A Conceptual Model of Somali Jet Based on the Biot--Savart Law
FENG Shi-De1, DONG Ping2, ZHONG Lin-Hao1
1LACS and LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, PO Box 9804, Beijing 1000292School of Engineering, Physics and Mathematics, University of Dundee, Dundee, DD1 4HN, United Kingdom
A Conceptual Model of Somali Jet Based on the Biot--Savart Law
FENG Shi-De1, DONG Ping2, ZHONG Lin-Hao1
1LACS and LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, PO Box 9804, Beijing 1000292School of Engineering, Physics and Mathematics, University of Dundee, Dundee, DD1 4HN, United Kingdom
摘要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.
Abstract：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.
FENG Shi-De;DONG Ping;ZHONG Lin-Hao. A Conceptual Model of Somali Jet Based on the Biot--Savart Law[J]. 中国物理快报, 2008, 25(12): 4321-4324.
FENG Shi-De, DONG Ping, ZHONG Lin-Hao. A Conceptual Model of Somali Jet Based on the Biot--Savart Law. Chin. Phys. Lett., 2008, 25(12): 4321-4324.
[2} Findlater J 1966 Met. Mug. 95 353 [3] Findlater J 1969 Q. J. Roy. Meteor. Soc. 9591 [4] Cadet D Reverdin G 1981 Tellus 33 476 [5] Cadet D Reverdin G 1981 Monthly Weather Review 109148 [6] Bannon P R 1979 J. Atmos. Sci. 36 2139 [7] Bannon P R 1982 J. Atmos. Sci. 39 2267 [8] Xu X D Zhao T L He J H and Z Q G 1993 Sci. Atmosph.Sinsca 17 641 [9] Qian Y F Wang Q Q DongY P and Gong Y F 1987 Sci.Atmosph. Sin. 11 176 [10] Zeng Q C Li J P 2002 Sci. Atmosph. Sin. 26433 [11] Holton J R 1979 An Introduction to Dynamic Meteorology(New York: Academic)
2008, Vol. 25 
