Geology Reference
In-Depth Information
(a)
500
Summer insolation+uniform noise
480
460
440
420
5 kyr-lagged summer insolation+gaussian noise
500
450
Time
400
36300
36400
36500
36600
Kiloyears bp
36700
36800
36900
37000
(b)
(c)
10
5
1
24
19
22
22
19
24
41
Series 2
10
3
0.8
41
10
1
0.6
400
17
128
95
28
99% sig. level
405
10
-1
54
17
0.4
10
-3
0.2
Series 1
10
-5
0
0.00 0.01
0.00 0.01 0.02
0.03 0.04
Cycles/kyr
0.05 0.06 0.07 0.08
0.02
0.03 0.04
Cycles/kyr
0.05 0.06 0.07 0.08
(d)
(e)
15
17
150
Series 1
leads
Series 2
24
22
19
22
24
19
41
14
100
50
0
5 kyr
41
13
128
405
95
28
17
54
12
-50
-100
-150
11
Series 2
leads
Series 1
10
0.00
0.01
0.02
0.03 0.04
Cycles/kyr
0.05 0.06 0.07
0.08
0.00 0.01
0.02
0.03 0.04
Cycles/kyr
0.05 0.06 0.07 0.08
Figure 4.26
4π multitaper coherency and cross-phase spectral analysis of two insolation models for the interval
36.230-37.0 Ma (Arguis Formation time). (a) Two time series, sampled at Δt = 1 kyr, of 65ºNorth summer
half-year insolation: one with uniform noise and the other with Gaussian white noise, with Series 2 lagging Series
1 by 5 kyr (time proceeds from right to left). (b). Power spectra of the series with strong spectral peaks at the
obliquity and precession index frequencies; Series 1, with its lower noise level, picks up the eccentricity
frequencies, which contributes only 100th of the solar radiation variation in the Milankovitch cycles. (c). Effective
dof for the spectral estimates of the two time series. (d). MSC with Series 1 entered first and Series 2 entered
second into |C(f )|
2
. (e). Cross-phase analysis; Series 1 leads in frequency with positive cross phase, and Series 2
leads in frequency with negative cross phase. The dashed green line indicates cross phase for a 5 kyr lead of Series
1 over Series 2. Calculated using
pmtm,m, mtmdofs.m
, and
mtmcoherency.m
(see Appendix).
