Interannual variability in millennial climate proxy data

Annual records of ice core dD values from the Greenland Ice Sheet Project 2 core define a temporally ordered normal distribution over an interval of 686 yr ( AD 1300-1985) about a mean value of ( standard mean -270.3% +/- 8.41% ocean water) and suggest that a significant component of year-to-year variation may exist as an unrelated series of ice compositions comprising Gaussian white noise. Importantly, while rates of interannual change in composition also define a symmetric modal distribution ( as would be expected from random variation), year-to-year differences display a standard deviation ( 9.47%) that is significantly smaller than that expected for a distribution of temporally independent compositions ( 11.90%). This reduction in variance in year-to-year delta D changes reflects a partial correlation between successive annual compositions. Several numerical aspects of annual isotope values suggest that similar to 33% of compositional variation is controlled by system memory and similar to 67% reflects the imposition of Gaussian noise on the annual isotope composition. Likewise, other proxy millennial records of paleoclimate variation embodied as year-to-year differences in delta O-18 of coral aragonite and widths of annually accreted tree rings are found to exhibit similar degrees of interannual memory. Such dependence on the compositions of the previous year could record multiyear changes in local weather patterns but could also reflect more specific processes such as interlayer transport by vapor diffusion in polar ice or the variable influences of vital inertia in different biologic systems.