Seminars

Lecturer: B. Olsthoorn (The Hague)
Date: 2015-06-04 10:00
Place: Aniara

Long-term analysis of geomagnetic disturbances

B. Olsthoorn
The Hague University of Applied Sciences, Delft

Abstract.
In this seminar, I will present the results of my bachelor thesis.
The bachelor thesis features a long-term trend in the geomagnetic activity, using data from individual geomagnetic stations since 1845. The official index is only available since 1932, but this thesis introduces a method to extend the dataset with 88 years. By using hourly data of individual geomagnetic observatories, a Kp-index equivalent data set is systematically calculated.
The thesis also includes an analysis of the correlation of sunspot numbers and geomagnetic activity. The analysis shows that the current solar cycle #24 has the lowest geomagnetic activity recorded since at least 1915. Additionally, during declining phase of the solar cycles, more geomagnetic activity for the same number of sunspots is found compared to the other phases of the cycle. When comparing individual cycles, some cycles also show different geomagnetic activity for the same number of sunspots, suggesting that some cycles are more geo-effective than others. The number of sunspots at the maximum of the solar cycle appears to be an indicator of the strength of the solar cycle.
One of the consequences of geomagnetic activity is aurora, for which all-sky cameras are now commonly used all over the world. Since the relation between the aurora and geomagnetic activity is not clear, auroral activity must also be quantified. Such a quantification requires automatic detection of aurora from all-sky camera images. The thesis introduces an algorithm for detection of auroras using all-sky camera images.


Created 2015-04-24 14:46:36 by Mats Holmström
Last changed 2015-06-03 12:10:58 by Mats Holmström