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

该奖项支持开展研究，记录北美东部千年尺度上气候变化和土地覆盖变化的时空模式，评估气候的全球作用力(轨道变化、微量气体浓度)和区域控制(土地覆盖变化、地形、湖泊影响)之间的相互作用及其对全新世气候变异性的相对影响，并确定控制地面-大气反馈的关键机制。这项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，详细说明全新世地表大气反馈对大气过程的影响。将根据气候代理记录的多个网络，对照北美东部千年分辨率的气候重建对模型结果进行评估。密集的代理记录网络以及全新世温度、干旱和土地覆盖的大而不同的变化，使北美东部成为研究气候系统外部作用力与温带地区内部反馈之间相互作用的极好案例。这项研究很重要，因为全新世的气候变化是巨大的，在空间上是可变的，并且跨越了广泛的频率和变化速度。虽然这些变化在一定程度上是由气候系统外部的机制迫使的，但大气、海洋和陆地生物圈之间的内部相互作用是气候变异性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，这种反馈对全新世和最近在区域到全球范围内的气候过程产生了强烈影响，其规模相当于轨道和温室气体的强迫作用。总而言之，该项目将促进我们对全新世气候变异性以及气候和植被动态之间相互作用的理解，加强科学基础设施，在机构之间建立伙伴关系，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合成在出版后将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.