Prospects for Resolving Short-term Variations in the Paleomagnetic Dipole Moment

Cathy Constable [cconstable@ucsd.edu], IGPP, Scripps Institution of Oceanography, University of California, San Diego;and Monika Korte, GeoForschungsZentrum, Potsdam, Germany.

    The study of solar climate connections through temporal variations in cosmogenic nuclides is complicated by the fact that in general production rates depend on both solar activity and geomagnetic dipole moment variations. A recent time varying paleo-field model known as CALS7K.2 (Korte and Constable, 2005)extends to 7~ka. The dipole moment from CALS7K.2 changes on a broad range of time scales, and thus dipole moment variations are likely to influence attempts to estimate centennial to millennial scale changes in solar flux. The rates of change in geomagnetic dipole moment inferred from direct observation since 1840, are as high as 10% per century, and for CALS7K.2 the rates have been as high or higher. However, the temporal resolution in current paleofield models can be no better than 100 years, and is likely to be considerably worse in some time intervals. The primary factor limiting resolution in short term fluctuations of the dipole moment is dating paleomagnetic records. We evaluate the temporal resolution for CALS7K.2 and explore the possibility of developing high resolution dipole moment estimates from selected high quality records.

Korte, M., and C.G. Constable (2005), Continuous geomagnetic models for the past 7 millennia II: CALS7K, Geochem. Geophys. Geosyst., 6(2), Q02H16 DOI 10.1029/2004GC000801.