Thaw Depth
Under Construction
Tundra soils are underlain by permanently frozen ground (permafrost). During the summer a thin layer thaws annually. This layer is commonly referred to as the active layer because most of the biological activity happens here. Roots grow through the active layer and take up nutrients. Invertebrates and microbes are plentiful in the active layer.
We measure active layer on our plots.
The simplest low-tech measurement is to poke a probe until you reach the frozen surface. In areas with lots of water it is easy to tell when you reach the frozen surface (it is literally as hard as ice). In drier regions of the tundra it is less easy to measure and requires probes that measure the temperature.
Click here for thaw-depth summaries through the years
Learn More
AJ Smith & Michaela Clingaman - Predicting landscape heterogeneity in thaw depth in arctic Alaska
Hannah Clarida - Landscape Effects and Changes in Permafrost Depth in Atqasuk, Alaska
Related Papers
Hollister, R.D., P.J. Webber, F.E. Nelson, and C.E. Tweedie. 2006. Soil thaw and temperature response to air warming varies by plant community: Results from an open-top chamber experiment in northern Alaska. Arctic Antarctic and Alpine Research 38:206–215. 10.1657/1523-0430(2006)38[206:STATRT]2.0.CO;2.
Shiklomanov, N.I., D.A. Streletskiy, F.E. Nelson, R.D. Hollister, V.E. Romanovsky, C.E. Tweedie, J.G. Bockheim, and J. Brown. 2010. Decadal variations of active-layer thickness in moisture-controlled landscapes, Barrow, Alaska. Journal of Geophysical Research 115:G00I04. 10.1029/2009JG001248.