Six Temperature Proxies of Scots Pine from the Interior of Northern Fennoscandia Combined in Three Frequency Ranges

Figure 1

The Fourier spectra of the six growth-based chronologies (RCS indexing) of Scots pine. Smooth lines are 0.95 confidence levels, calculated for red noise with AR(1) coefficients 𝛼: (a) SRW (𝛼=0.7), (b) SXD (𝛼=0.20), (c) FRW (𝛼=0.77), (d) FHI (𝛼=0.75), (e) FXD (𝛼=0.43), and (f) RRW (𝛼=0.69). Cpa is cycles per annum.

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