New frontiers in remote sensing of periglacial landscapes and permafrost

Remote sensing has been a tool of choice for decades for studying periglacial landscape dynamics and for scaling-up field data. Remoteness, geographic extent, and harsh climates of study areas as well as logistical challenges in visiting them make aerial or satellite imagery key components of studies focusing on mapping of landforms, vegetation and hydrologic features, or simply planning field research. For some regions, the historical aerial image record now extends back >80 years, allowing tremendous insights into scales and rates of land surface processes such as thermokarst lake dynamics, coastal erosion, peat plateau collapse, thaw slump development, or rock glacier movement. Such long temporal archives increasingly allow correlation of observed changes with climatic or anthropogenic disturbances. Classical remote sensing tools include panchromatic and color-infrared aerial imagery, widely available across the Arctic since the 1950s and 1970s, respectively. Stereo-photogrammetric analyses provided critical three-dimensional insights for many studies. The advent of earth surface-observing satellite sensors in the 1970s brought multi-spectral Landsat and other imagery to researchers. In the 1990s, satellite synthetic aperture radar (SAR) data became widely available. Another enormous boost in usage of remote sensing data was achieved by rendering data archives public and freely available in the 2000s, namely the full Landsat and MODIS archives. In addition, commercial, very high-resolution platforms have provided sufficient spatial resolution for detecting periglacial landscape dynamics during the last decade. The 4th International Polar Year 2007/08 also helped directing remote sensing efforts to permafrost regions, followed by international activities such as the ESA Data User Element Permafrost project, an upcoming large NASA field campaign termed the Arctic Boreal Vulnerability Experiment (ABoVE), and a recent US National Academy of Sciences workshop report on Remote Sensing of Permafrost guided by numerous international experts. New sensors, processing techniques, and analysis methods available today provide promising avenues to monitor periglacial landscapes and even permafrost directly, to support and scale field research, and to parameterize and validate modeling. Here we show some of the developments in technology and applications for periglacial environments and for observing characteristics of permafrost, including multi-temporal high-resolution imagery in the visible to infrared range for change detection studies, hemispherical-scale remote sensing datasets of the physical state of the earth surface such as freeze-thaw state, interferometric SAR for detection of seasonal or long-term surface deformation in periglacial regions, airborne geophysical sensors used to map permafrost extent and talik distribution, and high-resolution elevation data from airborne interferometric SAR, LIDAR, or stereo-optical sensors to characterize periglacial features and their deformation over time