Snow megadunes in Antarctica: Sedimentary structure and genesis

• Published in: Journal of Geophysical Research
• Main Authors: Frezzotti, M., Gandolfi, S., Urbini, S.
• Other Authors: Frezzotti, M.; Ente per le Nuove Tecnologie, l’Energia e l’Ambiente, Roma, Italy, Gandolfi, S.; Dipartimento di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento, del Territorio, University of Bologna, Bologna, Italy, Urbini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Ente per le Nuove Tecnologie, l’Energia e l’Ambiente, Roma, Italy, Dipartimento di Ingegneria delle Strutture, dei Trasporti, delle Acque, del Rilevamento, del Territorio, University of Bologna, Bologna, Italy, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia
• Format: Article in Journal/Newspaper
• Language: English
• Published: AGU 2002
• Subjects: snow dune; aeolian morphology; mass balance; ice core; katabatic wind; Antarctica; 02. Cryosphere::02.02. Glaciers::02.02.02. Cryosphere/atmosphere Interaction; 02. Cryosphere::02.02. Glaciers::02.02.05. Ice dynamics; 02. Cryosphere::02.02. Glaciers::02.02.10. Instruments and techniques; Antarctic; East Antarctic Ice Sheet; Sastrugi; Antarc*; Ice Sheet
• Online Access: http://hdl.handle.net/2122/4040; https://doi.org/10.1029/2001JD000673

Megadune fields occupy large areas in the interior of the East Antarctic ice sheet and are the result of unusual snow accumulation and redistribution processes. They therefore are important to surface mass balance and ice core interpretation. Field observations (GPS, GPR, and surface measurements) have provided a detailed description of megadune sedimentation and morphology over a 70 km2 area, located 200 km east of Dome C. A combination of remote sensing analysis (using Landsat and satellite radar altimetry) and field measurements indicate that slope in the prevailing wind direction (SPWD) and climatic conditions play a crucial role in megadune genesis. The megadune areas tend to be characterized by slightly steeper regional slope and the presence of highly persistent katabatic winds. The megadunes represent 2 to 4 m amplitude waves of 2 to 5 km wavelength formed by variable net accumulation, ranging between 25% (leeward faces) to 120% (windward faces) of the accumulation in adjacent nonmegadune areas. Leeward faces are characterized by glazed, sastrugi-free surfaces and extensive depth hoar formation. Windward faces are covered by large rough sastrugi up to 1.5 m in height. Published 4344 3.8. Geofisica per l'ambiente JCR Journal reserved