Thermal State of Permafrost in North America - Orthomosaic Images and Digital Surface Models for Old Man, Alaska, United States 2020-2025

This dataset contains orthomosaic images and digital surface models (DSMs) for an area of study near Old Man Camp in northern Alaska, USA (United States of America). The data were collected to further support ongoing research that aims to assess geomorphological and environmental changes near ground temperature monitoring sites, and to provide spatial data for validation of land surface deformation models. Flights from 2020 to 2022 were conducted using a DJI (Da-Jiang Innovations) Phantom 4 RTK (P4RTK) equipped with a DJI D-RTK 2 Mobile Base Station for real-time kinematic (RTK) positioning. For flight missions in 2023 through 2025, we utilized a DJI Matrice M300 RTK (M300RTK) drone equipped with a DJI Zenmuse P1 camera and a 35mm (millimeter) lens (45MP [megapixels]). An Emlid RS3 GNSS (Global Navigation Satellite System) base station was used for RTK positioning. All images were processed using Agisoft Metashape (v.2.2.0) following a standard three-dimensional mapping processing workflow utilizing ground control points measured in the field for horizontal and vertical corrections and reliable reproduction from year to year. All DSM and orthomosaic files are projected using NAD83 (North American Datum of 1983) State Plane 4 and ellipsoidal heights in meters. The Old Man site is located approximately 310 miles (499km [kilometer]) south of Deadhorse on a wide subarctic valley floor. Landcover units include Graminoid-moss tundra and graminoid, prostrate-dwarf-shrub, moss tundra (wet and moist nonacidic).