Multispectral analysis of Northern Hemisphere temperature records over the last five millennia

作者：Taricco C^*; Mancuso S; Ljungqvist F C; Alessio S; Ghil M

来源：Climate Dynamics, 2015, 45(1-2): 83-104.

DOI：10.1007/s00382-014-2331-1

• Space-and-time domain analysis
• Multi-scale analysis of time series
• Climatic oscillations
• Recent paleoclimate
• Temperature proxy records
• Past two millennia
• Solar forcing

Aiming to describe spatio-temporal climate variability on decadal-to-centennial time scales and longer, we analyzed a data set of 26 proxy records extending back 1,000-5,000 years; all records chosen were calibrated to yield temperatures. The seven irregularly sampled series in the data set were interpolated to a regular grid by optimized methods and then two advanced spectral methods-namely singular-spectrum analysis (SSA) and the continuous wavelet transform-were applied to individual series to separate significant oscillations from the high noise background. This univariate analysis identified several common periods across many of the 26 proxy records: a millennial trend, as well as oscillations of about 100 and 200 years, and a broad peak in the 40-70-year band. To study common NH oscillations, we then applied Multichannel SSA. Temperature variations on time scales longer than 600 years appear in our analysis as a dominant trend component, which shows climate features consistent with the Medieval Warm Period and the Little Ice Age. Statistically significant NH-wide peaks appear at 330, 250 and 110 years, as well as in a broad 50-80-year band. Strong variability centers in several bands are located around the North Atlantic basin and are in phase opposition between Greenland and Western Europe.

• 出版日期2015-7