Stan D. Wullschleger
November 7, 2019
Identification of correspondences between permafrost, soil, topography, and vegetation properties.
A new strategy called distributed temperature profiling (DTP) was developed for advancing the characterization and monitoring of soil thermal properties. Combining DTP data with co-located topographic and vegetation maps and geophysical data allowed the identification of correspondences between above- and belowground property distribution.
The low cost, portability, and ease of deploying the DTP system make this method efficient for investigating the significant variability in and complexity of subsurface thermal and related hydrological regimes. The potential of this method is significant for informing investigations aimed at quantifying permafrost evolution, water infiltration, snowmelt dynamics, evaporation, biogeochemical processes, and hyporheic exchange.
Soil temperature has been recognized as a property that strongly influences myriad hydro-biogeochemical processes and reflects how various properties modulate the soil thermal flux. In spite of its importance, the ability to acquire soil temperature data with high spatial and temporal resolution and coverage has been limited because of the high cost of equipment, the difficulties of deployment, and the complexities of data management. The developed new strategy, called DTP, enables measurements of soil temperature at an unprecedented number of locations due to its low cost, low impact, and ease of deployment. The DTP system concept was tested by moving the system sequentially across the landscape to identify near-surface permafrost distribution and correspondences with topography and vegetation properties in a discontinuous permafrost environment near Nome, Alaska, during the summer. Results show that DTP enabled high-resolution identification and lateral delineation of near-surface permafrost locations from surrounding zones with no permafrost or deep permafrost table locations overlain by a perennially thawed layer. Further, the DTP data indicated that changes in soil temperatures often correspond to changes in topography, vegetation, and soil moisture. Near-surface permafrost identified in the study area using the DTP data is primarily co-located under topographic highs and under areas covered with graminoids such as grasses and sedges.
BER Program Manager
U.S. Department of Energy Office of Science, Office of Biological and Environmental Research
Earth and Environmental Systems Sciences Division (SC-33.1)
Environmental System Science
Stan D. Wullschleger
Oak Ridge National Laboratory
Oak Ridge, TN
The Next-Generation Ecosystem Experiments (NGEE)–Arctic project is supported by the Terrestrial Ecosystem Science program of the U.S. Department of Energy (DOE) Office of Biological and Environmental Research within the DOE Office of Science. This NGEE–Arctic research is supported through Contract No. DE-AC02-05CH11231 to Lawrence Berkeley National Laboratory.
Léger, E., B. Dafflon, Y. Robert, C. Ulrich, J. E. Peterson, S. C. Biraud, V. E. Romanovsky, and S. S. Hubbard. “A distributed temperature profiling method for assessing spatial variability in ground temperatures in a discontinuous permafrost region of Alaska.” The Cryosphere 13(11), 2853–67 (2019). [DOI:10.5194/tc-13-2853-2019].