Comparison of Airborne Electromagnetic Induction and Subsurface Radar Sounding of Freshwater Bathymetry.

摘要

A helicopter-borne electromagnetic induction (EMI) sounding system, operating at frequencies of 0.9, 4.6 and 33 kHz, was used in an attempt to profile freshwater bathymetry under an ice-covered lake. The EMI sounding results were compared with bathymetric measurements made by tape sounding and impulse radar sounding (approx. 120 and 280 MHz). As expected, the radar-measured depths were in excellent agreement with the tape measurements. The EMI bathymetry determinations were not representative of the lake bed topography. It is speculated that the EMI system was affected by an electromagnetic response from other than the freshwater/sediment interface.... Electromagnetic induction sounding, Freshwater ice, Freshwater bathymetry, Radar sounding.