Troposphere-Stratosphere Coupling in Subseasonal-to-Seasonal Models and Its Importance for a Realistic Extratropical Response to the Madden-Julian Oscillation

Chen Schwartz*, Chaim I. Garfinkel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The representation of upward and downward stratosphere-troposphere coupling and its influence on the teleconnections of the Madden-Julian oscillation (MJO) to the European sector is examined in five subseasonal-to-seasonal models. We show that while the models simulate a realistic stratospheric response to transient anomalies in troposphere, they overestimate the downward coupling. The models with a better stratospheric resolution capture a more realistic stratospheric response to the MJO, particularly after the first week of the integration. However, in all models examined here the connection between the MJO and vortex variability is weaker than that observed. Finally, we focus on the MJO-SSW (sudden stratospheric warming) teleconnection and specifically initializations during the MJO phase with enhanced convection in the west/central pacific (i.e., 6 and 7) that preceded observed SSW. The integrations that simulated a SSW (as observed) can be distinguished from those that failed to simulate a SSW by the realism of the Pacific response to MJO 6/7, with only the simulations that successfully simulate a SSW capturing the North Pacific low. Furthermore, only the simulations that capture the SSW subsequently simulate a realistic surface response over the North Atlantic and Europe.

Original languageAmerican English
Article numbere2019JD032043
JournalJournal of Geophysical Research: Atmospheres
Volume125
Issue number10
DOIs
StatePublished - 27 May 2020

Bibliographical note

Funding Information:
C. I. G. and C. S. are supported by the ISF-NSFC joint research program (grant No.3259/19) and by the European Research Council starting grant under the European Unions Horizon 2020 research and innovation program (Grant Agreement 677756). This work is based on S2S data. S2S is a joint initiative of the World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP). The original S2S database is hosted at ECMWF as an extension of the TIGGE database and can be downloaded from the ECMWF server http://apps.ecmwf.int/datasets/data/s2s/levtype=sfc/type=cf/. Correspondence and requests for data should be addressed to C. S. (email:chen.schwartz1@mail.huji.ac.il). We thank the three anonymous reviewers for their helpful comments.

Funding Information:
C. I. G. and C. S. are supported by the ISF‐NSFC joint research program (grant No.3259/19) and by the European Research Council starting grant under the European Unions Horizon 2020 research and innovation program (Grant Agreement 677756). This work is based on S2S data. S2S is a joint initiative of the World Weather Research Programme (WWRP) and the World Climate Research Programme (WCRP). The original S2S database is hosted at ECMWF as an extension of the TIGGE database and can be downloaded from the ECMWF server http://apps.ecmwf.int/datasets/data/s2s/levtype=sfc/type=cf/ . Correspondence and requests for data should be addressed to C. S. (email: chen.schwartz1@mail.huji.ac.il ). We thank the three anonymous reviewers for their helpful comments.

Publisher Copyright:
©2020. The Authors.

Keywords

  • MJO
  • S2S
  • stratosphere

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