Collaborative Research: Quantification of Dominant Heat Fluxes in Streams and Rivers in Arctic Alaska

了解气候变化对淡水生态系统的影响高度依赖于对河流温度相关变化的量化。然而，这可能会很复杂，因为这些温度与不断变化的气象学（例如，气温和降水）和水文学（例如，河流流量和侧向流入）有关。由于对关键过程的了解很少，以及缺乏量化热通量的数据，预测北极河流中与气候有关的热状态变化的能力受到限制。研究人员假设，北极河流中的主要热通量与温带气候中的热通量相似，但热通量的相对大小不同，而侧向流入的量化是预测水温的关键。为了验证这一假设，他们将解决以下三个研究问题：1)整个温暖季节关键热通量的重要性变化；2)侧向流入对了解河流温度状况的重要性；3)河流温度对气候变化驱动因素的敏感性。为了回答前两个问题，他们将：利用数据收集和建模工作来量化阿拉斯加图里克湖附近两种具有代表性的北极河流类型（冲积河和泥炭河）的热通量；适应基于温带水文研究的河流温度模式，以确定哪些热通量对预测北极河流温度的时空变化是必要的；并使用河段和流域尺度的差分测量，以及分布的河流温度和其他措施，来量化山坡-河流的连通性和横向流入。鉴于这些结果，他们将通过对预期气候变化的敏感性分析来解决问题3，以确定河流温度制度的关键水文和气象驱动因素。最终，他们将开发一个北极特有的温度模型，提供对河流温度的预测能力。在研究过程中，研究人员将与犹他州和阿拉斯加州的高中科学教师密切合作，开发相关的课程练习，并随后在全国范围内推广。研究生和本科生将参与实地和分析工作，调查人员将与阿拉斯加当地以水生资源为食物的社区分享他们的结果。

Understanding the impacts of climate change on freshwater ecosystems is highly dependent on quantifying the associated changes in instream temperatures. However, this can be complicated because these temperatures are related to both changing meteorology (e.g., air temperature and precipitation) and hydrology (e.g., instream flows and lateral inflows). The ability to predict climate related changes on instream thermal regimes in Arctic streams is limited by the minimal understanding of key processes and the availability of data to quantify heat fluxes. The investigators hypothesize that the dominant heat fluxes within Arctic streams are similar to those in temperate climates but that the relative magnitude of the heat fluxes differ, and that quantification of lateral inflows is key in predicting water temperatures. To test this hypothesis, they would address three research questions regarding 1) the changing importance of key heat fluxes throughout the warm season; 2) the importance of lateral inflows to understanding instream temperature regimes; and 3) the sensitivity of instream temperatures to climate change drivers. To answer the first two questions, they would: quantify heat fluxes using data collection and modeling efforts in two representative arctic river types (alluvial and peat lined, beaded) near Toolik Lake, Alaska; adapt instream temperature models based on prior temperate zone hydrologic research to determine which heat fluxes are necessary to predict the spatial and temporal variability of Arctic instream temperatures; and use differential gauging at the reach and basin scales, along with distributed instream temperatures and other measures, to quantify hillslope-stream connectivity and lateral inflows. Given these results, they would address question 3 by conducting sensitivity analyses of anticipated climatic variability to identify the key hydrologic and meteorological drivers of instream temperature regimes. Ultimately, they would develop an Arctic-specific temperature model that provides predictive capabilities of instream temperatures. In the course of this research, the investigators would develop related curriculum exercises in close collaboration with high school science teachers in both Utah and Alaska, and subsequently make these available nationally. Graduate and undergraduate students would participate in the field and analytical work, and the investigators would share their results with local communities in Alaska who depend on aquatic resources for food.