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

黑云杉树木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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709623
• 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.

NSERC DG的长期目标是在温带和寒带等地区进行基于树木年轮的水文气候重建，这些地区严重缺乏过去水文波动的知识。这些重建将提供一个更准确的基线，可以与最近的变化进行比较，并将对这些研究不足的地区长期水文气候变化的起源提出新的见解。为了实现这一目标，我们将提出一种新的代理模型融合方法，专门用于克服树木生长远离环境压力条件地区的树木年代学家遇到的困难。