New views of tropical paleoclimates from corals
New views of tropical paleoclimates from corals
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DOI：
10.1016/s0277-3791(99)00054-2
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发表时间：
2000-01-01
影响因子：
4
通讯作者：
Schrag, DP
中科院分区：
文献类型：
--
作者：
Gagan, MK;Ayliffe, LK;Schrag, DP
珊瑚为热带海洋地区过去的气候变化提供了丰富的档案，这些地区的仪器数据有限，我们对数十年气候敏感性的了解也不完整。在赤道太平洋东部，珊瑚同位素记录跟踪ENSO相关的海面温度变化的变化;再往西，珊瑚记录ENSO事件期间伴随印度尼西亚低压纬向位移的海面温度和降雨量的变化。这些多世纪的记录揭示了以前未被认识到的ENSO在几十年到几个世纪的时间尺度上的变化。在对ENSO敏感的赤道太平洋以外，近期暖/湿条件的长期趋势表明热带地区对全球强迫作出了反应。新的珊瑚古温度计表明，在新仙女木气候事件期间，热带西南太平洋的海洋表面温度降低了4-6摄氏度，并在接下来的4000年中周期性地上升。珊瑚中Sr/Ca和Delta（18）O的高时间分辨率测量提供了有关表层海洋水文平衡的信息，并可以解决降水和蒸发之间的季节平衡。珊瑚中的放射性碳测量，加上海洋环流模型，可用于重建近地表海洋环流，过去的混合率，以及化石燃料CO2在上层海洋的分布。最近，赤道太平洋珊瑚的放射性碳的季节至年际变化与ENSO相关的表面沃茨重新分布有关。(C)1999爱思唯尔科技有限公司。保留所有权利。
Corals offer a rich archive of past climate variability in tropical ocean regions where instrumental data are limited and where our knowledge of multi-decadal climate sensitivity is incomplete. In the eastern equatorial Pacific, coral isotopic records track variations in ENSO-related changes in sea-surface temperature; further west, corals record variability in sea-surface temperature and rainfall that accompanies zonal displacement of the Indonesian Low during ENSO events. These multi-century records reveal previously unrecognised ENSO variability on time scales of decades to centuries. Outside the ENSO-sensitive equatorial Pacific, long-term trends towards recent warmer/wetter conditions suggest the tropics respond to global forcings. New coral paleothermometers indicate that surface-ocean temperatures in the tropical southwestern Pacific were depressed by 4-6 degrees C during the Younger Dryas climatic event and rose episodically during the next 4000 yr. High temporal-resolution measurements of Sr/Ca and delta(18)O in corals provide information about the surface-ocean hydrologic balance and can resolve the seasonal balance between precipitation and evaporation. Radiocarbon measurements in corals, coupled with ocean circulation models, may be used to reconstruct near-surface ocean circulation, past mixing rates, and the distribution of fossil fuel CO2 in the upper ocean. Most recently, seasonal to interannual variations in the radiocarbon of corals from the equatorial Pacific have been linked to the redistribution of surface waters associated with the ENSO. (C) 1999 Elsevier Science Ltd. All rights reserved.