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)地区的表层海洋热量助长了大西洋飓风的活动，并对太平洋东北部、中美洲和美国东南部的降雨产生了强烈影响。然而，AWP的大小和温度如何对气候变化作出反应还没有得到很好的理解，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十年和几十年时间尺度上的可变性。在AWP的珊瑚礁上生长的巨大的长寿珊瑚在它们骨骼的地球化学中记录了这一信息。该项目将利用新开发的珊瑚古温度计，锶-U，重建小冰期(过去约500年)以来AWP地区温度的连续记录。该项目包括指导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，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必要的数据，以确定人为变暖对AWP的影响，并评估大西洋地区未来气候变化模型预测的技能。作为地球上第二大温暖水域，AWP对气候产生了重大影响。热带AWP西部海面温度(SST)与太平洋东北部、中美洲和美国东南部的大西洋年代际涛动(AMO)、飓风强度和降水异常相关。然而，20世纪以前AWP的SST演变受到的限制很小，限制了我们对AWP温度、大小和变率对自然和人为气候强迫的敏感性的理解。该项目将应用一种新的珊瑚古温度计--锶-U，重建过去500年来SST的连续记录，使用在三个理想位置采样的珊瑚，以研究AWP在数十年时间尺度上的扩张和收缩。新的数据来自尤卡坦半岛东部、美属维尔京群岛和巴哈马附近采集的珊瑚，将有助于评估AWP人为影响的时间和性质、AWP中多年代际变化的持续性、AWP海温对太阳、火山和内部强迫的敏感性，以及AWP与大西洋飓风变化之间的联系。这三个地点的SST记录也将为WTA的LIA冷却的总体规模提供新的证据，这是一个具有很大不确定性的主题，并将被用于评估未来气候变化的模型预测的技能。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.