• Akiyama, T., 1973: The large-scale aspects of the characteristic features of the Baiu front. Pap. Meteor. Geophys., 24 (2) 157188.

  • Bennetts, D. A., and B. J. Hoskins, 1979: Conditional symmetric instability–a possible explanation for frontal rainbands. Quart. J. Roy. Meteor. Soc., 105 , 945962.

    • Search Google Scholar
    • Export Citation
  • Bolton, D., 1980: The computation of equivalent potential temperature. Mon. Wea. Rev., 108 , 10461053.

  • Chang, C-P., Ed. 2004: East Asian Monsoon. World Scientific, 564 pp.

  • Chang, C-P., S. C. Hou, H. C. Kuo, and T-J. G. Chen, 1998: The development of an intense East Asian summer monsoon disturbance with strong vertical coupling. Mon. Wea. Rev., 126 , 26922712.

    • Search Google Scholar
    • Export Citation
  • Chen, T-J. G., and C-P. Chang, 1980: The structure and vorticity budget of an early summer monsoon trough (Mei-Yu) over southeastern China and Japan. Mon. Wea. Rev., 108 , 942953.

    • Search Google Scholar
    • Export Citation
  • Chen, T-J. G., C-C. Wang, and S. C-S. Liu, 2003: Potential vorticity diagnostics of a Mei-Yu front case. Mon. Wea. Rev., 131 , 26802696.

    • Search Google Scholar
    • Export Citation
  • Cho, H-R., and T-J. G. Chen, 1995: Mei-Yu frontogenesis. J. Atmos. Sci., 52 , 21092120.

  • Chou, C., J. D. Neelin, and H. Su, 2001: Ocean-atmosphere-land feedbacks in an idealized monsoon. Quart. J. Roy. Meteor. Soc., 127 , 18691891.

    • Search Google Scholar
    • Export Citation
  • Ding, Y., and J. C. L. Chan, 2005: The East Asian summer monsoon: an overview. Meteor. Atmos. Phys., 89 , 117142.

  • Enomoto, T., B. J. Hoskins, and Y. Matsuda, 2003: The formation mechanism of the Bonin high in August. Quart. J. Roy. Meteor. Soc., 129 , 157178.

    • Search Google Scholar
    • Export Citation
  • Gritsun, A., and G. Branstator, 2007: Climate response using a three-dimensional operator based on the fluctuation–dissipation theorem. J. Atmos. Sci., 64 , 25582575.

    • Search Google Scholar
    • Export Citation
  • Hahn, D. G., and S. Manabe, 1975: The role of mountains in the South Asian monsoon circulation. J. Atmos. Sci., 32 , 15151541.

  • Huang, R., W. Chen, B. Yang, and R. Zhang, 2004: Recent advances in studies of the interaction between the East Asian winter and summer monsoons and ENSO cycle. Adv. Atmos. Sci., 21 , 407424.

    • Search Google Scholar
    • Export Citation
  • Huffman, G. J., and Coauthors, 1997: The Global Precipitation Climatology Project (GPCP) combined precipitation dataset. Bull. Amer. Meteor. Soc., 78 , 520.

    • Search Google Scholar
    • Export Citation
  • Jin, F-F., L-L. Pan, and M. Watanabe, 2006: Dynamics of synoptic eddy and low-frequency flow interaction. Part I: A linear closure. J. Atmos. Sci., 63 , 16771694.

    • Search Google Scholar
    • Export Citation
  • Kato, K., 1989: Seasonal transition of the lower-level circulation systems around the Baiu Front in China in 1979 and its relation to the Northern Summer Monsoon. J. Meteor. Soc. Japan, 67 , 249265.

    • Search Google Scholar
    • Export Citation
  • Kawamura, R., and T. Murakami, 1998: Baiu near Japan and its relation to summer monsoons over Southeast Asia and the western North Pacific. J. Meteor. Soc. Japan, 76 , 619639.

    • Search Google Scholar
    • Export Citation
  • Kawatani, Y., and M. Takahashi, 2003: Simulation of the Baiu front in a high resolution AGCM. J. Meteor. Soc. Japan, 81 , 113126.

  • Kitoh, A., 2004: Effects of mountain uplift on East Asian summer climate investigated by a coupled atmosphere–ocean GCM. J. Climate, 17 , 783802.

    • Search Google Scholar
    • Export Citation
  • Kodama, Y-M., 1992: Large-scale common features of subtropical precipitation zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part I: Characteristics of subtropical frontal zones. J. Meteor. Soc. Japan, 70 , 813836.

    • Search Google Scholar
    • Export Citation
  • Kodama, Y-M., 1993: Large-scale common features of subtropical convergence zones (the Baiu frontal zone, the SPCZ, and the SACZ). Part II: Conditions of the circulations for generating the STCZs. J. Meteor. Soc. Japan, 71 , 581610.

    • Search Google Scholar
    • Export Citation
  • Kosaka, Y., and H. Nakamura, 2006: Structure and dynamics of the summertime Pacific–Japan teleconnection pattern. Quart. J. Roy. Meteor. Soc., 132 , 20092030.

    • Search Google Scholar
    • Export Citation
  • Lau, N-C., and J. J. Ploshay, 2009: Simulation of synoptic- and subsynoptic-scale phenomena associated with the East Asian summer monsoon using a high-resolution GCM. Mon. Wea. Rev., 137 , 137160.

    • Search Google Scholar
    • Export Citation
  • Li, C., and M. Yanai, 1996: The onset and interannual variability of the Asian summer monsoon in relation to land–sea thermal contrast. J. Climate, 9 , 358375.

    • Search Google Scholar
    • Export Citation
  • Liu, Y., B. J. Hoskins, and M. Blackburn, 2007: Impact of Tibetan orography and heating on the summer flow over Asia. J. Meteor. Soc. Japan, 85B , 119.

    • Search Google Scholar
    • Export Citation
  • Lu, R., and B. Dong, 2001: Westward extension of North Pacific subtropical high in summer. J. Meteor. Soc. Japan, 79 , 12291241.

  • Matsumoto, S., K. Ninomiya, and S. Yoshizumi, 1971: Characteristic features of “Baiu” front associated with heavy rainfall. J. Meteor. Soc. Japan, 49 , 267281.

    • Search Google Scholar
    • Export Citation
  • Murakami, T., 1958: The sudden change of upper westerlies near the Tibetan Plateau at the beginning of summer season. J. Meteor. Soc. Japan, 36 , 239247.

    • Search Google Scholar
    • Export Citation
  • Murakami, T., and J. Matsumoto, 1994: Summer monsoon over the Asian continent and western Pacific. J. Meteor. Soc. Japan, 72 , 719745.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., 1992: Midwinter suppression of baroclinic wave activity in the Pacific. J. Atmos. Sci., 49 , 16291642.

  • Nakamura, H., and A. S. Kazmin, 2003: Decadal changes in the North Pacific oceanic frontal zones as revealed in ship and satellite observations. J. Geophys. Res., 108 , 3078. doi:10.1029/1999JC000085.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., and T. Fukamachi, 2004: Evolution and dynamics of summertime blocking over the Far East and the associated surface Okhotsk high. Quart. J. Roy. Meteor. Soc., 130 , 12131233.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., 1980: Enhancement of Asian subtropical front due to thermodynamic effect of cumulus convections. J. Meteor. Soc. Japan, 58 , 115.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., 1984: Characteristics of Baiu front as a predominant subtropical front in the summer Northern Hemisphere. J. Meteor. Soc. Japan, 62 , 880894.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., 2000: Large- and meso-α-scale characteristics of Meiyu/Baiu front associated with intense rainfalls in 1-10 July 1991. J. Meteor. Soc. Japan, 78 , 141157.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., and H. Muraki, 1986: Large-scale circulations over East Asia during Baiu period of 1979. J. Meteor. Soc. Japan, 64 , 409429.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., and T. Murakami, 1987: The early summer rainy season (Baiu) over Japan. Monsoon Meteorology, C.-P. Chang, and T. N. Krishnamurti, Eds., Oxford University Press, 93–121.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., and Y. Shibagaki, 2003: Cloud system families in the Meiyu-Baiu front observed during 1-10 July 1991. J. Meteor. Soc. Japan, 81 , 193209.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., and Y. Shibagaki, 2007: Multi-scale features of the Meiyu-Baiu front and associated precipitation systems. J. Meteor. Soc. Japan, 85B , 103122.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., T. Enomoto, T. Nishimura, T. Suzuki, and S. Matsumura, 2003: Synoptic- and meso-α-scale variations of the Baiu front simulated in an AGCM. J. Meteor. Soc. Japan, 81 , 13871405.

    • Search Google Scholar
    • Export Citation
  • Nitta, T., 1987: Convective activity in the tropical western Pacific and their impact on the Northern Hemisphere summer circulation. J. Meteor. Soc. Japan, 65 , 373390.

    • Search Google Scholar
    • Export Citation
  • Onogi, K., and Coauthors, 2007: The JRA-25 reanalysis. J. Meteor. Soc. Japan, 85 , 369432.

  • Okajima, H., and S-P. Xie, 2007: Orographic effects on the northwestern Pacific monsoon: Role of air-sea interaction. Geophys. Res. Lett., 34 , L21708. doi:10.1029/2007GL032206.

    • Search Google Scholar
    • Export Citation
  • Ose, T., 1998: Seasonal change of Asian summer monsoon circulation and its heat source. J. Meteor. Soc. Japan, 76 , 10451063.

  • Rodwell, M. J., and B. J. Hoskins, 1996: Monsoons and the dynamics of deserts. Quart. J. Roy. Meteor. Soc., 122 , 13851404.

  • Rodwell, M. J., and B. J. Hoskins, 2001: Subtropical anticyclones and summer monsoons. J. Climate, 14 , 31923211.

  • Saito, N., 1966: A preliminary study of the summer monsoon of southern and eastern Asia. J. Meteor. Soc. Japan, 44 , 4459.

  • Saito, N., 1985: Quasi-stationary waves in mid-latitudes and the Baiu in Japan. J. Meteor. Soc. Japan, 63 , 983995.

  • Tanimoto, Y., S-P. Xie, K. Kai, H. Okajima, H. Tokinaga, T. Murayama, M. Nonaka, and H. Nakamura, 2009: Observations of marine atmospheric boundary layer transitions across the summer Kuroshio Extension. J. Climate, 22 , 13601374.

    • Search Google Scholar
    • Export Citation
  • Tao, S., and Y. Ding, 1981: Observational evidence of the influence of the Qinghai-Xizang (Tibet) Plateau on the occurrence of heavy rain and severe convective storms in China. Bull. Amer. Meteor. Soc., 62 , 2330.

    • Search Google Scholar
    • Export Citation
  • Tao, S., and L. Chen, 1987: A review of recent research on the East Asian summer monsoon in China. Monsoon Meteorology, C.-P. Chang and T. N. Krishnamurti, Eds., Oxford University Press, 60–92.

    • Search Google Scholar
    • Export Citation
  • Tokinaga, H., Y. Tanimoto, S-P. Xie, T. Sampe, H. Tomita, and H. Ichikawa, 2009: Ocean frontal effects on the vertical development of clouds over the western North Pacific: In situ and satellite observations. J. Climate, 22 , 42414260.

    • Search Google Scholar
    • Export Citation
  • Ueda, H., T. Yasunari, and R. Kawamura, 1995: Abrupt seasonal change of large-scale convective activity over the western Pacific in the northern summer. J. Meteor. Soc. Japan, 73 , 795809.

    • Search Google Scholar
    • Export Citation
  • Ueda, H., M. Ohba, and S-P. Xie, 2009: Important factors for the development of the Asian–Northwest Pacific summer monsoon. J. Climate, 22 , 649669.

    • Search Google Scholar
    • Export Citation
  • Wang, B., Ed. 2006: The Asian Monsoon. Springer-Praxis, 844 pp.

  • Wang, B., and LinHo, 2002: Rainy season of the Asian–Pacific summer monsoon. J. Climate, 15 , 386398.

  • Watanabe, M., and M. Kimoto, 2000: Atmosphere-ocean thermal coupling in the North Atlantic: A positive feedback. Quart. J. Roy. Meteor. Soc., 126 , 33433369.

    • Search Google Scholar
    • Export Citation
  • Watanabe, M., and M. Kimoto, 2001: Corrigendum. Quart. J. Roy. Meteor. Soc., 127 , 733734.

  • Wu, G., and Y. Liu, 2003: Summertime quadruplet heating pattern in the subtropics and the associated atmospheric circulation. Geophys. Res. Lett., 30 , 1201. doi:10.1029/2002GL016209.

    • Search Google Scholar
    • Export Citation
  • Xie, S-P., and N. Saiki, 1999: Abrupt onset and slow seasonal evolution of summer monsoon in an idealized GCM simulation. J. Meteor. Soc. Japan, 77 , 949968.

    • Search Google Scholar
    • Export Citation
  • Xie, S-P., K. Hu, J. Hafner, H. Tokinaga, Y. Du, G. Huang, and T. Sampe, 2009: Indian Ocean capacitor effect on Indo–western Pacific climate during the summer following El Niño. J. Climate, 22 , 730747.

    • Search Google Scholar
    • Export Citation
  • Yamazaki, N., and T-C. Chen, 1993: Analysis of the East Asian monsoon during early summer of 1979: Structure of the Baiu front and its relationship to large-scale fields. J. Meteor. Soc. Japan, 71 , 339355.

    • Search Google Scholar
    • Export Citation
  • Yang, J., Q. Liu, S-P. Xie, Z. Liu, and L. Wu, 2007: Impact of the Indian Ocean SST basin mode on the Asian summer monsoon. Geophys. Res. Lett., 34 , L02708. doi:10.1029/2006GL028571.

    • Search Google Scholar
    • Export Citation
  • Yasunari, T., and T. Miwa, 2006: Convective cloud systems over the Tibetan Plateau and their impact on meso-scale disturbances in the Meiyu/Baiu frontal zone–a case study in 1998. J. Meteor. Soc. Japan, 84 , 783803.

    • Search Google Scholar
    • Export Citation
  • Zhang, S-P., S-P. Xie, Q-Y. Liu, Y-Q. Yang, X-G. Wang, and Z-P. Ren, 2009: Seasonal variations of Yellow Sea fog: Observations and mechanisms. J. Climate, 22 , 67586772.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 52 52 52
PDF Downloads 47 47 47

Large-Scale Dynamics of the Meiyu-Baiu Rainband: Environmental Forcing by the Westerly Jet

View More View Less
  • 1 International Pacific Research Center, SOEST, University of Hawaii at Manoa, Honolulu, Hawaii
Restricted access

Abstract

Meiyu-baiu is the major rainy season from central China to Japan brought by a zonally elongated rainband from June to mid-July. Large-scale characteristics and environmental forcing of this important phenomenon are investigated based on a reanalysis dataset. The meiyu-baiu rainband is accompanied by a trough of sea level pressure, horizontal shears, and sharp moisture gradients near the surface, a westerly jet tilted northward with height, and large northeastward moisture transport from the south.

The analysis here reveals the westerly jet as an important culprit for meiyu-baiu. Along the rainband, mean ascending motion corresponds well with a band of warm horizontal temperature advection in the midtroposphere throughout summer. This adiabatic induction of upward motion originates from the advection of warm air by the westerlies from the eastern flank of the Tibetan Plateau. The ascending motion both induces convection and is enhanced by the resultant condensational heating. The westerly jet anchors the meiyu-baiu rainband also by steering transient eddies, creating periods conducive to convection through convective instability and adiabatic updrafts. Indeed, in meiyu-baiu, the probability distribution of convective instability shows large spreads and is strongly skewed, with a sharp cutoff on the unstable side resulting from the effective removal of instability by convection. Thus, active weather disturbances in the westerly waveguide explain a paradox that convection is active in the meiyu-baiu rainband while mean convective instability is significantly higher to the south over the subtropical North Pacific warm pool. In addition to the westerly jet, low-level southerly winds over eastern China between the heat low over Asia and the subtropical high pressure belt over the Pacific are another important environmental forcing for meiyu-baiu by supplying moisture. A conceptual model for meiyu-baiu is presented, and its implications for seasonal and interannual variations are discussed.

+ Additional affiliation: Department of Meteorology, University of Hawaii at Manoa, Honolulu, Hawaii.

Corresponding author address: Takeaki Sampe, IPRC, SOEST, University of Hawaii, 1680 East West Road, Honolulu, HI 96822. Email: takeaki@hawaii.edu

Abstract

Meiyu-baiu is the major rainy season from central China to Japan brought by a zonally elongated rainband from June to mid-July. Large-scale characteristics and environmental forcing of this important phenomenon are investigated based on a reanalysis dataset. The meiyu-baiu rainband is accompanied by a trough of sea level pressure, horizontal shears, and sharp moisture gradients near the surface, a westerly jet tilted northward with height, and large northeastward moisture transport from the south.

The analysis here reveals the westerly jet as an important culprit for meiyu-baiu. Along the rainband, mean ascending motion corresponds well with a band of warm horizontal temperature advection in the midtroposphere throughout summer. This adiabatic induction of upward motion originates from the advection of warm air by the westerlies from the eastern flank of the Tibetan Plateau. The ascending motion both induces convection and is enhanced by the resultant condensational heating. The westerly jet anchors the meiyu-baiu rainband also by steering transient eddies, creating periods conducive to convection through convective instability and adiabatic updrafts. Indeed, in meiyu-baiu, the probability distribution of convective instability shows large spreads and is strongly skewed, with a sharp cutoff on the unstable side resulting from the effective removal of instability by convection. Thus, active weather disturbances in the westerly waveguide explain a paradox that convection is active in the meiyu-baiu rainband while mean convective instability is significantly higher to the south over the subtropical North Pacific warm pool. In addition to the westerly jet, low-level southerly winds over eastern China between the heat low over Asia and the subtropical high pressure belt over the Pacific are another important environmental forcing for meiyu-baiu by supplying moisture. A conceptual model for meiyu-baiu is presented, and its implications for seasonal and interannual variations are discussed.

+ Additional affiliation: Department of Meteorology, University of Hawaii at Manoa, Honolulu, Hawaii.

Corresponding author address: Takeaki Sampe, IPRC, SOEST, University of Hawaii, 1680 East West Road, Honolulu, HI 96822. Email: takeaki@hawaii.edu

Save