Evaluation of COSMOS (COsmic-ray Soil Moisture Observing System) Soil Moisture Product in a Peatland Environment

Elizabeth Erin Wrona, University of Guelph, Guelph, ON, Canada, Aaron A Berg, University of Guelph, Department of Geography, Environment and Geomatics, Guelph, ON, Canada and Philip Marsh, Wilfrid Laurier University, Geography, Waterloo, ON, Canada

Contact First Author: Elizabeth Erin Wrona; ewrona@uoguelph.ca

Previously Published Material: Preliminary results of this research were presented at Arctic Change 2014 in Ottawa, Canada, in December of 2014.

Abstract ID#: 35088

 

English Abstract:
Permafrost is a vital component of environmental processes occurring in the Canadian Arctic; however, it is sensitive to disturbance. Warming of near surface ground temperatures has been observed and it is anticipated that this region will experience further changes to temperature and precipitation regimes. Soil moisture is a key variable in understanding Arctic terrestrial hydrology due to the implications of these changes for Canada’s climate, and consequently, establishing reliable methods to monitor active layer soil moisture is increasingly important. An emerging in-situ technology is the COsmic-ray Soil Moisture Observing System (COSMOS), which operates by measuring cosmic ray neutron intensity over an aerial footprint at an intermediate field scale (10s to 100s of metres). These sensors have shown promise for use in agricultural mineral soils; however, investigation into the performance of this technology over porous organic peat found in the Arctic tundra remains minimal. Research is needed to establish the approximate COSMOS measurement footprint and contributing depth over unique application environments. The objective of this study is to evaluate the efficacy of COSMOS in peat soil, and to establish the horizontal footprint and soil depth contributing to COSMOS measurements of soil moisture. Research was conducted at Trail Valley Creek, NWT, from July to August, 2014. Six in-situ stations were positioned within the COSMOS footprint measuring soil moisture at 5, 40, 75, 150, 175, and 200 m distances from the COSMOS base. Soil moisture sensors were installed at each station measuring soil moisture, temperature and dielectric permittivity at the surface, 5 cm, and 20 cm depths. Results of these soil moisture time series data show COSMOS is most highly correlated with closer in-situ stations, and furthermore, the sensor is most highly correlated with probes positioned at the soil surface (0.411 at the 5 m station surface probe).
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