HR: 18:05h
AN: GP54A-07    [Abstracts]
TI: Multidecadal Oscillations in Climate and Earth Rotation: Signatures of Internal Core Variability?
AU: * Marcus, S L
EM: steven.marcus@jpl.nasa.gov
AF: Jet Propulsion Laboratory / California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Dickey, J
EM: jean.dickey@jpl.nasa.gov
AF: Jet Propulsion Laboratory / California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AB: Multidecadal oscillations have been well documented in the Earth's climate. We use a simple energy-balance model with greenhouse gas, sulphate aerosol and parameterized solar irradiance forcing to account for external effects in the global mean surface temperature record since 1850. The residual temperature variation shows a pronounced 60-70 year oscillation, which is further clarified through the use of singular spectral analysis (SSA). The record of length-of-day (LOD) variation since 1835 shows oscillations of similar period, with the SSA- reconstructed LOD signal robustly tracking the residual temperature variation over more than two complete cycles. Similar variability is found in a record of geomagnetic (aa) variations since 1870 following removal of the 11-year solar cycle, and in reconstructed series of core angular momentum. This study supports the notion that multidecadal variability in the Earth's core may affect both solid Earth rotation through angular momentum exchange with the mantle, and surface temperature through modulation of terrestrial magnetic shielding of charged particle fluxes into the atmosphere.
DE: 1239 Earth rotation variations
DE: 1507 Core processes (1213, 8115)
DE: 1645 Solid Earth (1225)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly