Seasonal Dependence of the MJO-ENSO Relationship

Abstract Observations of the development of recent El Nino events suggest a pivotal role for the Madden–Julian oscillation (MJO). Previous attempts to uncover a systematic relationship between MJO activity and the El Nino–Southern Oscillation (ENSO), however, have yielded conflicting results. In this study the MJO–ENSO relationship is stratified by season, and the focus is on MJO activity in the equatorial western Pacific. The results demonstrate that MJO activity in late boreal spring leads El Nino in the subsequent autumn–winter for the period 1979–2005. Spring is the season when MJO activity is least asymmetric with respect to the equator and displays the most sensitivity to SST variations at the eastern edge of the warm pool. Enhanced MJO activity in the western Pacific in spring is associated with an eastward-expanded warm pool and low-frequency westerly surface zonal wind anomalies. These sustained westerly anomalies in the western Pacific are hypothesized to project favorably onto a developing El N...

[1]  Chidong Zhang,et al.  SST Anomalies of ENSO and the Madden–Julian Oscillation in the Equatorial Pacific* , 2002 .

[2]  A. Fink,et al.  Some potential forcing mechanisms of the year‐to‐year variability of the tropical convection and its intraseasonal (25–70‐day) variability , 1997 .

[3]  Michael J. McPhaden,et al.  Tropical Pacific Ocean heat content variations and ENSO persistence barriers , 2003 .

[4]  H. Hendon,et al.  Interannual Variation of the Madden–Julian Oscillation during Austral Summer , 1999 .

[5]  Matthew C. Wheeler,et al.  Convectively Coupled Equatorial Waves: Analysis of Clouds and Temperature in the Wavenumber–Frequency Domain , 1999 .

[6]  Andrew M. Moore,et al.  Stochastic forcing of ENSO by the intraseasonal oscillation , 1999 .

[7]  Thomas M. Smith,et al.  Improved Global Sea Surface Temperature Analyses Using Optimum Interpolation , 1994 .

[8]  Bin Wang,et al.  Synoptic climatology of transient tropical intraseasonal convection anomalies: 1975–1985 , 1990 .

[9]  Peter M. Inness,et al.  Simulation of the Madden–Julian Oscillation in a Coupled General Circulation Model. Part I: Comparison with Observations and an Atmosphere-Only GCM , 2003 .

[10]  E. Rasmusson,et al.  Variations in Tropical Sea Surface Temperature and Surface Wind Fields Associated with the Southern Oscillation/El Niño , 1982 .

[11]  J. Picaut,et al.  The oceanic zone of convergence on the eastern edge of the Pacific warm pool: A synthesis of results and implications for El Niño‐Southern Oscillation and biogeochemical phenomena , 2001 .

[12]  P. Delecluse,et al.  Ocean response to the March 1997 Westerly Wind Event , 2001 .

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

[14]  D. E. Harrison,et al.  Tropical Pacific Sea Surface Temperature Anomalies, El Niño, and Equatorial Westerly Wind Events* , 2000 .

[15]  M. Mcphaden,et al.  Forcing of intraseasonal Kelvin waves in the equatorial Pacific , 1995 .

[16]  Interannual fluctuations of intraseasonal variance of near‐equatorial zonal winds , 1991 .

[17]  A. Moore,et al.  The Linear Response of ENSO to the Madden–Julian Oscillation , 2005 .

[18]  A. Fedorov,et al.  The response of the coupled tropical ocean–atmosphere to westerly wind bursts , 2002 .

[19]  H. Spencer.  Role of the atmosphere in seasonal phase locking of El Niño , 2004 .

[20]  W. Timothy Liu,et al.  Case analysis of a role of ENSO in regulating the generation of westerly wind bursts in the Western Equatorial Pacific , 2003 .

[21]  Klaus M. Weickmann,et al.  Intraseasonal Air–Sea Interactions at the Onset of El Niño , 2001 .

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

[23]  D. E. Harrison,et al.  Zonal Winds in the Central Equatorial Pacific and El Ni�o , 1983, Science.

[24]  K. Weickmann,et al.  El Niño/Southern Oscillation and Madden‐Julian (30–60 day) oscillations during 1981–1982 , 1991 .

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

[26]  H. Hendon,et al.  Upper-Ocean Heat Budget in Response to the Madden–Julian Oscillation in the Western Equatorial Pacific , 2001 .

[27]  H. Hendon,et al.  Intraseasonal behavior of clouds, temperature, and motion in the tropics , 1994 .

[28]  Rectified wind forcing and latent heat flux produced by the Madden-Julian oscillation , 2002 .

[29]  Characteristics of Stochastic Variability Associated with ENSO and the Role of the MJO , 2005 .

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

[31]  J. Slingo,et al.  On the predictability of the interannual behaviour of the Madden‐Julian oscillation and its relationship with el Nin̄o , 1998 .

[32]  Min Dong,et al.  Seasonality in the Madden–Julian Oscillation , 2004 .

[33]  W. Kessler,et al.  Rectification of the Madden-Julian Oscillation into the ENSO Cycle. , 2000 .

[34]  Andrew T. Wittenberg,et al.  Reassessing the role of stochastic forcing in the 1997–1998 El Niño , 2006 .

[35]  W. Lau,et al.  El Niño Southern Oscillation connection , 2005 .

[36]  E. Guilyardi,et al.  The March 1997 Westerly Wind Event and the onset of the 1997/98 El Niño: understanding the role of the atmospheric response , 2003 .

[37]  Harry H. Hendon,et al.  Oceanic Kelvin Waves and the Madden–Julian Oscillation , 1998 .

[38]  Mechanisms of Seasonal – ENSO Interaction , 1995, ao-sci/9508001.

[39]  Quasi‐biennial winds in the far western equatorial Pacific phase‐Locking El Niño to the seasonal cycle , 2000 .

[40]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

[41]  W. Kessler.  EOF Representations of the Madden–Julian Oscillation and Its Connection with ENSO* , 2001 .

[42]  Eli Tziperman,et al.  Westerly Wind Bursts: ENSO's tail rather than the dog? , 2004 .