Thermal regime of ice‐wedge cracking in Adventdalen, Svalbard

One year of monitoring (2002–2003) at a low‐centred ice‐wedge polygon site on Svalbard is described. Ground temperatures were recorded hourly from the top of an ice wedge through the active layer to the ground surface in the central part of a trough and in the adjacent rampart. Daily data on snow‐cover depth were collected by automatic digital photography. Cracks were mapped in February, April and July. The results show that cracking occurred after ground temperatures at the centre of the ice‐wedge top decreased to below −15°C. Ground cooling in mid‐winter occurred mainly through the snow‐free ramparts because the ice‐wedge troughs were filled by snow to depths of up to 30 cm. Copyright © 2005 John Wiley & Sons, Ltd.