Collaborative Research: P2C2--High Frequency Hydroclimate Extremes and Synoptic Climate Drivers in Western North America at the End of the Little Ice Age

鉴于未来极端气候的潜在变化，了解洪水和干旱等对社会和生态系统有重大影响的极端气候事件变得尤为重要。古气候数据在将最近的水气候极端放在较长期的背景下发挥了关键作用，但古气候指标的偏差仍然是重建和解释过去气候极端的主要挑战。这尤其适用于北美西海岸，那里的季节性极端降水事件数量有限，占年总降水量的很大比例。这项研究将结合历史气候学和树状气候学，通过重点关注19世纪，解决仪器捕获之前的极端情况，这一时间段包括仪器记录中没有代表的一系列气候极端事件。具体地说，这个项目的目标是：(1)从档案和储存库中提取19世纪的历史数据，以获得亚季节降水和降雪频率的重建；(2)使用树轮数据来评估现有记录捕获极端水文气候(重点是大气河流事件)和西海岸特定季节降水的能力；以及(3)综合历史和树轮数据来创建19世纪极端事件的空间气候面，并使用再分析数据、网格化的古气候重建数据和古气候模式输出来评估这些极端的天气气候驱动因素(B.I.)。包括改进对季节性极端气候事件的了解具有广泛的社会影响，因为这些极端事件是代价高昂的危险，对农业、供水、发电、火灾和社会其他部门都有影响。这项研究得出的信息可能对水资源管理者、气候模型师和其他对过去极端事件的特征感兴趣的人有用，包括影响和驱动机制，以及未来的水气候极端事件。该项目的其他影响包括：(1)对研究生进行研究方法和传播、科学交流和教育推广方面的教育和培训；(2)让本科生参与实践研究，使他们能够在科学过程中工作；(3)对NOAA古气候学资料库作出新的、空间上明确的气候重建的贡献；以及(4)利用我们研究主题的兴奋性，通过与莫尔黑德天文馆和科学中心合作的K-12教育推广活动，吸引未来几代科学家。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。

Understanding extreme climate events like floods and droughts, which have major impacts on society and ecosystems, has become particularly important in light of potential future changes in climatic extremes. Paleoclimate data have played a critical role in placing recent hydroclimate extremes within a longer-term context, but biases in paleoclimate proxies remain a major challenge for the reconstruction and interpretation of past climate extremes. This is particularly applicable to the North American West Coast where a limited number of seasonal extreme precipitation events account for a large proportion of annual precipitation totals. This research will integrate historical climatology and dendroclimatology to address pre-instrumental capture of extremes through a focus on the 1800s, a time period including a range of climate extremes that are not represented in the instrumental record. Specifically, the aims of this project are to: (1) extract 19th century historical data from archives and repositories to derive subseasonal precipitation and snow frequency reconstructions; (2) use tree-ring data to assess the ability of existing records to capture hydroclimatic extremes (with a focus on atmospheric river events) and seasonally-specific precipitation on the West Coast; and (3) integrate historical and tree-ring data to create spatial climate surfaces for extreme events in the 1800s and use reanalysis data, gridded paleoclimate reconstruction data, and paleoclimate model output to assess synoptic climate drivers of those extremes.The potential Broader Impacts (B.I.) include improved understanding of extreme climate events at a seasonal level has broad societal implications, as these extremes are costly hazards with implications for agriculture, water supply, power generation, fire, and other sectors of society. The information derived from this research is potentially useful to water managers, climate modelers, and others who are interested in the characterization of past extreme events, including impacts and driving mechanisms, as well as future hydroclimate extremes. Further impacts of this project include: (1) education and training of graduate students in research methods and dissemination, science communication, and educational outreach; (2) involving undergraduates in hands-on research experiences, allowing them to work through the scientific process; (3) contribution of new, spatially explicit climate reconstructions to the NOAA Paleoclimatology repository; and (4) capitalizing on the excitement of our research themes to engage future generations of scientists through K-12 educational outreach activities involving a partnership with the Morehead Planetarium and Science Center.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.