H.-J. Lüdecke, A. Hempelmann, and C.O. Weiss: Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records, Clim. Past., 9, 447-452, 2013, doi:10.5194/cp-9-447-2013, www.clim-past.net/9/447/2013/
Abstract:
The longest six instrumental temperature records of monthly means
reach back maximally to 1757 AD and were recorded in Europe. All six
show a V-shape, with temperature drop in the 19th and rise in the
20th century. Proxy temperature time series of Antarctic ice cores
show this same characteristic shape, indicating this pattern as a
global phenomenon. We used the mean of the 6 instrumental records
for analysis by discrete Fourier transformation (DFT), wavelets, and
the detrended fluctuation method (DFA). For comparison, a
stalagmite record was also analyzed by DFT. The harmonic
decomposition of the above mentioned mean shows only 6 significant
frequencies above periods over 30 yr. The Pearson correlation
between the mean, smoothed by a 15 yr running average (boxcar) and
the reconstruction using the 6 significant frequencies yields r =
0.961. This good agreement has a 99.9% confidence level
confirmed by Monte Carlo simulations. It shows that the climate
dynamics is governed at present by periodic oscillations. We find
indications that observed periodicities result from intrinsic
dynamics.
Abstract:
The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores
show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the 6 instrumental records for analysis by discrete Fourier transformation (DFT), wavelets, and the detrended fluctuation method (DFA). For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the above mentioned mean shows only 6 significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15 yr running average (boxcar) and the reconstruction using the 6 significant frequencies yields r = 0.961. This good agreement has a 99.9% confidence level
confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.
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