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Zusammenfassung:
Penitentes are peculiar spikes of snow and ice that form in sublimation-dominated regions exposed to high incoming radiation. On Earth, they typically occur on high-altitude tropical and subtropical glaciers or snow patches, mainly in the Andes, where they reach a height of several metres. Recent advances in cosmic missions and modelling studies revealed the plausible presence of penitentes outside our planet (Mars, Europa, Pluto); they might also exist on the surface of some exoplanets. The extreme surface roughness of the penitente field has a profound impact on the exchange of energy with the atmosphere and on the radiative balance. Additionally, their presence provides an important sink for dust deposition in their troughs, protected from wind gusts. Surprisingly, our knowledge regarding penitente formation and evolution on terrestrial surfaces is still limited, as the observations are sparse and models are oversimplified. Although there are some snow penitente surveys, little information has been published on the geometry of large ice penitentes. In this contribution, we analyse data collected on the Tapado glacier (Desert Andes), which can be considered a natural laboratory for penitente formation studies. We present a spatiotemporal analysis of penitente field morphology, comparing available close-range remote sensing data (lidar, time-lapse camera) with satellite imagery to derive metrics of penitente field and present seasonal and multi-year changes in spacing and orientation of the penitente peaks. Finally, we discuss methods for detecting the penitentes fields in optical and SAR imagery with implications for the design of future spacecraft missions to icy extraterrestrial bodies.
