Editorial Type:
Article
Article Type:
Research Article

The Elements of Climate Variability in the Tropical Atlantic Region

R. T. Sutton Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, Reading, United Kingdom

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S. P. Jewson Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, Reading, United Kingdom

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D. P. Rowell Hadley Centre for Climate Prediction and Research, The Met. Office, Bracknell, Berkshire, United Kingdom

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Print Publication:
15 Sep 2000
DOI:
https://doi.org/10.1175/1520-0442(2000)013<3261:TEOCVI>2.0.CO;2
Page(s):
3261–3284
Restricted access

Abstract

The tropical Atlantic region, unlike the tropical Pacific, is not dominated by any single mode of climate variability such as the El Niño–Southern Oscillation (ENSO). Rather, this region is subject to multiple competing influences of comparable importance. The nature and potential predictability of these various influences has been investigated by analysis of an ensemble of atmospheric GCM integrations forced with observed SST for the period December 1948–November 1993.

The dominant modes of internal atmospheric and SST-forced variability are determined. Internal variability in the tropical Atlantic region is dominated by the equatorward extension of extratropical patterns, especially the North Atlantic oscillation. Three different SST-forced signals are identified. These are (a) a remote response to ENSO, (b) a response to the so-called Atlantic Dipole SST pattern, and (c) a response to equatorial Atlantic SST anomalies. The spatial structure and seasonality of these different elements of climate variability are diagnosed and feedbacks onto the ocean are assessed. The evidence presented supports the possibility of ENSO-like variability in the equatorial Atlantic, but does not support the suggestion that the Atlantic Dipole is a coupled ocean–atmosphere mode of variability.

An important feature of this study is that the results include quantitative estimates of the comparative importance, in different regions and different seasons, of the various influences on tropical Atlantic climate variability. These estimates are used to assess the potential predictability of key climatic indices.

Corresponding author address: Dr. Rowan Sutton, Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, P. O. Box 243, Earley Gate, Reading RG6 6BB, United Kingdom.

Abstract

The tropical Atlantic region, unlike the tropical Pacific, is not dominated by any single mode of climate variability such as the El Niño–Southern Oscillation (ENSO). Rather, this region is subject to multiple competing influences of comparable importance. The nature and potential predictability of these various influences has been investigated by analysis of an ensemble of atmospheric GCM integrations forced with observed SST for the period December 1948–November 1993.

The dominant modes of internal atmospheric and SST-forced variability are determined. Internal variability in the tropical Atlantic region is dominated by the equatorward extension of extratropical patterns, especially the North Atlantic oscillation. Three different SST-forced signals are identified. These are (a) a remote response to ENSO, (b) a response to the so-called Atlantic Dipole SST pattern, and (c) a response to equatorial Atlantic SST anomalies. The spatial structure and seasonality of these different elements of climate variability are diagnosed and feedbacks onto the ocean are assessed. The evidence presented supports the possibility of ENSO-like variability in the equatorial Atlantic, but does not support the suggestion that the Atlantic Dipole is a coupled ocean–atmosphere mode of variability.

An important feature of this study is that the results include quantitative estimates of the comparative importance, in different regions and different seasons, of the various influences on tropical Atlantic climate variability. These estimates are used to assess the potential predictability of key climatic indices.

Corresponding author address: Dr. Rowan Sutton, Centre for Global Atmospheric Modelling, Department of Meteorology, University of Reading, P. O. Box 243, Earley Gate, Reading RG6 6BB, United Kingdom.

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  • Allen, M. R., and L. A. Smith, 1994: Invesigating the origins and significance of low frequency modes of climate variability. Geophys. Res. Lett.,21, 883–886.

  • ——, and ——, 1997: Optimal filtering in singular spectrum analysis. Phys. Lett.,234, 419–428.

  • Bjerknes, J., 1969: Atmospheric teleconnections from the equatorial pacific. Mon. Wea. Rev.,97, 163–172.

  • Bretherton, C. S., C. Smith, and J. M. Wallace, 1992: An intercomparison of methods for finding coupled patterns in climate data. J. Climate,5, 541–560.

  • Carson, D. J., 1998: Seasonal forecasting. Quart. J. Roy. Meteor. Soc.,124, 1–26.

  • Carton, J. A., X. Cao, B. S. Giese, and A. M. da Silva, 1996: Decadal and interannual SST variability in the tropical Atlantic Ocean. J. Phys. Oceanogr.,26, 1165–1175.

  • Cayan, D. R., 1992: Latent and sensible heat-flux anomalies over the northern oceans—driving the sea-surface temperature. J. Phys. Oceanogr.,22, 859–881.

  • Chang, P., L. Ji, and H. Li, 1997: A decadal climate variation in the tropical Atlantic Ocean from thermodynamic air&ndash≃a interactions. Nature,385, 516–518.

  • ——, R. Saravanan, L. Ji, and G. C. Hegerl, 2000: The effect of local sea surface temperatures on atmospheric circulation over the tropical Atlanic sector. J. Climate,13, 2195–2216.

  • Cullen, M. J. P., 1993: The unified forecast/climate model. Meteor. Mag.,122, 81–94.

  • Curtis, S., and S. Hastenrath, 1995: Forcing of anomalous sea surface temperature evolution in the tropical Atlantic during pacific warm events. J. Geophys. Res.,100, 15 835–15 847.

  • da Silva, A., A. C. Young, and S. Levitus, 1994: Atlas of surface marine data. Tech. Rep. 6, U.S. Department of Commerce, NOAA, NESDIS, 83 pp.

  • Davies, J. R., D. P. Rowell, and C. K. Folland, 1997: North Atlantic and European seasonal predictability using an ensemble of multi-decadal agcm simulations. Int. J. Climatol.,17, 1263–1284.

  • Enfield, D. B., and D. A. Mayer, 1997: Tropical Atlantic SST variability and its relation to El Niño–Southern Oscillation. J. Geophys. Res.,102 (C1), 929–945.

  • Folland, C. K., T. N. Palmer, and D. Parker, 1986: Sahel rainfall and worldwide sea temperatures: 1901–85. Nature,320, 602–606.

  • ——, J. Owen, M. N. Ward, and A. Colman, 1991: Prediction of seasonal rainfall in the sahel region using empirical and dynamical methods. J. Forecasting,10, 21–56.

  • Frankignoul, C., and K. Hasselmann, 1977: Stochastic climate models. Part II. Application to sea-surface temperature anomalies and thermocline variability. Tellus,29, 289–305.

  • Gates, W. L., 1992: AMIP: The atmospheric model intercomparison project. Bull. Amer. Meteor. Soc.,73, 1962–1970.

  • Goldenberg, S. B., and L. J. Shapiro, 1996: Physical mechanisms for the association of El Niño and West African rainfall with Atlantic major hurricane activity. J. Climate,9, 1169–1187.

  • Gray, W. M., C. W. Landsea, P. W. Mielke Jr., and K. J. Berry, 1993:Predicting Atlantic basin seasonal tropical cyclone activity by 1 August. Wea. Forecasting,8, 73–86.

  • Hasselmann, K., 1979: On the signal-to-noise problem in atmospheric response studies. Meteorology of Tropical Oceans, D. B. Shawn, Ed., Royal Meteorological Society, 251–259.

  • Hastenrath, S., and L. Greischar, 1993: Further work on the prediction of northeast Brazil rainfall anomalies. J. Climate,6, 743–758.

  • Houghton, R. W., and Y. M. Tourre, 1992: Characteristics of low-frequency sea surface temperature fluctuations in the tropical atlantic. J. Climate,5, 765–771.

  • Huang, B., and J. Shukla, 1997: Characteristics of the interannual and decadal variability in general circulation model of the tropical Atlantic ocean. J. Phys. Oceanogr.,27, 1693–1712.

  • Hulme, M., Y. Biot, J. Borton, M. Buchanan-Smith, S. Davies, C. Folland., N. Nicholds, D. Seddon, and N. Ward, 1992a: Seasonal rainfall forecasting for Africa. Part I: Current status and future developments. Int. J. Environ. Stud.,39, 245–256.

  • ——, and Coauthors, 1992b: Seasonal rainfall forecasting for Africa. Part II. Application and impact assessment. Int. J. Environ. Stud.,40, 103–121.

  • Landsea, C. W., 1993: A climatology of intense (or major) Atlantic hurricanes. Mon. Wea. Rev.,121, 1703–1713.

  • Latif, M., and A. Gr&oumlñer, 2000: The equatorial Atlantic oscillation and its response to ENSO. Climate Dyn.,16, 213–218.

  • Lindzen, R. S., and S. Nigam, 1987: On the role of sea-surface temperature-gradients in forcing low level winds and convergence in the Tropics. J. Atmos. Sci.,44, 2418–2436.

  • Lough, J. M., 1986: Tropical Atlantic sea surface temperature and rainfall variations in subsaharan Africa. Mon. Wea. Rev.,114, 561–570.

  • Mehta, V., 1998: Variability of the tropical ocean surface temperatures at decadal–multidecadal timescales. Part 1: The Atlantic Ocean. J. Climate,11, 2351–2375.

  • Moura, A. D., and J. Shukla, 1981: On the dynamics or droughts in northeast brazil: Observations, theory and numerical experiments with a general circulation model. J. Atmos. Sci.,38, 2653– 2675.

  • Nobre, P., and J. Shukla, 1996: Variations of sea surface temperature, wind stress, and rainfall over the tropical Atlantic and South America. J. Climate,9, 2464–2479.

  • Parker, D. E., C. K. Folland, A. Bevan, M. N. Ward, M. Jackson, and F. Maskell, 1995: Marine surface data for analysis of climate fluctuations on interannual to century timescales. Natural Climate Variability on Decadal to Century Timescales, D. G. Martinson, Ed., National Academy Press, 241–250.

  • Phillips, T. J., 1994: A summary documentation of the AMIP models. Tech. Rep. 18, PCMDI, Lawrence Livermore National Laboratory. [Available from Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550-9234.].

  • Potts, J. M., C. K. Folland, I. T. Jolliffe, and D. Sexton, 1996: Revised “leps” scores for assessing climate model simulations and long-range forecasts. J. Climate,9, 34–53.

  • Rajagopalan, B., Y. Kushnir, and Y. M. Tourre, 1998: Observed midlatitude and tropical Atlantic climate variability. Geophys. Res. Lett.,25, 3967–3970.

  • Renshaw, A. C., D. P. Rowell, and C. K. Folland, 1998: Enso responses and low frequency weather variability in the North Pacific/American sector 1943–93. J. Climate,11, 1073–1093.

  • Rodwell, M. J., D. P. Rowell, and C. K. Folland, 1999: Oceanic forcing of the winter North Atlantic oscillation and European climate. Nature,398, 320–323.

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

  • ——, and F. W. Zweirs, 1999: The global distribution of sources of atmospheric decadal variability and mechanisms over the tropical Pacific and southern North America. Climate Dyn.,15, 751– 772.

  • ——, C. K. Folland, K. Maskell, and M. N. Ward, 1995: Variability of summer rainfall over tropical North Africa (1906–92): Observations and modelling. Quart. J. Roy. Meteor. Soc.,121, 669– 704.

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

  • Venzke, S., M. R. Allen, R. T. Sutton, and D. P. Rowell, 1999: The atmospheric response over the North Atlantic to decadal changes in sea surface temperature. J. Climate,12, 2562–2584.

  • Ward, M. N., and C. K. Folland, 1991: Prediction of seasonal rainfall in the north nordeste of Brazil using eigenvectors of sea-surface temperature. Int. J. Climatol.,11, 711–743.

  • ——, ——, K. Maskell, A. Colman, D. P. Rowell, and K. Lane, 1993:Experimental seasonal forecasting of tropical rainfall at the U.K. Meteorological Office. Prediction of Interannual Climate Variations, J. Shukla, Ed., NATO ASI Series, Vol. 16, Springer-Verlag, 197–216.

  • Willmott, C. J., C. M. Rowe, and T. Minz, 1985: A global archive or land cover and soils data for use in general circulation models. J. Climatol.,5, 119–143.

  • Yang, J., 1999: A linkage between decadal climate variations in the Labrador Sea and the tropical Atlantic Ocean. Geophys. Res. Lett,26, 1023–1026.

  • Zebiak, S. E., 1993: Air&ndash≃a interaction in the equatorial Atlantic region. J. Climate,6, 1567–1586.

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