日本地球惑星科学連合2018年大会

講演情報

[EE] ポスター発表

セッション記号 A (大気水圏科学) » A-AS 大気科学・気象学・大気環境

[A-AS02] 大規模な水蒸気場と組織化した雲システム

2018年5月22日(火) 10:45 〜 12:15 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:三浦 裕亮(国立大学法人 東京大学大学院 理学系研究科 地球惑星科学専攻)、濱田 篤(富山大学都市デザイン学部)、横井 覚(海洋研究開発機構、共同)、佐藤 正樹(東京大学大気海洋研究所)

[AAS02-P02] Enhancement of Madden-Julian Oscillation realization by low-frequency zonal SST gradient

★Invited Papers

*末松 環1,2三浦 裕亮1 (1.東京大学大学院理学系研究科地球惑星科学専攻、2.海洋研究開発機構)

キーワード:マッデン・ジュリアン振動、大気海洋相互作用

An environment favorable for development of the Madden-Julian Oscillation (MJO) is investigated by classifying MJO-like atmospheric patterns into MJO and regionally confined convective events (RCC). Comparison of MJO and RCC events show that even with preceding major event of convective suppression, convective events do not develop into an MJO when it is not accompanied by large scale buildup of moist static energy (MSE). The difference in the MSE accumulation between MJO and RCC is related to the contrasting low-frequency basic state sea surface temperature (SST) pattern, in which MJO and RCC are associated with prevalence of anomalously warm and cold low-frequency SST over western to central Pacific respectively. Distinct difference in the SST anomaly field between MJO and RCC identified in the low-frequency range is missing in the intraseasonal frequency range of 20-60 days. During the MJO low-frequency SST pattern is characterized by positive zonal SST gradient from the Indian Ocean to the central Pacific. This low-frequency SST pattern contributes to the sufficient build-up of MSE across Indian Ocean to the Western Pacific by providing long-standing condition that induces large-scale low-level convergence. The results of this study propose the potential importance of the low-frequency SST pattern with positive zonal SST gradient in enhancing convective activities on longer than intraseasonal time scale and realizing a complete lifecycle of the MJO.