A kinematic estimate of the large-scale motion fields over West Africa during the special observation period of WAMEX

O. O. Jegede; E. E. Balogun

doi:10.3402/tellusa.v43i2.11922

A kinematic estimate of the large-scale motion fields over West Africa during the special observation period of WAMEX

Tellus

Volume 43 (1991): Issue 2

By: O. O. Jegede and E. E. Balogun

Open Access

|Jan 1991

Abstract

The kinematic method has been employed in this study to estimate the large-scale fields for horizontal divergence, relative vorticity and vertical motion over West Africa during the Special Observation Period (14 July to 15 August 1979) of WAMEX. The procedure is simply to generate a multiple stations array (with the horizontal length scale ≤ 1000 km) covering the entire area for a least-squares-plane approximation of the windfield. That this technique is practicable has been demonstrated by its being able to reproduce some of the recognized synoptic scale features over the region for the study period.

References

Adefolalu , D. O . 1972 . On the mean equivalent poten-tial temperature of the tropical atmosphere and the “Little Dry Season” of West Africa. Nigerian Quart. Met. Mag. 2 ( 1 ), Lagos, Nigeria , 15 – 40 .
Search in Google Scholar Back to article
Adefolalu , D. O . 1985 . On transport of zonal momen-tum and energy exchange processes . Arch. Met. Geoph. Bloc!., Ser. A 33 , 277 – 285 .
Search in Google Scholar Back to article
Balogun , E. E . 1981 . Convective activity over Nigeria during the monsoon season. In: Proceedings of the International Conference On Early Results of FGGE and Large-Scale Aspects of Its Monsoon Experiments. Tallahassee, Florida 12-17 January : 8 , 22 – 27 .
Search in Google Scholar Back to article
Balogun , E. E . 1982 . West African monsoon windsets from geostationary satellite. Space Science and Engineering Centre, Univ. of Wisconsin-Madison . ( NSF Grant ATM- 8024910 ). 96pp .
Search in Google Scholar Back to article
Bellamy , J. C . 1949 . Objective calculation of divergence, vertical velocity and vorticity . Bull. Amer. Met. Soc . 30 , 45 – 49 .
Search in Google Scholar Back to article
Burpee , R. W . 1972 . The origin and structure of easterly waves in the lower troposphere of North Africa , J. Atm. Sc . 19 , 17 – 99 .
Search in Google Scholar Back to article
Hamilton , R. A. and Archbold , J. W . 1945 . Meteorol-ogy of Nigeria and adjacent territory . Quart. J. R. Met. Soc . 71 , 231 – 265 .
Search in Google Scholar Back to article
Harwood , R. S . 1981 . Atmospheric vorticity and divergence. In: Dynamical meteorology: an introduc-tory selection (ed. W. B. Atkinson ). Methuen and Co. , London 33 – 54 .
Search in Google Scholar Back to article
Kung , E. C . 1972 . A scheme for kinematic estimate of large-scale vertical motion with an upper-air network . Quart. J. R. Met. Soc . 98 , 402 – 411 .
Search in Google Scholar Back to article
Kung , E. C . 1973 . Note on design of an optimized com-putation scheme for kinematic vertical motion fields . Mon. Wea. Rev . 101 , 685 – 690 .
Search in Google Scholar Back to article
Lateef , M. A . 1967 . Vertical motion, divergence and vorticity in the troposphere over the Caribbean, August 3-5, 1963 . Mon. Wea. Rev . 95 , 778 – 790 .
Search in Google Scholar Back to article
O'Brien , J . J . 1970. Alternative solution to the classical vertical velocity problem , J. Appl. Met . 9 , 197 – 203.
Search in Google Scholar Back to article
Obasi , G. O. P . 1965 . Atmospheric synoptic and climatological features of the West African region. Nigerian Met. Serv. Tech. Note #28. Nigerian Met. Dept., Lagos, Nigeria. 36pp.
Search in Google Scholar Back to article
Omotosho , J. A . 1988 . Spatial variation of rainfall in Nigeria during the “Little Dry Season . ” Atm. Research 22 , 137 – 147 .
Search in Google Scholar Back to article
Pedder , M. A . 1981 . Practical analysis of dynamic and kinematic structure: principles, practice and errors. In: Dynamical Meteorology: An Introductory Selec-tion (ed. W. B. Atkinson ). Methuen and Co. , London . 55 – 68 .
Search in Google Scholar Back to article
Sherman , L . 1952 . On the scalar-vorticity and horizon-tal divergence equations . J. Met . 9 , 359 – 366 .
Search in Google Scholar Back to article
Smith , P. J . 1971 . An analysis of kinematical vertical motions . Mon. Wea. Rev . 99 , 715 – 724 .
Search in Google Scholar Back to article