IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

1W_4F-P10

Date/Time: July 21 Poster

Observations by the JMA weather radar network and quantitative predictions oftephra-fall with the JMA RATM for the eruptions at Shinmoe-dake volcano in 2011
Toshiki Shimbori1 , Akihiro Hashimoto1 , Shin’ya Onizawa1 , Akimichi Takagi1 , Tetsuya Yamamoto1 ,Keiichi Fukui2 , Yosuke Hayashi3 , Shota Imamura3 , Akira Sugai3 , Yoshihiko Hasegawa3 , Reiko Kai4 ,Satoshi Sugiura4 , Tetsuyuki Ueyama4 , Toshiyuki Sakurai4 , Shomei Shirato4
1Meteorological Research Institute, Japan, 2 Kakioka Magnetic Observatory, Japan, 3 Japan
Meteorological Agency, Japan, 4 Tokyo Volcanic Ash Advisory Center, Japan
E-mail: shimbori@mri-jma.go.jp

The JMA implemented the Volcanic Ash Fall Forecast in March 2008 and is considering the predictions of lapilli-fall.
The Tokyo VAAC has also been provided the Volcanic Ash Dispersion Chart for Sakurajima and Shinmoe-dakevolcanoes on trial since July 2010. The technical methods are based on the JMA Regional Atmospheric Transport
Model (RATM) driven by the GPVs of operational Mesoscale Model (MSM) or Local Forecast Model (LFM), both ofwhich originated from the JMA Nonhydrostatic Model (NHM).
The RATM for volcanic ash and others has been developed at the MRI (Shimbori et al., 2010; Saito et al., 2013).
This is an off-line Lagrangian model which considered the processes of three-dimensional advection, horizontaland vertical diffusion, gravitational settling, dry deposition and wet scavenging. When using the GPVs of LFM(hourly intervals up to 9 hours, 2 km grid spacing, 60 hybrid layers), the number of tracers is 250,000 and thecalculation grid spacing of concentration or deposition is 2 km in latitude-longitude coordinate. For the quantitative
predictions of tephra-fall, the initial condition of RATM is given by the eruption column model according to Suzuki(1983). Variable input parameters of the model are eruption column height and duration.
In the case of the 2011 eruptions of Shinmoe-dake, one of the active volcanoes in the Kirishima volcano grouplocated in southwestern Japan, many eruption clouds were observed by weather radars. From the radar reflectivity
factor observed by JMA’s operational C-band weather Doppler radars at Tanegashima, Fukuoka and Kagoshima
airport, the time series of the eruption cloud echo heights have been analyzed in detail (Shimbori et al., 2013).
Hashimoto et al. (2012) showed that these radar observations yield effective initial data of the eruption column
model to well simulate the ash deposition pattern. In the presentation, results of RATM calculations using the radar
data will be shown with comparison to the observed ash-fall quantity and lapilli-fall area.

References
Hashimoto, A., T. Shimbori and K. Fukui, 2012: Tephra fall simulation for the eruptions at Mt. Shinmoe-dake during
26-27 January 2011 with JMANHM. SOLA, 8, 37-40.
Saito, K., T. Shimbori and R. Draxler, 2013: JMA’s Regional ATM calculations for the WMO technical task team on
meteorological analyses for Fukushima Daiichi Nuclear Power Plant accident. Extended abstract, 93rd Amer. Met.
Soc. Annual Meeting.
Shimbori, T., Y. Aikawa, K. Fukui, A. Hashimoto, N. Seino and H. Yamasato, 2010: Quantitative tephra fall prediction
with the JMA mesoscale tracer transport model for volcanic ash. Pap. Met. Geophys., 61, 13-29 (in Japanese).
Shimbori, T., T. Sakurai, M. Tahara and K. Fukui, 2013: Observation of eruption clouds with weather radars andmeteorological satellites. Submitted to Q. J. Seismol. (in Japanese).
Suzuki, T., 1983: A theoretical model for dispersion of tephra. Arc Volcanism. TERRAPUB, 95-113.
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