SECULAR BEHAVIOR IN THE GEOMAGNETIC DATA AT PERMANENT OBSERVATORIES IN ARGENTINA

Abstract

The ionospheric currents that flow in the E layer, the magnetospheric currents and the induced currents in the
lithosphere under the station are the sources of geomagnetic variations in the calm days Sq. There exist several
methods for estimating the values corresponding to magnetospheric currents. The magnitude of the induced
currents contribution is considered about one third of the measured horizontal variation Sq. In this work, one
proceeds to produce the correction for magnetospheric effects by analyzing the ring current index SMR, getting
an efficient correction. Subsequently, the values of the north and east components of the surface current densities
above ROMP stations are estimated for calm days with a Kp index less than or equal to 2 in the 2019-2021
interval. It is found that at 14hs LT, the maximum KN and KE values are recorded at PIL on 12.4.2020, while the
minimum KN and KE values are recorded at ORC on 10.19.19 and 11.16.20, respectively.