A Madden‐Julian Oscillation event remotely accelerates ocean upwelling to abruptly terminate the 1997/1998 super El Niño

The termination of the super-intense 1997/1998 El Nino was extraordinarily abrupt. The May 1998 Madden-Julian Oscillation (MJO), a massive complex of stormy tropical clouds, is among possible contributors to the abrupt termination. Despite having been sensationally proposed 18 years ago, the role of the MJO remained controversial and speculative because of the difficulty of sufficiently simulating the El Nino and MJO simultaneously. An ensemble simulation series using a newly developed, fully ocean-coupled version of a global cloud-system resolving numerical model replicated the specific atmosphere and ocean conditions of May 1998 in unprecedented detail, extending the prediction skill of the MJO to 46 days. Simulation ensemble members with stronger MJO activities over the Maritime Continent experienced quicker sea-surface temperature drop in the eastern Pacific, confirming that the easterly winds associated with the remote MJO accelerated ocean upwelling to abruptly terminate the El Nino.

[1]  Klaus M. Weickmann,et al.  A Comparison of OLR and Circulation-Based Indices for Tracking the MJO , 2014 .

[2]  C. Chow,et al.  Extratropical Forcing Triggered the 2015 Madden–Julian Oscillation–El Niño Event , 2017, Scientific Reports.

[3]  G. Vecchi The Termination of the 1997-98 El Niño. Part II: Mechanisms of Atmospheric Change , 2006 .

[4]  G. Vecchi,et al.  Improved Simulation of Tropical Cyclone Responses to ENSO in the Western North Pacific in the High-Resolution GFDL HiFLOR Coupled Climate Model* , 2016 .

[5]  M. Mcphaden,et al.  Genesis and evolution of the 1997-98 El Nino , 1999, Science.

[6]  D. E. Harrison,et al.  The Termination of the 1997–98 El Niño. Part I: Mechanisms of Oceanic Change* , 2006 .

[7]  B. Liebmann,et al.  Description of a complete (interpolated) outgoing longwave radiation dataset , 1996 .

[8]  J. Hansen,et al.  Global temperature change , 2006, Proceedings of the National Academy of Sciences.

[9]  Tomoe Nasuno,et al.  Intraseasonal variability and tropical cyclogenesis in the western North Pacific simulated by a global nonhydrostatic atmospheric model , 2015 .

[10]  Steven J. Woolnough,et al.  Atmosphere‐ocean coupled processes in the Madden‐Julian oscillation , 2015 .

[11]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[12]  Taisuke Boku,et al.  First-principles calculations of electron states of a silicon nanowire with 100,000 atoms on the K computer , 2011, 2011 International Conference for High Performance Computing, Networking, Storage and Analysis (SC).

[13]  Hirofumi Tomita,et al.  A new dynamical framework of nonhydrostatic global model using the icosahedral grid , 2004 .

[14]  Fuyuki Saito,et al.  Data exchange algorithm and software design of KAKUSHIN coupler Jcup , 2011, ICCS.

[15]  Y. Takayabu,et al.  Equatorial Circumnavigation of Moisture Signal Associated with the Madden-Julian Oscillation (MJO) during Boreal Winter , 2003 .

[16]  Takemasa Miyoshi,et al.  The Non-hydrostatic Icosahedral Atmospheric Model: description and development , 2014, Progress in Earth and Planetary Science.

[17]  P. R. Julian,et al.  Description of Global-Scale Circulation Cells in the Tropics with a 40–50 Day Period , 1972 .

[18]  Hiroaki Miura,et al.  A Madden-Julian Oscillation Event Realistically Simulated by a Global Cloud-Resolving Model , 2007, Science.

[19]  H. Hasumi,et al.  CCSR Ocean Component Model (COCO), version 2.1 , 2000 .

[20]  G. Kiladis,et al.  The role of equatorial waves in the onset of the South China Sea summer monsoon and the demise of El Niño during 1998 , 2006 .

[21]  Hirofumi Tomita,et al.  Madden–Julian Oscillation prediction skill of a new-generation global model demonstrated using a supercomputer , 2014, Nature Communications.

[22]  Duane E. Waliser,et al.  Cracking the MJO nut , 2013 .

[23]  Hiroaki Miura,et al.  Convective Momentum Transport by Rainbands within a Madden-Julian Oscillation in a Global Nonhydrostatic Model with Explicit Deep Convective Processes. Part I: Methodology and General Results , 2012 .

[24]  K. Straub MJO Initiation in the Real-Time Multivariate MJO Index , 2013 .

[25]  M. Wheeler,et al.  An All-Season Real-Time Multivariate MJO Index: Development of an Index for Monitoring and Prediction , 2004 .

[26]  H. Tomita,et al.  A global cloud‐resolving simulation: Preliminary results from an aqua planet experiment , 2005 .

[27]  A. E. Gill Some simple solutions for heat‐induced tropical circulation , 1980 .

[28]  E. Kintisch CLIMATE. How a 'Godzilla' El Niño shook up weather forecasts. , 2016, Science.

[29]  Misako Kachi,et al.  Abrupt termination of the 1997–98 El Niño in response to a Madden–Julian oscillation , 1999, Nature.

[30]  J. Picaut,et al.  Mechanisms of the 1997–1998 El Niño–La Niña, as inferred from space‐based observations , 2002 .

[31]  E. Hand The storm king. , 2015, Science.

[32]  Masayuki Nakagawa,et al.  A Framework for Assessing Operational Madden–Julian Oscillation Forecasts: A CLIVAR MJO Working Group Project , 2010 .

[33]  T. Matsuno,et al.  Quasi-geostrophic motions in the equatorial area , 1966 .