Thermal remote sensing of ice-debris landforms using ASTER: an example from the Chilean Andes

Abstract. Remote sensors face challenges in characteriz-ing mountain permafrost and ground thermal conditions or mapping rock glaciers and debris-covered glaciers. We ex-plore the potential of thermal imaging and in particular ther-mal inertia mapping in mountain cryospheric research, fo-cusing on the relationships between ground surface temper-atures and the presence of ice-debris landforms on one side and land surface temperature (LST) and apparent thermal in-ertia (ATI) on the other. In our case study we utilize ASTER daytime and nighttime imagery and in-situ measurements of near-surface ground temperature (NSGT) in the Mediter-ranean Andes during a snow-free and dry observation period in late summer. Spatial patterns of LST and NSGT were mostly consistent with each other both at daytime and at nighttime. Daytime LST over ice-debris landforms was de-creased and ATI consequently increased compared to other debris surfaces under otherwise equal conditions, but NSGT showed contradictory results, which underlines the complex-ity and possible scale dependence of ATI in heterogeneous substrates with the presence of a thermal mismatch and a heat sink at depth. While our results demonstrate the utility of thermal imaging and ATI mapping in a mountain cryospheric context, further research is needed for a better interpretation of ATI patterns in complex thermophysical conditions.