[M-IS13] 火山噴煙・積乱雲のモデリングと観測

[MIS13-P02] マルチセンシング観測による積雲から積乱雲への成長過程

*前坂 剛¹、大東 忠保¹、岩波 越¹、鈴木 真一¹、櫻井 南海子¹、出世 ゆかり¹、木枝 香織¹、清水 慎吾¹、宇治 靖¹、高橋 暢宏²、花土 弘³、中川 勝広³、牛尾 知雄⁴ (1.防災科学技術研究所、2.名古屋大学、3.情報通信研究機構、4.大阪大学)

キーワード：積雲、積乱雲、雲レーダー、MP-PAWR

Recently, weather radar network which consists of X- and C-band polarimetric radars has matured in Japan. This nationwide network enables Quantitative Precipitation Estimation (QPE) with high resolutions (1 minute and 250 m), and is used for a monitoring of localized heavy rain. So now a social request is shifting from the monitoring to the forecast of the heavy rain. This kind of forecast needs a seed of cumulonimbus development as an initial condition. The weather radar is a suitable instrument to find the seed. But when the ordinary weather radar finds it, the rainfall has already started. To make the lead time of the forecast longer, we should monitor the pre-stages of cumulonimbus, such as horizontal convergence and cumulus clouds. For this purpose, we installed microwave radiometers, Doppler lidars, Ka-band cloud radars around Tokyo metropolitan area. Furthermore, X-band Multi-Parameter Phased Array Weather Radar (MP-PAWR) also covers the area, and is a powerful instrument to capture the three-dimensional structure of precipitation system. In this presentation, an evolution from cumulus to cumulonimbus is analyzed by using multi-sensor data.

We analyzed the cloud activities on 3 August 2018. Many cumulus clouds appeared and dissipated, before the precipitation started, cloud size and its reflectivity gradually became larger with time. Finding the clouds in transition stage (reflectivity of about -5 dBZ, and echo size of about 5 km²) is important for monitoring the evolution from cumulous to cumulonimbus. Cumulus activity moistened mid-troposphere, and this moistening may help the cumulonimbus development.