Abstract
This study is diagnostic in character and entails a systematic investigation of the kinematic parameters of the mean monthly 300 mb horizontal-motion field for the global tropical region during January, April, and October.
The kinematic parameters analysed include the horizontal velocity divergence, relative vorticity, velocity potential, and stream function. The magnitude of relative voritcity has been observed to be nearly equal to that of the horizontal velocity divergence in the equatorial latitudes and an order of magnitude larger in the subtropics. The magnitudes of∂u/∂x, ∂v/∂y, and horizontal velocity divergence are comparable and vary very little with latitude, while that of∂u/∂y is an order of magnitude larger than that of∂v/∂x, confirming its dominance in the computation of relative vorticity.
The latitudinal position of zero absolute vorticity isopleth fluctuates within 5 degrees of the equator and is confined more to the winter hemisphere than to the summer hemisphere.
The rotational component of wind is large compared with the divergent wind component. The magnitude of the rotational vector wind is four times that of the divergent vector wind in the equatorial latitudes and an order of magnitude larger in the subtropical latitudes.
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References
Corby, C. A. (1961),Some experiments in objective analysis of contour charts, Quart. J. Roy. Meteorol. Soc.87, 34–42.
Freeman, M. H. (1963),The computation of geostrophic winds by objective analysis, Met. Mag.92, 329–332.
Gilchrist, B., andCressman, G. P. (1954),An experiment in objective analysis, Tellus6, 309–318.
Haltiner, G. H., andMartin, F. L.,Dynamical and Physical Meteorology (McGraw-Hill, New York 1957) pp. 381–382.
Hawkins, H. F., andRosenthal, S. L. (1965),On the computation of stream functions from the wind field, Mon. Wea. Rev.93, 245–252.
Hess, S. L.,Introduction to theoretical meteorology, (Holt, New York 1959), pp. 306–309.
Krishnamurti, T. N., andRodgers, E. G. (1970),200 Millibar Wind Field June, July, August 1967, Report No. 70-2, (Dept. Meteorol. Florida State Univ., U.S.A.).
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 tropospheric motion field during the northern hemisphere summer, J. Appl. Met.10, 1066–1096.
Krishnamurti, T. N., Kanamitsu, M., Koss, W. J., andLee, J. (1973),Tropical east-west circulations during the northern winter, J. Atmos. Sci.30, 780–787.
Newell, R. E., Kidson, J. W., Vincent, D. G., andBoer, J. G.,The General Circulation of the Tropical Atmosphere and Interactions with Extra-Tropical Latitudes (MIT Press, Cambridge, Mass. 1972), Vol. 1, pp. 26–130.
Ramanathan, Y., andBassi, M. R. (1976),Computation of divergence and vorticity from observed winds over the Indian region during monsoon, Indian J. Meteorol. Hydrol. Geophys.27, 409–416.
Rayleigh, L. (1916),On the dynamics of revolving fluids, Proc. Roy. Soc. LondonA93, 148–154.
Riehl, H.,Tropical Meteorology (McGraw-Hill, New York 1954), p. 392.
Sadler, J. C. (1975),The Upper Tropospheric Circulation over the Global Tropics (Dept. Meteorology, Univ. Hawaii).
Sajnani, P. P. (1968),Use of Observed Winds for Computation of Divergence and Vorticity over India, InProc. WMO/IVGG Sym. Numer. Wea. Pred. (Tokyo), pt. VI, pp. 45–52.
Sangster, W. E. (1960),A method of representing the horizontal pressure force without reduction of station pressures to sea-level, J. Meteorol.17, 166–176.
Solberg, H.,Le Mouvement d’Inertie de l’Atmosphère stable et son Rôle dans la Théorie de Cyclones, Memoir presented Meteor. Ass. UGGI, Lisbon, (Dupont Press 1933), pp. 66–82.
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Pyuzza, N.D., Asnani, G.C. & Kiangi, P.M.R. An observational study of 300 mb winds in the tropical belt. Part I: Kinematic parameters. PAGEOPH 121, 655–683 (1983). https://doi.org/10.1007/BF02590160
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DOI: https://doi.org/10.1007/BF02590160