HR: 0800h
AN: H51E-09    [Abstracts]
TI: Exploring Seasonal Variations in Near Surface Soil Moisture Using Differential Electrical Resistivity Tomography
AU: * Jayawickreme, D H
EM: jayawick@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States
AU: van Dam, R L
EM: rvd@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States
AU: Hyndman, D W
EM: hyndman@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824, United States
AB: The rates of hydrologic processes are strongly influenced by spatial and temporal characteristics of near surface soil moisture. While climate variables play a major role in determining the distribution of soil moisture over large areas, vegetation characteristics may introduce significant spatial heterogeneity in soil moisture and recharge at local scales. Results from a Michigan site equipped for long-term electrical resistivity tomography (ERT), provides quantitative evidence of land cover effects on the spatial and temporal characteristics of near surface soil moisture. Data acquired during the late growing season of 2006 shows that the soil zone up to 5 meters deep below mature deciduous trees have lower moisture contents than similar soils under open grassy areas. During the early winter months, the measured resistivity in the deciduous forest declined significantly as the moisture content increased. The resistivity response in the upper meter of soil to seasonal fluctuations in atmospheric temperature and solar radiation is also different between the two land use types at the site during the late fall and early winter months. Such differences however diminish with the onset of soil freezing at the site. Our findings highlight important correlations between vegetation and near surface soil moisture characteristics in space and time, and they also demonstrate the usefulness of fixed surface ERT arrays for imaging such changes.
DE: 1632 Land cover change
DE: 1835 Hydrogeophysics
DE: 1866 Soil moisture
DE: 1875 Vadose zone
DE: 1895 Instruments and techniques: monitoring
SC: Hydrology [H]
MN: 2007 Joint Assembly