Regolith-tree-atmosphere water transport on bedrock, rock joints, and talus and wildfire-mesoscale coupled models

基岩、岩石节理和距骨上的风化层-树木-大气水传输以及野火-中尺度耦合模型

• 批准号: RGPIN-2018-03798
• 负责人: Johnson, Edward
• 金额: $ 2.4万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654724
• 关键词: Regolith; tree; atmosphere; water; transport

This research program's goal is to enhance understanding of ecosystem processes by focusing on the integrative connections between ecological processes and the geosphere, hydrosphere, and atmosphere processes. ***Our first set of projects is to model the processes that connect wildfire, fuel, and weather dynamics to the ecological effects of the wildfire at the individual plant and population levels. The project proposes coupling (interacting) a wildfire process model to a mesoscale weather model. The significant advance is the beginnings of a complete fire behaviour-fire ecology- atmospheric model that can be tested in operational situations. This model can be used for hindcasting and forecasting of wildfires (Bakhshaii & Johnson 2017). We have already incorporated as a subprogram in the wildfire model the ecological effect of necrosis and mortality of trees (Michaletz & Johnson 2006; 2008; 2012). The innovation is the coupling of weather at multiple scales and in the use of assimilation methods to improve accuracy of wildfire behaviour (flame length, smoke distribution, rate of spread and pattern of spread) in boreal and subalpine forests. The model proposed here is a coupled system between the combustion and atmospheric processes. This is an important change in viewpoint from the current correlations of fire heat output and rate of spread with temperature, relative humidity. precipitation and wind to a coupled combustion and fluid dynamics process model, in other words showing how the fire works and is influenced by its interaction with mesoscale weather. ***Our second set of projects is to explain how trees survive on three extreme but abundant habitats in the Canadian Rockies that are rarely studied and make up more then half of the area. The significance is that these projects combine geomorphic, hydrologic, and ecologic processes and that these abundant mountain habitats play an important role in the water budgets of these mountain water towers. The approach is to model the water budgets as a soil-root-stem-leaf-atmosphere continuum of water flow to understand their regulation. In addition, the use of stable isotopes will allow determination of the length of time it takes for water from various sources (precipitation, in rocks, in joints, in talus or different rock types) to be transpired by trees. The factors affecting trees on each habitat are different. The cliff habitat has stress joints and bedding planes that have little soil and limited water supply and hence high-water stress. Talus (scree) have talus movement and a surface layer of larger rocks and the subsurface layer of smaller sediment (i.e. well drained surface and moister subsurface). Consequently, the trees have to deal with the competing processes of uprooting and water stress. The third habitat of bedrock hillslopes has varied bedrock types and slope angles and thus varied soil depth and water supply over very short distances. **

该研究计划的目标是通过关注生态过程与地圈、水圈和大气过程之间的综合联系来加强对生态系统过程的理解。*我们的第一套项目是模拟将野火、燃料和天气动态与野火在单个植物和种群水平上的生态影响联系起来的过程。该项目建议将野火过程模式与中尺度天气模式耦合(相互作用)。这一重大进展是一个完整的火灾行为-火灾生态-大气模型的开始，该模型可以在操作情况下进行测试。该模型可用于野火的事后预测和预测(Bakhshaii&Johnson 2017)。我们已经将树木死亡和死亡的生态效应作为一个子项目纳入了野火模型(Michaletz&Johnson，2006；2008；2012)。创新之处在于结合了多个尺度的天气，并使用同化方法来提高北部和亚高山森林野火行为(火焰长度、烟雾分布、蔓延速度和蔓延模式)的准确性。该模型是一个燃烧过程和大气过程之间的耦合系统。从目前火灾热输出和蔓延速度与温度、相对湿度的关系来看，这是一个重要的观点变化。将降水和风转化为燃烧和流体动力学耦合过程模型，换言之，显示了火灾是如何工作的，并受到其与中尺度天气相互作用的影响。*我们的第二套项目是解释树木如何在加拿大落基山脉的三个极端但丰富的栖息地生存，这些栖息地很少被研究，占面积的一半以上。其意义在于，这些工程结合了地貌、水文和生态过程，这些丰富的山地栖息地在这些山脉水塔的水量收支中发挥着重要作用。方法是将水收支模拟为土壤-根-茎-叶-大气的水流动连续体，以了解它们的调节。此外，稳定同位素的使用将能够确定来自各种来源(降水、岩石、节理、距岩或不同岩石类型)的水被树木蒸发所需的时间长度。影响每个栖息地的树木的因素是不同的。悬崖栖息地有应力节理和层面，土壤很少，供水有限，因此水压力很大。滑石(碎石)有滑石运动，表层有较大的岩石，次表层有较小的沉积物(即排水良好的表面和较潮湿的地下)。因此，树木必须应对拔掉根和水分胁迫的相互竞争的过程。基岩山坡的第三个生境具有不同的基岩类型和坡度，因此在很短的距离内土壤深度和供水也不同。**