HR: 09:30h
AN: GC41B-07    [Abstracts]
TI: Impact of Solar Variability on the Earth's Annular Modes
AU: * Feynman, J
EM: Joan. Feynman@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Ruzmaikin, A
EM: Alexander.Ruzmaikin@jpl.nasa.gov
AF: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AB: We investigate the effect of solar variability on the Annular Modes in the Earth's atmosphere. The Northern Annular Mode (NAM), and Southern Annular Mode (SAM) have two basic states corresponding to higher pressure at high latitudes with a band of lower pressure at lower latitudes and the other way round (Thompson and Wallace, 1998). Two states arise due to the dynamical interaction of planetary waves and zonal mean wind (Limpasuvan and Hartmann, 2001; Ruzmaikin et al., 2006). Solar variability influences the modes via the change of the UV flux in upper atmosphere. The influence depends on the phase of the Quasi Biennial Oscillation and time in the winter season (Ruzmaikin and Feynman, 2002). We investigate the effects on the Annular Modes caused by the Maunder Minimum, the 11-year cycle, and the 27-day solar variabilities using the NCEP Reanalysis, the solar UV flux from SORCE mission and ozone and temperature data from the MLS instrument on Aura spacecraft. We discuss a possible mechanism by which solar variability can affect the Annular Modes and the climate patterns in general involving the Rossby-Palmer conjecture (Palmer, 1999). In contrast to the standard linear evaluation of climate sensitivity to an external forcing we outline a non-linear approach to the forcing problem (Ruzmaikin, 2007). In particular, we evaluate the distributions of residence times spent in each state of the pattern and show how these distributions depend on solar variability. References: Thompson, D. W. J. and J. M. Wallace, Geophys. Res. Lett., 25, 1297, 1998; Limpasuvan, V., and D. Hartmann, J. Climate, 13, 4414, 2001; Ruzmaikin, A., J, Feynman, J. Geophys. Res., 107, D14, 10.1029/2001JD001239, 2002; Ruzmaikin, A., J. K. Lawrence and A. C. Cadavid, J. Atmos. Space Phys., 68, 1311, 2006; Palmer, T. N., Bull. Amer. Meteor. Soc., 79, 1412 1998: Ruzmaikin, A., Advances in Space Res., doi:10.1016/j.asr.2007.01.076 2007.
DE: 0341 Middle atmosphere: constituent transport and chemistry (3334)
DE: 1610 Atmosphere (0315, 0325)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1650 Solar variability (7537)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting