• Hoskins, B. J., and T. Ambrizzi, 1993: Rossby wave propagation on a realistic longitudally varying flow. J. Atmos. Sci., 50 , 16611671.

    • Search Google Scholar
    • Export Citation
  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Kurashima, A., 1969: Reports on Okhotsk high–Report of the annual meeting on forecasting technique for the year 1966 (in Japanese). J. Meteor. Res. Japan, 21 , 170193.

    • 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
  • Nakamura, H., M. Nakamura, and J. L. Anderson, 1997: The role of high- and low-frequency dynamics in blocking formation. Mon. Wea. Rev., 125 , 20742093.

    • Search Google Scholar
    • Export Citation
  • Ninomiya, K., and H. Mizuno, 1985: Anomalous cold spell in summer over northeastern Japan caused by northeasterly wind from polar maritime airmass. Part 2: Structure of the northeasterly flow from polar maritime airmass. J. Meteor. Soc. Japan, 63 , 859871.

    • Search Google Scholar
    • Export Citation
  • Nishimori, M., 1999: Analysis of the characteristics of the occurrence of hot and cool summer in Japan (in Japanese). Tenki, 46 , 269280.

    • Search Google Scholar
    • Export Citation
  • Ogi, M., Y. Tachibana, and K. Yamazaki, 2004: The connectivity of the Okhotsk Sea ice with the Okhotsk high and their relation to the winter North Atlantic Oscillation (NAO). J. Meteor. Soc. Japan, 82 , 905913.

    • Search Google Scholar
    • Export Citation
  • Sardeshmukh, R. D., and B. J. Hoskins, 1988: The generation of global rotational flow by steady idealized tropical divergence. J. Atmos. Sci., 45 , 12281251.

    • Search Google Scholar
    • Export Citation
  • Sato, N., and M. Takahashi, 2006: Dynamical processes related to the appearance of quasi-stationary waves on the subtropical jet in the midsummer Northern Hemisphere. J. Climate, 19 , 15311544.

    • Search Google Scholar
    • Export Citation
  • Simmons, A. J., J. M. Wallance, and G. W. Branstator, 1983: Barotropic wave propagation and instability, and atmospheric teleconnection patterns. J. Atmos. Sci., 40 , 13631392.

    • Search Google Scholar
    • Export Citation
  • Tachibana, Y., T. Iwamoto, M. Ogi, and Y. Watanabe, 2004: Abnormal meridional temperature gradient and its relation to the Okhotsk high. J. Meteor. Soc. Japan, 82 , 13991415.

    • Search Google Scholar
    • Export Citation
  • Takaya, K., and H. Nakamura, 2001: A formulation of a phase-independent wave-activity flux for stationary and migratory quasigeostrophic eddies on a zonally varying basic flow. J. Atmos. Sci., 58 , 608627.

    • Search Google Scholar
    • Export Citation
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Dynamical Processes Related to the Appearance of the Okhotsk High during Early Midsummer

Naoki SatoInstitute of Observational Research for Global Change, Japan Agency for Marine–Earth Science and Technology, Kanagawa, Japan

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Masaaki TakahashiCenter for Climate System Research, University of Tokyo, Chiba, and Frontier Research Center for Global Change, Kanagawa, Japan

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Abstract

The authors identified an upper-level pressure anomaly pattern corresponding to the interannual variability of the Okhotsk high in midsummer (late July and early August) as a predominant anomaly pattern in the Northern Hemisphere, by using objectively analyzed data. According to the results of empirical orthogonal function (EOF) analyses and composite analyses, a positive pressure anomaly appeared near the tropopause over eastern Siberia in years with strong Okhotsk highs. Examination of the heat budget in the lower troposphere revealed that a negative surface temperature anomaly observed in northern Japan was brought by the advection of the climatological temperature gradient from the anomalous wind associated with the upper-level anticyclonic anomaly. It was also demonstrated that the anomaly field over Siberia does not accompany predominant vorticity forcing or Rossby wave propagation from the west with a specific phase. However, positive kinetic energy conversion from the climatological basic field to the anomaly field is estimated. The energy conversion contributes to maintaining the anomaly pattern. By the numerical experiments using a linear barotropic model, it is suggested that the upper-level anomaly pattern related to the anomalous Okhotsk high appears through the interaction with the climatological basic field, even though the external forcings are homogeneously distributed.

Corresponding author address: Naoki Sato, Center for Climate System Research, University of Tokyo, 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan. Email: naoki@jamstec.go.jp

Abstract

The authors identified an upper-level pressure anomaly pattern corresponding to the interannual variability of the Okhotsk high in midsummer (late July and early August) as a predominant anomaly pattern in the Northern Hemisphere, by using objectively analyzed data. According to the results of empirical orthogonal function (EOF) analyses and composite analyses, a positive pressure anomaly appeared near the tropopause over eastern Siberia in years with strong Okhotsk highs. Examination of the heat budget in the lower troposphere revealed that a negative surface temperature anomaly observed in northern Japan was brought by the advection of the climatological temperature gradient from the anomalous wind associated with the upper-level anticyclonic anomaly. It was also demonstrated that the anomaly field over Siberia does not accompany predominant vorticity forcing or Rossby wave propagation from the west with a specific phase. However, positive kinetic energy conversion from the climatological basic field to the anomaly field is estimated. The energy conversion contributes to maintaining the anomaly pattern. By the numerical experiments using a linear barotropic model, it is suggested that the upper-level anomaly pattern related to the anomalous Okhotsk high appears through the interaction with the climatological basic field, even though the external forcings are homogeneously distributed.

Corresponding author address: Naoki Sato, Center for Climate System Research, University of Tokyo, 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan. Email: naoki@jamstec.go.jp

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