THE EFFECT OF THE LARGE SCALE MAGNETOSPHERIC DISTURBANCE ON THE EQUATORIAL ELECTROJET——DATA ANALYSIS OF THE LOW-LATITUDINALGEOMAGNETIC STATIONS FROM INDIA AND CHINA

Z-component of geomagnetic measurements of 1983-1984 from several low-latitudinal stations are used for further study of the effect of the large scale magnetospheric disturbance on the equatorial electrojet. Data presented in this paper are from India (TRI, KOD, ANN, ...) and China (Qiong Zhong, ...). The results of event analysis and superposed epoch analysis confirm the conclution deduced by the same authors in a previous paper using the Chinese data only, i.e. corresponding to the development of the ring current in the magnetosphere, there is a negative perturbation AZ (it means an additional eastward electrojet). The contrast between the results from a pair of stations of different longitudes and the local time distribution of AZshows that the effect is strongest at daytime and weakest from midnight to dawn. It is basically in accordance with the model calculation of the authors. The results also prove the idea that in analysing the variation of the equatorial electrojet on disturbed days, one should distinguish the effects occured at different storm phases, and draw a distinction between the effects of dynamic and electrodynamic couplings, In order to ascertain the local time and the longitudinal variations of the effect, analyses for simultaneous measurements of global distributed stations are necessary.