Journal Article

FZJ-2023-02289

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Interhemispheric Coupling Study by Observations and Modelling (ICSOM): Concept, Campaigns, and Initial Results

Sato, K. (Corresponding author) ; Tomikawa, Y. ; Kohma, M. ; Yasui, R. ; Koshin, D. ; Okui, H. ; Watanabe, S. ; Miyazaki, K. ; Tsutsumi, M. ; Murphy, D. ; Meek, C. ; Tian, Y. ; Ern, M.FZJ* ; Baumgarten, G. ; Chau, J. L. ; Chu, X. ; Collins, R. ; Espy, P. J. ; Hashiguchi, H. ; Kavanagh, A. J. ; Latteck, R. ; Lübken, F.-J. ; Milla, M. ; Nozawa, S. ; Ogawa, Y. ; Shiokawa, K. ; Alexander, M. J. ; Nakamura, T. ; Ward, W. E.

2023
Wiley Hoboken, NJ

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Please use a persistent id in citations: doi:10.1029/2022JD038249  doi:10.34734/FZJ-2023-02289

Abstract: An international joint research project, entitled Interhemispheric Coupling Study by Observations and Modelling (ICSOM), is ongoing. In the late 2000s, an interesting form of interhemispheric coupling (IHC) was discovered: when warming occurs in the winter polar stratosphere, the upper mesosphere in the summer hemisphere also becomes warmer with a time lag of days. This IHC phenomenon is considered to be a coupling through processes in the middle atmosphere (i.e., stratosphere, mesosphere, and lower thermosphere). Several plausible mechanisms have been proposed so far, but they are still controversial. This is mainly because of the difficulty in observing and simulating gravity waves (GWs) at small scales, despite the important role they are known to play in middle atmosphere dynamics. In this project, by networking sparsely but globally distributed radars, mesospheric GWs have been simultaneously observed in seven boreal winters since 2015/16. We have succeeded in capturing five stratospheric sudden warming events and two polar vortex intensification events. This project also includes the development of a new data assimilation system to generate long-term reanalysis data for the whole middle atmosphere, and simulations by a state-of-the-art GW-permitting general circulation model using the reanalysis data as initial values. By analyzing data from these observations, data assimilation, and model simulation, comprehensive studies to investigate the mechanism of IHC are planned. This paper provides an overview of ICSOM, but even initial results suggest that not only GWs but also large-scale waves are important for the mechanism of the IHC.

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. 2112 - Climate Feedbacks (POF4-211) (POF4-211)

Appears in the scientific report 2023

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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