The 1500 Year Quasiperiodicity During the Holocene - Abrupt Climate Change: Mechanisms, Patterns, and Impacts - page 162

2. Holocene variations in subtropical Atlantic sea surface
temperature (SST) at the west coast of Africa from the World
Data Center A for Paleoclimatology [deMenocal et al., 2000]
are used. The data were taken at site 658C and were recon-
structed using planktonic foraminiferal assemblage data. Counts
of 29 species were converted to warm and cold season SSTs
using a special transfer function. Average temporal resolution of
the SST data ranges between approximately 50 and 100 years.
Warm and cold season SSTanomalies relative to core top values
and the warm-cold season SST seasonality were also computed.
3. Cariaco Basin SSTs were reconstructed based on fora-
miniferal Mg/Ca measurements in the western tropical At-
lantic from the World Data Center for Paleoclimatology [Lea
et al., 2003]. The data were taken from Cariaco Basin core
PL07-39PC (10.70°N, 64.90°W, 790 m).
4. Greenland Ice Sheet Project 2 (GISP2) ions and tem-
perature data were used. The ion data set was produced by
the Glacier Research Group for the GISP2 core from 2 to
3040 m depth in Greenland [Mayewsky et al., 2004]. The
temperature data are provided by Alley [2004].

c
[Isono et al., 2009]. Analysis of alkenones and calculation
of temperature were conducted at tree cores, labeled MD01-
2421, KR02-06 St.A GC, and KR02-06 St.A MC sampled at
36°N, 141.5°E, at a water depth of 2224 m off the coast of
central Japan in the northwestern Paci

5. Alkenone SSTs were reconstructed from the Paci

c.
6. SSTs were reconstructed for the eastern Mediterranean
from a site located near the Nile River Delta [Castañeda et
al., 2010]. This reconstruction utilized two organic geochem-
ical proxies, the U 3 k .

7. Sunspot numbers were reconstructed for 11,000 years
based on dendrochronologically dated radiocarbon concen-
tration and models relating the radiocarbon to the sunspot
number [Solanki et al., 2004].
The paleodata have different intervals of record and dif-
ferent time cadences. For comparison of the data and data
analysis, we selected equal record intervals covering the
Holocene and interpolated the data to 20 year time steps
using the MatLab

“ ” and “ TEX 86 ”

“ pschip ” interpolation code similar to a

cubic spline.

Figure 3. (top) Temperature and (middle) Na ion data in Greenland [Alley, 2004; Mayewsky et al., 2004] and their wavelet
decompositions. (bottom ) Sunspot number reconstruction [Solanki et al., 2004] and its wavelet decomposition. The solid
line marks 1500 year period. The dashed line shows the cone of in

uence of edges. The major solar variations are seen at

2100 - 2400 year periods.