The Circumpolar Active Layer Monitoring Network-CALM II (2004-2008): Long-Term Observations on the Climate-Active Layer-Permafrost System

环极活动层监测（CALM）计划的总体目标是在数十年的时间尺度上观察活动层和近地表永久冻土对气候变化的响应。 CALM观测网络于20世纪90年代建立，将继续观测活动层和近地表永久冻土层对气候变化和变化的长期响应，覆盖两个半球超过125个地点，涉及14个参与国家。大约 60 个站点将测量 1 公顷至 1 平方公里网格上的活动层厚度，100 个站点将观测土壤温度，包括钻孔的永久冻土温度。 CALM 网络中的大多数站点位于北极和亚北极低地，但有 20 个钻孔位于北半球海拔 1300 米以上的山区。该项目的更广泛影响源于这样的假设：活动层厚度的广泛、系统性变化可能对温室气体通量、寒冷地区的人类基础设施以及景观过程产生深远影响。 因此，观察和分析程序持续十年以评估趋势并发现累积的长期变化至关重要。

The overall goal of the Circumpolar Active Layer Monitoring (CALM) program is to observe the response of the active layer and near-surface permafrost to climate change at multi-decade time scales. The CALM observational network, established in the 1990s, will continue to observe the long-term response of the active layer and near-surface permafrost to changes and variations in climate at more than 125 sites in both hemispheres and involving 14 participating countries. Approximately 60 sites will measure active-layer thickness on grids ranging from 1 ha to 1 km2, and 100 sites will observe soil temperatures, including permafrost temperatures from boreholes. Most sites in the CALM network are located in Arctic and Subarctic lowlands, although 20 boreholes are in mountainous regions of the Northern Hemisphere above 1300 m elevation. The broader impacts of this project are derived for the hypothesis that widespread, systematic changes in the thickness of the active layer could have profound effects on the flux of greenhouse gases, on the human infrastructure in cold regions, and on landscape processes. It is therefore critical that observational and analytical procedures continue over decadal periods to assess trends and detect cumulative, long-term changes.