Influence of Climate and Environmental Factors on the Thermal Regime of the Active Layer and Permafrost

永久冻土是北极陆地-大气-冰系统的主要组成部分之一。最近在多年冻土中发现了一个振幅较大的温度循环和活动层厚度的大而系统的变化（自1986年以来），这些意外发现表明，目前对气候活动层-永久冻土相互作用的理解需要改进。这些相互作用很重要，因为据预测，由于温室气体的增加，北极地区的气温会升高，这将导致永久冻土融化，因为活土层变厚了。需要更好地了解大气、土壤表面、活动层和永久冻土之间的联系，以回答以下问题：永久冻土退化的速度和程度、其热状态的改变、永久冻土融化释放的碳和微量气体、土壤湿度的变化、生物群、水循环、这些变化将如何影响极地土地的利用，以及开发、校准、以及验证陆地-大气相互作用的小尺度数值模型（2公里网格），这些模型将嵌套在更大尺度模型中。一项永久冻土研究计划被提出，该计划结合了实地测量、实验室测量以及对从普拉德霍湾横跨沿海平原和山麓到布鲁克斯山脉的六个长期研究地点获得的数据的分析和解释。这些地点位于未受干扰的地区，跨越了广泛的永久冻土、气候和环境条件，包括永久冻土中的钻孔（40至75米深），并具有长时间序列的数据（自1983年以来）。这项研究将扩展这些地点的测量时间序列，并将重点研究在各种气候和环境环境下，活土层和连续永久冻土如何对气候变化做出反应并继续做出反应。拟议研究的主要重点是调查气候（特别是气温、雪、风和降水）和环境因素（特别是植被和地表形态）及其相互作用对活动层和永久冻土的热和水分状况的影响，以努力回答目前研究提出的问题。

Permafrost is one of the primary components of the Arctic land-atmosphere-ice system. Recent unexpected discoveries of a large-amplitude temperature cycle in the permafrost and of large and systematic changes in active layer thicknesses (since 1986) indicate that the current understanding of climate-active layer-permafrost interactions needs improvement. These interactions are important because warmer air temperatures predicted in the Arctic from increases in greenhouse gases will cause permafrost to thaw as the active layer becomes thicker. A better understanding of the linkages between the atmosphere, soil surface, active layer, and permafrost is required to answer questions regarding the rate and extent of permafrost degradation, modifications to its thermal regime, release of carbon and trace gases by thawing permafrost, changes in soil moisture, the biota, the hydrological cycle, how these changes will influence the use of polar lands, and the development, calibration, and validation of small-scale numerical models (2 km grids) of land-atmosphere interactions that are to be nested in larger scale models. A permafrost research program is propose that combines field measurements, laboratory measurements, and analyses and interpretation of data to be obtained at six long-term study sites along a transect from Prudhoe Bay across the coastal plain and foothills into the Brooks Range. These sites are in undisturbed areas, span a wide range of permafrost, climatic, and environmental conditions, include drillholes in the permafrost (40 to 75 m in depth), and have a long time series of data (since 1983). This research will extend the time series of measurements at the sites and will focus on investigating how the active layer and continuous permafrost, in a variety of climatic and environmental setting, has responded and continues to respond to climate change. The primary thrust of the proposed research is to investigate the effects of climate (especially air temperatures, snow, wind and precipitation) and environmental factors (especially vegetation and surface morphology) and their interactions on the thermal and moisture regimes of the active layer and permafrost in an effort to answer questions raised by current research.