
TY  - JOUR
A1  - Reid, J.E. 
A1  - Vrbancich, J. 
A1  - Worby, A.P. 
T1  - A comparison of shipborne and airborne electromagnetic methods for Antarctic sea ice thickness measurements
JF  - Exploration Geophysics
JO  - Explor. Geophys.
Y1  - 2003
VL  - 34
IS  - 2
SP  - 46
EP  - 50
KW  - 
UR  - https://doi.org/10.1071/EG03046 
N2  - The three-dimensional modelling program MARCO_AIR has been used to calculate the response of idealized sea-ice pressure ridge models to practical airborne and shipborne electromagnetic systems. The model results clearly show the superior lateral resolution of the horizontal coplanar shipborne system compared to higher-altitude airborne measurements. However, sea-ice keel thicknesses estimated via one-dimensional inversion of shipborne single-frequency electromagnetic data are strongly dependent on relatively small variations in survey altitude. One-dimensional inversion of synthetic helicopter electromagnetic data over three-dimensional pressure ridge models shows that the maximum ice keel thickness is consistently underestimated, although airborne EM methods yield reliable thickness estimates over level ice. The vertical-coaxial coil survey geometry offers excellent lateral resolution of multiple targets, but the anomalies of typical Antarctic sea-ice pressure ridges would be too small to be reliably detected in practical surveys using an HEM system with a transmitter-receiver separation of 2?3 m. For an HEM system with a coil separation of 8 m, the vertical coaxial responses are larger, and lateral resolution of the vertical coaxial measurements at a flight height of 20 m is superior to a close-coupled horizontal coplanar system flown at an altitude of 10 m. 
ER  -

