Seasonal soil active layer measurements from a Circumpolar Active Layer Monitoring (CALM) grid, (U9B) 'Happy Valley 1km Grid', Alaska, 1995-2020

This site is registered with the Circumpolar Active Layer Monitoring (CALM) program. It is one among a network of sites that represent a coordinated effort to standardize the collection and access to thaw measurements in representative undisturbed permafrost landscapes. This dataset contains long-term spatial thaw depth observations using mechanical probing on dates indicated by file column headers. To ensure relative consistency within the record, end-of-season measurement dates are within the same Julian calendar week during the height of the thaw season (mid-August to mid-September). It is important to note that the date of maximum annual thaw, interpreted as the active layer thickness, can vary from year to year and between sites.

本站点已注册加入环极活动层监测（Circumpolar Active Layer Monitoring, CALM）计划。该站点隶属于一个协同运作的站点网络，该网络旨在规范典型未受干扰永久冻土景观中解冻测量数据的采集与共享流程。本数据集包含通过机械探测法获取的长期空间解冻深度观测数据，观测日期由文件列标题标注。为保障数据集记录的相对一致性，季末测量日期均落在解冻高峰期（8月中旬至9月中旬）的同一儒略历周内。需要特别说明的是，作为活动层厚度表征的年度最大解冻日期，会随年份与站点的不同而发生变化。