Magnetic Diurnal Variation Using Satellites and Observatories

Diurnal variation with a fundamental period of 24hours is one of the most spectacular variations exhibited by geomagnetic elements and shows a myriad of irregular changes in the field. These changes or variation are easiest to observe during periods of low solar activity when large irregular disturbances are less frequent. As a result they are referred to as Solar Quiet, Sq. This research is motivated by the fact that a lot still needs to be learnt about Sq and its induced component. This will directly inform our understanding and its application in magnetic method; since it has considerable economic application, as the diurnal (particularly its non-diurnal variation) is the primary source of noise in aeromagnetic surveying. Better understanding of Sq and its induced component may lead to better procedures for correction of survey data. Currently, we are studying and comparing Sq diurnal variation over Africa, Europe and Asia using observatory records from some observatories located in these regions. We present some results from this study showing Sq variation in X, Y and Z components of the geomagnetic elements. The results also show the comparison between the model (CM4) and the observatory record/data showing how well or poorly the model is able to predict the data over these regions.