The UNderstanding Severe Thunderstorms and Alberta Boundary Layer Experiment (UNSTABLE) in July 2008 was a field project to investigate the initiation of thunderstorms in southern Alberta. Special field observations included an enhanced surface network augmented with instrumented vehicles. Upper air observations were taken from four sites every two hours. This thesis focuses on the case study day of 17 July 2008 when a dryline formed parallel to the Rocky Mountains at 1030 MDT and persisted for up to nine hours. The vapour mixing ratio changed from 4.5 to 8.5 g/kg over 5 km. We documented the spatial and temporal distribution of cloud and precipitation relative to the dryline. Initially, extensive cloud formed over the dry air to the west of the dryline, while the capping inversion at 800 mb inhibited cloud formation in the moist air. In the afternoon, convection was triggered along the dryline and severe thunderstorms were observed.

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京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18640号 / 理博第4019号 / 新制||理||1579(附属図書館) / 31554 / 京都大学大学院理学研究科地球惑星科学専攻 / (主査)教授 石川 裕彦, 准教授 林 泰一, 教授 余田 成男 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM