Observations of Volcanic Ashes with a 3-cm Polarimetric Radar

Radar observation of volcanic ashes on the Miyake Island, Japan was made from 26th September 2000 to 20th November 2000. The 3-cm wavelength polarimetric radar that was completed in 2000 was used for the observation. The mobile radar was set up at the Shikine Island located about 40 km from the Miyake Island. The purpose of the radar observations were to provide information on volcanic activities to residences in the Miyake Island and people who were charged in countermeasures against volcano calamities. Several data that seem to be associated with volcanic activities are analyzed. This paper will discuss about the possibility of the polarimetric radar parameters such as the differential reflectivity, specific differential phase shift for the detection of volcanic ash particles and the estimation of their size distribution.