Carbon dioxide fluxes on canadian arctic tundra

由于全球变暖，北极正在经历前所未有的变化。生态系统过程，如冻土带和大气之间的二氧化碳交换，受到这种变暖的影响。我们预测未来气候变化的能力取决于对这些变化的理解。在过去的八年里，我一直在与我的学生和合作者一起建立一个研究项目，以调查西北地区达令湖附近的北极冻土带大气二氧化碳交换，那里的二氧化碳通量站设在四个不同的冻土带环境中。它现在是加拿大北极地区运行时间最长、范围最广的碳通量测量计划。我建议扩大这项研究，以解决新的关键科学问题，这些问题将改善对北极冻土带过程的理解，从而产生有助于预测未来气候变化的知识。我将研究植物生长的变化(以叶面积表示)如何控制二氧化碳通量的季节和年际变化，并将这些变化与温度和降水等气候因素进行比较。假设植物因子只与气候因子间接相关，对于决定冻土带吸收的大气二氧化碳总量而言，植物因子比气候因子更重要。我还将探索监测这些植被变化的新方法，并最终监测二氧化碳通量，这可以外推到大范围的地理区域。我将把测量扩展到冬末和秋季，那时我们认为冻土带的二氧化碳损失是巨大的。过去，由于技术限制，测量主要限于无雪生长季节，但现在可以通过更新设备来克服这一点，并将为我们提供为冻土带生态系统构建准确的年度碳预算所需的信息。这项研究将增进我们对冻土带过程和气候反馈的了解，解决加拿大北极碳通量研究不足的问题，培训北极环境科学方面的新学生，并最终通过改进气候预测使北方人受益，这将帮助社区规划和适应气候变化。

The Arctic is experiencing unprecedented change due to global warming. Ecosystem processes, such as the exchange of carbon dioxide between tundra and atmosphere, are impacted by this warming. Our ability to predict future climate rests on understanding these changes. For the past eight years I have been building a research program with my students and collaborators to investigate Arctic tundra-atmosphere carbon dioxide exchange near Daring Lake, NWT, where carbon dioxide flux stations are set up in four different tundra environments. It is now the longest running and most extensive carbon flux measurement program in Arctic Canada. I am proposing to expand this research to address new crucial scientific issues that will improve out understanding of Arctic tundra processes and thus, generate knowledge that will assist in predictions of future climatic change. I will investigate how variations in plant growth, expressed as leaf area, control seasonal and interannual variations in carbon dioxide fluxes and compare these with climate factors such as temperature and precipitation. It is hypothesized that the plant factors are only indirectly related to climate factors and are more important than climate for determining the total amount of atmospheric carbon dioxide absorbed by the tundra. I will also explore novel ways for monitoring these vegetation changes, and ultimately carbon dioxide fluxes, which can be extrapolated to large geographic areas. I will extend the measurements into the late-winter and autumn seasons when we believe that the loss of carbon dioxide from the tundra is significant. In the past, due to technological limitations, measurements were primarily restricted to the snow-free growing season, but this can now be overcome with updated equipment and will give us the information needed to construct accurate annual carbon budgets for tundra ecosystems. This research will advance our knowledge of tundra processes and climate feedbacks, address the lack of carbon flux research in the Canadian Arctic, train new students in Arctic environmental science and ultimately, benefit northerners by improving climate predictions that will help communities plan for and adapt to climate change.