Investigation of the Effects of Climatic Change and Human Activities on Discontinuous Permafrost in Alaska

该奖项支持对阿拉斯加北部不连续永久冻土的研究。永久冻土层存在于北极和亚北极地区，那里的气候变化最有可能是最大的，也是最先发生的。在气候变暖的情况下，温暖的不连续永久冻土将首先融化。气候数据表明，阿拉斯加目前正以每世纪约2.4摄氏度的速度变暖。已经获得的数据显示，阿拉斯加育空河以南不连续的永久冻土最近变暖了1.5摄氏度，其中一些已经开始融化。本研究的目的是更好地了解不连续永久冻土对气候变化和人类活动的响应。多年冻土在气候变化研究中的重要意义在于它可以探测和记录其热状态下的气候变化。在解冻过程中，它可以作为影响生态和人类社区的环境变化的因素，并可以通过与永久冻土中储存的碳释放相关的反馈效应放大气候变化。这项研究包括分析和解释从十几个地点获得的广泛的长期（18年）数据集，这些数据集代表了阿拉斯加南北横断面的不连续永久冻土带的各种环境条件，测量当前条件，并评估已经发生和仍在发生的变化。六个地点将配备仪器，测量空气、活动层和永久冻土的温度、水分含量（包括未冻结的水）、热参数、积雪和活动层特征以及起伏。将在其他八个地点进行不太详细的测量。这项研究还将包括调查数据的时空趋势、热量和水分的流动（包括几个现有的假设），以及应用一个分析模型和两个现有的数值模型来预测温暖和融化的永久冻土的热状态和对话发展。将对气候变量和活动层特征变化对不连续永久冻土热状态的影响进行敏感性分析。

9423426 Osterkamp This award supports a study of discontinuous permafrost in northern Alaska. Permafrost exists in arctic and subarctic regions where changes in climate are most likely to be largest and to occur first. Warm discontinuous permafrost will be the first to thaw in the event of any climatic warming. Climatic data indicate that Alaska is currently warming at a rate of about 2.4 C per century. Data has been obtained which shows that the discontinuous permafrost south of the Yukon river in Alaska has recently warmed by as much as 1.5 C and that some of it is already thawing. The objective of this research is to develop a better understanding of the response of discontinuous permafrost to changes in climate and human activities. The significance of permafrost in the context of climatic change studies is that permafrost can detect and record climatic changes in its thermal regime. In thawing, it can act as an agent of environmental changes that influences ecological and human communities and it can amplify climatic change by feedback effects associated with the release of carbon stored in the permafrost. This research includes analyses and interpretations of an extensive long-term (18 years) data set obtained at more than a dozen sites representing a wide range of environmental conditions that span the discontinuous permafrost zone along a north-south transect of Alaska, measurements of current conditions, and assessing changes that have occurred and those that are still occurring. Six sites will be instrumented to measure temperatures in the air, active layer, and permafrost, moisture contents (including unfrozen water), thermal parameters, snow cover and active layer characteristics, and heave. Less detailed measurements will be made at eight other sites. This research will also include an investigation of temporal and spatial trends in the data, the flow of heat and moisture (including several existing hypotheses), and the application of an analyti cal model and of two existing numerical models for predicting the thermal regime and talik development in warm and thawing permafrost. A sensitivity analysis will be carried out on the effects of changes in climatic variables and active layer characteristics on the thermal regime of the discontinuous permafrost.