Collaborative Research: Multi-century hydrologic and NAO variability in the tropical Western Atlantic - A Marine NAO Synthesis

了解北大西洋地区的气候变化对美国东部、西欧和其他地区的社会至关重要。 特别是北大西洋涛动（NAO），一种改变海面温度的大气压力系统，影响美国和欧洲人口密集中心的陆地温度，干旱和风暴轨迹。 虽然我们现在可以每年测量NAO，但对其长期行为或未来行为如何变化知之甚少。 该项目将利用加勒比海南部托巴哥岛的珊瑚记录过去的气候变化，该地区对北大西洋涛动的影响特别敏感。 将使用水下呼吸器采集巨型脑珊瑚的钻芯，并对钻芯进行化学分析，以生成过去几个世纪以来的温度、盐度和降雨量的月度历史。 这些气候记录将有助于深入了解热带大西洋气候变率的时空模式，特别是与NAO相关的大尺度过程。 这项国际合作将支持特立尼达和托巴哥大学的一名研究生前往AMNH和WHOI接受珊瑚X射线和地球化学分析方面的指导和培训。 该项目还包括积极参与AMNH和WHOI的教育和推广计划，包括行星地球厅，AMNH游客和学校团体选择的前五个霍尔斯之一。该项目将通过生成高分辨率（每月），多世纪的南加勒比海水文特性记录，直接促进NSF的气候变化古观点（P2 C2）目标。包括海表温度（SST）、海表盐度（SSS）和当地河流径流。 这项研究将导致从东北部托巴哥收集两个多世纪的珊瑚钻芯，并随后构建古气候记录，解决整个季节性周期，关键是确定北大西洋涛动（NAO）等区域强迫的签名。锶钙（Sr/Ca）比值将用于重建SST，氧同位素（del 18 O）比值与Sr/Ca将用于重建SSS。 最后，钡钙（Ba/Ca）比值将产生陆地输入和河流径流的记录。 这项调查将针对Siderastrea和Colpophyllia珊瑚物种以前显示，忠实地记录气候变量与骨骼地球化学代理。 从这个敏感站点重建冬季SST将捕获长期NAO变率，与大西洋和红海的NAO和SST的现有记录进行比较，将允许调查过去几个世纪海洋NAO信号的区域一致性和空间稳定性的变化。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准。

Understanding climate variability in the North Atlantic region is critical to society in the Eastern United States, Western Europe and beyond. In particular, the North Atlantic Oscillation (NAO), an atmospheric pressure system that alters sea surface temperatures, influences land temperature, drought, and storm tracks across the dense population centers of the US and Europe. While we can now measure the NAO each year, little is known about its longer-term behavior, or how its behavior may change in the future. This project will generate records of past climate change using corals from the island of Tobago in the southern Caribbean Sea, a region especially sensitive to the effects of the NAO. Drill cores of giant brain corals will be taken using SCUBA, and chemical analysis of the cores will be used to generate monthly histories of temperature, salinity and rainfall that extend back over the past several centuries. These climate records will provide insights into the temporal and spatial patterns of tropical Atlantic climate variability, particularly the large-scale processes associated with the NAO. This international collaboration will support a graduate student from The University of Trinidad and Tobago to travel to AMNH and WHOI for mentorship and training in coral x-ray and geochemical analysis. The project also includes active participation in the educational and outreach programs at both AMNH and WHOI, including the Hall of Planet Earth, among the top five halls chosen by AMNH visitors and school groups.This project will contribute directly to NSF's Paleo Perspectives on Climate Change (P2C2) goals by generating high resolution (monthly), multi-century long records of the hydrologic properties in the southern Caribbean Sea, including sea surface temperature (SST), sea surface salinity (SSS) and local river runoff. The study will result in collection of two multi-century coral drill cores from northeastern Tobago, and subsequently the construction of paleoclimate records that resolve the full seasonal cycle, critical for identifying signatures of regional forcing such as the North Atlantic Oscillation (NAO). Strontium-calcium (Sr/Ca) ratios will be used to reconstruct SST, and oxygen isotope (del18O) ratios together with Sr/Ca will be used to reconstruct SSS. Finally, barium-calcium (Ba/Ca) ratios will yield records of terrestrial input and river runoff. This investigation will target Siderastrea and Colpophyllia coral species previously shown to faithfully record climatic variables with skeletal geochemical proxies. A winter-season SST reconstruction from this sensitive site will capture long-term NAO variability, and comparison with existing records of the NAO and SST from the Atlantic and Red Sea will allow investigation of regional coherence and changes in the spatial stationarity of the marine NAO signal over the past few centuries.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.