Editorial Type:
Article
Article Type:
Research Article

Reorganization of Tropical Climate during El Niño: A Weak Temperature Gradient Approach

Benjamin R. Lintner Department of Geography, and Berkeley Atmospheric Sciences Center, University of California, Berkeley, Berkeley, California

Search for other papers by Benjamin R. Lintner in
Current site
Google Scholar
PubMed Close
and
John C. H. Chiang Department of Geography, and Berkeley Atmospheric Sciences Center, University of California, Berkeley, Berkeley, California

Search for other papers by John C. H. Chiang in
Current site
Google Scholar
PubMed Close
Print Publication:
15 Dec 2005
DOI:
https://doi.org/10.1175/JCLI3580.1
Page(s):
5312–5329
Restricted access

We are aware of a technical issue preventing figures and tables from showing in some newly published articles in the full-text HTML view.
While we are resolving the problem, please use the online PDF version of these articles to view figures and tables.

Abstract

The applicability of a weak temperature gradient (WTG) formulation for the reorganization of tropical climate during El Niño–Southern Oscillation (ENSO) events is investigated. This idealized dynamical framework solves for the divergent portion of the tropical circulation by assuming a spatially homogeneous perturbation temperature profile and a mass balance constraint applied over the tropical belt. An intermediate-level complexity model [the Quasi-Equilibrium Tropical Circulation Model (QTCM)] configured with the WTG assumptions is used to simulate El Niño conditions and is found to yield an appropriate level of tropospheric warming, a plausible pattern of precipitation anomalies in the tropical Pacific source region of El Niño, and a gross precipitation deficit over the Tropics outside the Pacific (hereafter the “remote Tropics”). Additional tests of the WTG framework with La Niña forcing conditions and enhanced greenhouse gas concentrations support its applicability. However, the ENSO response under the WTG framework fails in some respects when compared to the standard QTCM: in particular, some regional features of the anomalous precipitation response, especially in the remote Tropics, differ markedly between the two model versions. These discrepancies appear to originate in part from the lack of anomalous tropospheric temperature gradients (and circulations) in the framework presented here. Nevertheless, the WTG approach appears to be a useful lowest-order model for the tropical climate adjustment to ENSO. The WTG framework is also used to argue that El Niño may not represent a good proxy for tropical rainfall changes under greenhouse gas warming scenarios because the large-scale subsidence occurring with the tropospheric warming in the El Niño scenario has an effect on rainfall that is distinct from the effect of increased tropospheric temperatures common to both the greenhouse gas warming and El Niño scenarios.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California

Corresponding author address: Benjamin R. Lintner, Dept. of Atmospheric and Oceanic Sciences, University of California, Los Angeles, 7127 Mathematical Sciences Bldg., Los Angeles, CA 90095-1565. Email: ben@atmos.ucla.edu

Abstract

The applicability of a weak temperature gradient (WTG) formulation for the reorganization of tropical climate during El Niño–Southern Oscillation (ENSO) events is investigated. This idealized dynamical framework solves for the divergent portion of the tropical circulation by assuming a spatially homogeneous perturbation temperature profile and a mass balance constraint applied over the tropical belt. An intermediate-level complexity model [the Quasi-Equilibrium Tropical Circulation Model (QTCM)] configured with the WTG assumptions is used to simulate El Niño conditions and is found to yield an appropriate level of tropospheric warming, a plausible pattern of precipitation anomalies in the tropical Pacific source region of El Niño, and a gross precipitation deficit over the Tropics outside the Pacific (hereafter the “remote Tropics”). Additional tests of the WTG framework with La Niña forcing conditions and enhanced greenhouse gas concentrations support its applicability. However, the ENSO response under the WTG framework fails in some respects when compared to the standard QTCM: in particular, some regional features of the anomalous precipitation response, especially in the remote Tropics, differ markedly between the two model versions. These discrepancies appear to originate in part from the lack of anomalous tropospheric temperature gradients (and circulations) in the framework presented here. Nevertheless, the WTG approach appears to be a useful lowest-order model for the tropical climate adjustment to ENSO. The WTG framework is also used to argue that El Niño may not represent a good proxy for tropical rainfall changes under greenhouse gas warming scenarios because the large-scale subsidence occurring with the tropospheric warming in the El Niño scenario has an effect on rainfall that is distinct from the effect of increased tropospheric temperatures common to both the greenhouse gas warming and El Niño scenarios.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California

Corresponding author address: Benjamin R. Lintner, Dept. of Atmospheric and Oceanic Sciences, University of California, Los Angeles, 7127 Mathematical Sciences Bldg., Los Angeles, CA 90095-1565. Email: ben@atmos.ucla.edu

Save
Cover Journal of Climate
Journal of Climate

  • Betts, A. K., and M. J. Miller, 1986: A new convective adjustment scheme. 2. Single column tests using gate wave, Bomex, Atex and Arctic air-mass data sets. Quart. J. Roy. Meteor. Soc., 112 , 693–709.

    • Search Google Scholar
    • Export Citation

  • Brown, R. G., and C. S. Bretherton, 1997: A test of the strict quasi-equilibrium theory on long time and space scales. J. Atmos. Sci., 54 , 624–638.

    • Search Google Scholar
    • Export Citation

  • Chiang, J. C. H., and A. H. Sobel, 2002: Tropical tropospheric temperature variations caused by ENSO and their influence on the remote tropical climate. J. Climate, 15 , 2616–2631.

    • Search Google Scholar
    • Export Citation

  • Chiang, J. C. H., and B. R. Lintner, 2005: Mechanisms of remote tropical surface warming during El Niño. J. Climate, 18 , 4130–4149.

  • Chiang, J. C. H., M. Biasutti, and D. S. Battisti, 2003: Sensitivity of the Atlantic Intertropical Convergence Zone to Last Glacial Maximum boundary conditions. Paleoceanography, 18 .1094, doi:10.1029/2003PA000916.

    • Search Google Scholar
    • Export Citation

  • Chou, C., and J. D. Neelin, 2004: Mechanisms of global warming impacts on regional tropical precipitation. J. Climate, 17 , 2688–2701.

  • Chou, C., J. D. Neelin, and H. Su, 2001: Ocean–atmosphere–land feedbacks in an idealized monsoon. Quart. J. Roy. Meteor. Soc., 127 , 1869–1891.

    • Search Google Scholar
    • Export Citation

  • Giannini, A., J. C. H. Chang, M. A. Cane, Y. Kushnir, and R. Seager, 2001: The ENSO teleconnection to the tropical Atlantic Ocean: Contributions of the remote and local SSTs to rainfall variability in the tropical Americas. J. Climate, 14 , 4530–4544.

    • Search Google Scholar
    • Export Citation

  • Gill, A. E., 1980: Some simple solutions for heat-induced tropical circulation. Quart. J. Roy. Meteor. Soc., 106 , 447–462.

  • Hastenrath, S., and L. Heller, 1977: Dynamics of climatic hazards in Northeast Brazil. Quart. J. Roy. Meteor. Soc., 103 , 77–92.

  • Janicot, S., S. Trzaska, and I. Poccard, 2001: Summer Sahel–ENSO teleconnection and decadal time scale SST variations. Climate Dyn., 18 , 303–320.

    • Search Google Scholar
    • Export Citation

  • Kidson, J. W., 1975: Tropical eigenvector analysis and the Southern Oscillation. Mon. Wea. Rev., 103 , 187–196.

  • 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 , 1131–1149.

    • Search Google Scholar
    • Export Citation

  • Klein, S. A., B. J. Soden, and N. C. Lau, 1999: Remote sea surface temperature variations during ENSO: Evidence for a tropical atmospheric bridge. J. Climate, 12 , 917–932.

    • Search Google Scholar
    • Export Citation

  • Neelin, J. D., and N. Zeng, 2000: A quasi-equilibrium tropical circulation model—Formulation. J. Atmos. Sci., 57 , 1741–1766.

  • Neelin, J. D., C. Chou, and H. Su, 2003: Tropical drought regions in global warming and El Niño teleconnections. Geophys. Res. Lett., 30 .2275, doi:10.1029/2003GL018625.

    • Search Google Scholar
    • Export Citation

  • Quinn, W. H., D. O. Zopf, K. S. Short, and R. T. W. K. Yang, 1978: Historical trends and statistics of Southern Oscillation, El Niño, and Indonesian droughts. Fish. Bull., 76 , 663–678.

    • Search Google Scholar
    • Export Citation

  • Ropelewski, C. F., and M. S. Halpert, 1987: Global and regional scale precipitation patterns associated with the El Niño–Southern Oscillation. Mon. Wea. Rev., 115 , 1606–1626.

    • Search Google Scholar
    • Export Citation

  • Saravanan, R., and P. Chang, 2000: Interactions between tropical Atlantic variability and El Niño–Southern Oscillation. J. Climate, 13 , 2177–2194.

    • Search Google Scholar
    • Export Citation

  • Shaevitz, D. A., and A. H. Sobel, 2004: Implementing the weak temperature gradient approximation with full vertical structure. Mon. Wea. Rev., 132 , 662–669.

    • Search Google Scholar
    • Export Citation

  • Sobel, A. H., and C. S. Bretherton, 2000: Modeling tropical precipitation in a single column. J. Climate, 13 , 4378–4392.

  • Soden, B. J., 1997: Variations in the tropical greenhouse effect during El Niño. J. Climate, 10 , 1050–1055.

  • Su, H., and J. D. Neelin, 2002: Teleconnection mechanisms for tropical Pacific descent anomalies during El Niño. J. Atmos. Sci., 59 , 2694–2712.

    • Search Google Scholar
    • Export Citation

  • Su, H., J. D. Neelin, and C. Chou, 2001: Tropical teleconnection and local response to SST anomalies during the 1997–1998 El Niño. J. Geophys. Res., 106D , 20025–20043.

    • Search Google Scholar
    • Export Citation

  • Su, H., J. D. Neelin, and J. E. Meyerson, 2004: Tropical tropospheric temperature and precipitation response to sea surface temperature forcing. Ocean–Atmosphere Interaction and Climate Variability, Geophys. Monogr., Vol. 147, Amer. Geophys. Union, 379–392.

  • Torrence, C., and P. J. Webster, 1999: Interdecadal changes in the ENSO–monsoon system. J. Climate, 12 , 2679–2690.

  • Webster, P. J., and S. Yang, 1992: Monsoon and ENSO—Selectively interactive systems. Quart. J. Roy. Meteor. Soc., 118 , 877–926.

  • Wu, Z. X., and R. E. Newell, 1998: Influence of sea surface temperatures on air temperatures in the tropics. Climate Dyn., 14 , 275–290.

    • Search Google Scholar
    • Export Citation

  • Yulaeva, E., and J. M. Wallace, 1994: The signature of ENSO in global temperature and precipitation fields derived from the Microwave Sounding Unit. J. Climate, 7 , 1719–1736.

    • Search Google Scholar
    • Export Citation

  • Zeng, N., and J. D. Neelin, 1999: A land–atmosphere interaction theory for the tropical deforestation problem. J. Climate, 12 , 857–872.

    • Search Google Scholar
    • Export Citation

  • Zeng, N., J. D. Neelin, and C. Chou, 2000: A quasi-equilibrium tropical circulation model—Implementation and simulation. J. Atmos. Sci., 57 , 1767–1796.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 463 205 36
PDF Downloads 116 26 2