日本地球惑星科学連合2018年大会

講演情報

[JJ] ポスター発表

セッション記号 A (大気水圏科学) » A-OS 海洋科学・海洋環境

[A-OS18] 海洋物理学一般

2018年5月22日(火) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:岡 英太郎(東京大学大気海洋研究所)、川合 義美(国立研究開発法人海洋研究開発機構 地球環境観測研究開発センター)、東塚 知己(東京大学大学院理学系研究科地球惑星科学専攻)

[AOS18-P02] 爆弾低気圧下における海洋表面波の発達

*北 祐樹1早稲田 卓爾1Webb Adrean (1.東京大学大学院新領域創成科学研究科)

キーワード:海洋表面波、爆弾低気圧、北西太平洋

Ocean wave developments under explosive cyclone (EC) conditions are investigated with hindcast simulations of ocean waves in the Northwestern Pacific between 1994 and 2014. Composite analyses of the ocean wave field under EC conditions are conducted in order to obtain an overall depiction of spatio-temporal developments of ocean waves. Because of the rapid development of ECs, ocean waves beneath ECs continue to grow for about half a day after the EC begins to decay. ECs generate two areas with narrow directional spectra: on the cold side of a warm front and on the right-hand-side of the cyclone center, relative to the propagating direction. In comparison, typhoons usually generate just one area with a sharp peak. This research successfully provides a schematic diagram which illustrates the ocean wave development under an EC condition with atmospheric system (Fig. 1). This EC feature is derived from the existence of atmospheric fronts, which produce a complex wind system for the ECs. In one case study, spectral analysis of wave spectra from an EC in January 2013 indicates that the warm front plays a critical role in generating the distinctive ocean wave system in the warm and cold zones along the warm front, both of which have a narrow spectrum in direction and frequency. In contrast, ocean waves on the left-hand-side and in the backward area relative to the propagation direction are composed of swell and wind-wave systems propagating in different directions. Ocean wave disasters under ECs are proved to show dissimilar features from typhoons and should provide substantial information to maritime disaster risk management.