[M-IS16] Dynamics of eruption cloud and cumulonimbus; modelling and observation

[MIS16-P07] Characteristics of polarimetric radar parameters of dry volcanic ash clouds

*Yura Kim¹, Masayuki Maki¹, Masato Iguchi², Dong-In Lee³ (1.Research and Education Center for Natural Hazards, Kagoshima University, Korimoto, Kagoshima, Japan, 2.Sakurajima Volcano Research Center/DPRI, Kyoto University, Sakurajima, Kagoshima, Japan, 3.Department of Atmospheric Sciences, Pukyong National University, Namgu, Busan, Republic of Korea)

Keywords:polarimetric radar parameters, volcanic ash, statistical analysis

We analyzed statistically the polarimetric radar data of 9 Sakurajima volcanic eruption clouds in 2013. All eruption clouds have a height exceeding 3000m. According to the results, Z_H has positively skewed distributions (Skewness of 1.6; mean Z_H of 9.77 dBZ and median of 7.4 dBZ), Z_DR has normal distributions (Skewness of 0.02; mean Z_DR of 1.58 dB and median of 1.6 dB), K_DP has positively skewed distributions (Skewness of 7.12; mean K_DP of 0.03 deg/km and median of 0.0 deg/km), and ρ_hv has negatively skewed distributions (Skewness of -1.02; mean ρ_hv of 0.77 and median of 0.8). Depending on time after the eruption, the average Z_H decreased from 22.3 dBZ to 6.75 dBZ while the average Z_DR and ρ_hv tended to increase from 1.24 dB to 1.67 dB, and from 0.47 to 0.83, respectively.