Longitudinal variation of equatorial electrojet and the occurrence of its counter electrojet
Longitudinal variation of equatorial electrojet and the occurrence of its counter electrojet
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DOI：
10.5194/angeo-35-535-2017
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发表时间：
2017-04
影响因子：
1.9
通讯作者：
A. Rabiu;Olanike Olufunmilayo Folarin;T. Uozumi;N. S. A. Hamid;A. Yoshikawa
中科院分区：
文献类型：
--
作者：
A. Rabiu;Olanike Olufunmilayo Folarin;T. Uozumi;N. S. A. Hamid;A. Yoshikawa
抽象的。我们研究了纵向变化的赤道电喷流（EEJ）和它的逆电喷流（CEJ）的发生，同时记录在2009年（平均年太阳黑子数Rz = 3.1）沿着磁赤道在南美，非洲和菲律宾部门的地磁场的水平分量H的可用记录。我们的研究结果表明，EEJ经历的变化，从一个纵向代表站到另一个，最强的EEJ约192.5 nT在南美轴在万卡约和最低峰40.7 nT在伊洛林在非洲西部。在EEJ获得的纵向不平等是可以解释的本地风，迁移潮的动力学，传播的昼夜潮，和季风的影响。非洲的伊洛林和阿迪斯观测站记录的CEJ发生率最高。南美洲的万卡约具有最强的电射流强度，被发现CEJ的发生率最低。这表明，活动，支持强EEJ抑制CEJ的发生。CEJ的发生率随季节而变化。早晨出现的季节变化顺序与任何一个站的晚上出现顺序都不一致。在万卡约和阿迪斯获得了一个半年的春分最大的百分比早晨发生的CEJ。只有阿迪斯记录了同样的春分最大值的百分比晚上发生的CEJ。在不同的时间制度的CEJ发生的季节性分布意味着季节性变化的成因机制负责的CEJ的发生。
Abstract. We examined the longitudinal variability of the equatorial electrojet (EEJ) and the occurrence of its counter electrojet (CEJ) using the available records of the horizontal component H of the geomagnetic field simultaneously recorded in the year 2009 (mean annual sunspot number Rz = 3.1) along the magnetic equator in the South American, African, and Philippine sectors. Our results indicate that the EEJ undergoes variability from one longitudinal representative station to another, with the strongest EEJ of about 192.5 nT at the South American axis at Huancayo and a minimum peak of 40.7 nT at Ilorin in western Africa. Obtained longitudinal inequality in the EEJ was explicable in terms of the effects of local winds, dynamics of migratory tides, propagating diurnal tide, and meridional winds. The African stations of Ilorin and Addis Ababa registered the greatest % of CEJ occurrence. Huancayo in South America, with the strongest electrojet strength, was found to have the least occurrence of the CEJ. It is suggested that activities that support strong EEJ inhibits the occurrence of the CEJ. Percentage of occurrence of the CEJ varied with seasons across the longitudes. The order of seasonal variation of morning occurrence does not tally with the evening occurrence order at any station. A semiannual equinoctial maximum in percentage of morning occurrence of the CEJ was obtained at Huancayo and Addis Ababa. Only Addis Ababa recorded equal equinoctial maxima in percentage of evening occurrence of the CEJ. The seasonal distribution of the occurrences of the CEJ at different time regimes implies a seasonal variability of causative mechanisms responsible for the occurrence of the CEJ.