Fig. 1: Average spectral estimates of local land temperature over the Northern Hemisphere.
From: Millennial-scale climate variability over land overprinted by ocean temperature fluctuations
a, PSD estimates of land air temperature (T land) from pollen-based reconstructions along instrumental data and model simulations, both extracted at the pollen record locations; logarithmically spaced axes were used. Also shown are estimates from timeseries detrended with a 23-kyr sinusoidal or with respect to log(CO2) (dashed). The number of pollen records contributing to each timescale is indicated below (brown axis). b, Average spectral estimates from reconstructed annual SSTs9, and instrumental data at the corresponding locations. Observational spectra from a are reproduced. Linear combinations of power laws with slope β = 1.2 and white-noise series are shown as dashed-dotted lines (land in green, sea in blue and white-noise levels in grey). Shading indicates 90% confidence intervals around the mean.
