Empirical Models for Predicting Water and Heat Flow Properties of Permafrost...

O'Connor, M. T., M. B. Cardenas, S. B. Ferencz, Y. Wu, B. T. Neilson, A. Chen, and G. W. Kling (2020), Empirical Models for Predicting Water and Heat Flow Properties of Permafrost Soils, Geophys. Res. Lett., 47, e2020GL087646, doi:10.1029/2020GL087646.
Abstract: 

Warming and thawing in the Arctic are promoting biogeochemical processing and hydrologic transport in carbon‐rich permafrost and soils that transfer carbon to surface waters or the atmosphere. Hydrologic and biogeochemical impacts of thawing are challenging to predict with sparse information on arctic soil hydraulic and thermal properties. We developed empirical and statistical models of soil properties for three main strata in the shallow, seasonally thawed soils above permafrost in a study area of ~7,500 km2 in Alaska. The models show that soil vertical stratification and hydraulic properties are predictable based on vegetation cover and slope. We also show that the distinct hydraulic and thermal properties of each soil stratum can be predicted solely from bulk density. These findings fill the gap for a sparsely mapped region of the Arctic and enable regional interpolation of soil properties critical for determining future hydrologic responses and the fate of carbon in thawing permafrost. Plain Language Summary Arctic permafrost holds about as much carbon as currently present in the atmosphere. Rapid warming in the Arctic has raised concerns that this stored carbon could thaw and get released into the atmosphere, which would substantially amplify global warming. The rate of this carbon release to the atmosphere depends on the rate of environmental processes such as microbial respiration and heat and groundwater flow. The soil properties controlling these processes are currently unknown across most of the Arctic, making predictions of the processes highly uncertain at larger scales. This study uses hundreds of measurements of soil properties across an area of land larger than Delaware to show that soil properties in the foothills of the Brooks Range in northern Alaska are predictable if the landscape slope, dominant vegetation type, and local topography are known. This study provides a base for calculating transport processes related to soil carbon in the Arctic.

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Research Program: 
Terrestrial Hydrology Program (THP)
Funding Sources: 
This work was funded by the National Science Foundation grants NSF ARC 1204220, DEB 1026843 and 0639805, PLR 1504006, and OPP 1107593, as well as with generous support from The University of Texas at Austin Geology Foundation, the Geological Society of America Student Research Grant program, and the American Geophysical Union Horton Research Grant. Field work in 2018 and 2019 was supported by a grant from the NASA Terrestrial Hydrology Program (grant 80NSSC18K0983) to JC, MBC, and GWK.