Ecohydrology in Permafrost Systems: The Impact of Watershed Heterogeneity on Stream Flow Dynamics and Hydrologic Pathways

多年冻土系统的生态水文学：流域异质性对溪流动力学和水文路径的影响

• 批准号: 1114457
• 负责人: William Bolton
• 金额: $ 54.45万
• 依托单位: University of Alaska Fairbanks Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1114457&HistoricalAwards=false
• 关键词: Ecohydrology; Permafrost; Systems; Impact; Watershed

The overall objective of this study is to quantify the relative roles of vegetation water use and soil water storage dynamics associated with permafrost presence/absence in determining the water flow pathways, mechanisms, timing and magnitudes in the sub-Arctic boreal forest ecosystem. This ecosystem is located in the zone of discontinuous permafrost and has two primary ecosystem types: permafrost free, deciduous dominated and permafrost affected, coniferous dominated. This study will integrate climatic, ecologic, thermal, and hydrologic processes through an intense field study program using hydrologic modeling. The field site comprises three catchments that represent a gradient of varying permafrost extent and ecosystem-type composition at the Caribou Poker Creeks Research Watershed (CPCRW) Long Term Ecological Research (LTER) site. In addition to stream flow observations, measurements of plant water use, soil moisture, seasonal soil thaw, and meteorologic variables will be collected along a north-facing (permafrost affected) coniferous dominated ecosystem to a south-facing (permafrost free) deciduous dominated ecosystem. Data from the field study will be used to develop and parameterize a vegetation water use model, which in turn will be integrated into a hybrid hydrologic model. Development of this semi-distributed, process-based hybrid hydrologic model will simulate the major hydrologic processes of the boreal forest ecosystem, emphasizing the water storage and release mechanisms. The boreal forest is a critical source of Alaska?s freshwater. This study will contribute to improved understanding and prediction of freshwater availability that will be affected by changes in permafrost and ecosystem distributions in the boreal forest. This study will also advance the field of ecohydrology, which is relatively under-explored in northern systems. The sub-Arctic environment will be the first in the Arctic to experience most of the current or expected climate-associated changes. Such changes have the potential to shift the magnitude and timing of freshwater delivery to the Arctic Ocean which is anticipated to lead to changes in sea-ice formation, thermohaline circulation, and ultimately the climate system from local to global scales. Outreach is an important aspect of this study. Teachers from local K-12 schools will participate in training workshops focused on the boreal forest ecosystem that will be conducted in conjunction with the Global Learning and Observations to Benefit the Environment program (GLOBE) program at the University of Alaska Fairbanks. Prior experience shows that the approach that will be used in this project is an effective means to integrate the natural science of the region into local classrooms.

本研究的总体目标是量化与永久冻土存在/缺失相关的植被水分利用和土壤水分储存动态在确定亚北极北方森林生态系统水流路径、机制、时间和规模方面的相对作用。该生态系统位于断续多年冻土带，主要有两种生态系统类型：无多年冻土、落叶为主和受多年冻土影响、针叶林为主。本研究将整合气候，生态，热，和水文过程，通过一个密集的实地研究计划，利用水文模型。现场包括三个集水区，代表了北美驯鹿扑克溪研究流域（CPCRW）长期生态研究（LTER）站点不同的永久冻土范围和生态系统类型组成的梯度。除了河流流量观测，植物水分利用、土壤湿度、季节性土壤解冻和气象变量的测量将沿着朝北（受永久冻土层影响）的针叶林为主的生态系统到朝南（无永久冻土层）的落叶为主的生态系统收集。实地研究的数据将用于开发和参数化植被用水模型，该模型又将被纳入混合水文模型。该半分布式、基于过程的混合水文模型的开发将模拟北方森林生态系统的主要水文过程，强调水的储存和释放机制。北方森林是阿拉斯加的重要资源。淡水。这项研究将有助于提高对受冻土带和北方森林生态系统分布变化影响的淡水供应的认识和预测。该研究还将推动生态水文学领域的发展，这一领域在北方系统中开发相对不足。亚北极环境将是北极地区首先经历当前或预期的大部分气候相关变化的环境。这种变化有可能改变向北冰洋输送淡水的规模和时间，预计这将导致海冰形成、温盐环流的变化，并最终导致气候系统从局部尺度到全球尺度的变化。外展是本研究的一个重要方面。当地K-12学校的教师将参加以北方森林生态系统为重点的培训讲习班，该讲习班将与阿拉斯加费尔班克斯大学的全球学习和观察环境项目（GLOBE）项目一起进行。以往的经验表明，该项目将采用的方法是将该地区的自然科学融入当地课堂的有效手段。