HR: 12:05h
AN: PP51D-08    [PDF]
TI: Global Multidecadal to Century-Scale Climate Oscillations During the Last 1000 Years
AU: * Hughes, M K
EM: mhughes@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, University of Arizona, 105 W. Stadium, Tucson, AZ 85721 United States
AU: Ni, F
EM: fenbiao@ltrr.arizona.edu
AF: Laboratory of Tree-Ring Research, University of Arizona, 105 W. Stadium, Tucson, AZ 85721 United States
AU: Mann, M E
EM: mann@virginia.edu
AF: Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22903 United States
AU: Park, J
EM: park@geology.yale.edu
AF: Department of Geology and Geophysics, Yale University, P.O.Box 20819, New Haven, CT 06520-8109 United States
AB: The problem we address is the detection, distribution and analysis of quasiperiodic features in the climate system at time scales approaching the length of the instrumental record. There are multiple lines of evidence for the existence of roughly century-scale oscillations in the instrumental temperature record, and in annual-resolution proxy records from many parts of the world. Clearly, the instrumental record of 100-150 years in length is of limited help in identifying and explaining such oscillations. Mann et al. (1995), in a multivariate analysis of a globally distributed set of temperature proxy records of several centuries' duration, produced evidence for persistent natural interdecadal and century-scale climate oscillations. They saw a coherent signal with roughly 50-year period before AD 1650, which got stronger and more significant after that date, drifting into a 60-70 year periodicity in recent centuries. We attempt to place these changing patterns of oscillation in a global perspective for the past 1000 years, using a greatly expanded data set of high quality proxy records. We use approximately 100 existing quality-controlled annual or near-annual resolution proxy records valid for all or most of the last 1000 years. As we are interested specifically in the frequency-domain structure of past climate variability, it is advantageous to use frequency-domain methods applied to the raw proxy data, rather than to climate reconstructions based on time-domain based eigenvector techniques, to elucidate, with greatest fidelity, the frequency-domain structure of any underlying climate. For this reason, we use the Mann et al (1995) MTM-SVD and evolutive MTM-SVD method. Preliminary results confirm and extend the conclusions of Mann et al. (1995). Reference. Mann, Michael E., Jeffrey Park, and Raymond S. Bradley. 1995. Global Interdecadal and Century-Scale Climate Oscillations During the Past Five Centuries. Nature 378: 266-70.
DE: 3309 Climatology (1620)
DE: 3344 Paleoclimatology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting