JpGU-AGU Joint Meeting 2020

Presentation information

[E] Poster

S (Solid Earth Sciences ) » S-VC Volcanology

[S-VC42] Dynamics of volcanic eruptions and their physical and chemical processes

convener:Atsuko Namiki(Graduate School of Integrated Arts and Sciences, Hiroshima University), Christian Huber(Brown University), Michael Manga(University of California Berkeley), Yujiro Suzuki(Earthquake Research Institute, The University of Tokyo)

[SVC42-P08] Ash fall observation using 2D-Video Disdrometer

*Eiichi Sato1, Masato Iguchi2 (1.Meteorological Research Institute, 2.Kyoto Univ.)

Keywords:2D-Video Disdrometer, Sakurajima volcano, ash fall, dual-polarization/polarimetric radar, volcanic eruption plume/cloud

Meteorological Research Institute (MRI) conducts ash fall observation using two-dimensional video disdrometers (2DVDs) in Sakurajima, Kagoshima. 2DVD is a ground-based instrument that originally observes precipitation particles, and is used for verification of dual-polarization radar observation. 2DVD can obtain particle size distribution, three-dimensional shape, and fall velocity of the targets by using an optical method. It is expected that it enable us to observe ash fall precisely, however, there are some drawbacks. One of the drawbacks is lowness of the ashfall capture rate, because it performs an "in situ" observation at a fixed point. In addition, the instrument is so sensitive that frequent maintenance is required.
On October 14, 2019, ash fall was successfully captured using a 2DVD in Kurokami, Sakurajima. As a result, it was found that a group of small and flat particles existed in the volcanic ash. It is known that a polarimetric parameter called differential reflectivity increases after secession of large particles from volcanic ash plume, and the observation result using 2DVD can be the evidence of this parameter change.
In this presentation, the outline of the observation method using 2DVD and some observation results will be shown.