Bridging Timescales of Climate and Vegetation Change Effects on Denudation: A Coupled Modeling Approach

弥合气候和植被变化对剥蚀影响的时间尺度：耦合建模方法

• 批准号: 280608291
• 负责人: Professor Dr. Todd Alan Ehlers
• 金额: --
• 依托单位: School of Geographical and Earth Sciences
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/280608291?language=en
• 关键词: Bridging; Timescales; Climate; Vegetation; Change

This proposal is a continuation of our work conducted in EarthShape phase 1. Our phase 1 research quantifies how climate and vegetation changes since the Last Glacial Maximum to present impacted topography and erosion rates in the EarthShape study areas. We found significant changes in vegetation and erosion over the last 21 ka, and a non-linear response and thresholds in erosion to vegetation cover change. Based on these results, the dramatic environmental and tectonic changes of the Cenozoic motivate us in this second phase to bridge across longer (million year) timescales to evaluate larger magnitude climate change effects on vegetation related weathering and erosion in the Chilean Coastal Cordillera. We do this by testing the overarching hypothesis that if atmospheric CO2 levels and warmer and wetter paleoclimate in the Cenozoic (Eocene-Oligocene boundary) decreased by an order of magnitude to lower values towards present then: (1) This change would drive a marked decrease in plant productivity and vegetation cover over the Cenozoic, and (2) The vegetation changes would fundamentally alter erosion rates and plant-facilitated weathering would decrease. Thus, present day topography may contain a strong imprint of past vegetation processes. Our exploration and evaluation of this hypothesis will build upon our own and others technical achievements of the first phase. We will apply a coupled dynamic vegetation (LPJ-GUESS) and a landscape evolution (LandLab) model that will be driven by predicted paleoclimate changes (ECHAM5) over the last 34 Ma. Integral and cutting edge to our approach is linking the vegetation and landscape evolution models to calculate changes in biotic (plant facilitated) and abiotic weathering. From this, we will: a) evaluate how transient vegetation changes influence catchment denudation rates, topography, and deep weathering; b) identify the sensitivity of vegetation modulated erosion and weathering to changes in paleo atmospheric CO2, precipitation, and temperature, and c) integrate existing phase 1, and new phase 2 soil, geochemical (denudation rate), geologic, and ecologic data from other projects into our modeling framework.

该提案是我们在Earthhape F阶段进行的工作的延续。我们的第一阶段研究量化了自上次冰川最大值以来的气候和植被的变化如何变化，以目前受影响的地形和地球研究领域的侵蚀率。我们发现在过去的21 ka中，植被和侵蚀发生了显着变化，侵蚀植被覆盖变化的非线性反应和阈值。基于这些结果，新生代的戏剧性环境和构造变化激发了我们在第二阶段的启动，使我们跨越了更长的时间（百万年）时间表，以评估智利沿海地区对植被相关的风化和侵蚀的更大幅度变化影响。我们通过测试总体假设来做到这一点，即，如果大气中的二氧化碳水平以及在新生代（始新世 - 新世边界）中较温暖和湿润的古气候较高，则通过数量级减少到较低的价值降低，而当前的降低值：（1）这种变化将使植物和植物的植物范围内的植物范围弥补，植物和植物的变化将覆盖植物和植物的变化（2）植物的变化（2）植物的变化，植被构成了植物的变化。会减少。因此，当今的地形可能包含过去植被过程的强烈烙印。我们对这一假设的探索和评估将基于我们自己和其他第一阶段的技术成就。我们将采用耦合的动态植被（LPJ-Guess）和景观演化（Landlab）模型，该模型将由最后34 MA中预测的古气候变化（ECHAM5）驱动。我们方法的积分和最前沿是将植被和景观演化模型联系起来，以计算生物（植物促进）和非生物风化的变化。从中，我们将：a）评估瞬态植被的变化如何影响集水剥离率，地形和深层风化； b）确定植被调节侵蚀的敏感性和对古大气二氧化碳，降水量和温度变化的敏感性，以及c）整合现有阶段1，以及新的2期土壤，地球化学（剥夺率），地质和生态数据，来自其他项目。