The Cryosphere www.the-cryosphere.net 1994-0416 1994-0424 3 2 2009 10.5194/tc-3-195-2009 http://www.the-cryosphere.net/3/195/2009/ http://www.the-cryosphere.net/3/195/2009/tc-3-195-2009.html http://www.the-cryosphere.net/3/195/2009/tc-3-195-2009.pdf 195 203 2009-08-25 Layer disturbances and the radio-echo free zone in ice sheets R. Drews reinhard.drews@awi.de O. Eisen I. Weikusat S. Kipfstuhl A. Lambrecht D. Steinhage F. Wilhelms H. Miller Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven, Germany Institut für Umweltphysik, Heidelberg, Germany now at: DMT GmbH & Co. KG, Am Technologiepark 1, 45307 Essen, Germany Radio-echo sounding of the Antarctic and Greenlandic ice sheets often reveals a layer in the lowest hundreds of meters above bedrock more or less free of radio echoes, known as the echo-free zone (EFZ). The cause of this feature is unclear, so far lacking direct evidence for its origin. 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