抄録
This paper describes an observation experiment of Volcano Unzen using an airborne imaging radar. The purpose of the observation is to confirm the potential of the microwave imaging radar for a practical use. Microwave images do not suffer from cloud or rain. This is a great advantage over the visible images. Volcano Unzen is very active and it is producing a lava dome and causes pyroclastic flows which killed people and damaged farms and houses, but Volcano Unzen was hard to observe because of rain cloud, especially in the raining season in Japan.
We obtained thirteen images of Volcano Unzen. The best image was the one taken from west side of the mountain. The topography of Volcano Unzen was clearly shown. The active lava dome which has a dimension of about 100 m by 200 m was not clearly identified because of the relatively poor horizontal resolution of the imaging radar which was about 40 m by 40 m.
The recorded data were corresponding to a pixel of 6.3 m by 15 m which is much smaller than the resolution of the radar determined by the pulse length and the antenna beam width. The oversampled data were averaged over eight data, which was very effective to improve the quality of the image without degradation of the resolution.
Some problems for the practical use of the microwave imaging radar, including the resolution, aircraft flight conditions, were also pointed out.
