST变化的气候模型等应该成为今后研究工作的重点.

The high-resolution sea surface temperature(SST)records of tropical oceans of the past 2 000 years are crucial in understanding changes of the Holocene climate,which are essential for assessing the current global warming and forecasting the trends of future climate.The Northern South China Sea(NSCS)has a high deposition rate,where widely distributed corals and other archives can provide high-resolution climate records.This makes it an ideal area to study high-resolution SST changes in the past 2 000 years.We here summarized and recalculated the reconstructed high-resolution SST records of the NSCS in recent years.The SST evolutionary features in this region in the past 2 000 years was summed up,and its enlightenment on the understanding of global warming was discussed.Current studies have reported high-resolution SST time series of 596 years across 10 time periods,including monthly resolution SST records of months in 41 years and annual resolution records of 555 years.The trend of the SST variations formed by the SST anomaly values in these 10 periods has divided the climate in the NSCS of the past 2 000 years into five stages,warm period-cold period-warm period-cold period-warm period.Factors affecting the SST changes in the NSCS may include the volcanic activity,East Asian Monsoon,El Niño-Southern Oscillation,solar activity and human activity.Compared with the climate change driven by the natural forcing before the Industrial Revolution(the 1760s),current global warming is influenced both by the natural and human disturbances.Although the superposition of the strong human disturbances has not made the SST of the Current Warm Period significantly higher than that of the Medieval Warm Period,it appears to increase the frequency and magnitude of the SST variations,which likely generates more extreme climates and has great impacts on human's life.Considering that the existing reconstruction results are limited and they are far from elaborating the SST changes in the past 2 000 years in this region,more studies are needed to enlarge the database of high-resolution SST changes in the NSCS.This may help to accurately divide the characteristic periods of the climate change in the past 2 000 years in the NSCS,and to establish climate models for finely inverting SST changes.