Temperature and variability of the Atlantic Warm Pool during and since the Little Ice Age

热带大西洋西部，特别是大西洋暖池（AWP）区域的海洋表面热量，为大西洋飓风活动提供燃料，并对太平洋东北部、中美洲和美国东南部的降雨产生强烈影响。然而，AWP的大小和温度如何对气候变化作出反应还不是很清楚，这在很大程度上是因为海洋温度的仪器记录太短，无法准确评估气候变化发生的年代际和多年代际时间尺度上的变率。生长在AWP珊瑚礁上的大量长寿珊瑚在其骨骼的地球化学中记录了这些信息。该项目将利用一种新开发的珊瑚古温度计Sr-U，重建小冰期（最近~500年）以来AWP的连续温度记录。该项目包括对来自墨西哥自治大学（UNAM）和波多黎各大学（UPR）的一名博士后研究员和两名研究生的指导，他们将参与实地考察、实验室分析和手稿准备。一个成功的结果将提供描述人为变暖对AWP影响的特征和评估大西洋部门未来气候变化模式预估技能所需的数据。作为地球上第二大暖水区，AWP对气候有着重要的影响。西部热带AWP海温（SST）与大西洋多年代际涛动（AMO）、飓风强度和东北太平洋、中美洲和美国东南部降水异常相关。然而，20世纪前南极海温的演变缺乏约束，限制了我们对南极海温、大小和变率对自然和人为气候强迫的敏感性的理解。本计划将采用一种新的珊瑚古温度计Sr-U，在三个理想地点取样珊瑚，重建过去500年的连续海温记录，以研究多年代际尺度上AWP的扩张和收缩。来自尤卡坦半岛东部、美属维尔京群岛和巴哈马群岛附近的珊瑚的新数据，将有助于评估AWP上人为印记的时间和性质、AWP多年代际变率的持久性、AWP海温对太阳、火山和内部强迫的敏感性，以及AWP与大西洋飓风变率之间的联系。这三个站点的海温记录也将为WTA低热降温的总体幅度提供新的证据，这是一个具有很大不确定性的主题，并可用于评估模式预测未来气候变化的技能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Surface ocean heat in the western tropical Atlantic, specifically the Atlantic Warm Pool (AWP) region, fuels Atlantic hurricane activity and exerts strong influence on rainfall in the northeastern Pacific, Central America, and southeastern United States. How the size and temperature of the AWP responds to climate change, however, is not well-understood, in large part because the instrumental record of ocean temperature is too short to enable accurate evaluation of variability on the decadal and multi-decadal timescales over which climate change occurs. Massive long-lived corals that grew on reefs in the AWP record this information in the geochemistry of their skeletons. This project will utilize a newly developed coral paleothermometer, Sr-U, to reconstruct continuous records of temperature in the AWP during and since the Little Ice Age (the last ~500 years). The project includes mentorship of a postdoctoral researcher and two graduate students from the Autonomous University of Mexico (UNAM) and University of Puerto Rico (UPR) who will participate in fieldwork, laboratory analyses and manuscript preparation. A successful outcome will provide the data needed to characterize the influence of anthropogenic warming on the AWP and to evaluate the skill of model projections of future climate change in the Atlantic sector. As the second largest body of warm water on the planet, the AWP exerts a significant influence on climate. Sea surface temperatures (SST) in the western tropical AWP are correlated to the Atlantic Multidecadal Oscillation (AMO), hurricane intensities and precipitation anomalies in the northeastern Pacific, Central America, and southeastern United States. Yet, the pre-20th century SST evolution of the AWP is poorly constrained, limiting our understanding of the sensitivity of AWP temperature, size, and variability to the natural and anthropogenic forcing of climate. This project will apply a novel new coral paleothermometer, Sr-U, to reconstruct continuous records of SST over the past 500 years using corals sampled at three locations ideally placed to study the expansion and contraction of the AWP on multidecadal time scales. The new data, from corals collected near the eastern Yucatan Peninsula, US Virgin Islands and Bahamas, will enable evaluation of the timing and nature of the anthropogenic imprint on the AWP, the persistence of multi-decadal variability in the AWP, the sensitivity of AWP SSTs to solar, volcanic and internal forcing, and the link between AWP and Atlantic hurricane variability. SST records from these three sites will also provide new evidence for the overall magnitude of LIA cooling in the WTA, a subject of great uncertainty, and be used to evaluate the skill of model projections of future climate change.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.