Detecting Seasonal through Centennial Variability in Sea Surface Temperatures of the Subtropical North Atlantic

根据这项拨款，研究小组将使用主要是迷状双弯珊瑚（Diploria labyrinformis）的大型珊瑚头，重建北大西洋副热带西部多个世纪以来的海温变化记录。这应该能够在十年和更长时间尺度上探索海洋在气候变化中的作用，特别是北大西洋涛动。现有的海温仪器记录可以追溯到一个多世纪以前。然而，数据的偏倚和稀疏使得较早的海温记录不可靠，NAO和中纬度海温异常之间的关联完全基于1950年以来收集的数据。该指数将利用在百慕大群岛收集的长寿脑珊瑚，延长北大西洋中纬度海温记录，百慕大群岛是亚热带环流指数的理想地点。三个独立的古温度计（18O， Sr/Ca和骨骼生长）将应用于两个大型菌落的骨骼，以建立500年的季节分辨率海温变化的多代理记录。此外，pi将对四个大规模的无生命殖民地进行采样，日期和分析，这些殖民地已经被确定为可能足够古老，可以将500年的代理记录延长到公元1000年。这一长达多个世纪的记录将使北大西洋气候中尚未解决的关键问题得以解决。特别是，估计中纬度大气对地表边界条件变化的敏感性需要跨越全新世晚期重要气候事件的季节性海温记录。ppi将研究与全球变暖有关的海温可能的长期变化，以及与过去30年NAO异常的联系。其他关键问题涉及海温对太阳强迫和火山爆发的敏感性，以及海洋表面条件存在年代际到百年尺度的周期性。

Under this award the PIs will use large corals heads primarily of the species Diploria labyrinthiformis to reconstruct multicentury long records of SST variability in the western subtropical North Atlantic. This should enable exploration of the ocean's role in climate change on decadal and longer time scales, specifically the North Atlantic Oscillation. The available instrumental record of SST extends back little more than a century. However, biases and sparseness of data render the older part of the SST record unreliable and the demonstrated association between NAO and mid-latitude SST anomalies is based exclusively on data gathered since 1950. The PIs will extend the SST record for the mid-latitude North Atlantic using long-lived brain corals collected on Bermuda, a site well placed to index the subtropical gyre. Three independent paleothermometers ( 18O, Sr/Ca and skeletal growth) will be applied to the skeletons of two massive colonies to construct a 500 year-long multiproxy record of SST variability at seasonal resolution. In addition the PIs will sample, date and analyze four massive non-living colonies already identified as potentially old enough to extend the 500 year-long proxy record back to 1000 AD. This multicentury long record will enable key, unresolved issues in North Atlantic climate to be addressed. In particular, estimates of the sensitivity of the mid-latitude atmosphere to changes in surface boundary conditions requires seasonally-resolved records of SST that span the significant climatic events of the late Holocene. The PIs will examine possible secular changes in SST related to global warming and the connection with the NAO anomaly of the past 30 years. Other key questions relate to the sensitivity of SST to solar forcing and volcanic eruptions, and the existence of decadal through centennial-scale periodicity in surface ocean conditions.