Japan Geoscience Union Meeting 2019

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A (Atmospheric and Hydrospheric Sciences ) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS05] Stratosphere-troposphere Processes And their Role in Climate

Wed. May 29, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yoshio Kawatani(Japan Agency for Marine-Earth Science and Technology), Shingo Watanabe(Japan Agency for Marine-Earth Science and Technology), Takashi Sekiya(Japan Agency for Marine-Earth Science and Technology), Kaoru Sato(Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo)

[AAS05-P06] Hindcasts of the 2016 Disruption of the Stratospheric Quasi-biennial Oscillation

*Shingo Watanabe1, Kevin Hamilton2, Scott Osprey3, Yoshio Kawatani1, Eriko Nishimoto (1.Japan Agency for Marine-Earth Science and Technology, 2.International Pacific Research Center, University of Hawaii at Manoa, 3.NCAS-Climate, University of Oxford)

Keywords:quasi-biennial oscillation, Rossby wave, extended range hindcast

In early 2016 the quasi-biennial oscillation in tropical stratospheric winds was disrupted by an anomalous easterly jet centered at ~40 hPa, a development that was completely missed by all operational extended range weather forecast systems. This event and its predictability are investigated through ensemble hindcasts using a global model notable for its sophisticated representation of the upper atmosphere. Key to prediction of this event is simulating the slowly evolving mean winds in the winter subtropics that provide a waveguide for Rossby waves propagating from the winter hemisphere. Its association to the strong El Nino condition in 2015 is also investigated by changing sea surface temperatures.