• Baldwin, M. P., 2001: Annular modes in global daily surface pressure. Geophys. Res. Lett, 28 , 41154118.

  • Bretherton, C. S., , M. Widmann, , V. P. Dymnikov, , J. M. Wallace, , and I. Blad, 1999: The effective number of spatial degrees of freedom of a time-varying field. J. Climate, 12 , 19902009.

    • Search Google Scholar
    • Export Citation
  • Czaja, A., , P. van der Vaart, , and J. Marshall, 2002: A diagnostic study of the role of remote forcing in tropical Atlantic variability. J. Climate, 15 , 32803290.

    • Search Google Scholar
    • Export Citation
  • Dima, I., 2002: Annular structures in low latitude wind and temperature variability. M.S. Thesis, Department of Atmospheric Sciences, University of Washington, 127 pp. [Available from the University of Washington Libraries, Box 352900, Seattle, WA 98195-2900.].

    • Search Google Scholar
    • Export Citation
  • Edmon, H. J., , B. J. Hoskins, , and M. E. McIntyre, 1980: Eliassen– Palm cross sections for the troposphere. J. Atmos. Sci, 37 , 26002616.

    • Search Google Scholar
    • Export Citation
  • Feldstein, S. B., 1998: An observational study of the intraseasonal poleward propagation of zonal mean flow anomalies. J. Atmos. Sci, 55 , 25162529.

    • Search Google Scholar
    • Export Citation
  • Gong, D., , and S. Wang, 1999: Definition of Antarctic Oscillation index. Geophys. Res. Lett, 26 , 459462.

  • Hartmann, D. L., , and F. Lo, 1998: Wave-driven zonal flow vacillation in the Southern Hemisphere. J. Atmos. Sci, 55 , 13031315.

  • Haynes, P. H., , C. J. Marks, , M. E. McIntyre, , T. G. Shepherd, , and K. P. Shine, 1991: On the downward control of extratropical diabatic circulations by eddy-induced mean zonal forces. J. Atmos. Sci, 48 , 651678.

    • Search Google Scholar
    • Export Citation
  • Hegerl, G. C., , and J. M. Wallace, 2002: Influence of patterns of climate variability on the difference between satellite and surface temperature trends. J. Climate, 15 , 24122428.

    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., , and D. J. Karoly, 1981: The steady linear response of a spherical atmosphere to thermal and orographic forcing. J. Atmos. Sci, 38 , 11791196.

    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., , and T. Ambrizzi, 1993: Rossby wave propagation on a realistic longitudinally varying flow. J. Atmos. Sci, 50 , 16611671.

    • Search Google Scholar
    • Export Citation
  • Hurrell, J. W., 1995: Decadal trends in the North Atlantic Oscillation region temperatures and precipitation. Science, 269 , 676679.

  • Hurrell, J. W., , Y. Kushnir, , G. Ottersen, , and M. Visbeck, Eds.,. 2002: The North Atlantic Oscillation: Climate Significance and Environmental Impact. Geophys. Monogr., No. 134, Amer. Geophys. Union, 279 pp.

    • Search Google Scholar
    • Export Citation
  • Jones, P. D., 1994: Hemispheric surface air temperature variations: A reanalysis and update to 1993. J. Climate, 7 , 17941802.

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

  • Karoly, D. J., 1990: The role of transient eddies in low-frequency zonal variations of the Southern Hemisphere circulation. Tellus, 42A , 4150.

    • Search Google Scholar
    • Export Citation
  • Kidson, J. W., 1988a: Indices of the Southern Hemisphere zonal wind. J. Climate, 1 , 183194.

  • Kidson, J. W., 1988b: Interannual variations in the Southern Hemisphere circulation. J. Climate, 1 , 11771198.

  • Kiladis, G. N., 1998: Observations of Rossby waves linked to convection over the eastern tropical Pacific. J. Atmos. Sci, 55 , 321339.

    • Search Google Scholar
    • Export Citation
  • Kiladis, G. N., , and K. M. Weickmann, 1992: Extratropical forcing of tropical Pacific convection during northern winter. Mon. Wea. Rev, 120 , 19241938.

    • Search Google Scholar
    • Export Citation
  • Kiladis, G. N., , and K. M. Weickmann, 1997: Horizontal structure and seasonality of large-scale circulations associated with tropical convection. Mon. Wea. Rev, 125 , 19972013.

    • Search Google Scholar
    • Export Citation
  • Lamb, P. J., , and R. A. Peppler, 1987: North Atlantic Oscillation: Concept and application. Bull. Amer. Meteor. Soc, 68 , 12181225.

  • Limpasuvan, V., , and D. L. Hartmann, 1999: Eddies and the annular modes of climate variability. Geophys. Res. Lett, 26 , 31333136.

  • Limpasuvan, V., , and D. L. Hartmann, 2000: Wave-maintained annular modes of climate variability. J. Climate, 13 , 44144429.

  • Lorenz, D. J., , and D. L. Hartmann, 2001: Eddy–zonal flow feedback in the Southern Hemisphere. J. Atmos. Sci, 58 , 33123327.

  • Lorenz, D. J., , and D. L. Hartmann, 2003: Eddy–zonal flow feedback in the Northern Hemisphere. J. Climate, 16 , 12121227.

  • Malmgren, B. A., , A. Winter, , and D. Chen, 1998: El Niño–Southern Oscillation and North Atlantic Oscillation control of climate in Puerto Rico. J. Climate, 11 , 27132718.

    • Search Google Scholar
    • Export Citation
  • Matthews, A. J., , and G. N. Kiladis, 1999: Interactions between ENSO, transient circulation, and tropical convection over the Pacific. J. Climate, 12 , 30623086.

    • Search Google Scholar
    • Export Citation
  • McHugh, M. J., , and J. C. Rogers, 2001: North Atlantic Oscillation influence on precipitation variability around the Southeast African convergence zone. J. Climate, 14 , 36313642.

    • Search Google Scholar
    • Export Citation
  • Meehl, G. A., , and H. van Loon, 1979: The seesaw in winter temperatures between Greenland and Northern Europe. Part II: Teleconnections with lower latitudes. Mon. Wea. Rev, 107 , 10951106.

    • Search Google Scholar
    • Export Citation
  • Mo, K. C., , and G. H. White, 1985: Teleconnections in the Southern Hemisphere. Mon. Wea. Rev, 113 , 2237.

  • Moulin, C., , C. E. Lambert, , F. Dulac, , and U. Dayan, 1997: Control of atmospheric export of dust from North Africa by the North Atlantic Oscillation. Nature, 387 , 691694.

    • Search Google Scholar
    • Export Citation
  • National Research Council Panel on Reconciling Temperature Observations, 2000: Reconciling Observations of Global Temperature Change. National Academy Press, 104 pp.

    • Search Google Scholar
    • Export Citation
  • Quadrelli, R., , and J. M. Wallace, 2002: Dependence of the structure of the Northern Hemisphere annular mode on the polarity of ENSO. Geophys. Res. Lett.,29, 2132, doi:10.1029/ 2002GL015807.

    • Search Google Scholar
    • Export Citation
  • Rasmusson, E., , and T. Carpenter, 1982: Variations in the tropical sea surface temperature and surface wind fields associated with the Southern Oscillation/El Niño. Mon. Wea. Rev, 110 , 354384.

    • Search Google Scholar
    • Export Citation
  • Robinson, W. A., 2000: A baroclinic mechanism for the eddy feedback on the zonal index. J. Atmos. Sci, 57 , 415422.

  • Robinson, W. A., 2002: On the midlatitude thermal response to tropical warmth. Geophys. Res. Lett.,29, 1190, doi:10.1029/2001GL014158.

  • Rogers, J. C., , and H. van Loon, 1982: Spatial variability of sea level pressures and 500 mb height anomalies over the Southern Hemisphere. Mon. Wea. Rev, 110 , 13751392.

    • Search Google Scholar
    • Export Citation
  • Seager, R., , N. Harnik, , Y. Kushnir, , W. Robinson, , and J. A. Miller, 2003: Mechanisms of hemispherically symmetric climate variability. J. Climate, 16 , 29602978.

    • Search Google Scholar
    • Export Citation
  • Shiotani, M., 1990: Low-frequency variations of the zonal mean state of the Southern Hemisphere troposphere. J. Meteor. Soc. Japan, 68 , 461471.

    • Search Google Scholar
    • Export Citation
  • Spencer, R. W., , and J. R. Christy, 1992: Precision and radiosonde validation of satellite gridpoint temperature anomalies. Part II: A tropospheric retrieval and trends during 1979–90. J. Climate, 5 , 858866.

    • Search Google Scholar
    • Export Citation
  • Thompson, D. W. J., , and J. M. Wallace, 1998: The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophys. Res. Lett, 25 , 12971300.

    • Search Google Scholar
    • Export Citation
  • Thompson, D. W. J., , and J. M. Wallace, 2000: Annular modes in the extratropical circulation. Part I: Month-to-month variability. J. Climate, 13 , 10001016.

    • Search Google Scholar
    • Export Citation
  • Thompson, D. W. J., , and S. Solomon, 2002: Interpretation of recent Southern Hemisphere climate change. Science, 296 , 895899.

  • Thompson, D. W. J., , J. M. Wallace, , and G. C. Hegerl, 2000: Annular modes in the extratropical circulation. Part II: Trends. J. Climate, 13 , 10181036.

    • Search Google Scholar
    • Export Citation
  • Tomas, R. A., , and P. J. Webster, 1994: Horizontal and vertical structure of cross-equatorial wave propagation. J. Atmos. Sci, 51 , 14171430.

    • Search Google Scholar
    • Export Citation
  • van Loon, H., , and J. Rogers, 1978: The seesaw in winter temperatures between Greenland and Northern Europe. Part I: General description. Mon. Wea. Rev, 106 , 296310.

    • Search Google Scholar
    • Export Citation
  • Walker, G. T., , and E. W. Bliss, 1932: World Weather V. Mem. Roy. Meteor. Soc, 4 , 5384.

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

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., , E. M. Rasmusson, , T. P. Mitchell, , V. E. Kousky, , E. S. Sarachik, , and H. von Storch, 1998: On the structure and evolution of ENSO-related climate variability in the tropical Pacific: Lessons from TOGA. J. Geophys. Res, 103C , 1424114259.

    • Search Google Scholar
    • Export Citation
  • Watanabe, M., , F-F. Jin, , and M. Kimoto, 2002: Tropical axisymmetric mode of variability in the atmospheric circulation: Dynamics as a neutral mode. J. Climate, 15 , 15371554.

    • Search Google Scholar
    • Export Citation
  • Waugh, D. W., , and L. M. Polvani, 2000: Climatology of intrusions into the tropical upper troposphere. Geophys. Res. Lett, 27 , 38573860.

    • Search Google Scholar
    • Export Citation
  • Webster, P. J., , and J. R. Holton, 1982: Cross-equatorial response to middle-latitude forcing with a latitudinally and zonally nonuniform basic state. J. Atmos. Sci, 39 , 722733.

    • Search Google Scholar
    • Export Citation
  • Yoden, S., , M. Shiotani, , and I. Hirota, 1987: Multiple planetary flow regimes in the Southern Hemisphere. J. Meteor. Soc. Japan, 65 , 571585.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 27 27 5
PDF Downloads 12 12 4

The Signature of the Annular Modes in the Tropical Troposphere

View More View Less
  • 1 Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado
  • | 2 Department of Atmospheric Sciences, University of Washington, Seattle, Washington
© Get Permissions
Restricted access

Abstract

The extratropical annular modes are coupled with a distinct pattern of climate anomalies that spans the circulation of the tropical troposphere. The signature of the annular modes in the tropical troposphere exhibits a high degree of equatorial symmetry. It is associated with upper-tropospheric zonal wind anomalies centered about the equator, midtropospheric temperature anomalies located ∼20°N and 20°S, and opposing mean meridional circulation anomalies that span the subtropics of both hemispheres. The linkages between the annular modes and the tropical circulation are only evident during the cold season months, and are most robust in association with the Northern Hemisphere annular mode (NAM).

The coupling between the annular modes and the circulation of the tropical troposphere is consistent with forcing by waves originating at extratropical latitudes. Both annular modes are characterized by anomalies in the eddy momentum flux convergence at tropical latitudes that act to reinforce the changes in the tropical wind and temperature fields. The most pronounced tropical anomalies lag indices of the annular modes by ∼2 weeks and are found over the eastern tropical Pacific, where climatological westerlies permit extratropical waves to propagate into the deep Tropics. The linkages between the NAM and the tropical tropospheric circulation are most pronounced during the cold phase of the El Niño–Southern Oscillation cycle.

The recent trend in the NAM is linearly congruent with a ∼0.1-K cooling of the tropical troposphere over the past two decades during the Northern Hemisphere winter season.

Corresponding author address: Dr. David W. Thompson, Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371. Email: davet@atmos.colostate.edu

Abstract

The extratropical annular modes are coupled with a distinct pattern of climate anomalies that spans the circulation of the tropical troposphere. The signature of the annular modes in the tropical troposphere exhibits a high degree of equatorial symmetry. It is associated with upper-tropospheric zonal wind anomalies centered about the equator, midtropospheric temperature anomalies located ∼20°N and 20°S, and opposing mean meridional circulation anomalies that span the subtropics of both hemispheres. The linkages between the annular modes and the tropical circulation are only evident during the cold season months, and are most robust in association with the Northern Hemisphere annular mode (NAM).

The coupling between the annular modes and the circulation of the tropical troposphere is consistent with forcing by waves originating at extratropical latitudes. Both annular modes are characterized by anomalies in the eddy momentum flux convergence at tropical latitudes that act to reinforce the changes in the tropical wind and temperature fields. The most pronounced tropical anomalies lag indices of the annular modes by ∼2 weeks and are found over the eastern tropical Pacific, where climatological westerlies permit extratropical waves to propagate into the deep Tropics. The linkages between the NAM and the tropical tropospheric circulation are most pronounced during the cold phase of the El Niño–Southern Oscillation cycle.

The recent trend in the NAM is linearly congruent with a ∼0.1-K cooling of the tropical troposphere over the past two decades during the Northern Hemisphere winter season.

Corresponding author address: Dr. David W. Thompson, Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371. Email: davet@atmos.colostate.edu

Save