Collaborative Research: Vegetation And Ecosystem Impacts On Permafrost Vulnerability

对多年冻土生态系统中的热交换进行非技术上的真实表述对于准确地预测未来气候情景下的多年冻土碳反馈是必要的。该项目将对植被和地貌特征对永久冻土热状况的影响进行全北极的定量评估。通过跨生态系统、景观特征和区域的研究，这项研究将确定广泛的趋势，而密集的能源平衡地点将提供生态系统对永久冻土对气候变化反应的影响的机械研究。这项研究的影响将通过将研究成果纳入区域和特定地点的永久冻土模型和综合活动来加强，这些综合活动将审查生态系统对能源平衡的影响和永久冻土对气候变化的脆弱性。这项工作将对科学界和普通公众产生广泛影响，因为它汇集了全球环境中的重要问题，并提高了人们对生态系统动态与永久冻土融化之间联系的认识。拟议的项目将通过研究人员与NSF资助的本科生实地研究经验之间的合作，为本科生提供培训机会。作为这项拟议工作的一部分，研究人员将指导几名学生，并将在一所以本科生为主的机构教授两门北极系统科学课程。该项目将通过继续与教育中心、当地社区，特别是与教师和外联协调员合作，增进科学了解。技术上，随着气候变暖，永久冻土的分布预计会显著下降，但在未来气候情景下决定永久冻土的命运仍然存在很大的不确定性。这些不确定性在很大程度上是由植被和生态系统特性驱动的，这些特性调节了气候对永久冻土温度的影响。对永久冻土温度的长期监测证明了这些当地条件的重要性，然而，没有泛北极地区的努力来测量与永久冻土温度监测相一致的生态和景观变量。该项目将使用实地和遥感数据相结合的方法，解决植被和景观因素如何调节永久冻土温度对气候变化的反应这一问题。为了解决这个问题，研究人员将结合广泛的泛北极植被-永久冻土动态评估，以及深入研究灌木和乔木树冠覆盖对生态系统能量平衡的影响。这项研究的第一部分将在西伯利亚和阿拉斯加的长期永久冻土温度监测点进行，第二部分将作为这项提议的一部分建立植被-能量平衡点，将在西伯利亚的灌木树冠覆盖坡度进行，西伯利亚是大多数永久冻土区的所在地。这些深入研究的能量平衡点将提供一个更好的机制，了解生态系统组成部分以及这些组成部分之间的相互作用对生态系统能量平衡和永久冻土对气候变化的脆弱性的影响。这一机械知识将反过来支持对通过对永久冻土温度监测点进行泛北极采样而观察到的广泛模式的解释。

NontechnicalRealistic representations of heat exchange in permafrost ecosystems are necessary for accurate predictive understanding of the permafrost carbon feedback under future climate scenarios. This project will provide a quantitative pan-arctic assessment of the effects of vegetation and landscape characteristics on permafrost thermal regimes. By working across ecosystems, landscape characteristics, and regions, the research will identify broad trends, and intensive energy balance sites will provide a mechanistic study of ecosystem impacts on permafrost response to climate change. The impacts of this study will be enhanced through integration of research results into regional and site-specific permafrost models and synthesis activities that will examine ecosystem impacts on energy balance and permafrost vulnerability to climate change. This work will have broad impacts on the scientific community and general public because it brings together important issues in the global environment and raises awareness of the connection between ecosystem dynamics and permafrost thaw. The proposed project will provide training opportunities for undergraduate students through collaboration between the researchers and an NSF funded field research experience for undergraduates. The researchers will mentor several students as part of this proposed work and will also teach two arctic system science courses at a predominantly undergraduate institution. This project will enhance scientific understanding through continued work with education centers, local communities and, in particular, with teachers and outreach coordinators. TechnicalSignificant declines in permafrost distribution are expected as the climate warms, but large uncertainties remain in determining the fate of permafrost under future climate scenarios. These uncertainties are driven, in large part, by vegetation and ecosystem properties that modulate the effect of climate on permafrost temperatures. Long-term monitoring of permafrost temperatures demonstrates the importance of these local conditions, yet there has been no pan-arctic effort to measure ecological and landscape variables in concert with permafrost temperature monitoring. This project will use a combination of field and remotely-sensed data to address the question of how vegetation and landscape factors modulate permafrost temperature response to climate change. To address this question the researchers will couple an extensive pan-arctic assessment of vegetation-permafrost dynamics with an intensive study of shrub and tree canopy cover effects on ecosystem energy balance. The first component of this research will be conducted at long-term permafrost temperature monitoring sites in Siberia and Alaska, and the second component, the vegetation-energy balance sites that will be established as part of this proposal, will be conducted at a shrub-tree canopy cover gradient in Siberia, where most permafrost regions are located. These intensively studied energy balance sites will provide an improved mechanistic understanding of the effects of ecosystem components, and interactions among these components, on ecosystem energy balance and permafrost vulnerability to climate change. This mechanistic knowledge will, in turn, support interpretation of broad patterns observed through a pan-arctic sampling of the permafrost temperature monitoring sites.