Core surface flow models from decadal and subdecadal secular variation of the main geomagnetic field [Elektronische Ressource] / Geoforschungszentrum Potsdam. Vorgelegt von Ingo Wardinski

ISSN 1610-0956 Core Surface Flow Models fromDecadal and Subdecadal Secular Variationof the Main Geomagnetic FieldDissertationzur Erlangung des Doktorgradesdes Fachbereiches Geowissenschaftender Freien Universitat Berlin2004vorgelegt vonIngo WardinskiScientific Technical Report STR 05/07 GeoForschungsZentrum PotsdamGutachter21Dr. Richard HolmeProf. Dr. Volker HaakDept of Earth and Ocean SciencesInstitut fur GeophysikUniversity of Liverpool, UKFreie Universit at Berlineingereicht im Winter 2004Disputation am 4. Februar 2005Scientific Technical Report STR 05/07 GeoForschungsZentrum PotsdamSummaryThe main objective of this thesis is an investigation and description of the secular variationof the Earth’s magnetic eld between 1980 and 2000. In particular, in the rst part of thisstudy the phenomenon of geomagnetic jerks are investigated by means of a deterministicmodel, which basically gives a description of the secular variation as a parameterizationof typical periodicities of the external eld. I argue that the conclusion drawn from thisapproach is not valid for explaining jerks as caused by external events and not valid todescribe the global secular variation.In the second part a time{dependent model of the secular variation between 1980 and2000 is developed.