Identifying areas of archaeological potential in the Swiss Alps using satellite-derived time-series of snow cover estimates

Abstract

The Alps have historically been crossed by populations moving between northern and southern Europe for various purposes. Testimonies of such human presence were long preserved from decomposition being covered and protected by perennial ice and snow. However, with ongoing climate change, large portion of these permanent snowed and frozen areas are being freed up exposing artifacts to rapid deterioration. Consequently, archaeologists are requiring new methods to monitor the cryosphere enabling them to efficiently identify potential areas of conservation and protection of archaeological remains. Herein, we used a 34-year satellite-derived time-series of snow cover estimates to identify potential zones for conservation of archaeological remains in the Valais alpine region (Switzerland). Findings suggest that over the considered analysis period (1984–2018), snow cover has declined of about 15% during the summer maximum melting season releasing a surface of approximately 45 km2 in the study area. Moreover, crossing snow probabilities with Topographic Position Index (TPI) and slope data allowed to compute an Archaeological Potential (AP) map to derive zones with high potential of current or imminent release of archaeological remains. Combining this map with density of wood artifacts found on the field in a test area showed that 92.5% are inside identified receding snow/ice areas. Results of this analysis demonstrate that the proposed methodology can be a valid approach to monitor snow/ice minimum extension and identify perennial snowed and iced fields with archaeological potential. It provides the basis for defining new archaeological protection areas, preventing the loss of threatened ancient organic remains and enhances future field research campaigns in mountainous regions.