鷹野 敏明

都市部での豪雨災害がクローズアップされ，都市型洪水に対する対策や短時間豪雨予測ナウキャストへの取り組みがなされている．通常の集中豪雨は組織化された積乱雲群によってもたらされ，激しい雨が数時間にわたって降り続くことにより，ごく狭い地域で数百ミリの雨量がもたらされ，防災上の観点から豪雨をもたらす積乱雲を出来る限り早く検知することは極めて大事である．気象学の観点からも対流雲の初期段階の挙動を様々な観測手段で捉えることは重要であることから，防衛大小林文明教授を中心とした研究チームによる総合観測がこれまでなされてきた（房総対流雲観測研究）．本発表では，房総対流雲観測研究チームによるこれまでの観測成果を俯瞰し，今後の展望について述べる．

Aerosols and clouds play important roles in the Arctic climate. Conversely, aerosol emissions and cloud formation are affected by changes in the Arctic climate. This paper reviews studies of aerosols and clouds performed during the Arctic Challenge for Sustainability (ArCS) project carried out by the National Institute of Polar Research (NIPR) in Japan and collaborating institutions. The ArCS project included intensive studies of black carbon aerosols (BC). We installed Continuous Soot Monitoring System (COSMOS) instruments to measure atmospheric BC at four locations in the Arctic, establishing the Arctic BC COSMOS Measurement Network (ABCMnet). We also measured BC concentrations in snowpack in extensive areas of the Arctic and showed that previous studies have greatly overestimated BC in snowpack. We developed and improved new aerosol models that achieved better agreements with measurements of BC in the Arctic atmosphere, snowpack, and falling snow. We made new estimates of radiative forcing of BC in the Arctic atmosphere and snow/ice surfaces that lower their albedo. In addition to these researches on BC, we made accurate measurements of ice nucleating particles (INPs) at Ny-?lesund, Svalbard, showing that their concentrations increased in summer as a result of dust particle emissions from glacial outwash sediments. This high ice nucleating ability was likely due to the presence of organic substances mixed with the dust particles. We also made continuous cloud radar measurements and the first continuous in-situ measurements of cloud microphysical properties in the Arctic at Ny-?lesund. Results from these cloud measurements and their relationship with aerosols are described.