Editorial Type:
Article
Article Type:
Research Article

Seasonal Modulations of the Active MJO Cycle Characterized by Nonlinear Principal Component Analysis

Johannes Jenkner The University of British Columbia, Vancouver, British Columbia, Canada

Search for other papers by Johannes Jenkner in
Current site
Google Scholar
PubMed Close
,
William W. Hsieh The University of British Columbia, Vancouver, British Columbia, Canada

Search for other papers by William W. Hsieh in
Current site
Google Scholar
PubMed Close
, and
Alex J. Cannon Environment Canada, Vancouver, British Columbia, Canada

Search for other papers by Alex J. Cannon in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Jul 2011
DOI:
https://doi.org/10.1175/2010MWR3562.1
Page(s):
2259–2275
Restricted access

Abstract

A novel methodology is presented for the identification of the mean cycle of the Madden–Julian oscillation (MJO) along the equator. The methodology is based on a nonlinear principal component (NLPC) computed with a neural network model. The bandpass-filtered input data encompass 30 yr with zonal winds at 850 and 200 hPa plus outgoing longwave radiation (OLR). The NLPC is conditioned on a sufficiently strong MJO activity and is computed both for the pooled dataset and for the dataset stratified into seasons. The NLPC for all data depicts a circular mode formed by the first two linear principal components (LPCs) with marginal contributions by the higher-order LPCs. Hence, the mean MJO cycle throughout the year is effectively captured by the amplitude of the leading two LPCs varying in quadrature. The NLPC for individual seasons shows additional variability, which mainly arises from a subordinate oscillation of the second pair of LPCs superimposed on the annual MJO signal. In reference to the all-year solution, the difference in resolved variability approximately accounts for 9% in solstitial seasons and 3% in equinoctial seasons. The phasing of the third LPC is such that convective activity oscillations over the Maritime Continent as well as wind oscillations over the Indian Ocean appear enhanced (suppressed) during boreal winter (summer). Also, convective activity oscillations appear more pronounced at the date line during both winter and summer. The phasing of the fourth LPC is such that upper-level westerlies over the Atlantic region are more persistent during boreal spring than during other seasons.

Corresponding author address: Johannes Jenkner, Department of Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Rd., Vancouver BC V6T 1Z4, Canada. E-mail: johannes.jenkner@alumni.ethz.ch

Abstract

A novel methodology is presented for the identification of the mean cycle of the Madden–Julian oscillation (MJO) along the equator. The methodology is based on a nonlinear principal component (NLPC) computed with a neural network model. The bandpass-filtered input data encompass 30 yr with zonal winds at 850 and 200 hPa plus outgoing longwave radiation (OLR). The NLPC is conditioned on a sufficiently strong MJO activity and is computed both for the pooled dataset and for the dataset stratified into seasons. The NLPC for all data depicts a circular mode formed by the first two linear principal components (LPCs) with marginal contributions by the higher-order LPCs. Hence, the mean MJO cycle throughout the year is effectively captured by the amplitude of the leading two LPCs varying in quadrature. The NLPC for individual seasons shows additional variability, which mainly arises from a subordinate oscillation of the second pair of LPCs superimposed on the annual MJO signal. In reference to the all-year solution, the difference in resolved variability approximately accounts for 9% in solstitial seasons and 3% in equinoctial seasons. The phasing of the third LPC is such that convective activity oscillations over the Maritime Continent as well as wind oscillations over the Indian Ocean appear enhanced (suppressed) during boreal winter (summer). Also, convective activity oscillations appear more pronounced at the date line during both winter and summer. The phasing of the fourth LPC is such that upper-level westerlies over the Atlantic region are more persistent during boreal spring than during other seasons.

Corresponding author address: Johannes Jenkner, Department of Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Rd., Vancouver BC V6T 1Z4, Canada. E-mail: johannes.jenkner@alumni.ethz.ch
Save
Cover Monthly Weather Review
Monthly Weather Review

  • An, S. I., W. W. Hsieh, and F. F. Jin, 2005: A nonlinear analysis of the ENSO cycle and its interdecadal changes. J. Climate, 18, 3229–3239.

    • Search Google Scholar
    • Export Citation

  • Chang, C. P., P. A. Harr, and H. J. Chen, 2005: Synoptic disturbances over the equatorial South China Sea and western Maritime Continent during boreal winter. Mon. Wea. Rev., 133, 489–503.

    • Search Google Scholar
    • Export Citation

  • Clivar Madden–Julian Oscillation Working Group, 2009: MJO simulation diagnostics. J. Climate, 22, 3006–3030.

  • De Angelis, D., and G. A. Young, 1992: Smoothing the bootstrap. Int. Stat. Rev., 60 (1), 45–56.

  • Duchon, C. E., 1979: Lanczos filtering in one and two dimensions. J. Appl. Meteor., 18, 1016–1022.

  • Efron, B., 1987: Better bootstrap confidence intervals. J. Amer. Stat. Assoc., 82 (397), 171–185.

  • Hall, P., T. J. DiCiccio, and J. P. Romano, 1989: On smoothing and the bootstrap. Ann. Stat., 17 (2), 692–704.

  • Hamilton, K., and W. W. Hsieh, 2002: Representation of the quasi-biennial oscillation in the tropical stratospheric wind by nonlinear principal component analysis. J. Geophys. Res., 107, 4232, doi:10.1029/2001JD001250.

    • Search Google Scholar
    • Export Citation

  • Haupt, S. E., A. Pasini, and C. Marzban, Eds., 2009: Artificial Intelligence Methods in the Environmental Sciences. Springer, 424 pp.

  • Hendon, H. H., and M. L. Salby, 1994: The life cycle of the Madden–Julian oscillation. J. Atmos. Sci., 51, 2225–2237.

  • Hendon, H. H., M. Wheeler, and C. Zhang, 2007: Seasonal dependence of the MJO–ENSO relationship. J. Climate, 20, 531–543.

  • Hsieh, W. W., 2001: Nonlinear principal component analysis by neural networks. Tellus, 53A, 599–615.

  • Hsieh, W. W., 2007: Nonlinear principal component analysis of noisy data. Neural Networks, 20, 434–443.

  • Hsieh, W. W., 2009: Machine Learning Methods in the Environmental Sciences. Cambridge University Press, 349 pp.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437–471.

  • Kessler, W. S., 2001: EOF representations of the Madden–Julian oscillation and its connection with ENSO. J. Climate, 14, 3055–3061.

  • Kiladis, G. N., K. H. Straub, and P. T. Haertel, 2005: Zonal and vertical structure of the Madden–Julian oscillation. J. Atmos. Sci., 62, 2790–2809.

    • Search Google Scholar
    • Export Citation

  • Kirby, M. J., and R. Miranda, 1996: Circular nodes in neural networks. Neural Comput., 8, 390–402.

  • Kramer, M. A., 1991: Nonlinear principal component analysis using autoassociative neural networks. Amer. Inst. Chem. Eng. J., 37, 233–243.

    • Search Google Scholar
    • Export Citation

  • Krasnopolsky, V. M., 2007: Neural network emulations for complex multidimensional geophysical mappings: Applications of neural network techniques to atmospheric and oceanic satellite retrievals and numerical modeling. Rev. Geophys., 45, RG3009, doi:10.1029/2006RG000200.

    • Search Google Scholar
    • Export Citation

  • Liebmann, B., and C. A. Smith, 1996: Description of a complete (interpolated) outgoing longwave radiation dataset. Bull. Amer. Meteor. Soc., 77, 1275–1277.

    • Search Google Scholar
    • Export Citation

  • Madden, R. A., and P. R. Julian, 1972: Description of global-scale circulation cells in tropics with a 40–50 day period. J. Atmos. Sci., 29, 1109–1123.

    • Search Google Scholar
    • Export Citation

  • Madden, R. A., and P. R. Julian, 1994: Observations of the 40–50-day tropical oscillation—A review. Mon. Wea. Rev., 122, 814–837.

  • Maloney, E., and D. L. Hartmann, 1998: Frictional moisture convergence in a composite life cycle of the Madden–Julian oscillation. J. Climate, 11, 2387–2403.

    • Search Google Scholar
    • Export Citation

  • Marzban, C., and G. J. Stumpf, 1996: A neural network for tornado prediction based on Doppler radar–derived attributes. J. Appl. Meteor., 35, 617–626.

    • Search Google Scholar
    • Export Citation

  • Masunaga, H., 2007: Seasonality and regionality of the Madden–Julian oscillation, Kelvin wave, and equatorial Rossby wave. J. Atmos. Sci., 64, 4400–4416.

    • Search Google Scholar
    • Export Citation

  • Matthews, A. J., 2000: Propagation mechanisms for the Madden-Julian Oscillation. Quart. J. Roy. Meteor. Soc., 126, 2637–2651.

  • Matthews, A. J., 2008: Primary and successive events in the Madden-Julian Oscillation. Quart. J. Roy. Meteor. Soc., 134, 439–453.

  • Milliff, R. F., and R. A. Madden, 1996: The existence and vertical structure of past, eastward-moving disturbances in the equatorial troposphere. J. Atmos. Sci., 53, 586–597.

    • Search Google Scholar
    • Export Citation

  • Monahan, A. H., 2001: Nonlinear principal component analysis: Tropical Indo-Pacific sea surface temperature and sea level pressure. J. Climate, 14, 219–233.

    • Search Google Scholar
    • Export Citation

  • North, G. R., T. L. Bell, R. F. Cahalan, and F. J. Moeng, 1982: Sampling errors in the estimation of empirical orthogonal functions. Mon. Wea. Rev., 110, 699–706.

    • Search Google Scholar
    • Export Citation

  • Roundy, P. E., and J. R. Kravitz, 2009: The association of the evolution of intraseasonal oscillations to ENSO phase. J. Climate, 22, 381–395.

    • Search Google Scholar
    • Export Citation

  • Rui, H., and B. Wang, 1990: Development characteristics and dynamic structure of tropical intraseasonal convection anomalies. J. Atmos. Sci., 47, 357–379.

    • Search Google Scholar
    • Export Citation

  • Slingo, J. M., D. P. Rowell, K. R. Sperber, and E. Nortley, 1999: On the predictability of the interannual behaviour of the Madden-Julian Oscillation and its relationship with El Niño. Quart. J. Roy. Meteor. Soc., 125, 583–609.

    • Search Google Scholar
    • Export Citation

  • Teng, Q., J. C. Fyfe, and A. H. Monahan, 2007: Northern Hemisphere circulation regimes: Observed, simulated and predicted. Climate Dyn., 28, 867–879.

    • Search Google Scholar
    • Export Citation

  • Wang, B., and H. Rui, 1990: Synoptic climatology of transient tropical intraseasonal convection anomalies: 1975–1985. Meteor. Atmos. Phys., 44 (1–4), 43–61.

    • Search Google Scholar
    • Export Citation

  • Wheeler, M., and G. N. Kiladis, 1999: Convectively coupled equatorial waves: Analysis of clouds and temperature in the wavenumber-frequency domain. J. Atmos. Sci., 56, 374–399.

    • Search Google Scholar
    • Export Citation

  • Wheeler, M., and H. H. Hendon, 2004: An all-season real-time multivariate MJO index: Development of an index for monitoring and prediction. Mon. Wea. Rev., 132, 1917–1932.

    • Search Google Scholar
    • Export Citation

  • Woolnough, S. J., J. M. Slingo, and B. J. Hoskins, 2000: The relationship between convection and sea surface temperature on intraseasonal time scales. J. Climate, 13, 2086–2104.

    • Search Google Scholar
    • Export Citation

  • Wu, M. C., S. D. Schubert, M. J. Suarez, P. J. Pegion, and D. Waliser, 2006: Seasonality and meridional propagation of the MJO. J. Climate, 19, 1901–1921.

    • Search Google Scholar
    • Export Citation

  • Zhang, C., 2005: Madden-Julian Oscillation. Rev. Geophys., 43, RG2003, doi:10.1029/2004RG000158.

  • Zhang, C., and J. Gottschalck, 2002: SST anomalies of ENSO and the Madden–Julian oscillation in the equatorial Pacific. J. Climate, 15, 2429–2445.

    • Search Google Scholar
    • Export Citation

  • Zhang, C., and M. Dong, 2004: Seasonality in the Madden–Julian oscillation. J. Climate, 17, 3169–3180.

  • Zhang, J., and X. Wang, 2009: Robust normal reference bandwidth for kernel density estimation. Stat. Neerl., 63 (1), 13–23.

  • Zhou, S. T., and A. J. Miller, 2005: The interaction of the Madden–Julian oscillation and the Arctic Oscillation. J. Climate, 18, 143–159.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 168 51 3
PDF Downloads 70 16 3