Meteorological control on interannual spatial and temporal variations in snow cover and ground thawing in two northeast Greenlandic Circumpolar‐Active‐Layer‐Monitoring (CALM) sites

Abstract Data on snow cover depletion and ground thawing at two sites at Zackenberg, in high arctic northeast Greenland, are presented from 1996 to 2002. Operation of the two Zackenberg Ecological Research Operations (ZERO) Circumpolar‐Active‐Layer‐Monitoring (ZEROCALM) sites is part of ZERO. Year‐round meteorological data from Zackenberg are also available from ZERO. The ZEROCALM1 site is located on flat ground, whereas ZEROCALM2 is a southward‐sloping site that includes a seasonal snowpatch, 750 m from ZEROCALM1. Average active‐layer thickness in the Zackenberg lowland is relatively consistent at 60 to 71 cm in flat parts of the landscape, but varies from 44 to 61 cm in snowpatch areas. The seasonal snow depletion and ground thaw in the two topographically different ZEROCALM sites are presented and their meteorological control discussed. Interannual variations in ground thawing are much larger at the ZEROCALM2 site compared to ZEROCALM1. Thawing at the ZEROCALM2 site was affected to a large degree by mid‐ to late‐winter wind conditions, while thaw at the ZEROCALM1 site was correlated with summer air temperature. Copyright © 2004 John Wiley & Sons, Ltd.