A study of variations of the Earth’s magnetic field over Dar es Salaam

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University of Dar es Salaam
The purpose of this study was to determine the diurnal and seasonal variations of the earth’s magnetic field and occurrence of magnetic storms over Dar es Salaam. The data used in this study were from records of geomagnetic variations measured by a fluxgate-type magnetometer installed at University of Dar es Salaam (395007’12”E and 6024’00”S). The instrument with a noise level of 0.02 nT recorded magnetic field components H, D and Z. It recorded both one – second and one-minute data sets. In this case, one-minute data sets. In this case, one-minute data set averaged hourly was used. The hourly means were plotted against local time of each day and analysed for each month to determine the diurnal variations. The seasonal variations were analysed using daily means, as well as the monthly means. Identification of the magnetic storms was done from the plots of daily variations for each day of the month. The severity of each storm observed was categorized using the K-index. From the analysis done, in most of the days, the H component followed a normal pattern of having a single maximum near midday and almost constant during the night. The D component had a morning minimum and afternoon maximum; Z component varied differently, in some days it showed a maximum at around noon, and in other days it showed a minimum. In the analysis of seasonal variations, components H and Z showed and increase from January to December, while component D increased from January to April, and then decreased constantly to December. During the study period, eight storms were recorded and observed to occur irregularly. Three of them were major, and five were minor ones. It is recommended that, future research that incorporates longer period’s data and from other observatories should be carried out for comparison purposes.
Available in printed form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF QC831.T34D38)
Geomagnetism, Dar es Salaam, Tanzania
Daudi, E. (2013) A study of variations of the Earth’s magnetic field over Dar es Salaam. Master dissertation, University of Dar es Salaam. Dar es Salaam.