A Conceptual Model of Somali Jet Based on the Biot--Savart Law

We study the relationship between thermal conditions on the earth bottom boundary and the formation of Somali jet based on the Biot--Savart law and the data from National Centres for Environmental Prediction (NCEP). As the radiation from the Sun gradually moves from the southern meridian, the temperature on the surface of Somali Peninsular and Arabic Peninsular gradually increases. During the same period the surface temperature of the Northern Indian Ocean increases much slower. It is shown that this increase of the temperature difference between the land and sea is inductive to the formation and development of Rayleigh--Benard convection and leads to the increasing relative vorticity strength between positive and negative vertical vortices over the land and sea. According to the Biot--Savart law, increase of vorticity strength will correspondingly induce the horizontal velocity. A pair of positive and negative vorticity fields over the two Peninsulars and the sea surface is effective in forming and maintaining this current. This mechanism is referred to as the `Somali suction pump'. It draws air continually from the Southern hemisphere and releases it at the coastal area of Somali.