The Cryosphere Discussions www.the-cryosphere-discuss.net 1994-0432 1994-0440 4 1 2010 10.5194/tcd-4-287-2010 http://www.the-cryosphere-discuss.net/4/287/2010/ http://www.the-cryosphere-discuss.net/4/287/2010/tcd-4-287-2010.html http://www.the-cryosphere-discuss.net/4/287/2010/tcd-4-287-2010.pdf 287 319 2010-03-22 Monitoring of active layer dynamics at a permafrost site on Svalbard using multi-channel ground-penetrating radar S. Westermann sebastian.westermann@awi.de U. Wollschläger J. Boike Alfred-Wegener-Institute for Polar and Marine Research, Telegrafenberg A43, 14473 Potsdam, Germany Institute of Environmental Physics, Ruprecht-Karls-University Heidelberg, Germany Multi-channel ground-penetrating radar is used to investigate the late-summer evolution of the thaw depth and the average soil water content of the thawed active layer at a high-arctic continuous permafrost site on Svalbard, Norway. Between mid of August and mid of September 2008, five surveys have been conducted over transect lengths of 130 and 175 m each. The maximum thaw depths range from 1.6 m to 2.0 m, so that they are among the deepest thaw depths recorded for Svalbard so far. The thaw depths increase by approximately 0.2 m between mid of August and beginning of September and subsequently remain constant until mid of September. The thaw rates are approximately constant over the entire length of the transects within the measurement accuracy of about 5 to 10 cm. The average volumetric soil water content of the thawed soil varies between 0.18 and 0.27 along the investigated transects. While the measurements do not show significant changes in soil water content over the first four weeks of the study, strong precipitation causes an increase in average soil water content of up to 0.04 during the last week. 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