Study on MJO initiation processes using CINDY2011/DYNAMO data and high resolution atmospheric models

2016 Fiscal Year Final Research Report

• Project/Area Number: 25287119
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: The University of Tokyo
• Principal Investigator: Miura Hiroaki 東京大学, 理学(系)研究科(研究院), 准教授 (70415991)
• Co-Investigator(Kenkyū-buntansha): 横井 覚 国立研究開発法人海洋研究開発機構, 大気海洋相互作用研究分野, 主任研究員 (40431902) ; 佐藤 薫 東京大学, 理学(系)研究科(研究院), 教授 (90251496)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: マッデン・ジュリアン振動 / 全球雲解像モデル / CINDY2011 / 大気海洋相互作用 / 熱帯気象

Outline of Final Research Achievements

One obvious feature of the Madden-Julian Oscillation (MJO) is a large-scale packet of convective clouds near the equator with a horizontal width of more than 1,000 km. The MJO not only directly influences equatorial regions through strong westerly and a large amount of precipitation but also indirectly modulates mid-latitude weather patterns by teleconnections. This study investigates the initiation and eastward movement mechanisms of the MJO by using the new observational data and a global cloud-system-resolving model. It is found that a zonal contraction of the equatorial mixed-Rossby-gravity waves due to the low-level westerly forced by a zonal sea surface temperature (SST) difference possibly induces the initiation of the MJO. It is also found that the seasonal SST change is fast enough to force the eastward movement of precipitating region, which can constitute a reason for the eastward shift of the MJO.

Free Research Field

大気科学