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

根据该奖项，PI将使用大型珊瑚头主要是Diploria criticalthiformis的物种，以重建多世纪以来北大西洋西部亚热带SST变化的长期记录。 这将有助于在十年和更长的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。可用 SST仪器记录可以追溯到世纪以前。 然而，数据的偏差和稀疏性使得SST记录的较旧部分不可靠，NAO和中纬度SST异常之间的关联仅基于1950年以来收集的数据。 PI将使用在百慕大收集的长寿脑珊瑚来扩展中纬度北大西洋的SST记录，百慕大是一个很好的位置来索引亚热带环流。 三个独立的古温度计（18 O，Sr/Ca和骨骼生长）将被应用到两个大规模的殖民地的骨骼，以构建一个500年之久的多代理记录的SST变化在季节分辨率。 此外，PI将对四个大规模的非生命殖民地进行采样、日期确定和分析，这些殖民地已经被确定为可能足够古老，可以将500年的代理记录追溯到公元1000年。 这一长达数世纪的记录将使北大西洋气候中尚未解决的关键问题得到解决。 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季节性分辨的SST记录，这些记录跨越了全新世晚期的重大气候事件。研究结果将探讨与全球变暖有关的海表温度可能的长期变化，以及与过去30年北大西洋涛动异常的关系。其他关键问题涉及海表温度对太阳强迫和火山爆发的敏感性，以及海洋表层状况存在着十年至百年尺度的周期性。

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.