Holocene Climate Variability on the Centennial and Millennial Time Scale

There have been many suggestions and much debate about climate variability during the Holocene. However, their complex forcing factors and mechanisms have not yet been clearly identified. In this paper, we have examined the Holocene climate cycles and features based on the wavelet analyses of C-14, Be-10, and O-18 records. The wavelet results of the C-14 and Be-10 data show that the cycles of similar to 180-2310, similar to 970, similar to 500-520, similar to 350-360, and similar to 210-220 years are dominant, and the similar to 1720 and similar to 1500 year cycles are relatively weak and subdominant. In particular, the similar to 2180-2310 year periodicity corresponding to the Hallstatt cycle is constantly significant throughout the Holocene, while the similar to 970 year cycle corresponding to the Eddy cycle is mainly prominent in the early half of the Holocene. In addition, distinctive signals of the similar to 210-220 year period corresponding to the de Vries cycle appear recurrently in the wavelet distribution of C-14 and 10Be, which coincide with the grand solar minima periods. These de Vries cycle events occurred every similar to 2270 years on average, implying a connection with the Hallstatt cycle. In contrast, the wavelet results of O-18 data show that the cycles of similar to 1900-2000, similar to 900-1000, and similar to 550-560 years are dominant, while the similar to 2750 and similar to 2500 year cycles are subdominant. The periods of similar to 2750, similar to 2500, and similar to 1900 years being derived from the O-18 records of NGRIP, GRIP and GISP2 ice cores, respectively, are rather longer or shorter than the Hallstatt cycle derived from the C-14 and Be-10 records. The records of these three sites all show the similar to 900-1000 year periodicity corresponding to the Eddy cycle in the early half of the Holocene.