• Chan, J. C. L., and M. C. Wu, 2003: Outlook for the 2003/04 East Asian winter monsoon. Extended Abstracts, Joint Meeting on Seasonal Prediction of 2003/04 East Asian Winter Monsoon, Tokyo, Japan, Japan Meteorological Agency, 7–12.

  • Chang, C. P., and K-M. Lau, 1980: Northeasterly cold surges and near-equatorial disturbances over the winter MONEX area during December 1974. Part II: Planetary-scale aspects. Mon. Wea. Rev., 108 , 298312.

    • Search Google Scholar
    • Export Citation
  • Chang, C. P., and K-M. Lau, 1982: Short-term planetary-scale interaction over the tropics and midlatitudes during northern winter. Part I: Contrasts between active and inactive periods. Mon. Wea. Rev., 110 , 933946.

    • Search Google Scholar
    • Export Citation
  • Chen, W., H-F. Graf, and H. Ronghui, 2000: The interannual variability of East Asian winter monsoon and its relation to the summer monsoon. Adv. Atmos. Sci., 17 , 4860.

    • Search Google Scholar
    • Export Citation
  • Compo, G. P., G. N. Kiladis, and P. J. Webster, 1999: The horizontal and vertical structure of east Asian winter monsoon pressure surges. Quart. J. Roy. Meteor. Soc., 125 , 2954.

    • Search Google Scholar
    • Export Citation
  • Ding, Y-H., 1990: Build-up, air mass transformation and propagation of Siberian high and its relation to cold surge in east Asia. Meteor. Atmos. Phys., 44 , 281292.

    • Search Google Scholar
    • Export Citation
  • Ding, Y-H., and T. N. Krishnamurti, 1987: Heat budget of Siberian high and winter monsoon. Mon. Wea. Rev., 115 , 24282449.

  • Gong, D-Y., S-W. Wang, and J-H. Zhu, 2001: East Asian winter monsoon and Arctic Oscillation. Geophys. Res. Lett., 28 , 20732076.

  • Jhun, J-G., and E-J. Lee, 2004: A new East Asian winter monsoon index and associated characteristics of the winter monsoon. J. Climate, 17 , 711726.

    • Search Google Scholar
    • Export Citation
  • Ji, L., S. Sun, K. Arpe, and L. Bengtsson, 1997: Model study on the interannual variability of Asian winter monsoon and its influence. Adv. Atmos. Sci., 14 , 122.

    • Search Google Scholar
    • Export Citation
  • Kaihatu, J. M., R. A. Handler, G. O. Marmorino, and L. K. Shay, 1998: Empirical orthogonal function analysis of ocean surface current using complex and real-vector methods. J. Atmos. Oceanic Technol., 15 , 927941.

    • Search Google Scholar
    • Export Citation
  • Kundu, P. K., and J. S. Allen, 1976: Some three-dimensional characteristics of low-frequency current fluctuations near the Oregon coast. J. Phys. Oceanogr., 6 , 181199.

    • Search Google Scholar
    • Export Citation
  • Li, C., 1990: Interaction between anomalous winter monsoon in East Asia and El Niño events. Adv. Atmos. Sci., 7 , 3646.

  • Lu, E., and J. Chan, 1999: A unified monsoon index for south China. J. Climate, 12 , 23752385.

  • Murakami, T., 1987: Effects of the Tibetan Plateau. Monsoon Meteorology, C.-P. Zhang and T. N. Krishnamurti, Eds., Oxford University Press, 235–270.

    • Search Google Scholar
    • Export Citation
  • Murakami, T., and A. Sumi, 1981: Large-scale aspects of the 1978–79 winter circulation over the greater WMONEX region. Part II: Long-period perturbations. J. Meteor. Soc. Japan, 59 , 646671.

    • Search Google Scholar
    • Export Citation
  • Shi, N., J. J. Xu, and Q. G. Zhu, 1996: The intensity index of winter and summer monsoon over East Asia and its variations. (in Chinese). J. Nanjing Inst. Meteor., 19 , 168176.

    • Search Google Scholar
    • Export Citation
  • Tomita, T., and T. Yasunari, 1996: Role of the northeast winter monsoon on the biennial oscillation of the ENSO/monsoon system. J. Meteor. Soc. Japan, 74 , 399413.

    • Search Google Scholar
    • Export Citation
  • Walland, D. J., and I. Simmonds, 1997: Modeled atmospheric response to changes in Northern Hemisphere snow cover. Climate Dyn., 13 , 2534.

    • Search Google Scholar
    • Export Citation
  • Wang, B., and Q. Zhang, 2002: Pacific–East Asian teleconnection. Part II: How the Philippine Sea anomalous anticyclone is established during El Niño development. J. Climate, 15 , 32523265.

    • Search Google Scholar
    • Export Citation
  • Wang, B., R-G. Wu, and X-H. Fu, 2000: Pacific–East Asian teleconnection: How does ENSO affect East Asian climate? J. Climate, 13 , 15171536.

    • Search Google Scholar
    • Export Citation
  • Watanabe, M., and T. Nitta, 1999: Decadal change in the atmospheric circulation and associated surface climate variations in the Northern Hemispheric winter. J. Climate, 12 , 494510.

    • Search Google Scholar
    • Export Citation
  • Wu, B-Y., and R-H. Huang, 1999: Effects of the extremes in the North Atlantic Oscillation on the East Asia winter monsoon. Chin. J. Atmos. Sci., 23 , 226236.

    • Search Google Scholar
    • Export Citation
  • Wu, B-Y., and J. Wang, 2002a: Possible impacts of winter Arctic Oscillation on Siberian high, the East Asian winter monsoon and sea-ice extent. Adv. Atmos. Sci., 19 , 297320.

    • Search Google Scholar
    • Export Citation
  • Wu, B-Y., and J. Wang, 2002b: Winter Arctic Oscillation, Siberian high and East Asian winter monsoon. Geophys. Res. Lett., 29 .1897, doi:10.1029/2002GL015373.

    • Search Google Scholar
    • Export Citation
  • Yang, S., K-M. Lau, and K. M. Kim, 2002: Variations of the East Asian jet stream and Asian–Pacific–American winter climate anomalies. J. Climate, 15 , 306325.

    • Search Google Scholar
    • Export Citation
  • Zhang, R., A. Sumi, and M. Kimoto, 1996: Impacts of El Niño on the East Asian monsoon: A diagnostic study of the ‘86/87 and ‘91/92 events. J. Meteor. Soc. Japan, 74 , 4962.

    • Search Google Scholar
    • Export Citation
  • Zhang, Y., K. Sperber, and J. Boyle, 1997: Climatology and interannual variation of the East Asian winter monsoon: Results from the 1979–95 NCEP/NCAR reanalysis. Mon. Wea. Rev., 125 , 26052619.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 357 182 8
PDF Downloads 311 159 1

Distinct Modes of the East Asian Winter Monsoon

View More View Less
  • 1 Chinese Academy of Meteorological Sciences, Beijing, and Key Laboratory of Cryosphere and Environment, Chinese Academy of Sciences, Lanzhon, China
  • | 2 Tree-Ring Laboratory, Lamont-Doherty Earth Observatory, Palisades, New York
Restricted access

Abstract

Two distinct modes of the East Asian winter monsoon (EAWM) have been identified, and they correspond to real and imaginary parts of the leading mode of the EAWM, respectively. Analyses of these modes used the National Centers for Environment Prediction (NCEP) and National Center for Atmospheric Research (NCAR) monthly mean reanalysis datasets for the period 1968–2003, as well as the Southern Oscillation index (SOI), North Atlantic Oscillation index, and eastern equatorial Pacific sea surface temperature (SST) data. Results were obtained by resolving a complex Hermite matrix derived from 850-hPa anomalous wind fields, and determining the resulting modes’ associations with several climate variables. The first distinct mode (M1) is characterized by an anomalous meridional wind pattern over East Asia and the western North Pacific. Mode M1 is closely related to several features of the atmospheric circulation, including the Siberian high, East Asian trough, East Asian upper-tropospheric jet, and local Hadley circulation over East Asia. Thus, M1 reflects the traditional EAWM pattern revealed in previous studies. The second distinct EAWM mode (M2), which was not identified previously, displays dominant zonal wind anomalies over the same area. Mode M2 exhibits a closer relation than M1 to sea level pressure anomalies over the northwestern Pacific southeast of Japan and with the SOI and equatorial eastern Pacific SST. Unlike M1, M2 does not show coherent relationships with the Siberian high, East Asian trough, and East Asian upper-tropospheric jet. Since atmospheric circulation anomalies relevant to M2 exhibit a quasi-barotropic structure, its existence cannot simply be attributed to differential land–sea heating. El Niño events tend to occur in the negative phase of M1 and the positive phase of M2, both corresponding to a weakened EAWM. The Arctic Oscillation does not appear to impact the EAWM on interannual time scales. Although the spatial patterns for the two modes are very different, the two distinct modes are complementary, with the leading EAWM mode being a linear combination of the two. The results herein therefore demonstrate that a single EAWM index may be inappropriate for investigating and predicting the EAWM.

Corresponding author address: Bingyi Wu, Chinese Academy of Meteorological Sciences, Beijing 100081, China. Email: wby@cams.cma.gov.cn

Abstract

Two distinct modes of the East Asian winter monsoon (EAWM) have been identified, and they correspond to real and imaginary parts of the leading mode of the EAWM, respectively. Analyses of these modes used the National Centers for Environment Prediction (NCEP) and National Center for Atmospheric Research (NCAR) monthly mean reanalysis datasets for the period 1968–2003, as well as the Southern Oscillation index (SOI), North Atlantic Oscillation index, and eastern equatorial Pacific sea surface temperature (SST) data. Results were obtained by resolving a complex Hermite matrix derived from 850-hPa anomalous wind fields, and determining the resulting modes’ associations with several climate variables. The first distinct mode (M1) is characterized by an anomalous meridional wind pattern over East Asia and the western North Pacific. Mode M1 is closely related to several features of the atmospheric circulation, including the Siberian high, East Asian trough, East Asian upper-tropospheric jet, and local Hadley circulation over East Asia. Thus, M1 reflects the traditional EAWM pattern revealed in previous studies. The second distinct EAWM mode (M2), which was not identified previously, displays dominant zonal wind anomalies over the same area. Mode M2 exhibits a closer relation than M1 to sea level pressure anomalies over the northwestern Pacific southeast of Japan and with the SOI and equatorial eastern Pacific SST. Unlike M1, M2 does not show coherent relationships with the Siberian high, East Asian trough, and East Asian upper-tropospheric jet. Since atmospheric circulation anomalies relevant to M2 exhibit a quasi-barotropic structure, its existence cannot simply be attributed to differential land–sea heating. El Niño events tend to occur in the negative phase of M1 and the positive phase of M2, both corresponding to a weakened EAWM. The Arctic Oscillation does not appear to impact the EAWM on interannual time scales. Although the spatial patterns for the two modes are very different, the two distinct modes are complementary, with the leading EAWM mode being a linear combination of the two. The results herein therefore demonstrate that a single EAWM index may be inappropriate for investigating and predicting the EAWM.

Corresponding author address: Bingyi Wu, Chinese Academy of Meteorological Sciences, Beijing 100081, China. Email: wby@cams.cma.gov.cn

Save