Collaborative Research: The carbon balance of Lake Superior: Modeling lake processes and understanding impacts on the regional carbon budget

北美碳计划(NACP)的目的是(1)发展定量的科学知识、强有力的观测和模型，以确定二氧化碳、甲烷和CO的排放和吸收、碳储量的变化，以及控制北美和邻近海洋盆地这些过程的因素；(2)为区域和大陆尺度上的全面碳核算奠定科学基础。劳伦斯大湖覆盖了8个五大湖州25%的陆地面积，它们的二氧化碳排放和季节循环可能与当地陆地生态系统相当。尽管它们对区域碳平衡的贡献可能很大，但目前人们对这些通量知之甚少。苏必利尔湖的二氧化碳通量特别令人感兴趣，因为它们可能直接影响附近ameriFlux塔的观测，但由于目前缺乏量化，目前在分析这些数据时忽略了苏必利尔湖的通量。由于需要改善对大湖二氧化碳通量的了解，该项目将把一个生态系统碳模块与苏必利尔湖现有的水动力学模型相结合。这一模型将导致对大气-水二氧化碳通量及其时空变异性的估计。还将获得新的观察结果，以改善对冬季碳循环的了解，并限制该模型。通过模型输出，将评估苏必利尔湖二氧化碳通量对ameriFlux塔观测和区域碳收支的影响。五个关键的研究问题是：1.苏必利尔湖的空气-水碳通量有多大？2.物理气候的变化如何影响这些通量？3.苏必利尔湖的碳循环在冬季表现如何？4.苏必利尔湖碳收支中最重要的不确定因素是什么？5.苏必利尔湖的碳通量如何影响区域碳收支？这个项目汇集了一个跨学科的团队，以增进对“全球水和碳循环之间及其内部的复杂关系”的理解。通过联合考虑沿海碳处理和陆地碳预算，该项目解决了海洋和地球科学部门的研究重点。广泛影响本项目将解决有关中西部北部碳预算的基本问题，提高沿海碳循环的知识，并为未来的五大湖研究产生一套研究重点。两名学生和一名博士后将使用数据和模型学习苏必利尔湖碳循环，该项目将增加五大湖碳科学的区域合作。来自代表性不足群体的本科生将通过MTU的REU计划积极参与该项目。该团队还将努力将他们的发现传达给公众。

The North American Carbon Program (NACP) intends (1) to develop quantitative scientific knowledge, robust observations, and models to determine emissions and uptake of CO2, CH4 and CO, changes in carbon stocks, and factors regulating these processes for North America and adjacent ocean basins; and (2) to develop the scientific basis for full carbon accounting on regional and continental scales. The Laurentian GreatLakes cover 25% of the land area of the 8 Great Lakes states, and CO2 emission and seasonal cycling from them may be comparable to local terrestrial ecosystems. Though their contributions to the regional carbon balance may be significant, these fluxes are currently poorly understood. CO2 fluxes from Lake Superior are of particular interest because they may directly impact observations at nearby AmeriFlux towers, yet due to the current lack of quantification, Lake Superior fluxes are presently neglected in analysis of these data.Motivated by the need for improved knowledge of Great Lake CO2 fluxes, this project will couple an ecosystem-carbon module with an existing hydrodynamic model of Lake Superior. This model will lead to estimates of the air-water CO2 fluxes and their spatial and temporal variability. New observations to improve knowledge of carbon cycling in winter and to constrain the model will also be obtained. With model output, the impact of Lake Superior CO2 fluxes on observations at AmeriFlux towers and on the regional carbon budget will be evaluated. The five key research questions are:1. What is the magnitude of the air-water carbon flux in Lake Superior?2. How are the fluxes influenced by variability in the physical climate?3. How does Lake Superior's carbon cycle behave in winter?4. What are the most important uncertainties in the Lake Superior carbon budget?5. How do Lake Superior carbon fluxes impact the regional carbon budget?This project brings together an interdisciplinary team to improve understanding of the "complex relationships between and within the global water and carbon cycles". By jointly considering coastal carbon processing and terrestrial carbon budgets, this project addresses research priorities of both the Ocean and Earth Sciences divisions.Broader ImpactsThis project will address fundamental questions about the upper Midwest carbon budget, improve knowledge of coastal carbon cycling, and generate a set of research priorities for future study of Great Lakes. Two students and one postdoc will learn about Lake Superior carbon cycling using data and models, and the project will increase regional collaborations for Great Lakes carbon science. Undergraduates from under-represented groups will actively participate in the project through MTU's REU program. The team will also work to communicate their findings to the general public.