Seasonal variations and ground‐penetrating radar data repeatability

Abstract

A ground-penetrating radar (GPR) study conducted over sandy soil during the fall of 1990 and winter of 1991 reveals important conclusions concerning the climatic effects on the repeatability and interpretability GPR data. Despite significant changes in the degree of ground surface saturation between the GPR data sets collected in October 1990, December, 1990 and late January, 1991, much of the data show a high degree of repeatability. GPR data collected during the coldest day over partially frozen ground yielded the highest resolution data. Direct comparison between seasonal data sets allowed the identification of a local low permeability zone likely associated with concentrated fine-grained sediment. The transparency of the near-surface low electrical permeability zone from the January data over frozen ground allowed detection of the water table which could not be identified in the other data sets. This study suggests that long-term GPR investigations over unconsolidated sediments that incorporate seasonal data sets can greatly enhance the interpretability of GPR data. In addition, the tests indicate the potential usefulness of the GPR data for long-term monitoring of hydrogeolgic conditions.