HR: 09:30h
AN: U41B-07 INVITED     [Abstracts]
TI: Solar forced Dansgaard/Oeschger events?
AU: * Muscheler, R
EM: raimund.muscheler@geol.lu.se
AF: Lund University / Quaternary Sciences, Soelvegatan 12, Lund, 22362 Sweden
AU: Beer, J
EM: beer@eawag.ch
AF: EAWAG / ETH, Ueberlandstr. 133, Duebendorf, 8600 Switzerland
AB: Prior to the period of direct satellite-based solar observations (last 25 years) and indirect solar observations based on sunspots (400 years) most evidence for a solar influence on climate is based on the comparison of radionuclide with climate records. For this period radionuclide records represent the most reliable proxies to reconstruct changes in solar activity. Cosmogenic radionuclides are produced in the atmosphere by the interaction of galactic cosmic rays with the atoms of the atmosphere. The solar and geo-magnetic field influence the production rates indirectly by deflecting the galactic cosmic rays. However, radionuclide records are also influenced by climatic changes. Atmospheric radiocarbon concentration, for example, can be influenced by changes in oceanic ventilation. 10Be and 36Cl measured in ice cores can be influenced by changes in atmospheric transport and deposition. It is crucial to identify potential climatic influence on radionuclide records since otherwise the comparison of radionuclide with climate records could feign a solar influence on climate. This is extremely important for the period of the last ice age where the strong climate changes during the Dansgaard/Oeschger events significantly influenced the radionuclide concentration in ice cores. We will discuss if it is possible to assess the solar influence on climate based on radionuclide data sets from the GRIP ice core during the period of the last ice age. Since the radionuclide records from Greenland also reliably record past changes in the Earth magnetic field it is also possible to study the suggested influence of cosmic rays on climate.
DE: 3344 Paleoclimatology
DE: 2162 Solar cycle variations (7536)
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
SC: Union [U]
MN: 2004 AGU Fall Meeting