1:45 PM - 3:15 PM
[MIS23-P05] Quantitative volcanic ash estimation using dual-polarization weather radar
Keywords:dual-polarization weather radar, volcanic ash, remote sensing, quantitative volcanic ash estimation
The Meteorological Research Institute (MRI) is conducting observations around Sakurajima using X-band dual-polarization (dual-pol) weather radar (MRI-XMP) and two-dimensional video disdrometers (2DVDs); MRI-XMP is used to observe volcanic plumes, and 2DVDs are used for ground-based ash fall observations. Dual-pol radar can obtain more information than conventional single-pol radar since it can acquire parameters related to particle shape. 2DVD was originally developed for observations of precipitation particles and can observe size, shape, and fall velocity of each particle in addition to grain (particle) size distribution of ashfall.
In this presentation, a method under development at MRI to quantitatively estimate the amount of volcanic ash in the atmosphere using dual-pol radar will be presented. In this method, a data set of particle size, shape, and fall velocity observed by 2DVD is prepared as an independent material in advance. The relationship between particle size and shape is used for scattering simulations. Fall velocity is used to determine particle density. Then, assuming a grain size distribution for each radar bin, the reflectivity and differential reflectivity can be calculated. Finally, the differences between the simulated and actual observed values are calculated, and the final estimate of the grain size distribution is obtained when the cost function that includes them is minimized.
Examples of the results of estimating volcanic ash concentrations inside the volcanic plume will also be presented in this presentation.
In this presentation, a method under development at MRI to quantitatively estimate the amount of volcanic ash in the atmosphere using dual-pol radar will be presented. In this method, a data set of particle size, shape, and fall velocity observed by 2DVD is prepared as an independent material in advance. The relationship between particle size and shape is used for scattering simulations. Fall velocity is used to determine particle density. Then, assuming a grain size distribution for each radar bin, the reflectivity and differential reflectivity can be calculated. Finally, the differences between the simulated and actual observed values are calculated, and the final estimate of the grain size distribution is obtained when the cost function that includes them is minimized.
Examples of the results of estimating volcanic ash concentrations inside the volcanic plume will also be presented in this presentation.