Seasonal soil active layer measurements from a Circumpolar Active Layer monitoring (CALM) grid, (U3) Atkasuk, Alaska 1995-2024.

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.