Magnetic disturbance effect on geomagnetic field at low latitudes

Abstract

Relationship between daily means of <i>H </i>and <i>Y </i>fields with D_stindex for stations with in a low latitude belt around the world has been investigated. The <i>H </i>field decreases linearly with decreasing D_st, the slope being less than unity at all stations. But <i>Y </i>field variation with D_st exhibited a longitudinal dependence. The ring current follows the dipole coordinates and not

the dip coordinates and hence changes in <i>Y </i>field are related to both dipole declination (ѱ) and dip declination (<i>D</i>)<i> </i>such that Δ<i>Y</i>/Δ<i>H </i>= sin(ѱ-<i>D</i>), both in sign and magnitude. Good correspondence is seen between Δ<i>Y</i>/Δ<i>H </i>and sin(ѱ-<i>D</i>) for all stations in the equatorial belt.