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

为了提高对多百年尺度气候变化的预测，记录过去区域大气过程对气候强迫的响应是至关重要的。同时，东南太平洋虽然是全球气候过程中具有重要反馈作用的区域，但目前缺乏沉积记录档案提供的该区域高分辨率连续记录。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。研究人员将提供一个高分辨率的年表和过去降水的初步记录，这将有助于促进对这个全球关键地区的百年气候变化的分析，以了解自然气候变化的原因、时间和幅度。这些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可用的基于媒体的外联活动，通过复活节岛的镜头传播气候科学，将结果与水资源管理者交流。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3万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来评估末次冰期后该地区大气格局的演变或多百年尺度变率的特征。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时间框架。该项目还将制作共同时代的记录，当时复活节岛被拉帕努伊文化占领。隐球菌分析将加强人类活动时期基于14c的深度年龄模型。该项目的目标是：1)通过生成过去3万年的复活节岛降水连续记录，记录和比较末次冰川期和当前间冰期特征的东南太平洋大气变率模式，包括平均气候学和百年际和千年尺度变率的差异；2)记录复活节岛在过去几个世纪、期间、公元700年至1000年，古波利尼西亚人在复活节岛定居，以及公元第二个千年期间拉帕努伊文化的兴衰。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。

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.