Summary
An attempt is made to identify the basic structure of the planetary scale monsoon and to define and describe the various mechanisms effecting or producing that structure and its variation on a variety of time scales. Both observational and theoretical descriptions are used to define the monsoon system or to point towards problems that require clarification.
The basic mean summer and winter monsoon regimes are described and a discussion presented on their degree of dependence on the distributions of orography, the form and distribution of land and ocean and the state of the interactive oceans adjacent to the major land masses. It is suggested that orography plays a critical role in determining the state of the mean summer and winter circulations behaving principally as an elevated heat source in summer and a mechanical perturber of the mean flow in winter. The spatial variation of sea-surface temperature and the distribution of land are shown to be theprimum mobile of the mean seasonal monsoon.
Various modes and time scales of the variable monsoon are defined. It is shown that the principal time scale variation or phasing of theinterseasonal transition is determined by the different response times of the oceans and land areas to variable solar heating. The reaction of the ocean is a strong function of latitude because of its ability to be heated by solar radiation and mixed mechanically by the atmosphere. The return heating distribution imposed on the atmosphere by the ocean strongly effects the circulation. The inclusion of a hydrology cycle adds a further time scale to the monsoon system allowing much more rapid variations to be superimposed on the modulations caused by radiative and sensible heating effects. The inclusion of clouds introduces a furtherintra-seasonal time-scale into the monsoon circulation causing ‘break-like’ variations of the precipitation pattern and circulation fields during the late summer.
Finally, a brief discussion is given on the various forms of interhemispheric interaction. It is suggested that contrary to earlier theoretical speculation, the equatorial latitudes may be considerably more ‘porous’ to mid-latitude disturbances than hitherto anticipated.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Asnani, G. C. (1967),Meridional circulation in summer monsoon of South-east Asia, Nature214, 73–74.
Blackmon, M., Wallace, J. M., Lau, N. G. andMullen, S. (1977),An observational study of the northern hemisphere wintertime circulation, to appear in J. Atmos. Sci.34, July.
Bennett, J. R. andYoung, J. A. (1971),The influence of latitudinal wind shear upon large-scale propagation into the tropics, Mon. Wea. Rev.99, 202–214.
Chang, C. P. (1977),Viscous internal gravity waves and low-frequency oscillations in the tropics, J. Atmos. Sci.34, 901–910.
Charney, J. G. (1969),A further note on large-scale motions in the tropics, J. Atmos. Sci.26, 182–185.
Colton, D. E. (1973),Barotropic scale interactions in the tropical troposphere during the northern summer. J. Atmos. Sci.30, 1287–1302.
Findlater, J. (1969),Interhemispheric transport of air in the lower troposphere over the western Indian Ocean, Quart. J. Roy. Met. Soc.95, 400–403.
Flohn, H. (1950),Studien zur allgemeinen Zirkolation der Atmosphäre III, Ber. Dent. Wetterd.18, 34–50.
Flohn, H. (1960),Recent investigations on the mechanism of the ‘Summer Monsoon’ of Southern and Eastern Asia, Proc. Symp. Monsoons of the World.
Flohn, H. (1968),Contributions to a meteorology of the Tibetan Highlands, Atmospheric Sci. Paper No. 130, Colorado State University, 120 pp. (Available from National Technical Information Service, Springfield, VA, 22161, No. PB-182255.)
Hahn, D. G. andManabe, S. (1975),The role of mountains in the South Asian monsoon circulation, J. Atmos. Sci.32, 1515–1541.
Hahn, D. G. andManabe, S. (1976),Reply to ‘Comments on “The Role of Mountains in the South Asian Monsoon Circulation”’, J. Atmos. Sci.33, 2255–2258.
Halley, E. (1686),An historical account of the trade winds and monsoons observable in the seds between and near the tropics with an attempt to assign a physical cause of the said winds, Phil. Trans. Roy. Soc. London16, 153–168.
Koteswarain, P.,Monsoons of the World (Indian Meteorological Department 1958), p. 105.
Krishnamurti, T. N. (1971a),Tropical east-west circulations during the northern summer, J. Atmos. Sci.28, 1342–1347.
Krishnamurti, T. N. (1971b),Observational study of the tropical upper troposphere motion field during the northern hemisphere summer, J. Appl. Meteor.10, 1066–1096.
Krishnamurti, T. N., Kanamitsu, N., Koss, W. J. andLee, J. D. (1973),Tropical east-west circulations during the northern winter, J. Atmos. Sci.30, 780–787.
Krishnamurti, T. N. andBhalme, H. N. (1976),Oscillations of a monsoon system, Part 1. Observational Aspects, J. Atmos. Sci.33, 1937–1954.
Lau, K. M. W. (1977),A large-scale ocean-atmosphere interaction model, Ph.D. Thesis, Department of Atmospheric Sciences, University of Washington, Seattle, July.
Lau, K. M. W. andWebster, P. J. (1977),Simulation of the annual cycle with a simple interactive ocean-atmosphere model, to be submitted toJ. Atmos. Sci.
Matsuno, T. (1970),Vertical propagation of stationary planetary waves in the winter northern hemisphere. J. Atmos. Sci.27, 871–883.
Manabe, S., Bryan, K. andSpelman, M. J. (1975),A global ocean-atmosphere climate model. Part 1. The atmospheric circulation, J. Phys. Oceanogr.5, 3–29.
Murakami, T., Godbole, R. V. andKelkar, R. R.,Numerical simulation of the monsoon along 80°E, in Proceedings Conf. Summer Monsoon Southeast Asia (ed. C. S. Ramage) (Navy Weather Res. Facility, Norfolk, Virginia 1970), pp. 39–51.
Murakami, T. andUnninayar, M. S. (1977),Changes in atmospheric circulations during the northern hemisphere winter, submitted to Mon. Wea. Rev.
Newell, R. E., Kidson, J. W., Vincent, D. G. andBoer, G. J.,The General Circulation of the Tropical Atmosphere and Interaction with Extratropical Latitudes, Vol. 1 (MIT Press, Cambridge, Mass. 1972), 258 pp.
Pike, A. C. (1971),Intertropical convergence zone studied with an interacting atmosphere and ocean model, Mon. Wea. Rev.99, 469–477.
Radok, U. andGrant, A. M. (1957),Variation in the high tropospheric mean flow over Australia and New Zealana, J. Meteor.14, 141–149.
Ramage, C. (1968),Role of a tropical ‘Maritime Continent’ in the atmospheric circulation, Mon. Wea. Rev.96, 385–390.
Ramage, C.,Monsoon Meteorology (Academic Press, New York and London 1971), 296 pp.
Ramage, C. andRaman, C. V. R.,Meteorological Atlas of the International Indian Ocean Expedition, Vol. 2 (National Science Foundation, Washington, D.C. 1972). (Superintendent of Documents, Washington, D.C., Stock No. 3800-00124.)
Riehl, H.,On production of kinetic energy from condensational heating inThe Atmosphere and Sea in Motion, The Rossby Memorial Volume (The Rockefeller Institute Press, New York 1959), pp. 381–399.
Rossby, C. G. et al. (1939),Relation between the intensity of the zonal circulation of the atmosphere and the displacements of the semipermanent centers of action, J. Mar. Res.2, 38–55.
Sadler, J. C. (1975),The upper tropospheric circulation over the global tropics, Rept. UHMET 75-05, Dept. of Meteorology, University of Hawaii, Honolulu, 35 pp.
Sadler, J. C., Oda, L. andKilonsky, B. J. (1976),The Pacific Ocean cloudiness from satellite observations, UHMET 76-01, Department of Meteorology, University of Hawaii.
Sadler, J. C. andRamage, C. (1976),Comments on ‘The role of mountains in the South Asian Monsoon Circulation’, J. Atmos. Sci.33, 2255–2258.
Smagorinsky, J. (1953),The dynamic influence of the large-scale heat sources and sinks on the quasistationary mean motions of the atmosphere, Quart. J. Roy. Met. Soc.75, 417–428.
Staff Members Academic Sinica, Inst. Geophys. Meteor. Peking (1957–58),On the general circulation over Eastern Asia I–III, Tellus9, 432–446, Tellus10, 58–75 and 299–312.
van Loon, H. (1972),Wind in the southern hemisphere, meteorology of the southern hemisphere, Meteorological Monographs 13 (ed. Chester W. Newton), 283 pp.
Walker, J. M. (1972),The monsoon of southern Asia: A review, Weather27, 178–189.
Washington, W. M. andDaggupaty, S. M. (1975),Numerical simulation with the NCAR global circulation model of the mean conditions during the Asian-African summer monsoon, Mon. Wea. Rev.103, 105–114.
Webster, P. J. (1972),Response of the tropical atmosphere to local steady forcing, Mon. Wea. Rev.100, 518–541.
Webster, P. J. (1977),Lateral effects on monsoon systems, Proceedings of the International Symposium on Monsoons, New Delhi, March 1977 (in press).
Webster, P. J. andCurtin, D. G. (1975),Interpretations of the EOLE experiment II, Spatial variation of transient and stationary modes, J. Atmos. Sci.32, 1848–1863.
Webster, P. J. andLau, K. M. W. (1977b),A simple ocean-atmosphere climate model: Basic model and a simple experiment, J. Atmos. Sci.34, 1063–1084.
Webster, P. J. andLau, K. M. W. (1977b),Simulation of the global monsoon sequence by a simple oceanatmospheric interaction model, Proceedings of the International Symposium on Monsoons, New Delhi, March 1977 (in press).
Webster, P. J. andChou, L. (1977),A simple model of monsoon transitions, to be submitted to J. Atmos. Sci.
Author information
Authors and Affiliations
Additional information
Contribution number 432, Department of Atmospheric Sciences, University of Washington, USA.
Rights and permissions
About this article
Cite this article
Webster, P.J., Chou, L. & Lau, K.M. Mechanisms effecting the state, evolution and transition of the planetary scale monsoon. PAGEOPH 115, 1463–1491 (1977). https://doi.org/10.1007/BF00874419
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00874419