Mid- to late Holocene changes in tropical Atlantic temperature seasonality and interannual to multidecadal variability documented in southern Caribbean corals
Mid- to late Holocene changes in tropical Atlantic temperature seasonality and interannual to multidecadal variability documented in southern Caribbean corals
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DOI：
10.1016/j.epsl.2012.03.019
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发表时间：
2012-05-15
影响因子：
5.3
通讯作者：
Scheffers, Sander
中科院分区：
文献类型：
--
作者：
Giry, Cyril;Felis, Thomas;Scheffers, Sander
热带大西洋海表温度（SST）的代理重建，延长仪器观测期间主要集中在百年到千年的变化，而不是季节性的几十年的变化。在这里，我们提出了每月解决的Sr/Ca（SST的代理）从化石年度带状的Diploria strigosa珊瑚博内尔岛（加勒比海南部）的记录。个体珊瑚提供了长达68年的时间窗，295年的记录总数允许评估在全新世中期至晚期快照期间热带大西洋西部季节性至数十年SST变化的自然范围。与现代气候相比，珊瑚Sr/Ca记录显示，全新世中期至晚期SST的特点是明确的季节性周期，持续准两年期和突出的年际以及跨到多年代尺度的变化。然而，这些时间尺度上的SST变化的幅度在过去的6.2 ka有所不同。珊瑚记录显示，在全新世中期增加的季节性与气候模型模拟一致，表明南加勒比海温季节性是由轨道时间尺度上的日照变化引起的，而气候系统的内部动态在较短的时间尺度上发挥着重要作用。SST年际变率与大西洋和太平洋起源的海洋-大气相互作用有关。显著的年际变化在热带大西洋西部的2.35万年的珊瑚，可能与加强整个全新世的厄尔尼诺/南方涛动的变化。突出的跨到几十年SST的变化是显而易见的珊瑚记录和稍微更明显的中全新世。最后，我们认为，我们的珊瑚数据提供了一个目标，研究全新世气候变化的季节性和年际到几十年的时间尺度上，当使用进一步的数值模型和高分辨率的代理数据。(C)2012爱思唯尔有限公司版权所有。
Proxy reconstructions of tropical Atlantic sea surface temperature (SST) that extend beyond the period of instrumental observations have primarily focused on centennial to millennial variability rather than on seasonal to multidecadal variability. Here we present monthly-resolved records of Sr/Ca (a proxy of SST) from fossil annually-banded Diploria strigosa corals from Bonaire (southern Caribbean Sea). The individual corals provide time-windows of up to 68 years length, and the total number of 295 years of record allows for assessing the natural range of seasonal to multidecadal SST variability in the western tropical Atlantic during snapshots of the mid- to late Holocene. Comparable to modern climate, the coral Sr/Ca records reveal that mid- to late Holocene SST was characterised by clear seasonal cycles, persistent quasi-biennial and prominent interannual as well as inter- to multidecadal-scale variability. However, the magnitude of SST variations on these timescales has varied over the last 6.2 ka. The coral records show increased seasonality during the mid-Holocene consistent with climate model simulations indicating that southern Caribbean SST seasonality is induced by insolation changes on orbital timescales, whereas internal dynamics of the climate system play an important role on shorter timescales. Interannual SST variability is linked to ocean-atmosphere interactions of Atlantic and Pacific origin. Pronounced interannual variability in the western tropical Atlantic is indicated by a 2.35 ka coral, possibly related to a strengthening of the variability of the El Nino/Southern Oscillation throughout the Holocene. Prominent inter- to multidecadal SST variability is evident in the coral records and slightly more pronounced in the mid-Holocene. We finally argue that our coral data provide a target for studying Holocene climate variability on seasonal and interannual to multidecadal timescales, when using further numerical models and high-resolution proxy data. (C) 2012 Elsevier B.V. All rights reserved.