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

摘要

Remote sensors face challenges in characterizing mountain permafrost andground thermal conditions or mapping rock glaciers and debris-coveredglaciers. We explore the potential of thermal imaging and in particularthermal inertia mapping in mountain cryospheric research, focusing on therelationships between ground surface temperatures and the presence ofice-debris landforms on one side and land surface temperature (LST) andapparent thermal inertia (ATI) on the other. In our case study we utilizeASTER daytime and nighttime imagery and in-situ measurements of near-surfaceground temperature (NSGT) in the Mediterranean Andes during a snow-free anddry observation period in late summer. Spatial patterns of LST and NSGT weremostly consistent with each other both at daytime and at nighttime. DaytimeLST over ice-debris landforms was decreased and ATI consequently increasedcompared to other debris surfaces under otherwise equal conditions, but NSGTshowed contradictory results, which underlines the complexity and possiblescale dependence of ATI in heterogeneous substrates with the presence of athermal mismatch and a heat sink at depth. While our results demonstrate theutility of thermal imaging and ATI mapping in a mountain cryosphericcontext, further research is needed for a better interpretation of ATIpatterns in complex thermophysical conditions.