Collaborative Research: Surface-Atmosphere Feedbacks and Holocene Climate Variations in Eastern North America: Linkages, Impacts, and Governing Mechanisms

该奖项支持以下研究：记录北美东部千年尺度的气候变化和土地覆盖变化的时空模式，评估气候的全球强迫（轨道变化、微量气体浓度）和区域控制（土地覆盖变化、地形、湖泊效应）之间的相互作用及其对全新世气候变率的相对影响，并确定控制地表-大气反馈的关键机制。本研究将利用区域气候模式（RegCM2）与新一代土地覆盖重建相结合，详细描述全新世地表-大气反馈对大气过程的影响。模式结果将根据基于多个气候代理记录网络的北美东部千年分辨率气候重建结果进行评估。密集的代用记录网络以及全新世温度、干旱和土地覆盖的大范围和区域性变化，使北美东部成为温带地区研究气候系统外部强迫与内部反馈之间相互作用的绝佳案例。这项研究很重要，因为全新世期间的气候变化是实质性的，空间可变的，并且跨越了广泛的频率和变化速率。尽管这些变化部分受到气候系统外部机制的强迫，但大气、海洋和陆地生物圈之间的内部相互作用是气候变率的关键来源和调节器。特别是，地表-大气反馈正受到越来越多的科学关注，因为最近有证据表明，这种反馈在区域到全球尺度上对全新世和近代气候过程产生强烈影响，其影响程度可与轨道强迫和温室气体强迫相比较。总而言之，该项目将促进我们对全新世气候变率以及气候与植被动态之间相互作用的理解，加强科学基础设施，建立机构间的伙伴关系，并帮助支持新一代气候科学家。在这项工作过程中产生的所有模型和数据综合将在出版后储存在世界数据中心。

This award supports research to document the spatial and temporal modes of climate variation and land-cover change in eastern North America at millennial scales, assess the interactions between global forcings (orbital variations, trace gas concentrations) and regional controls (land-cover change, topography, lake effects) of climate and their relative effects on Holocene climate variability, and identify the critical mechanisms governing surface-atmosphere feedbacks. This research will utilize a Regional Climate Model (RegCM2) in combination with a new generation of land-cover reconstructions to detail the effect of Holocene surface-atmosphere feedbacks on atmospheric processes. Model results will be evaluated against millennially resolved climate reconstructions for eastern North America based upon multiple networks of climate proxy records. The dense networks of proxy records and the large and regionally varied changes in Holocene temperature, aridity, and land cover make eastern North America an excellent case study for the interplay between forcings external to the climate system and internal feedbacks in temperate regions. This research is important because climate variations during the Holocene were substantial, spatially variable, and spanned a wide range of frequencies and rates of change. Although these variations are in part forced by mechanisms external to the climate system, internal interactions among the atmosphere, oceans, and terrestrial biosphere are a critical source and modulator of climate variability. In particular, surface-atmosphere feedbacks are receiving increased scientific interest, due to recent demonstrations that such feedbacks exert a strong influence on Holocene and Recent climate processes at regional to global scales, with a magnitude comparable to orbital and greenhouse gas forcings. In summary, this project will advance our understanding of Holocene climate variability and the interactions between climate and vegetation dynamics, enhance the scientific infrastructure, build partnerships among institutions, and help support a new generation of climate scientists. All model and data syntheses produced during the course of this work will be stored at the World Data Center upon publication.