Heat-Transfer Processes in Discontinuous Permafrost Regions

高纬度地区气候变暖的可能性引发了人们越来越多的担忧，即北极大片地区的永久冻土可能会普遍融化。然而，永冻层融化的动力学还没有完全被理解。长期以来认为导热是主要机制的观点受到了新理论的挑战，新的理论认为非导热在冻土的冻结和融化过程中也起着重要的作用。该项目将评估这些机制和其他可能的过程在多大程度上影响阿拉斯加中部各种环境下的永久冻土动力学。将在一组成对的永久冻土和非永久冻土场地收集各种不同土壤、冰雪、温度和水分条件的测量数据。这些数据将被用来分析这些不同变量之间的关系，并测试永久冻土中不同的热量传输模型。该项目将提供关于多年冻土和非多年冻土区土壤内部和紧邻其上的条件的有价值的新数据，并将有效地检验关于影响永久冻土稳定性的热传递机制的相互竞争的假说。除了有助于对永久冻土动力学的新见解，该项目还将通过测试新仪器在恶劣环境中的效力来做出方法学上的贡献。

The possibility of climatic warming in high-latitude zones has fueled growing concern about prospects for widespread melting of permafrost across large areas of the Arctic. The dynamics by which permafrost melts are not fully understood, however. Longstanding views that held conductive heat transfer as the primary mechanism have been challenged by new theories that hold that nonconductive heat transfer also plays an important role in the freezing and thawing of permafrost. This project will assess the degree to which each of these mechanisms and other possible processes affects permafrost dynamics in a variety of settings in central Alaska. Measurements of a variety of different soil, snow and ice, temperature, and moisture conditions will be collected at a set of paired permafrost and non-permafrost sites. These data will be used to analyze relationships among these different variables and to test different models of heat transfer within permafrost. This project will provide valuable new data on conditions within and immediately above the soil in permafrost and non-permafrost regions, and it will provide an effective test of competing hypotheses regarding heat transfer mechanisms that affect the stability of permafrost. In addition to contributing to new insights about permafrost dynamics, this project also will make methodological contributions by testing the efficacy of new instruments in harsh environments.