- 著者
- Hiroyuki IWASAKI
- 出版者
- (公社)日本気象学会
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.94, no.5, pp.431-442, 2016 (Released:2016-10-31)
- 参考文献数
- 25
- 被引用文献数
- 7
Lightning features over the Tibetan Plateau were studied in relation to topography using the World Wide Lightning Location Network (WWLLN) dataset obtained from April 2009 until December 2014. To describe the strength of lightning strokes, lightning strokes with energies above the 90th percentile (7666 J) were defined as strong lightning (S-lightning) strokes, and the ratio of S-lightning strokes to the overall number of lightning (O-lightning) strokes was defined as the strong ratio (S-ratio). O-lightning density over the Tibetan Plateau was found to be high in general, except over the western part of analysis region. Minimum-density zones were observed along the Himalayas approximately 6 km above sea level and in deep valleys within the Tibetan Plateau. The maximum- and minimum-density zones also exhibited maximum and minimum annual rainfall amounts, respectively. S-lightning strokes were also found to frequently occur over the Tibetan Plateau, and most S-ratios in the analysis units exceeded 30 %, which corresponds to three times the global mean. In particular, the S-ratios over the southern part of the Tibetan Plateau, including the Himalayas, were found to be high (50 %) and to correspond with the zone that had the minimum O-lightning density. The maximum O-lightning density was observed to occur during the summer at an elevation approximately 0.2-1.0 km higher than the plateau level. The O-lightning and S-lightning densities around the Nagqu sonde station were negatively correlated with the Showalter stability index (SSI) and the vertical wind shear. The S-ratio and average stroke energy were found to be negatively correlated with the vertical shear but not with the SSI.
- 著者
- Hiroyuki Iwasaki
- 出版者
- (公社)日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.10, pp.98-102, 2014 (Released:2014-06-06)
- 参考文献数
- 19
- 被引用文献数
- 4 7
Features of lightning around Japan over a four-year period are described using World Wide Lightning Location Network data based on global observations of very low frequency radio waves. Lightning density over land is lower than that over the ocean and the oceanic area of high density runs along the Kuroshio Current. The zone of highest density is found to the west of the Nansei Islands; however, very strong lightning rarely occurs there. Conversely, lightning density decreases gradually towards the eastern part of the Kuroshio Current, where the occurrence of very strong lightning increases.The ratio of very strong lightning in most of the analysis area tends to increase in the cold season, and it becomes large in areas where lightning frequency is low. Furthermore, both very weak and strong lightning have a tendency to occur in areas where rain intensity is not strong.
1 0 0 0 OA ヒッグス粒子の発見―質量をつかさどるヒッグス粒子とは?―
- 著者
- 岩崎 博行 Hiroyuki IWASAKI イワサキ ヒロユキ
- 出版者
- 総合研究大学院大学
- 巻号頁・発行日
- (Released:2013-07-10)
基本的な力(相互作用)には重力、電磁力、弱い力、強い力の4種類あることが分かっています。このうち重力は他の3つの力と比べて非常に弱いため、素粒子の標準模型では電磁力、弱い力、強い力を扱います。標準模型は非常に強力な理論で、あらゆる精密実験において標準模型とは明らかに矛盾するという事象は見つかっていません。 この標準模型に導入されている素粒子の中で唯一未発見だったのが、素粒子に質量を与えることになるヒッグス粒子です。約半世紀前に提唱されたヒッグス粒子は標準理論の根幹をなす粒子であるにもかかわらず、今までの加速器では性能が十分ではなくずっと未発見のままでした。 LHC計画ではヒッグス粒子が考えられるどの質量であっても必ず発見できるだけの性能を持った加速器と検出器を製作することにしました。こうして国際協力体制でLHC計画が開始されてから約15年の歳月を経て、2012年についにヒッグス粒子発見につながりました。 今回はヒッグス粒子とはどういう粒子なのかということと、LHC加速器や実験装置も含めその発見に至るまでの物語を語りたいと思います。 サイエンス・カフェ「ヒッグス粒子の発見―質量をつかさどるヒッグス粒子とは?― 」平成25年7月6日(土) 於湘南国際村センター1階展示室 (葉山町);後援 葉山町*この資料は著者の希望により閲覧のみ、印刷不可です 岩崎博行[総合研究大学院大学教授 / 高エネルギー加速器研究機構素粒子原子核研究所教授]