y2019m01b12 20190122083000 assa sbonga@assaf.org.za assa South African Journal of Science S. Afr. J. Sci 1996-7489 01302019 115 1/2 Emmanuel Nahayo South African National Space Agency (SANSA), Hermanus, South Africa Pieter B. Kotzé South African National Space Agency (SANSA), Hermanus, South Africa Pierre J. Cilliers South African National Space Agency (SANSA), Hermanus, South Africa Stefan Lotz South African National Space Agency (SANSA), Hermanus, South Africa Geomagnetic storms are space weather events that result in a temporary disturbance of the earth’s magnetosphere caused by a solar wind that interacts with the earth’s magnetic field. We examined more closely how some southern African magnetic observatories responded to the Saint Patrick’s Day storm using local K-indices. We show how this network of observatories may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. We show an example of the correlation between a modelled induced electric field and measured geomagnetically induced currents in southern Africa. The data show that there are differences between global and local indices, which vary with the phases of the storm. We show the latitude dependence of geomagnetic activity and demonstrate that the direction of the variation is different for the X and Y components. Significance: • The importance of ground-based data in space weather studies is demonstrated. • We show how SANSA’s geomagnetic network may be utilised to model induced electric field, which is useful for the monitoring of geomagnetically induced anomalous currents capable of damaging power distribution infrastructure. 01302019 1 10.17159/sajs.2016/crossmark sajs.co.za false 2018-06-05 2018-10-19 2019-01-30 https://creativecommons.org/licenses/by/4.0/ https://creativecommons.org/licenses/by/4.0/ 10.17159/sajs.2019/5204 20190122083000 https://www.sajs.co.za/article/view/5204 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422 https://www.sajs.co.za/article/view/5204/7422