Climate and Dynamics
Spatial and temporal variability in active layer thickness over the Russian Arctic drainage basin
Article first published online: 18 AUG 2005
Copyright 2005 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 110, Issue D16, 27 August 2005
How to Cite
2005), Spatial and temporal variability in active layer thickness over the Russian Arctic drainage basin, J. Geophys. Res., 110, D16101, doi:10.1029/2004JD005642., et al. (
- Issue published online: 18 AUG 2005
- Article first published online: 18 AUG 2005
- Manuscript Accepted: 1 JUN 2005
- Manuscript Revised: 7 MAY 2005
- Manuscript Received: 30 NOV 2004
- active layer;
- Russian Arctic
 Changes in active layer thickness (ALT) over northern high-latitude permafrost regions have important impacts on the surface energy balance, hydrologic cycle, carbon exchange between the atmosphere and the land surface, plant growth, and ecosystems as a whole. This study examines the 20th century variations of ALT for the Ob, Yenisey, and Lena River basins. ALT is estimated from historical soil temperature measurements from 17 stations (1956–1990, Lena basin only), an annual thawing index based on both surface air temperature data (1901–2002) and numerical modeling (1980–2002). The latter two provide spatial fields. Based on the thawing index, the long-term average (1961–1990) ALT is about 1.87 m in the Ob, 1.67 in the Yenisey, and 1.69 m in the Lena basin. Over the past several decades, ALT over the three basins shows positive trends, but with different magnitudes. Based on the 17 stations, ALT increased about 0.32 m between 1956 and 1990 in the Lena. To the extent that results based on the soil temperatures represent ground “truth,” ALT obtained from both the thawing index and numerical modeling is underestimated. It is widely believed that ALT will increase with global warming. However, this hypothesis needs further refinement since ALT responds primarily to summer air temperature while observed warming has occurred mainly in winter and spring. It is also shown that ALT exhibits complex and inconsistent responses to variations in snow cover.