1985年4月24日の降ひょうに関する気象解析   :   Meteorological Analysis on the Hail Precipitation of April 24th, 1985 

作成者 今, 久, 羽生, 寿郎
作成者 (ヨミ) コン, ヒサシ
作成者の別表記 KON, Hisashi, HANYU, Juro
日本十進分類法 (NDC) 451
内容 1985年4月24日関東地方の広い範囲でひょうが降った.被害は約5億円に達したが, 季節的に早かったせいもあり, 規模の割には少なかったといえる.しかし, 降ひょうの規模が大きかったので, 降ひょう予測という点に注目しながら解析を行なった.その結果, 次のような知見が得られた.1.進行速度は日本海上で少し遅くなるが, 500mbの寒気の大陸上の移動速度を使って外挿することでおおむね予想できた.2.降ひょう日には対流不安定が地上から3000mまで達し, 下層は南よりの風で湿度が高く, 上層は北よりの風が卓越していた.3.ショワルターの安定指数を用いた降ひょう子測では850mbより900mbの気塊を用いた方がうまく予報できた.4.クラスターの南側と東側では風向・風速・気温降下の間に異なる関係が見られた.5.風向が変化した時から降ひょうと風速ピークが生ずるまでの時間は, 平均的に見ると30から40分程度であった.6.降雨域と気温降下域にずれがあったが, 最大の気温降下量は温度の時間変化の軌跡から, 連続した複数の積乱雲による下降気流によってもたらされたと判断された.
The hail precipitated in the large extent of Kanto Plain in April 24th, 1985. The damage reached about 500, 000, 000 yen which was less than expected from the strength and the scale of the hail precipitation. One of the reason is that it occurred in the early cropping season. In this study, meteorological factors on this hail event were analyzed with paying attention to the forecast of hail precipitation, because the strength and the scale were so large. As the results, following features were found: 1. Arrival of the upper cold air mass could be predicted by using the movement speed of the 500mb height air mass over the continent. 2. In the day of the hail precipitation, the convective instability of air column existed upto 3000m height from the surface. The lower layer than lOOOm height was moistened and the wind had a southern component. On the other hand, the wind in the upper layer had a northern component. 3. The prediction of hail precipitation was better when an air mass of 900mb was used instead of 850mb in the method of Sowalter instability index. 4. The relations among the wind direction, the wind speed and the temperature depression which were found in the south of the radar echo clusters were different from that found in the east. 5. The hail precipitation and the peak of wind speed were observed after 30-40min of the change in wind direction. 6. The area of the maximum precipitation was apart from the area of the maximum temperature depression. It was considered from the trajectories of the temperature depression curves that the maximum temperature depression was due to multiple passages of thunderstorms.

公開者 千葉大学園芸学部
コンテンツの種類 紀要論文 Departmental Bulletin Paper
ファイル形式 application/pdf
ISSN 0069-3227
NCID AN00142658
掲載誌情報 千葉大学園芸学部学術報告 Vol.39 page.17-22 (19870330)
情報源 The technical bulletin of Faculty of Horticulture, Chiba University
言語 日本語
著者版フラグ publisher

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