Nature 278, 538 - 540 (05 April 1979); doi:10.1038/278538a0

Low-level air flow over the western Indian Ocean as seen from METEOSAT

D. CADET & M. DESBOIS

Laboratoire de Météorologie Dynamique du CNRS Ecole Polytechnique, 91128 Palaiseau Cedex, France

DURING the northern summer, the low-level air circulation over the Indian Ocean is characterised by cross-equatorial flow from the Southern to the Northern Hemisphere. The south-east trade winds of the Southern Hemisphere are sucked in by the zone of continental low pressure located over central India and are mainly deflected by the Coriolis force after crossing the Equator; they give rise to the south-west Indian monsoon and associated precipitation during the summer months¹. The cross-equatorial air flow is not uniform at all longitudes: it is weak over the eastern Indian Ocean and particularly strong along the East African coast, where it is concentrated into a low-level jet (maximum intensity 30 ms^-1 at between 1 and 3 km) flowing to the Somalia coast from the northern tip of Madagascar². We now report the first results from a study of the low-level airflow circulation over the western Indian Ocean and more particularly the Somali low-level jet stream. Successive images taken by the European geostationary satellite METEOSAT were used to determine wind vectors.

References

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