Interannual and Decadal Modulations Recently Observed in the Pacific Storm Track Activity and East Asian Winter Monsoon

Hisashi Nakamura Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan

Search for other papers by Hisashi Nakamura in
Current site
Google Scholar
PubMed
Close
,
Takuya Izumi Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan

Search for other papers by Takuya Izumi in
Current site
Google Scholar
PubMed
Close
, and
Takeaki Sampe Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan

Search for other papers by Takeaki Sampe in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Interannual variability of the North Pacific storm track observed over 17 recent winters is documented. The local storm track activity is measured by a meridional flux of sensible heat associated with the lower-tropospheric subweekly fluctuations. The interannual variability in the heat flux over the northwestern (NW) Pacific is found to be strongest in midwinter. The first empirical orthogonal function of the interannual variability in midwinter captures the decadal tendency toward the enhanced storm track activity in midwinter over the NW Pacific, in association with the decadal weakening of the east Asian winter monsoon (Siberian high) and the Aleutian low that occurred in the late 1980s. The most marked signature of this enhancement is that the midwinter minimum in the storm track activity, which had been apparent in the early to mid-1980s, almost disappeared afterward. As opposed to linear theory of baroclinic instability, the enhanced activity occurred despite the weakening of the Pacific jet. As the excessively strong westerlies weakened, the eddy temperature field tended to become better correlated with the eddy meridional and vertical velocities, suggesting that eddy structure tends to become more efficient in converting the mean-flow available potential energy into eddy kinetic energy for growth. The weakened jet also acted to prolong the residence time for migratory eddies in the baroclinic zone, which seemingly overcompensated the effect of the reduced mean-flow baroclinicity but appeared to be of secondary importance. Over the Far East, tropospheric warming to the north of the weakened jet appears to be associated with an anomalous overturning in the thermally direct sense, which is not attributable to the feedback from the concomitant enhancement in the local storm track activity.

Over the NW Pacific, the enhanced poleward heat transport by the intensified storm track tended to be compensated by the reduced transport by the weakened monsoonal flow, leaving rather small anomalies in the net transport. Also over the NW Pacific, the weakened monsoonal flow and enhanced storm track activity since the late 1980s led to the reduction in the evaporation and associated latent heat release from the ocean surface and increased precipitation, respectively. The resultant anomalous moisture deficit was compensated by the anomalous moisture transport from the northeastern Pacific, where the enhanced evaporation and reduced precipitation gave rise to an anomalous moisture surplus.

Additional affiliation: IGCR, Frontier Research System for Global Change, Yokohama, Japan

Current affiliation: National Patent Office of Japan, Tokyo, Japan

Corresponding author address: Dr. Hisashi Nakamura, Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Email: hisashi@eps.s.u-tokyo.ac.jp

Abstract

Interannual variability of the North Pacific storm track observed over 17 recent winters is documented. The local storm track activity is measured by a meridional flux of sensible heat associated with the lower-tropospheric subweekly fluctuations. The interannual variability in the heat flux over the northwestern (NW) Pacific is found to be strongest in midwinter. The first empirical orthogonal function of the interannual variability in midwinter captures the decadal tendency toward the enhanced storm track activity in midwinter over the NW Pacific, in association with the decadal weakening of the east Asian winter monsoon (Siberian high) and the Aleutian low that occurred in the late 1980s. The most marked signature of this enhancement is that the midwinter minimum in the storm track activity, which had been apparent in the early to mid-1980s, almost disappeared afterward. As opposed to linear theory of baroclinic instability, the enhanced activity occurred despite the weakening of the Pacific jet. As the excessively strong westerlies weakened, the eddy temperature field tended to become better correlated with the eddy meridional and vertical velocities, suggesting that eddy structure tends to become more efficient in converting the mean-flow available potential energy into eddy kinetic energy for growth. The weakened jet also acted to prolong the residence time for migratory eddies in the baroclinic zone, which seemingly overcompensated the effect of the reduced mean-flow baroclinicity but appeared to be of secondary importance. Over the Far East, tropospheric warming to the north of the weakened jet appears to be associated with an anomalous overturning in the thermally direct sense, which is not attributable to the feedback from the concomitant enhancement in the local storm track activity.

Over the NW Pacific, the enhanced poleward heat transport by the intensified storm track tended to be compensated by the reduced transport by the weakened monsoonal flow, leaving rather small anomalies in the net transport. Also over the NW Pacific, the weakened monsoonal flow and enhanced storm track activity since the late 1980s led to the reduction in the evaporation and associated latent heat release from the ocean surface and increased precipitation, respectively. The resultant anomalous moisture deficit was compensated by the anomalous moisture transport from the northeastern Pacific, where the enhanced evaporation and reduced precipitation gave rise to an anomalous moisture surplus.

Additional affiliation: IGCR, Frontier Research System for Global Change, Yokohama, Japan

Current affiliation: National Patent Office of Japan, Tokyo, Japan

Corresponding author address: Dr. Hisashi Nakamura, Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Email: hisashi@eps.s.u-tokyo.ac.jp

Save
  • Blackmon, M. L., J. M. Wallace, N-C. Lau, and S. L. Mullen, 1977: An observational study of the Northern Hemisphere wintertime circulation. J. Atmos. Sci., 34 , 10401053.

    • Search Google Scholar
    • Export Citation
  • Blackmon, M. L., Y-H. Lee, and J. M. Wallace, 1984: Horizontal structure of 500-mb height fluctuations with long, intermediate and short time scales. J. Atmos. Sci., 41 , 961979.

    • Search Google Scholar
    • Export Citation
  • Carillo, A., P. M. Ruti, and A. Navarra, 2000: Storm tracks and zonal mean flow variability: A comparison between observed and simulated data. Climate Dyn., 16 , 219228.

    • Search Google Scholar
    • Export Citation
  • Chang, E. K. M., 1993: Downstream development of baroclinic waves as inferred from regression analysis. J. Atmos. Sci., 50 , 20382053.

    • Search Google Scholar
    • Export Citation
  • Chang, E. K. M., . 2001: GCM and observational diagnoses of the seasonal and interannual variations of the Pacific storm track during the cold season. J. Atmos. Sci., 58 , 17841800.

    • Search Google Scholar
    • Export Citation
  • Chang, E. K. M., and D. B. Yu, 1999: Characteristics of wave packets in the upper troposphere. Part I: Northern Hemisphere winter. J. Atmos. Sci., 56 , 17081728.

    • Search Google Scholar
    • Export Citation
  • Charney, J. G., 1947: The dynamics of long waves in a baroclinic westerly current. J. Meteor., 4 , 135163.

  • Christoph, M., U. Ulbrich, and P. Speth, 1997: Midwinter suppression of Northern Hemisphere storm track activity in the real atmosphere and in GCM experiments. J. Atmos. Sci., 54 , 15891598.

    • Search Google Scholar
    • Export Citation
  • Eady, E. T., 1949: Long waves and cyclone waves. Tellus, 1 , 3352.

  • Esbensen, S. K., and Y. Kushnir, 1981: The heat budget of the Global Ocean: An atlas based on estimates from surface marine observations. Climatic Research Institute Rep. 29, 27 pp. [Available from Department of Atmospheric Sciences, Oregon State University, Corvallis, OR 97331.].

    • Search Google Scholar
    • Export Citation
  • Higuchi, K., C. A. Lin, A. Shabbar, and J. L. Knox, 1991: Interannual variability of the January tropospheric meridional eddy sensible heat transport in the Northern Hemisphere. J. Meteor. Soc. Japan, 69 , 459472.

    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., and P. J. Valdes, 1990: On the existence of storm tracks. J. Atmos. Sci., 47 , 18541864.

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

  • Koide, H., and K. Kodera, 1999: A SVD analysis between the winter NH 500-hPa height and surface temperature fields. J. Meteor. Soc. Japan, 77 , 4761.

    • Search Google Scholar
    • Export Citation
  • Lau, N-C., 1988: Variability of the observed midlatitude storm tracks in relation to low-frequency changes in the circulation pattern. J. Atmos. Sci., 45 , 27182743.

    • Search Google Scholar
    • Export Citation
  • Lau, N-C., and M. J. Nath, 1991: Variability of the baroclinic and barotropic transient eddy forcing associated with monthly changes in the midlatitude storm tracks. J. Atmos. Sci., 48 , 25892613.

    • Search Google Scholar
    • Export Citation
  • Lin, S. J., and R. T. Pierrehumbert, 1993: Is the midlatitude zonal flow absolutely unstable? J. Atmos. Sci., 50 , 505517.

  • Lukas, R. B., 2001: Freshening of the upper pycnocline in the North Pacific subtropical gyre associated with decadal changes of rainfall. Geophys. Res. Lett., 28 , 34853488.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., 1992: Midwinter suppression of baroclinic wave activity in the Pacific. J. Atmos. Sci., 49 , 16291641.

  • Nakamura, H., . 1993: Horizontal divergence associated with zonally isolated jet streams. J. Atmos. Sci., 50 , 23102313.

  • Nakamura, H., and J. M. Wallace, 1990: Observed changes in baroclinic wave activity during the life cycles of low-frequency circulation anomalies. J. Atmos. Sci., 47 , 11001116.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., and T. Izumi, 1999: Out-of-phase relationship between the interannual fluctuations in the poleward heat transport by the East Asian winter monsoon and Pacific storm track. Preprints, 12th Conf. on Atmospheric and Oceanic Fluid Dynamics, New York, NY, Amer. Meteor. Soc., 139–142.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., and T. Yamagata, 1999: Recent decadal SST variability in the Northwestern Pacific and associated atmospheric anomalies. Beyond El Niño: Decadal and Interdecadal Climate Variability, A. Navarra, Ed., Springer, 49–72.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., G. Lin, and T. Yamagata, 1997: Decadal climate variability in the North Pacific during the recent decades. Bull. Amer. Meteor. Soc., 78 , 22152225.

    • Search Google Scholar
    • Export Citation
  • Peng, S., and J. S. Whitaker, 1999: Mechanisms determining the atmospheric response to midlatitude SST anomalies. J. Climate, 12 , 13931408.

    • Search Google Scholar
    • Export Citation
  • Robertson, A. W., and W. Mez, 1989: Three-dimensional linear instability of persistent anomalous large-scale flows. J. Atmos. Sci., 46 , 27832801.

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

    • Search Google Scholar
    • Export Citation
  • Trenberth, K. E., and C. J. Guillemot, 1998: Evaluation of the atmospheric moisture and hydrological cycle in the NCEP/NCAR reanalyses. Climate Dyn., 14 , 213231.

    • Search Google Scholar
    • Export Citation
  • van Loon, H., and J. Williams, 1979: The association between latitudinal temperature gradient and eddy heat transport. Part II: Relationships between sensible heat transport by stationary waves and wind, pressure and temperature in winter. Mon. Wea. Rev., 108 , 604614.

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., and D. S. Gutzler, 1981: Teleconnections in geopotential height field during the Northern Hemisphere winter. Mon. Wea. Rev., 109 , 784812.

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., G-H. Lim, and M. L. Blackmon, 1988: Relationship between cyclone tracks, anticyclone tracks and baroclinic waveguides. J. Atmos. Sci., 45 , 439462.

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

    • Search Google Scholar
    • Export Citation
  • Whittaker, L. M., and L. H. Horn, 1984: Northern Hemisphere extratropical cyclone activity for four mid-season months. J. Climatol., 4 , 297310.

    • Search Google Scholar
    • Export Citation
  • Xie, P., and P. A. Arkin, 1997: Global precipitation: 17-year monthly analysis based on gauge observations, satellite estimates and numerical model outputs. Bull. Amer. Meteor. Soc., 78 , 25392558.

    • Search Google Scholar
    • Export Citation
  • Xie, S-P., H. Noguchi, and S. Matsumura, 1999: A hemispheric-scale quasi-decadal oscillation and its signature in northern Japan. J. Meteor. Soc. Japan, 77 , 573582.

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

    • Search Google Scholar
    • Export Citation
  • Zhang, Yu, and I. M. Held, 1999: A linear stochastic model of a GCM's midlatitude storm tracks. J. Atmos. Sci., 56 , 34163435.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 752 256 29
PDF Downloads 497 194 29