AGS-PRF: The Impacts of Hemispheric Moisture Transport and Atmospheric Dynamics on Millennial-Scale Arctic Hydroclimate through the Holocene

北极变暖的速度是全球平均速度的两倍，预计将经历降水量增加速度最快的地区之一。在当地，北极水文循环是对冰盖物质平衡、生态系统以及淡水和辐射平衡的基本控制，从而影响全球海洋和大气环流的反馈。该项目旨在对北极地区过去在全新世期间的水文气候变异性进行综合，目的是填补对控制北极水分供应的机制的认识的重大空白。具体地说，研究人员将1)为北极全新世湿度敏感记录数据库的管理做出贡献，2)应用基于机制的模型来限制从过去气候记录推断的降水变化的幅度，以及3)合成湿度敏感记录，以便与全球全新世气候重建和气候模型模拟进行比较。数据合成和数据模型比较将被用来检验以下假设：1.北极湿度敏感数据显示出经向相干的千年尺度全新世变率。对这一假设的支持表明，北极的水分有效性对大尺度经向大气输送模式很敏感，而沿子午线的替代记录的空间一致性较低，可能表明局部过程驱动了空间变异性。2.在全新世早期至中期，一股减弱和更加蜿蜒的西风急流减少了向北大西洋地区的水汽输送，同时促进了向贝林贾东部和北极其他地区的强大水汽输送。中纬度气旋活动减少与减弱的西风急流有关，这可能是全新世早期至中期北美干旱的原因之一。在北极，这一机制可能会减少北大西洋东部地区的气旋活动，同时加强对欧亚大陆和北极西部的水汽平流。或者，所有部门的类似变化可能意味着，与温暖大气中大气水汽容量增加的热力学影响相比，动态影响微不足道。潜在的更广泛的影响包括更好地了解北极地区水文气候和水分变化的长期时空变异性及其与中高纬度大气遥相关的联系。该项目将制作一个有关北极地区全新世湿度敏感记录的精选数据库，并将向公众开放。其他更广泛的影响包括与部落环境专业人员研究所(北亚利桑那大学)合作编写教育材料，为北亚利桑那州K-12和部落大学教师关于气候变化和具有社会和人类影响的可变性的讲习班创建了一个单元。研究和推广活动将为早期职业科学家提供科学和专业发展。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。

The Arctic is warming at twice the global average rate and is projected to experience among the highest rates of precipitation increase. Locally, the Arctic hydrological cycle is an underlying control on ice sheet mass balance, ecosystems, and freshwater and radiative balances, and thereby influences feedbacks in global oceanic and atmospheric circulation. This project aims to develop a synthesis of past hydroclimate variability in the Arctic region during the Holocene with the goal to fill critical gaps in understanding of the mechanisms controlling Arctic moisture availability. Specifically, the researcher will 1) Contribute to curation of Arctic Holocene moisture-sensitive record database, 2) Apply mechanistic-based models to constrain the magnitude of precipitation changes inferred from past climate records, and 3) Synthesize moisture-sensitive records for comparison with a global Holocene climate reconstruction and climate model simulations. The data synthesis and data-model comparison will be used to test the following hypotheses:1. Arctic moisture-sensitive data demonstrate meridionally-coherent millennial-scale Holocene variability. Support for this hypothesis would suggest Arctic moisture availability was sensitive to large-scale meridional atmospheric transport patterns, whereas low spatial coherence among proxy records along lines of meridian could indicate local processes drove spatial variability. 2. In the early- to mid-Holocene, a weakened and more meandering westerly jet reduced moisture transport to the North Atlantic region, while promoting strong moisture transport to eastern Beringia and other Arctic sectors. Reduced mid-latitude cyclone activity linked to a weakened westerly jet may have contributed to North American aridity in the early to mid-Holocene. In the Arctic, this mechanism would likely reduce cyclone activity in the eastern North Atlantic region, while enhancing moisture advection to Eurasia and the western Arctic. Alternatively, similar changes across all sectors may imply dynamic impacts were trivial in comparison to the thermodynamic impact of increased atmospheric moisture capacity in a warmer atmosphere. The potential Broader Impacts include a greater understanding of long-term spatiotemporal variability of hydroclimate and moisture variability in the arctic region and their link to mid- to high-latitude atmospheric teleconnections. The project will produce a curated database of moisture sensitive records in the arctic region covering the Holocene which will be made publicly available. Other Broader Impacts include the development of educational materials in partnership with the Institute for Tribal Environmental Professionals (Northern Arizona University), creating a module for a workshop for k-12 and tribal college teachers in Northern Arizona on climate change and variability with social and human implications. The research and outreach activities will provide scientific and professional development for an early career scientist.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.