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Oscillations of upper-air circulation and anomalies in the surface climate of the tropics

  • St. Hastenrat
  • M. C. Wu
Article

Summary

Variations of upper-air circulation related to anomalies in the surface climate of the tropics are studied mainly on the basis of radiosonde and surface observations during 1960–79. Monthly anomalies of sea surface temperature (SST), sea level or station pressure (SLP/STP), 850 and 200 mb height and wind, and 200/850 mb thickness are examined by running mean plots and spectral analysis.

This empirical analysis provides the framework for a hypothesis of the mechanisms of large-scale pressure oscillations. During a stage of cold surface waters in the Equatorial Pacific, surface pressure is high over the Eastern South Pacific and low over Australasia. Enhanced cloudiness is conducive to a cooling of the upper ocean and subsequently of the overlying atmosphere over Australasia. The associated tendency towards a westward pressure gradient in the upper troposphere leads to a rise of surface pressure over Australasia and a drop over the Eastern South Pacific. This has as a consequence the warming of surface waters and of the overlying atmospheric column in the Eastern Equatorial Pacific. Effects are largest in the Central and Eastern Pacific, so that upper-tropospheric topographies decrease westward. This entails a continued drop of surface pressure over the Eastern South Pacific and a rise over Australasia. Decreased cloudiness over Australasia now allows warming of the upper ocean and later of the overlying atmospheric column. The implied change in the slope of upper-tropospheric topography leads to a surface pressure drop over Australasia and rise over the Eastern South Pacific. This in turn is cunducive to the cooling of surface waters, so that the cycle is completed. Upper-air processes and ocean-atmosphere coupling are thus essential for the seesaw of surface pressure between the centers of action.

Keywords

Indian Ocean Surface Pressure Zonal Wind Southern Oscillation Lower Troposphere 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Schwankungen der Zirkulation in der oberen Atmosphäre und Anomalien im Bodenklima der Tropen

Zusammenfassung

Zirkulationsänderungen in der freien Atmosphäre und Anomalien im Bodenklima der Tropen werden hauptsächlich auf Grund von Radiosondenaufstiegen und Bodenbeobachtungen im Zeitraum 1960–79 untersucht. Monatliche Anomalien von Meeresoberflächentemperatur (SST), Druck an Station oder im Meeresniveau (STP/SLP), absoluter Topographie und Wind der 850 and 200 mb Niveaus und relativer Topographie 200/850 mb werden in Form übergreifender Mittel und lurch Spektralanalyse dargestellt. Diese empirische Untersuchung liefert den Rahmen für eine Hypothese der Mechanismen großräumiger Druckschwankungen. In einem Stadium kalten Oberflächenwassers im aquatorialen Pazifik herrscht hoher Bodendruck über dem östlichen Siidpazifik und niederer Druck über Australasien. Verstärkte Bewölkung begünstigt eine Abkühlung der Meeresoberfläche und danach der darüberliegenden Luftsaule über Australasien. Die damit einhergehende Tendenz fur einen westwärtigen Druckgradienten in der Hochtroposphäre führt zu einem Anstieg des Bodendrucks über Ausiralasien und Druckfall über dem östlichen Südpazifik. Das hat eine Erwärmung der Meeresoberflache und später der darüberliegenden Luftsäule im östlichen äquatorialen Pazifik zur Folge. Die Auswirkungen sind im zentralen und Ostpazifik am größten, so daß die hochtroposphärischen Druckniveaus nach Westen abfallen. Das bewirkt weiteres Absinken des Bodendrucks über dem östlichen Südpazifik und Druckanstieg über Australasien. Bewölkungsabnahme über Australasien erlaubt jetzt eine Erwärmung der Meeresoberfläche und der darüberliegenden Luftsäule. Die damit einhergehende Änderung in der Neigung der hochtroposphärischen Druckniveaus führt zu Absinken des Bodendrucks über Australasien und Druckanstieg über dem östlichen Südpazifik. Dies wiederum ist einer Abkühlung der Meeresoberläche zuträglich, womit sich der Zyklus vollendet. Es zeigt sich also, daß Vorgänge in der freien Atmosphäre und die Koppelung zwischen Atmosphäre und Ozean für die gegenläufigen Änderungen des Bodendrucks an den zwei großen Aktionszentren wesentlich ist.

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References

  1. 1.
    Angell, J. K.: Comparison of Variations in Atmospheric Quantities with Sea Surface Temperature Variations in the Equatorial Eastern Pacific. Mon. Weath. Rev.109, 230–243 (1981).CrossRefGoogle Scholar
  2. 2.
    Angell, J. K., Korshover, J.: Quasi-Biennial and Long-Term Fluctuations in the Centers of Action. Mon. Weath. Rev.102, 669–678 (1974).CrossRefGoogle Scholar
  3. 3.
    Alexander, B., Keshavamurty, R. N., Mikhopadhyay, R. K., Bhosale, S. G.: Pacific Equatorial Pressure Gradient and Monsoon Rainfall. Nature252, 463–464 (1974).CrossRefGoogle Scholar
  4. 4.
    Berlage, H. P.: Fluctuations of the General Circulation of More Than One Year, Their Nature and Prognostic Value. Netherlands Met.-Inst., Mededelingen en Verhandelingen No. 69, 152 pp., 1957.Google Scholar
  5. 5.
    Berlage, H. P.: The Southern Oscillation and World Weather. Nederlands Met.-Inst., Mededelingen en Verhandelingen No. 88, 152 pp., 1966.Google Scholar
  6. 6.
    Bjerknes, J.: A Possible Response of the Atmospheric Hadley Circulation to Equatorial Anomalies of Ocean Temperature. Tellus18, 820–829 (1966).Google Scholar
  7. 7.
    Bjerknes, J.: Atmospheric Teleconnections from the Equatorial Pacific. Mon. Weath. Rev.97, 163–172 (1969).CrossRefGoogle Scholar
  8. 8.
    Brier, G. W.: The Quasi-Biennial Oscillation and Feedback Processes in the Atmosphere-Ocean-Earth System. Mon. Weath. Rev.106, 938–946 (1978).CrossRefGoogle Scholar
  9. 9.
    Budyko, M. I.: Climate and Life. Internat. Geoph. Series, Vol. 18, 508 pp. New York: Academic Press 1974.Google Scholar
  10. 10.
    Covey, D. L., Hastenrath, S.: The Pacific El Niño Phenomenon and the Atlantic Circulation. Mon. Weath. Rev.106, 1280–1287 (1978).CrossRefGoogle Scholar
  11. 11.
    Ebdon, R. A.: The Quasi-Biennial Oscillation and Its Association with Tropospheric Circulation Patterns. Met. Mag.104, 282–297 (1975).Google Scholar
  12. 12.
    Hastenrath, S.: Variations in Low-Latitude Circulation and Extreme Climatic Events in the Tropical Americas. J. Atmos. Sci.33, 202–215 (1976).CrossRefGoogle Scholar
  13. 13.
    Hastenrath, S.: On Modes of Tropical Circulation and Climate Anomalies. J. Atmos. Sci.35, 2222–2231 (1978).CrossRefGoogle Scholar
  14. 14.
    Hastenrath, S., Heller, L.: Dynamics of Climatic Hazards in Northeast Brazil. Quart. J. R. Met. Soc.103, 77–92 (1977).CrossRefGoogle Scholar
  15. 15.
    Hastenrath, S., Kaczmarczyk, E. B.: On Spectra and Coherence of Tropical Climate Anomalies. Tellus33, 453–462 (1981).Google Scholar
  16. 16.
    Hastenrath, S., Lamb, P.: Heat Budget Atlas of the Tropical Atlantic and Eastern Pacific Oceans. University of Wisconsin Press, 1978.Google Scholar
  17. 17.
    Hastenrath, S., Lamb, P.: Climatic Atlas of the Indian Ocean. Part I: The Surface Climate and Atmospheric Circulation. Part II: The Oceanic Heat Budget. University of Wisconsin Press, 1979.Google Scholar
  18. 18.
    Hastenrath, S., Wendland, W.: On the Secular Variation of Storms in the Tropical North Atlantic and Eastern Pacific. Tellus31, 28–38 (1979).Google Scholar
  19. 19.
    Hildebrandsson, H.: Les centres d'action de l'atmosphère. Kongl. Svenska Veten.-Akad. Handl.29, 36 pp., 1897.Google Scholar
  20. 20.
    Hotel, J. D., Wallace, J. M.: Planetary Scale Atmospheric Phenomena Associated with the Southern Oscillation. Mon. Weath. Rev.109, 813–823 (1981).CrossRefGoogle Scholar
  21. 21.
    Hurlburt, H., Kindle, J., O'Brien, J.: A Numerical Simulation of the Onset of El Niño. J. Phys. Oceanogr.6, 621–631 (1976).CrossRefGoogle Scholar
  22. 22.
    Kidson, J. W.: Tropical Eigenvector Analysis and Southern Oscillation. Mon. Weath. Rev.103, 187–196 (1975).CrossRefGoogle Scholar
  23. 23.
    Lamb, P.: Large-Scale Tropical Atlantic Surface Circulation Patterns Associated with Subsaharan Weather Anomalies. Tellus30, 240–251 (1978).Google Scholar
  24. 24.
    Lamb, P.: Case Studies of Tropical Atlantic Surface Circulation Patterns During Recent Subsaharan Weather Anomalies: 1967 and 1968. Mon. Weath. Rev.106, 482–491 (1978).CrossRefGoogle Scholar
  25. 25.
    Lockyer, W. J. S.: Barometric Variations of Long Duration Over Large Areas. Proc. Roy. Soc. A78, 43–60 (1906).CrossRefGoogle Scholar
  26. 26.
    Markham, C. G., McLain, D. R.: Sea Surface Temperature Related to Rain in Ceará, Northeastern Brazil. Nature265, 320–323 (1977).CrossRefGoogle Scholar
  27. 27.
    McCreary, J.: Eastern Tropical Ocean Response to Changing Wind Systems: with Application to El Niño. J. Phys. Oceanogr.6, 632–645 (1976).CrossRefGoogle Scholar
  28. 28.
    Meehl, G. A., Van Loon, H.: The See-saw in Winter Temperatures Between Greenland and Northern Europe, Part 3: Teleconnections with Lower Latitudes. Mon. Weath. Rev.107, 1095–1106 (1979).CrossRefGoogle Scholar
  29. 29.
    Moura, A. D., Shukla, J.: On the Dynamics of Droughts in Northeast Brazil: Observations, Theory, and Numerical Experiment with a General Circulation Model. (Submitted to J. Atmos. Sci.)Google Scholar
  30. 30.
    Namias, J.: Influence of Northern Hemisphere General Circulation on Drought in Northeast Brazil. Tellus24 336–343 (1972).CrossRefGoogle Scholar
  31. 31.
    Namias, J.: Some Statistical and Synoptic Characteristics Associated with El Niño. J. Phys. Oceanogr.6 130–138 (1976).CrossRefGoogle Scholar
  32. 32.
    Navato, A. R., Newell, R. E., Hsiung, J. C., Billing, C. B.: Tropospheric Mean Temperature and Its Relationship to the Oceans and Atmospheric Aerosols. Mon. Weath. Rev.109 405–416 (1981).CrossRefGoogle Scholar
  33. 33.
    Newell, R. E.: Climate and the Ocean. Amer. Scientist67 405–416 (1980).Google Scholar
  34. 34.
    Nicholls, N.: Air-Sea Interaction and the Quasi-biennial Oscillation. Mon. Weath. Rev.106, 1505–1508 (1978).CrossRefGoogle Scholar
  35. 35.
    Pant, G. B., Parthasarathy, B.: Some Aspects of an Association Between the Southern Oscillation and Indian Summer Monsoon. Arch. Met. Geoph. Biokl., Ser. B29 245–252 (1981).CrossRefGoogle Scholar
  36. 36.
    Quinn, W.: Monitoring and Predicting El Niño Invasions. J. Appl. Met.13 825–830 (1974).CrossRefGoogle Scholar
  37. 37.
    Quinn, W. H., Zopf, D. O., Short, K. S., Kuo Yang, R. T. W.: Historical Trends and Statistics of the Southern Oscillation, El Nino, and Indonesian Droughts. Fishery Bulletin76, 663–578 (1978).Google Scholar
  38. 38.
    Rasmusson, E. M., Carpenter, T. H.: Variations in Tropical Sea Surface Temperature and Surface Wind Fields Associated with the Southern Oscillation/El Niño. (Submitted to Mon. Weath. Rev.)Google Scholar
  39. 39.
    Reiter, E. R.: Trade-Wind Variability, Southern Oscillation, and Quasi-biennial Oscillation. Arch. Met. Geoph. Biokl. Ser. A28, 113–126 (1979).CrossRefGoogle Scholar
  40. 40.
    Rogers, J. C., Van Loon, H.: The See-saw in Winter Temperatures Between Greenland and Northern Europe, Part II: Some Oceanic and Atmospheric Effects in Middle and High Latitudes. Mon. Weath. Rev.107, 509–519 (1979).CrossRefGoogle Scholar
  41. 41.
    Schickedanz, P. T., Bowen, E. G.: The Computation of Climatological Power Spectra. J. Appl. Met.16, 359–367 (1977).CrossRefGoogle Scholar
  42. 42.
    Trenberth, K. E.: Spatial and Temporal Variations of the Southern Oscillation. Quart. J. R. Met. Soc.102, 639–653 (1976).CrossRefGoogle Scholar
  43. 43.
    Trenberth, K., Paolino, D. A.: Characteristic Patterns of Variability of Sea Level Pressure in the Northern Hemisphere. Mon. Weath. Rev.109, 1169–1189 (1981).CrossRefGoogle Scholar
  44. 44.
    Tsuchiya, I.: Year-to-Year Variations Over the India Equatorial Pacific Region and of Low and Middle Latitude Circulations in the Southern Hemisphere. Papers in Met. and Geoph., vol. 21, no. 2, pp. 73–87 (1970).Google Scholar
  45. 45.
    U.S. Weather Bureau, ESSA, NOAA: Climatological Data, National Summary, Years 1960–79. Asheville, N.C., 1960–1980.Google Scholar
  46. 46.
    U.S. Weather Bureau, ESSA, NOAA: Monthly Climatic Data for the World, Years 960–79. Asheville, N.C., 1960–1980.Google Scholar
  47. 47.
    Van Loon, H., Rogers, J. C.: The See-saw in Winter Temperatures Between Greenland and Northern Europe, Part 1: General Description. Mon. Weath. Rev.106, 296–310 (1978).CrossRefGoogle Scholar
  48. 48.
    Van Loon, H., Madden, R. A.: The Southern Oscillation, Part I: Global Associations with Pressure and Temperature in Northern Winter. Mon. Weath. Rev.109, 1150–1162 (1981).CrossRefGoogle Scholar
  49. 49.
    Van Loon, H., Rogers, J. C.: The Southern Oscillation, Part II: Associations with Changes in the Middle Troposphere in the Northern Winter. Mon. Weath. Rev.109, 1163–1168 (1981).CrossRefGoogle Scholar
  50. 50.
    Walker, G. T.: World Weather I and II. Mem. India Met. Dept.24, 75–131, 275–332 (1923-1924).Google Scholar
  51. 51.
    Walker, G. T.: World Weather III. Mem. Roy. Met. Soc.2, 97–106 (1928).Google Scholar
  52. 52.
    Walker, G. T., Bliss, E. W.: World Weather IV, V, VI. Mem. Roy. Met. Soc.3, 81–95;4, 53–84, 119–139 (1930, 1932, 1937).Google Scholar
  53. 53.
    Wallace, J. M., Gutzler, D. S.: Teleconnections in the Geopotential Height Fields During the Northern Hemisphere Winter. Mon. Weath. Rev.109, 784–812 (1981).CrossRefGoogle Scholar
  54. 54.
    Wright, P. B.: The Southern Oscillation — Patterns and Mechanisms of the Teleconnections and Persistence. Hawaii Inst. Geoph., HIG-77-13, 107 pp., 1977.Google Scholar
  55. 55.
    Wyrtki, K.: The Dynamic Response of the Equatorial Pacific Ocean to Atmospheric Forcing. J. Phys. Oceanogr.5, 572–582 (1975).CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • St. Hastenrat
    • 1
  • M. C. Wu
    • 1
  1. 1.Department of Meteorology, Meteorology and Space Science BuildingThe University of WisconsinMadisonUSA

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