P2C2: Towards a precipitation history of Easter Island since the last glacial period

为了改进对数百年尺度气候变化的预测，记录过去大气过程对气候强迫的区域响应至关重要。与此同时，虽然东南太平洋是一个重要的反馈在这样的全球气候过程的区域，目前有一个高分辨率的连续记录，可以提供该地区的沉积记录档案。 该项目将利用复活节岛湿地沉积物中记录的降水变化档案，从过去的气候中提供这一重要而新颖的视角。研究人员将提供高分辨率的年表和过去降水的初步记录，这将有助于分析数百年的气候变化，以了解这一全球关键地区自然气候变化的原因，时间和幅度。研究结果将为复活节岛的水资源管理提供有价值的信息，研究人员将通过叙述和广泛的媒体宣传，通过复活节岛的透镜与水资源管理人员交流结果。具体而言，该项目旨在开发复活节岛降水变化的连续定量记录，以记录过去30，000年东南太平洋大气环流模式的变化。目前没有来自东南太平洋中心的连续数据集可用于评估该区域在末次冰期之后大气模式的演变或数百年尺度变化的特征。研究人员将开始从最近从复活节岛收集的湿地沉积物岩心中开发基于化合物特定同位素的过去降水记录，并为这些记录开发一个精确且控制良好的年代框架。该项目还将为共同时代制作记录，当时复活节岛被拉帕努伊文化占领。Cryptotephra分析将加强14C为基础的深度年龄模型在人类占领期间。该项目的目标是：（1）通过生成复活节岛过去30 000年降雨量的连续记录，记录和比较东南太平洋大气变化的模式，这些模式是末次冰期和当前间冰期的特征，包括平均气候学的差异以及数百年和千年尺度的变化，2）记录了复活节岛在几个世纪前、期间和之后的降水变化。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

In order to improve forecasts of multi-centennial-scale climate change, it is critical to document past regional responses of atmospheric processes to climate forcing. Meanwhile, although the southeastern Pacific is a region with important feedbacks in such global climate processes, there is currently a lack of high-resolution continuous records from this region that can be provided by archives in sedimentary records. This project will provide this important and novel perspective from past climates by using archives of precipitation changes recorded in wetland sediments on Easter Island. The researchers will provide a high-resolution chronology and preliminary records of past precipitation, which will help facilitate analysis of multi-centennial climate change to inform the causes, timing and magnitudes of natural climate variation in this globally critical region. The results will provide valuable information for water resource management on Easter Island, and the researchers will communicate results with water managers through narratives and widely available media-based outreach for communication of climate science through the lens of Easter Island. Specifically, this project aims to develop continuous quantitative records of precipitation change on Easter Island to document changes in atmospheric circulation patterns in the SE Pacific spanning the past 30,000 years. There are currently no continuous data sets available from the heart of the SE Pacific to assess the evolution of atmospheric patterns in the region following the last glacial period or the character of multi-centennial-scale variability. The researchers will begin to develop compound-specific-isotope-based records of past precipitation from recently collected wetland sediment cores from Easter Island, and develop a precise and well-controlled chronological framework for these records. The project will also produce records for the Common Era, when Easter Island was occupied by the Rapanui culture. Cryptotephra analyses will reinforce 14C-based depth-age models during the period of human occupation. The objectives of the project are to 1) document and compare the patterns of SE Pacific atmospheric variability that characterized the last glacial and current interglacial periods, including differences in mean climatology and in the multicentennial- and millennial-scale variability, by generating continuous records of Easter Island rainfall for the past 30,000 years, and 2) document the precipitation changes on Easter Island that occurred in the centuries prior to, during, and following the settlement of Easter Island ca. 700-1000AD by ancient Polynesians, and throughout the rise and fall of the Rapanui culture during the second millennium AD.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.