Asian Summer Monsoon—ENSO Feedback on the Cane–Zebiak Model ENSO

Chul Chung Department of Meteorology, University of Maryland at College Park, College Park, Maryland

Search for other papers by Chul Chung in
Current site
Google Scholar
PubMed
Close
and
Sumant Nigam Department of Meteorology, University of Maryland at College Park, College Park, Maryland

Search for other papers by Sumant Nigam in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

The Asian summer monsoon heating anomalies are parameterized in terms of the concurrent ENSO SST anomalies and used as additional forcing in the Cane–Zebiak (CZ) Pacific ocean–atmosphere anomaly model. The Asian heating parameterization is developed from the rotated principal component analysis of combined interannual variability of the tropical Pacific SSTs, residually diagnosed tropical diabatic heating at 400 mb (from ECMWF’s analyses), and the 1000-mb tropical winds during the 1979–97 summer months of June, July, and August.

Analysis of the 95 000-yr-long model integrations conducted with and without the interactive Asian sector heating anomalies reveals that their influence on the Pacific surface winds leads to increased ENSO occurrence—an extra ENSO event every 20 yr or so. An examination of the ENSO distribution w.r.t. the peak SST anomaly in the eastern equatorial Pacific shows increased El Niño occurrence in the 2.2–3.6 K range (and −1.0 to −1.6 K range in case of cold events) along with a modest reduction in the 0.6–1.2 K range, that is, a population shift due to the strengthening of weak El Niños in the monsoon run. The interaction of ENSO-related Asian summer monsoon heating with the CZ model’s ocean–atmosphere also results in a wider period distribution of ENSO variability, but with the El Niño peak phase remaining seasonally locked with the northern winter months.

The above modeling results confirm the positive feedback between Asian summer monsoon and ENSO suggested by previous empirical and diagnostic modeling studies; the feedback is generated primarily by the diabatic heating changes in the Asian Tropics.

Corresponding author address: Dr. Sumant Nigam, Room 3403, Computer and Space Sciences Bldg., Dept. of Meteorology, University of Maryland at College Park, College Park, MD 20742.

Email: nigam@atmos.umd.edu

Abstract

The Asian summer monsoon heating anomalies are parameterized in terms of the concurrent ENSO SST anomalies and used as additional forcing in the Cane–Zebiak (CZ) Pacific ocean–atmosphere anomaly model. The Asian heating parameterization is developed from the rotated principal component analysis of combined interannual variability of the tropical Pacific SSTs, residually diagnosed tropical diabatic heating at 400 mb (from ECMWF’s analyses), and the 1000-mb tropical winds during the 1979–97 summer months of June, July, and August.

Analysis of the 95 000-yr-long model integrations conducted with and without the interactive Asian sector heating anomalies reveals that their influence on the Pacific surface winds leads to increased ENSO occurrence—an extra ENSO event every 20 yr or so. An examination of the ENSO distribution w.r.t. the peak SST anomaly in the eastern equatorial Pacific shows increased El Niño occurrence in the 2.2–3.6 K range (and −1.0 to −1.6 K range in case of cold events) along with a modest reduction in the 0.6–1.2 K range, that is, a population shift due to the strengthening of weak El Niños in the monsoon run. The interaction of ENSO-related Asian summer monsoon heating with the CZ model’s ocean–atmosphere also results in a wider period distribution of ENSO variability, but with the El Niño peak phase remaining seasonally locked with the northern winter months.

The above modeling results confirm the positive feedback between Asian summer monsoon and ENSO suggested by previous empirical and diagnostic modeling studies; the feedback is generated primarily by the diabatic heating changes in the Asian Tropics.

Corresponding author address: Dr. Sumant Nigam, Room 3403, Computer and Space Sciences Bldg., Dept. of Meteorology, University of Maryland at College Park, College Park, MD 20742.

Email: nigam@atmos.umd.edu

Save
  • An, S., 1996: A critical examination of the current theories on the ENSO dynamics using an intermediate coupled ocean–atmosphere model. Ph.D. dissertation, Seoul National University, 171 pp. [Available from Department of Atmospheric Sciences, Seoul National University, 151-742, Korea.].

  • Barnett, T. P., M. Latif, N. E. Graham, M. Flügel, S. Pazan, and W. White, 1993: ENSO and ENSO-related predictability. Part I: Prediction of equatorial Pacific sea surface temperature with a hybrid coupled ocean–atmosphere model. J. Climate,6, 1545–1566.

  • Bhalme, H. N., A. B. Sikder, and S. K. Jadhav, 1990: Coupling between the El Niño and planetary-scale waves and their linkage with the Indian monsoon rainfall. Meteor. Atmos. Phys.,44, 293–305.

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

  • Dickson, R. R., 1984: Eurasian snow cover versus Indian monsoon rainfall—An extension of the Hahn-Shukla results. J. Climate Appl. Meteor.,23, 171–173.

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

  • ——, and E. M. Rasmusson, 1983: The 1982–83 climate anomaly in the equatorial Pacific. Nature,305, 229–234.

  • Hartmann, D. L., H. H. Hendon, and R. A. Houze Jr., 1984: Some implications of the mesoscale circulations in tropical could clusters for large-scale dynamics and climate. J. Atmos. Sci.,41, 113–121.

  • Hastenrath, S., 1990: Tropical climate prediction: A progress report, 1985–1990. Bull. Amer. Meteor. Soc.,71, 819–825.

  • Holton, J. R., 1992: An Introduction to Dynamic Meteorology. Academic Press, 510 pp.

  • Horel, J. D., 1981: A rotated principal component analysis of the interannual variability of the Northern Hemisphere 500 mb height field. Mon. Wea. Rev.,109, 2080–2092.

  • ——, and J. M. Wallace, 1981: Planetary-scale atmospheric phenomena associated with the Southern Oscillation. Mon. Wea. Rev.,109, 813–829.

  • Hoskins, B. J., H. H. Hsu, I. N. James, M. Masutani, P. D. Sardeshmukh, and G. H. White, 1989: Diagnostics of the Global Atmospheric Circulation based on ECMWF analyses 1979–1989. WCRP-27, WMO/TD 326, 217 pp.

  • Ju, J., and J. Slingo, 1995: The Asian summer monsoon and ENSO. Quart. J. Roy. Meteor. Soc.,121, 1133–1168.

  • Kirtman, B. P., and J. Shukla, 1999: Influence of the Indian Summer Monsoon on ENSO. Quart. J. Roy. Meteor. Soc., in press.

  • Kousky, V. E., Ed., 1998: Climate Diagnostics Bulletin. NOAA/NWS/NCEP/CPC, U.S. Dept. of Commerce, 81 pp.

  • Lau, K.-M., and S. Yang, 1996: The Asian monsoon and predictability of the tropical ocean–atmosphere system. Quart. J. Roy. Meteor. Soc.,122, 945–957.

  • 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.

  • Mantua, N. J., and D. S. Battisti, 1995: Aperiodic variability in the Zebiak–Cane coupled ocean–atmosphere model: Air–sea interactions in the western equatorial Pacific. J. Climate,8, 2897–2927.

  • Meehl, G. A., 1987: The annual cycle and interannual variability in the tropical Pacific and Indian Ocean regions. Mon. Wea. Rev.,115, 27–50.

  • ——, 1994: Coupled land–ocean–atmosphere processes and South Asian monsoon variability. Science,265, 263–267.

  • Nigam, S., 1994: On the dynamical basis for the Asian summer monsoon rainfall–El Niño relationship. J. Climate,7, 1750–1771.

  • ——, 1997: The annual warm to cold phase transition in the eastern equatorial Pacific: Diagnosis of the role of stratus cloud-top cooling. J. Climate,10, 2447–2467.

  • ——, and H.-S. Shen, 1993: Structure of oceanic and atmospheric low-frequency variability over the tropical Pacific and Indian oceans. Part I: COADS observations. J. Climate,6, 657–676.

  • ——, and Y. Chao, 1996: Evolution-dynamics of tropical ocean–atmosphere annual-cycle variability. J. Climate,9, 3187–3205.

  • Normand, C., 1953: Monsoon seasonal forecasting. Quart. J. Roy. Meteor. Soc.,79, 463–473.

  • O’Brien, J. J., 1970: Alternative solutions to the classical vertical velocity problem. J. Appl. Meteor.,9, 197–203.

  • ——, T. S. Richards, and A. C. Davis, 1996: Climatology and multinational sporting events, Atlanta 1996. Bull. Amer. Meteor. Soc.,77, 771–774.

  • Palmer, T. N., C. Brankovic, P. Viterbo, and M. J. Miller, 1992: Modeling interannual variations of summer monsoons. J. Climate,5, 399–417.

  • Philander, S. G. H., 1985: El Niño and La Niña. J. Atmos. Sci.,42, 2652–2662.

  • Ramage, C. S., 1971: Monsoon Meteorology. International Geophysics Series, Vol. 15, Academic Press, 296 pp.

  • Rasmusson, E. M., and T. H. Carpenter, 1982: Variations in tropical sea surface temperature and surface wind fields associated with the Southern Oscillation/El Niño. Mon. Wea. Rev.,110, 354–384.

  • ——, and ——, 1983: The relationship between eastern equatorial Pacific sea surface temperatures and summer monsoon rainfall over India and Sri Lanka. Mon. Wea. Rev.,111, 517–528.

  • ——, and J. M. Wallace, 1983: Meteorological aspects of the El Niño/Southern Oscillation. Science,222, 1195–1202.

  • Reed, R. J., and E. E. Recker, 1971: Structure and properties of synoptic-scale wave disturbances in the equatorial western Pacific. J. Atmos. Sci.,28, 1117–1133.

  • Reynolds, R. W., 1988: A real-time global sea surface temperature analysis. J. Climate,1, 75–86.

  • ——, and T. M. Smith, 1994: Improved global sea surface temperature analyses using optimum interpolation. J. Climate,7, 929–948.

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

  • Syu, H.-H., J. D. Neelin, and D. Gutzler, 1995: Seasonal and interannual variability in a hybrid couled GCM. J. Climate,8, 2121–2143.

  • Troup, A. J., 1965: The Southern Oscillation. Quart. J. Roy. Meteor. Soc.,91, 490–506.

  • Verma, R. K., 1992: ENSO—Monsoon linkages as evidenced from Pacific SST correlations with monsoon precipitation. TOGA Notes,6, 1–3.

  • Vernekar, A. D., J. Zhou, and J. Shukla, 1995. The effect of Eurasian snow cover on the Indian monsoon. J. Climate,8, 248–266.

  • Wainer, I., and P. J. Webster, 1996: Monsoon/El Niño–Southern Oscillation relationships in a simple coupled ocean–atmosphere model. J. Geophys. Res.,101 (C11), 25 599–25 614.

  • Walker, G. T., 1923: Correlation in seasonal variations of weather. III: A preliminary study of world weather. Memo. Indian Meteor. Dept.,24, 75–131.

  • ——, 1924: Correlation in seasonal variations of weather. IV: A further study of world weather. Memo. Indian Meteor. Dept.,24, 275–332.

  • Webster, P. J., and S. Yang, 1992: Monsoon and ENSO: Selectively interactive systems. Quart. J. Roy. Meteor. Soc.,118, 877–900.

  • ——, J. P. Loschnigg, A. M. Moore, and R. R. Leben, 1999: The Great Indian Ocean Warming of 1997–1998: Evidence of coupled oceanic-atmospheric instabilities. Nature, in press.

  • Xie, P., and P. A. Arkin, 1997: Global precipitation: A 17-year monthly analysis based on gauge observations, satellite estimates, and numerical model outputs. Bull. Amer. Meteor. Soc.,78, 2539–2558.

  • Yamagata, T., and Y. Masumoto, 1989: A simple ocean–atmosphere coupled model for the origin of a warm El Niño Southern Oscillation event. Philos. Trans. Roy. Soc. London,A329, 225–236.

  • Yasunari, T., 1991: The Monsoon Year—A new concept of the Climate Year in the Tropics. Bull. Amer. Meteor. Soc.,72, 1331–1338.

  • Zebiak, S. E., and M. A. Cane, 1987: A model El Niño–Southern Oscillation. Mon. Wea. Rev.,115, 2262–2278.

  • Zhang, Y., J. M. Wallace, and D. S. Battisti, 1997: ENSO-like interdecadal variability: 1900–93. J. Climate,10, 1004–1020.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 525 166 9
PDF Downloads 149 31 1