Topographic and thermal mapping of volcanic terrain using AVTIS ground-based 94-GHz dual-mode radar/radiometric imager

The AVTIS remote sensing instrument is a custom built millimeter wave sensor that has been developed as a practical field tool for remote sensing of volcanic terrain at active lava domes. The portable instrument combines active and passive millimeter wave measurements to record topographic and thermal data in almost all weather conditions from ground-based survey points. We describe how the instrument is deployed in the field, the quality of the primary ranging and radiometric measurements and the post-processing techniques used to derive the geophysical products of the target terrain, surface temperature and reflectivity. By comparison of changing topography we estimate volume change and lava extrusion rate. Validation of the millimeter wave radiometry is also presented by quantitative comparison with coincident infrared thermal imagery.