Cover Journal of Climate
Journal of Climate

  • Alexander, M. A., I. Bladé, M. Newman, J. R. Lazante, N-C. Lau, and J. D. Scott, 2002: The atmospheric bridge: The influence of ENSO on air–sea interaction over the global oceans. J. Climate, 15 , 2205–2231.

    • Search Google Scholar
    • Export Citation

  • Barnston, A. G., 1994: Linear statistical short-term climate predictive skill in the Northern Hemisphere. J. Climate, 7 , 1513–1564.

  • Bjerknes, J., 1966: A possible response of the atmospheric Hadley circulation to equatorial anomalies of ocean temperature. Tellus, 18 , 820–829.

    • Search Google Scholar
    • Export Citation

  • Borges, M. D., and P. D. Sardeshmukh, 1995: Barotropic Rossby wave dynamics of zonally varying upper-level flows during northern winter. J. Atmos. Sci., 52 , 3779–3796.

    • Search Google Scholar
    • Export Citation

  • Branstator, G. W., 1990: Low-frequency patterns induced by stationary waves. J. Atmos. Sci., 47 , 629–648.

  • Broccoli, A. J., and S. Manabe, 1992: The effects of orography on midlatitude Northern Hemisphere dry climates. J. Climate, 5 , 1181–1201.

    • Search Google Scholar
    • Export Citation

  • Cane, M. A., and S. E. Zebiak, 1985: A theory for El Niño and the Southern Oscillation. Science, 228 , 1084–1087.

  • Diaz, H. F., M. P. Hoerling, and J. K. Eischeid, 2001: ENSO variability, teleconnections, and climate change. Int. J. Climatol., 21 , 1869–1886.

    • Search Google Scholar
    • Export Citation

  • Evans, M. N., A. Kaplan, M. A. Cane, and R. Villalba, 2001: Present and Past Inter-Hemispheric Climate Linkages in the Americas and Their Societal Effects. Cambridge University Press, in press.

    • Search Google Scholar
    • Export Citation

  • Geisler, J. E., M. L. Blackmon, G. T. Bates, and S. Muñoz, 1985: Sensitivity of January climate response to the magnitude and position of equatorial Pacific sea surface temperature anomalies. J. Atmos. Sci., 42 , 1037–1049.

    • Search Google Scholar
    • Export Citation

  • Graham, N. E., 1995: Simulation of recent global temperature trends. Science, 267 , 666–671.

  • Graham, N. E., and T. P. Barnett, 1987: Observations of sea surface temperatures, convection, and surface wind divergence over tropical oceans. Science, 238 , 657–659.

    • Search Google Scholar
    • Export Citation

  • Held, I. M., S. W. Lyons, and S. Nigam, 1989: Transients and the extratropical response to El Niño. J. Atmos. Sci., 46 , 163–174.

  • Hoerling, M. P., and M. Ting, 1994: On the organization of extratropical transients during El Niño. J. Climate, 7 , 745–766.

  • Hoerling, M. P., A. Kumar, and M. Zhong, 1997: El Niño, La Niña, and the nonlinearity of their teleconnections. J. Climate, 10 , 1769–1786.

    • Search Google Scholar
    • Export Citation

  • Hoerling, M. P., J. W. Hurrell, and T. Xu, 2001a: Tropical origins for recent North Atlantic climate change. Science, 292 , 90–92.

  • Hoerling, M. P., J. S. Whitaker, A. Kumar, and W. Wang, 2001b: The midlatitude warming during 1998–2000. Geophys. Res. Lett., 28 , 755–758.

    • Search Google Scholar
    • Export Citation

  • Hoerling, M. P., and T-Y. Xu, 2001c: Robustness of the nonlinear atmospheric response to opposite phases of ENSO. J. Climate, 14 , 1277–1293.

    • Search Google Scholar
    • Export Citation

  • Horel, J. D., and J. M. Wallace, 1981: Planetary-scale atmospheric phenomenon associated with the Southern Oscillation. Mon. Wea. Rev., 109 , 2080–2092.

    • 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 , 1179–1196.

    • Search Google Scholar
    • Export Citation

  • Hoskins, B. J., and P. D. Sardeshmukh, 1987: A diagnostic study of the dynamics of the northern hemisphere winter of 1985–86. Quart. J. Roy. Meteor. Soc., 113 , 759–778.

    • Search Google Scholar
    • Export Citation

  • Huffman, G. F., and Coauthors. 1997: The Global Precipitation Climatology Project (GPCP) combined precipitation dataset. Bull. Amer. Meteor. Soc., 78 , 5–20.

    • Search Google Scholar
    • Export Citation

  • Kalnay, E., and Coauthors. 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437–471.

  • Karoly, D. J., 1989: Southern Hemisphere circulation features associated with El Niño–Southern Oscillation. J. Climate, 2 , 1239–1252.

    • Search Google Scholar
    • Export Citation

  • Kiehl, J. T., J. J. Hack, G. B. Bonan, B. A. Boville, D. L. Williamson, and P. J. Rasch, 1998: The National Center for Atmospheric Research Community Climate Model: CCM3. J. Climate, 11 , 1131–1150.

    • Search Google Scholar
    • Export Citation

  • Knutson, T. R., and S. Manabe, 1998: Model assessment of decadal variability and trends in the tropical Pacific Ocean. J. Climate, 11 , 2273–2296.

    • Search Google Scholar
    • Export Citation

  • Kok, C. J., and J. D. Opsteegh, 1985: On the possible causes of anomalies in seasonal mean circulation pattern during the 1982–83 El Niño event. J. Atmos. Sci., 42 , 677–694.

    • Search Google Scholar
    • Export Citation

  • Kumar, A., and M. P. Hoerling, 1995: Prospects and limitations of seasonal atmospheric GCM predictions. Bull. Amer. Meteor. Soc., 76 , 335–345.

    • Search Google Scholar
    • Export Citation

  • Kumar, A., . 1997: Interpretation and implications of observed inter–El Niño variability. J. Climate, 10 , 83–91.

  • Kumar, A., . 1998: Annual cycle of Pacific/North American seasonal predictability associated with different phases of ENSO. J. Climate, 11 , 3295–3308.

    • Search Google Scholar
    • Export Citation

  • Kumar, A., A. Leetma, and M. Ji, 1994: Simulaton of atmospheric variablility induced by sea surface temperatures and implications for global warming. Science, 266 , 632–634.

    • Search Google Scholar
    • Export Citation

  • Kumar, A., M. P. Hoerling, M. Ji, A. Leetmaa, and P. D. Sardeshmukh, 1996: Assessing a GCM's suitability for making seasonal predictions. J. Climate, 9 , 115–129.

    • Search Google Scholar
    • Export Citation

  • Kumar, A., W. Wang, M. P. Hoerling, A. Leetmaa, and M. Ji, 2001: The sustained North American warming of 1997 and 1998. J. Climate, 14 , 345–353.

    • Search Google Scholar
    • Export Citation

  • Madden, R. A., 1976: Estimates of natural variability of time-averaged sea level pressure. Mon. Wea. Rev., 104 , 942–952.

  • Montroy, D. L., M. B. Richman, and P. J. Lamb, 1998: Nonlinearities of observed monthly teleconnections between tropical Pacific sea surface temperature anomalies and central and eastern North American precipitation. J. Climate, 11 , 1812–1835.

    • Search Google Scholar
    • Export Citation

  • Newman, M., P. D. Sardeshmukh, and C. Penland, 1997: Stochastic forcing of the wintertime extratropical flow. J. Atmos. Sci., 54 , 435–455.

    • Search Google Scholar
    • Export Citation

  • Palmer, T. N., and J. A. Owen, 1986: A possible relationship between some “severe” winters over North America and enhanced convective activity over the tropical West Pacific. Mon. Wea. Rev., 114 , 648–651.

    • Search Google Scholar
    • Export Citation

  • Pan, Y. H., and A. H. Oort, 1983: Global climate variations connected with sea surface temperature anomalies in the eastern equatorial Pacific Ocean for the 1958–73 period. Mon. Wea. Rev., 111 , 1244–1258.

    • Search Google Scholar
    • Export Citation

  • Penland, C., and P. D. Sardeshmukh, 1995: The optimal growth of sea surface temperature anomalies. J. Climate, 8 , 1999–2024.

  • Reynolds, R. W., and T. A. Smith, 1994: Improved global sea surface temperature analysis using optimum interpolation. J. Climate, 7 , 929–948.

    • Search Google Scholar
    • Export Citation

  • Roeckner, E., and Coauthors. 1992: Simulation of the present-day climate with the ECHAM model: Impact of model physics and resolution. Max-Planck-Institute für Meteorlogie Rep. 93, 171 pp. [Available from MPI für Meteorologie, Bundesstr. 55, D-20146 Hamburg, Germany.].

    • Search Google Scholar
    • Export Citation

  • Rowell, D. P., 1998: Assessing potential seasonal predictability with an ensemble of multidecadal GCM simulations. J. Climate, 11 , 109–120.

    • Search Google Scholar
    • Export Citation

  • Sardeshmukh, P. D., and B. J. Hoskins, 1988: The generation of global rotational flow by steady idealized tropical divergence. J. Atmos. Sci., 45 , 1228–1251.

    • Search Google Scholar
    • Export Citation

  • Shukla, J., and Coauthors. 2000: Dynamical seasonal prediction. Bull. Amer. Meteor. Soc., 81 , 2953–2606.

  • Simmons, A. J., 1982: The forcing of stationary wave motions by tropical diabatic forcing. Quart. J. Roy. Meteor. Soc., 108 , 503–534.

  • Simmons, A. J., J. M. Wallace, and G. Branstator, 1983: Barotropic wave propagation and instability, and atmospheric teleconnection patterns. J. Atmos. Sci., 40 , 1363–1392.

    • Search Google Scholar
    • Export Citation

  • Smith, T. M., R. W. Reynolds, R. E. Livezy, and D. Stokes, 1996: Reconstruction of historical sea surface temperatures using empirical orthogonal functions. J. Climate, 9 , 1403–1420.

    • Search Google Scholar
    • Export Citation

  • Sperber, K. R., and Coauthors. 2001: Dynamical seasonal predictability of the Asian summer monsoon. Mon. Wea. Rev., 129 , 2226–2248.

  • Ting, M., and P. D. Sardeshmukh, 1993: Factors determining the extratropical response to equatorial diabatic heating anomalies. J. Atmos. Sci., 50 , 907–918.

    • Search Google Scholar
    • Export Citation

  • Ting, M., and L. Yu, 1998: Steady response to tropical heating in wavy linear and nonlinear baroclinic models. J. Atmos. Sci., 55 , 3565–3582.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., 1993: The different flavors of El Niño. Proc. 18th Annual Climate Diagnostics Workshop, Boulder, CO, National Oceanic and Atmospheric Administration, 50–53.

    • Search Google Scholar
    • Export Citation

  • Trenberth, K. E., G. W. Branstator, D. Karoly, A. Kumar, N-C. Lau, and C. Ropelewski, 1998: Progress during TOGA in understanding and modeling global teleconnections associated with tropical sea surface temperatures. J. Geophys. Res., 103 , 14291–14324.

    • Search Google Scholar
    • Export Citation

  • Webster, P. J., 1981: Mechanisms determining the atmospheric response to sea surface temperature anomalies. J. Atmos. Sci., 38 , 554–571.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 667 176 17
PDF Downloads 341 100 11
Editorial Type:
Article
Article Type:
Research Article

Atmospheric Response Patterns Associated with Tropical Forcing

Martin P. HoerlingNOAA–CIRES, Climate Diagnostics Center, Boulder, Colorado

Search for other papers by Martin P. Hoerling in
Current site
Google Scholar
PubMedClose
and
Arun KumarNOAA/NCEP, Climate Prediction Center, Washington, D.C

Search for other papers by Arun Kumar in
Current site
Google Scholar
PubMedClose
Print Publication:
15 Aug 2002
DOI:
https://doi.org/10.1175/1520-0442(2002)015<2184:ARPAWT>2.0.CO;2
Page(s):
2184–2203
Restricted access

Abstract

Atmospheric response patterns associated with tropical forcing are examined with general circulation models driven by global sea surface temperature (SST) variations during 1950–99. Specifically the sensitivity of midlatitude responses to the magnitude and position of tropical SST anomalies is explored. This controversial problem, spanning more than a quarter century now, centers on whether response patterns over the Pacific–North American region are affected or changed by inter–El Niño variability in tropical forcing. Ensemble methods are used in this study to reliably identify the signals related to various tropical SST forcings, and the sensitivity is determined from analysis of four different climate models.

First, the fraction of Pacific–North American (PNA) wintertime 500-hPa height variability that is potentially predictable and is linked to interannual variations in the global SSTs is identified. This SST-forced component accounts for as much as 20%–30% of the total seasonal mean height variability over portions of the PNA region, and the most important boundary forcing originates from the tropical Pacific Ocean. The spatial expression of the teleconnections that are linked to this potentially predictable SST-forced fraction of height variability is next identified. The leading model pattern is similar to the classic observed teleconnection associated with the linear ENSO signal, and explains 80% of the SST-forced height variance over parts of the North Pacific and North America. Two additional wavelike patterns are identified that are also associated with tropical forcing. One is related to the pattern of tropical SST variations often seen during the transition of the tropical ocean that marks the interlude between ENSO extremes, and the pattern of forcing related to it is distinctly non-ENSO in character. The other is related to the nonlinear component of the atmospheric response to ENSO's extreme opposite phases. Response patterns having annular-like structures over the Northern Hemisphere that are related to multidecadal variations in tropical Indo-Pacific and Atlantic SSTs are also highlighted.

Subtle modifications in upper-level responses to different tropical SST forcings are shown to yield disproportionate sensitivity in North American surface climate. Particularly pronounced is the reversal in sign of the precipitation anomalies over the region spanning the Canadian border to southern California in response to equatorial Pacific convection anomalies shifting from 170°E to 140°W. The behavior is reproduced in experiments using both realistic and idealized SST anomalies, and this behavior is found to emerge particularly when the far eastern equatorial Pacific Ocean is strongly warmed as occurred during the 1982/83 and 1997/98 El Niños.

Despite the existence of different response patterns to tropical SST forcings, it is shown that the seasonal hindcast skill of PNA 500-hPa heights for 1950–99 originates mainly from the single, leading teleconnection structure. The conclusion drawn from this result is that the atmospheric sensitivity to different tropical SST forcings, though real, is weak and easily masked by the year-to-year climate variations due to internal atmospheric processes.

Corresponding author address: Dr. Martin P. Hoerling, NOAA–CIRES Climate Diagnostics Center, 325 Broadway, Boulder, CO 80303. Email: mph@cdc.noaa.gov

Abstract

Atmospheric response patterns associated with tropical forcing are examined with general circulation models driven by global sea surface temperature (SST) variations during 1950–99. Specifically the sensitivity of midlatitude responses to the magnitude and position of tropical SST anomalies is explored. This controversial problem, spanning more than a quarter century now, centers on whether response patterns over the Pacific–North American region are affected or changed by inter–El Niño variability in tropical forcing. Ensemble methods are used in this study to reliably identify the signals related to various tropical SST forcings, and the sensitivity is determined from analysis of four different climate models.

First, the fraction of Pacific–North American (PNA) wintertime 500-hPa height variability that is potentially predictable and is linked to interannual variations in the global SSTs is identified. This SST-forced component accounts for as much as 20%–30% of the total seasonal mean height variability over portions of the PNA region, and the most important boundary forcing originates from the tropical Pacific Ocean. The spatial expression of the teleconnections that are linked to this potentially predictable SST-forced fraction of height variability is next identified. The leading model pattern is similar to the classic observed teleconnection associated with the linear ENSO signal, and explains 80% of the SST-forced height variance over parts of the North Pacific and North America. Two additional wavelike patterns are identified that are also associated with tropical forcing. One is related to the pattern of tropical SST variations often seen during the transition of the tropical ocean that marks the interlude between ENSO extremes, and the pattern of forcing related to it is distinctly non-ENSO in character. The other is related to the nonlinear component of the atmospheric response to ENSO's extreme opposite phases. Response patterns having annular-like structures over the Northern Hemisphere that are related to multidecadal variations in tropical Indo-Pacific and Atlantic SSTs are also highlighted.

Subtle modifications in upper-level responses to different tropical SST forcings are shown to yield disproportionate sensitivity in North American surface climate. Particularly pronounced is the reversal in sign of the precipitation anomalies over the region spanning the Canadian border to southern California in response to equatorial Pacific convection anomalies shifting from 170°E to 140°W. The behavior is reproduced in experiments using both realistic and idealized SST anomalies, and this behavior is found to emerge particularly when the far eastern equatorial Pacific Ocean is strongly warmed as occurred during the 1982/83 and 1997/98 El Niños.

Despite the existence of different response patterns to tropical SST forcings, it is shown that the seasonal hindcast skill of PNA 500-hPa heights for 1950–99 originates mainly from the single, leading teleconnection structure. The conclusion drawn from this result is that the atmospheric sensitivity to different tropical SST forcings, though real, is weak and easily masked by the year-to-year climate variations due to internal atmospheric processes.

Corresponding author address: Dr. Martin P. Hoerling, NOAA–CIRES Climate Diagnostics Center, 325 Broadway, Boulder, CO 80303. Email: mph@cdc.noaa.gov

Save