Forward and inverse modeling of Black spruce tree ring series: applications to paleohydrology and paleoclimatology

黑云杉年轮系列的正向和逆向建模：在古水文学和古气候学中的应用

• 批准号: RGPIN-2016-05244
• 负责人: Boucher, Étienne
• 金额: $ 1.75万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679739
• 关键词: Forward; inverse; modeling; Black; spruce

The long-term objective of this NSERC DG is to produce hydro-climatic, tree-ring-based reconstructions in regions, such as the temperate and the boreal zones, where knowledge on past hydro-fluctuations is critically lacking. These reconstructions will provide a more accurate baseline to which recent changes can be compared and will cast a new light on the origin of long-term hydro-climatic variability in these understudied regions. To achieve this, we will propose a novel proxy-model fusion approach, specifically designed to overcome the difficulties encountered by dendrochronologists in regions where trees grow far from environmentally stressful conditions.*********In the past few decades, dendrochronology has greatly contributed to the understanding of long-term hydro-climatic changes. However, it led to equivocal results in regions where both temperature and precipitation control growth rates. The basic approach to climate reconstruction dictates a trade off between spatial resolution and climate-sensitivity, and favours the inclusion of either temperature-sensitive (restricted to latitudinal / altitudinal tree lines) or precipitation-sensitive (restricted to semi-arid regions) forest stands as proxies for past climates. However, refining our understanding of past instabilities will force tree ring scientists to extract robust hydro-climatic signals from regions that have contributed less to our understanding of global changes. Indeed, such regions are typically characterized by complex, multivariate and time-varying (divergent) proxy-climate relationships that represent major obstacles to the production of tree-ring-based reconstructions.******The novel reconstruction approach will be implemented in North-Eastern North-America (NENA)'s boreal forest which represents an archetypal example of a region where ambiguous tree-ring-to-climate relationships prevail. The approach will be based on two complementary aspects. First, climatic signal extraction will rely on multiple proxies (tree ring widths, carbon and oxygen stable isotopes) in order to strengthen the analysis of both temperature and precipitation signals. Second, relationships between proxies and climate will be assessed using process-based modeling anchored to a vast network of multi-proxy measurements that integrate all temporal scales relevant to infer past climates from tree rings: infra-annual, inter-annual, decadal, millennial. This research program will generate crucial information on long-term hydro-climate variability and persistence in NENA, which will help refine our capacity to predict (and adapt to) future changes. The program will rely on a strong and active network of collaborations at the national and international levels and will represent an excellent opportunity for trainees to be involved in a research initiative that represents the cutting edge of paleoclimatology.**

该NSERC DG的长期目的是在温带和北方地区等地区产生基于树环的重建水域的重建，在这些区域中缺乏有关过去水力透射的知识。这些重建将提供一个更准确的基准，可以比较最近的变化，并将对这些研究所研究区域的长期水性气候变异性的起源进行新的启示。为了实现这一目标，我们将提出一种新型的代理模型融合方法，专门设计，旨在克服树突年代学家在树木远离环保条件远远远远远离环境压力条件的地区遇到的困难。*********在过去的几十年中，树突年代学极大地有助于理解长期水性气候变化。但是，这导致了在温度和降水控制生长速率的区域中的模棱两可的结果。气候重建的基本方法决定了空间分辨率和气候敏感性之间的权衡，并有利于将温度敏感（仅限于纬度 /高度树线）或降水敏感（限于半干旱地区）的含义包括在内作为过去气候的代理。但是，完善我们对过去不稳定性的理解将迫使树环科学家从区域中提取强大的水力气候信号，这对我们对全球变化的理解做出了较小的贡献。实际上，此类区域通常以复杂，多元和时变（不同的）代理气候关系为特征，代表了基于树环的重建的主要障碍。******将实现新颖的重建方法在东北东北（Nena）的北方森林中，代表了一个模棱两可的树木环境关系占上风的地区的原型例子。该方法将基于两个互补方面。首先，气候信号提取将依赖于多个代理（树环宽度，碳和氧气稳定的同位素），以增强温度和降水信号的分析。其次，将使用基于过程的建模来评估代理与气候之间的关系。该研究计划将产生有关NENA长期水力气候变异性和持久性的关键信息，这将有助于完善我们预测（并适应）未来变化的能力。该计划将依靠国家和国际级别的强大而积极的合作网络，这将为受训者参与一项研究倡议的绝佳机会，该计划代表了古气候学的最前沿。