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    Milankovic Theory and

    Time Series Analysis

    Mudelsee M

    Institute of MeteorologyUniversity of Leipzig

    Germany

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    Climate: Statistical analysis

    Data (sample)

    Climate system (population, truth,theory)

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    Climate: Statistical analysis

    Data (sample)STATISTICS

    Climate system (population, truth,theory)

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), i= 1, ..., n

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), i= 1, ..., nUNI-VARIATE TIME SERIES

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nBI-VARIATE TIME SERIES

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nTIME SERIES: DYNAMICS

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nTIME SERIES: DYNAMICS

    [ t(i),x(i), y(i), z(i),..., i= 1 ]

    TIME SLICE: STATICS

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nCLIMATE TIME SERIES

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nCLIMATE TIME SERIES

    o uneven time spacing

    *

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    Low resolution High resolutionIce coreDirect observations,

    Archive, sampling

    Depth

    Sediment core Sediment core

    l(i+1)L(i)

    Climate

    Age, T

    t

    documents,

    climate model

    Recent Past

    Top Bottom

    Archive, sampling

    Estimated age, t

    d(i+1)D(i)

    Archive, time series, t(i)

    Estimated age, t

    Diffusion

    D'(i)

    Mudelsee M (in prep.) Statistical Analysis of Climate Time Series: A Bootstrap Approach. Kluwer.

    UNEVEN TIME SPACING

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    0 200 400t(i) (ka)

    0

    0.2

    0.4

    d(i)(ka)

    0 5,000 10,000t(i) (a B.P.)

    1

    10

    100

    d(i)(a)

    2,000 6,000 10,000t(i) (a B.P.)

    0

    10

    d(i)(a)

    Mudelsee M (in prep.) Statistical Analysis of Climate Time Series: A Bootstrap Approach. Kluwer.

    ICE CORE

    (Vostok D)

    TREE RINGS

    (atmospheric 14C)

    STALAGMITE

    (Qunf Cave 18O)

    UNEVEN TIME SPACING

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nCLIMATE TIME SERIES

    o uneven time spacing

    o persistence*

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    Mudelsee M (in prep.) Statistical Analysis of Climate Time Series: A Bootstrap Approach. Kluwer.

    PERSISTENCE

    Low resolution High resolutionIce coreDirect observations,

    Archive, sampling

    Depth

    Sediment core Sediment core

    l(i+1)L(i)

    Climate

    Age, T

    t

    documents,

    climate model

    Recent Past

    Top Bottom

    Archive, sampling

    Estimated age, t

    d(i+1)D(i)

    Archive, time series, t(i)

    Estimated age, t

    Diffusion

    D'(i)

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    ICE CORE

    (Vostok D)

    TREE RINGS

    (atmospheric 14C)

    STALAGMITE

    (Qunf cave 18O)

    PERSISTENCE

    Mudelsee M (in prep.) Statistical Analysis of Climate Time Series: A Bootstrap Approach. Kluwer.

    -20 0 20 40

    dD (t(i)) []

    -20

    0

    20

    40dD

    (t(i - 1))[]

    -30 0 30

    D14C (t(i)) []

    -30

    0

    30D14C

    (t(i- 1))[]

    -1 0 1

    d18O (t(i)) []

    -1

    0

    1d18O

    (t(i- 1))[]

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    Climate: Statistical analysis:

    Time series analysis

    Sample: t(i),x(i), y(i), i= 1, ..., nCLIMATE TIME SERIES

    o uneven time spacing

    o persistence

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    Milankovic theory

    Theory: Orbital variations influence

    Earths climate.

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    Milankovic theory

    Data: Climate time series

    Theory: Orbital variations influence

    Earths climate.

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    Milankovic theory

    Data: Climate time seriesTIME SERIES ANALYSIS: TEST

    Theory: Orbital variations influence

    Earths climate.

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    Milankovic theory and

    time series analysis

    Part 1: Spectral analysis

    Part 2: Milankovic & paleoclimate

    back to the Pliocene

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    Acknowledgements

    Berger A, Berger WH, Grootes P, Haug G, Mangini A, Raymo ME,Sarnthein M, Schulz M, Stattegger K, Tetzlaff G, Tong H, Yao Q,

    Wunsch C

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    Alert!

    Mudelsee-bias

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    Part 1: Spectral analysis

    Sample: t(i),x(i), y(i), i= 1, ..., n

    Simplification: uni-variate, onlyx(i),

    equidistance, t(i) = i

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    Part 1: Spectral analysis

    Sample: x(t) Time series

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    Part 1: Spectral analysis

    Sample: x(t) Time series

    Population: X(t)

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    Part 1: Spectral analysis

    Sample: x(t) Time series

    Population: X(t) Process

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    Part 1: Spectral analysis:

    Process level

    X(t)TIME DOMAIN

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    Part 1: Spectral analysis:

    Process level

    X(t)

    TIME DOMAIN

    FOURIER TRANSFORMATION: FREQUENCY DOMAIN

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    Part 1: Spectral analysis:

    Process level

    X(t) +T

    GT(f) = (2)1/2TXT(t) e2iftdt,

    XT= X(t), T t +T,

    0, otherwise.

    TIME DOMAIN

    FOURIER TRANSFORMATION: FREQUENCY DOMAIN

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    Part 1: Spectral analysis:

    Process level

    h(f) = limT[E {|GT(f)|2/(2T)} ]NON-NORMALIZED POWER SPECTRAL DENSITY FUNCTION,

    SPECTRUM

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    Part 1: Spectral analysis:

    Process level

    h(f) = limT[E {|GT(f)|2/(2T)} ]NON-NORMALIZED POWER SPECTRAL DENSITY FUNCTION,

    SPECTRUM

    ENERGY (VARIATION) AT SOME FREQUENCY

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    Part 1: Spectral analysis:

    Process level

    Discrete spectrum

    Harmonic process

    Astronomy

    0Frequency, f

    0

    h(f)

    0Frequency, f

    0

    h(f)

    Continuous spectrum

    Random process

    Climatic noise

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    Part 1: Spectral analysis

    The task of spectral analysis is toestimate the spectrum.

    There exist many estimation

    techniques.

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    Part 1: Spectral analysis:

    Harmonic regression

    X(t) = k[Akcos(2fk t) + Bksin(2fk t)]+ (t)

    HARMONIC PROCESS

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    Part 1: Spectral analysis:

    Harmonic regression

    X(t) = k[Akcos(2fk t) + Bksin(2fk t)]+ (t)

    If frequencies fk

    known a priori:

    Minimize Q =i {x(i) k[Akcos(2fk t) + Bksin(2fk t)]}2

    to obtain Akand Bk.

    HARMONIC PROCESS

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    Part 1: Spectral analysis:

    Harmonic regression

    X(t) = k[Akcos(2fk t) + Bksin(2fk t)]+ (t)

    If frequencies fk

    known a priori:

    Minimize Q =i {x(i) k[Akcos(2fk t) + Bksin(2fk t)]}2

    to obtain Akand Bk.

    HARMONIC PROCESS

    LEAST SQUARES

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    Part 1: Spectral analysis:

    Periodogram

    If frequencies fk not

    known a priori:

    Take least-squares

    solutions Akand Bk, fk = 0, 1/n, 2/n, ..., 1/2,

    to calculate P(fk) ~ (Ak)2+ (Bk)

    2.

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    Part 1: Spectral analysis:

    Periodogram

    If frequencies fk not

    known a priori:

    Take least-squares

    solutions Akand Bk, fk = 0, 1/n, 2/n, ..., 1/2,

    to calculate P(fk) ~ (Ak)2+ (Bk)

    2. PERIODOGRAM

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    Part 1: Spectral analysis:

    Periodogram

    If frequencies fk not

    known a priori:

    Take least-squares

    solutions Akand Bk, fk = 0, 1/n, 2/n, ..., 1/2,

    to calculate P(fk) ~ (Ak)2+ (Bk)

    2.

    Where fk true f P(fk) has a peak.

    PERIODOGRAM

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    Part 1: Spectral analysis:

    Periodogram

    0 fk

    0

    P(fk)

    1

    n

    _2

    n

    _ 1

    2_

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    Part 1: Spectral analysis:

    Periodogram

    Original paper:

    Schuster A (1898) On the investigation of hidden periodicities with

    application to a supposed 26 day period of

    meteorological phenomena.

    Terrestr ial Magnetism 3:1341.

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    Part 1: Spectral analysis:

    Periodogram

    Hypothesis test (significance of periodogram peaks):

    Fisher RA (1929) Tests of significance in harmonic analysis.

    Proceedings of the Royal Society of London,

    Series A, 125:5459.

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    Part 1: Spectral analysis:

    Periodogram

    A wonderful textbook:

    Priestley MB (1981) Spectral An alysis and Time Series.

    Academic Press, London, 890 pp.

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    Part 1: Spectral analysis:

    Periodogram

    Major problem with the periodogram as spectrum estimate:

    Relative error of P(fk) = 200% for fk= 0, 1/2,

    100% otherwise.

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    Part 1: Spectral analysis:

    Periodogram

    0 fk

    0

    P(fk)

    1

    n

    _2

    n

    _ 1

    2_

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    Part 1: Spectral analysis:

    Periodogram

    More l ives have been los t lookin g at the raw per iodog ram

    than by any other action involving time series!

    Tukey JW (1980) Can we predict where time series should go next?In: Direct ion s in t im e ser ies analysis (eds BrillingerDR, Tiao GC). Institute of Mathematical Statistics,

    Hayward, CA, 131.

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    Part 1: Spectral analysis:

    Smoothing

    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

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    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

    x(i)WELCH OVERLAPPED

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    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

    0 fk

    0

    h

    0 t(i)

    ( )

    1st

    Segment

    2nd

    Segment

    3rd

    Segment

    WELCH OVERLAPPED

    SEGMENT AVERAGING

    (WOSA)

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    Part 1: Spectral analysis:

    Smoothing

    Tapering: Weight time series

    Spectral leakage reduced

    (Hanning, Parzen,

    triangular windows, etc.)

    *

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    Part 1: Spectral analysis:

    Smoothing problem

    Several segments averaged

    Spectrum estimate more accurate :-)

    Fewer (n < n) data per segment

    Lower frequency resolution :-(

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    Part 1: Spectral analysis:

    Smoothing problem

    0 fk

    0

    h

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    Part 1: Spectral analysis:

    Smoothing problem

    Subjective judgement is unavoidable.

    Play with parameters and be honest.

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    Part 1: Spectral analysis:

    100-kyr problem

    t= 1 fk = 0, 1/n, 2/n, ...

    t = d fk = 0, 1/(nd), 2/(n d), ...

    f = (nd)1

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    Part 1: Spectral analysis:

    100-kyr problem

    t= 1 fk = 0, 1/n, 2/n, ...

    t = d fk = 0, 1/(nd), 2/(n d), ...

    f = (nd)1

    [ BW >(nd)1

    SMOOTHING]

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    Part 1: Spectral analysis:

    100-kyr problem

    nd 650 kyr f = (650 kyr)1*

    S

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    Part 1: Spectral analysis:

    100-kyr problem

    nd 650 kyr f = (650 kyr)1

    (100 kyr)1

    f = (118 kyr)1

    to(87 kyr)1

    *

    P 1 S l l i

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    Part 1: Spectral analysis:

    100-kyr problem

    nd 650 kyr f = (650 kyr)1

    (100 kyr)1

    f = (118 kyr)1

    to(87 kyr)1

    [ BW wider

    SMOOTHING]

    *

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    100-kyr problem

    The 100-kyr cycle existed not longenough to allow a precise enough

    frequency estimation.

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    ]

    h= Fourier transform of ACV

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    E[ X(t) X(t+ lag) ]

    h= Fourier transform of ACV

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    PROCESS LEVEL E[ X(t) X(t+ lag) ]

    h= Fourier transform of ACV

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    PROCESS LEVEL E[ X(t) X(t+ lag) ]

    h= Fourier transform of ACV

    SAMPLE [ x(t) x(t+ lag) ] / n

    h= Fourier transform of ACV

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    Fast Fourier Transform:

    Cooley JW, Tukey JW (1965) An algorithm for the machine calculation

    of complex Fourier series.

    Mathemat ics of Computation19:297301.

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    Some paleoclimate papers:

    Hays JD, Imbrie J, Shackleton NJ (1976) Variations in the Earth's orbit:

    Pacemaker of the ice ages. Science194:11211132.

    Imbrie J Hays JD, Martinson DG, McIntyre A, Mix AC, Morley JJ, Pisias

    NG, Prell WL, Shackleton NJ (1984) The orbital theory of

    Pleistocene climate: Support from a revised chronology of themarine 18O record. In: Milanko vi tch and Climate(eds Berger A,Imbrie J, Hays J, Kukla G, Saltzman B), Reidel, Dordrecht,

    269305.

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    BlackmanTukey

    Ruddiman WF, Raymo M, McIntyre A (1986) Matuyama 41,000-yearcycles: North Atlantic Ocean and northern hemisphere ice

    sheets. Earth and Planetary Science Letters80:117129.

    Tiedemann R, Sarnthein M, Shackleton NJ (1994) Astronomic timescale

    for the Pliocene Atlantic 18O and dust flux records of OceanDrilling Program Site 659. Paleoceanography9:619638.

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    Multitaper Method (MTM)

    Spectral estimation with optimal tapering

    Thomson DJ (1982) Spectrum estimation and harmonic analysis.Proceedings of the IEEE70:10551096.

    MINIMAL DEPENDENCE AMONG AVERAGED INDIVIDUAL SPECTRA

    MINIMAL ESTIMATION ERROR

    P t 1 S t l l i

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    Part 1: Spectral analysis:

    Multitaper Method (MTM)

    0 500 1000

    Age t (i) [kyr]

    22

    23

    24

    2526Obliquity

    x(i ) []

    -0.08

    -0.04

    0

    0.040.08 Taper value

    0 500 1000

    Age t (i) [kyr]

    -0.08

    00.08Tapered,detrended

    x(i ) []

    0 500 1000

    Age t (i) [kyr]

    0 0.02 0.04

    Frequency fk[kyr-1]

    0

    40

    80120

    160

    Multitaperspectrum

    k= 0

    k= 1

    k= 1

    Average(k= 0, 1)

    a b

    c d (41 kyr)-1

    Part 1 Spectral anal sis

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    Part 1: Spectral analysis:

    Multitaper Method (MTM)

    0 500 1000

    Age t (i) [kyr]

    22

    23

    24

    2526Obliquity

    x(i ) []

    -0.08

    -0.04

    0

    0.040.08 Taper value

    0 500 1000

    Age t (i) [kyr]

    -0.08

    00.08Tapered,detrended

    x(i ) []

    0 500 1000

    Age t (i) [kyr]

    0 0.02 0.04

    Frequency fk[kyr-1]

    0

    40

    80120

    160

    Multitaperspectrum

    k= 0

    k= 1

    k= 1

    Average(k= 0, 1)

    a b

    c d (41 kyr)-1

    [ BETTER: DIRECTLY VIA ASTRONOMY EQS.]

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Multitaper Method (MTM)

    Some paleoclimate papers:

    Park J, Herbert TD (1987) Hunting for paleoclimatic periodicities in ageologic time series with an uncertain time scale. Jou rnal of

    Geophysical Research92:1402714040.

    Thomson DJ (1990) Quadratic-inverse spectrum estimates: Applications

    to palaeoclimatology. Phi losophical Transact ions o f the RoyalSociety of London ,Series A 332:539597.

    Berger A, Melice JL, Hinnov L (1991) A strategy for frequency spectra of

    Quaternary climate records. Climate Dynam ics5:227240.

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Uneven time spacing

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Uneven time spacingUse X(t) = k[Akcos(2fk t) + Bksin(2fk t)]+ (t)

    Lomb NR (1976) Least-squares frequency analysis of unequallyspaced data. As trophys ics and Space Science39:447462.

    Scargle JD (1982) Studies in astronomical time series analysis. II.

    Statistical aspects of spectral analysis of unevenly spaced

    data. The Astrop hys ica l Jou rnal263:835853.

    HARMONIC PROCESS

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Red noise

    0Frequency, f

    0

    h(f) PERSISTENCE

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Red noise

    AR1 process for uneven spacing:

    Robinson PM (1977) Estimation of a time series model from unequally

    spaced data. Stochast ic Processes and th eir Appl icat ions6:924.

    0Frequency, f

    0

    h(f) PERSISTENCE

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Aliasing

    0Frequency, f

    0

    h(f)

    12d_

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Aliasing

    Safeguards: o uneven spacing (Priestley 1981)

    o for marine records: bioturbation

    Pestiaux P, Berger A (1984) In: Milankovi tch

    and Climate, 493510.

    0Frequency, f

    0

    h(f)

    12d_

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Running window Fourier Transform

    0 t(i)

    x(i)

    Priestley MB (1996) Wavelets and time-dependent spectral analysis.

    Journal of Time Series Analysis17:85103.

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Detrending*

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Errors in t(i): tuned dating,absolute dating,

    stratigraphy.

    Errors inx(i): measurement error,proxy error,

    interpolation error

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    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Higher-order spectra (bi-spectra, ...)

    Part 1: Spectral analysis:

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    Part 1: Spectral analysis:

    Further points

    Etc., etc.

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Less ice/warmer

    More ice/colder

    0 1 2 3 4

    Age t (i) [Myr]

    54

    3

    2

    1d18

    O [

    ]benthic

    ODP 659

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Less ice/warmer

    More ice/colder

    0 1 2 3 4

    Age t (i) [Myr]

    54

    3

    2

    1d18

    O [

    ]benthic

    ODP 659Northern Hemisphere Glaciation

    NHG

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Less ice/warmer

    More ice/colder

    0 1 2 3 4

    Age t (i) [Myr]

    5

    4

    3

    2

    1d18

    O [

    ]benthic

    ODP 659Northern Hemisphere Glaciation

    NHG

    Mid-Pleistocene Transition

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Climate transitions, trend

    Age t (i)

    fit(t)x2

    x1

    t1 t2

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Climate transitions, trend

    x1, t< t1,Xfit(t) = x2, t> t2,

    x1+ (tt1)

    (x2x1)/(t2t1), t1 t t2.

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Climate transitions, trend

    x1, t< t1,Xfit(t) = x2, t> t2,

    x1+ (tt1)

    (x2x1)/(t2t1), t1 t t2.

    LEAST SQUARES ESTIMATION

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Mid-Pleistocene TransitionLess ice/warmer

    More ice/colder

    0 0.5 1 1.5

    Age t (i) [Myr]

    5

    4

    3

    2d18

    O [

    ]benthic

    ODP 659

    MIS 23/24

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Mid-Pleistocene TransitionLess ice/warmer

    More ice/colder

    0 0.5 1 1.5

    Age t (i) [Myr]

    5

    4

    3

    2d18

    O [

    ]benthic

    ODP 659

    MIS 23/24100 kyr cycle

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    Mid-Pleistocene Transition

    Mudelsee M, Schulz M (1997) Earth and Planetary Science Letters 151:117123.

    DSDP 552

    DSDP 607ODP 659

    ODP 677

    ODP 806

    ~ size of Barents/

    Kara Sea ice sheets

    Part 2: Milankovic & paleoclimate

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    Part 2: Milankovic & paleoclimate

    NHG

    Database: 24 Myr, 45 marine 18O records, 4 temperature records

    benthic

    planktonic

    Mudelsee M, Raymo ME (submitted)

    NHG:2,000 3,000 4,000

    3 0

    4.0

    2,000 3,000 4,000

    4.0606 b G.s.o 982 b

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    NHG:

    Results

    3.0

    d18O(

    vs.

    PDBstandard)

    3.0

    4.0

    3.0

    4.0

    2.0

    3.0

    4.0

    3.0

    4.0

    3.0

    4.0

    3.0

    4.0

    3.0

    4.0

    3.0

    4.0

    3.0

    2.0

    3.0

    2.0

    3.0

    3.0

    4.0

    3.0

    4.0

    -1.0

    0.0

    0.0

    1.0

    -2.0

    -1.0

    0.0

    -2.0

    -1.0

    606 b P.w.

    607 b

    610 b

    659 b

    662 b

    722 b

    758 b

    806 b

    o

    x

    o

    o

    o

    o

    o

    o

    o

    o

    o o

    o

    o

    o

    o

    o

    o

    o

    999 b

    1085 b

    1143 b

    1148 b

    572 p

    606 p

    625 p

    758 p

    x

    x

    xx

    x

    High-resolution records

    Mudelsee M, Raymo ME (submitted)

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    Part 2: Milankovic & paleoclimate

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    NHG was a slowglobal climatechange (from ~3.6 to 2.4 Myr).

    NHG ice volume signal: ~0.4 .

    Part 2: Milankovic & paleoclimate

    NHG

    Milankovic theory and

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    Milankovic theory and

    time series analysis: Conclusions

    (1) Spectral analysis estimatesthespectrum.

    (2) Trend estimation is alsoimportant (climate transitions).

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    G O O I E S

    Climate transitions: error bars

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    Climate transitions: error bars

    t1, x1, t2, x2

    Time series,

    size n

    {t(i), x*(i)}

    {t(i),x(i); i= 1,, n} {t(i)}

    Ramp estimation

    t1*, x1*, t2*, x2*

    Take standard deviation

    of simulated ramp

    parameters

    Simulated time series,

    x*(i) = ramp + noise

    Simulated

    ramp parameters

    Bootstrap

    errors

    STD, PersistenceNoise estimation

    Repeat 400 times

    NHG amplitudes: temperature

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    G a p tudes te pe atu e

    2,000 3,000 4,000

    20.0

    25.0

    Temperature(C)

    1.03.0

    5.0

    3.0

    5.0

    25.0

    30.0

    2,000 3,000 4,000Age (kyr)

    DSDP 572SST(via ostracoda)

    DSDP 607

    BWT(via Mg/Ca)

    ODP 806BWT(via Mg/Ca)

    ODP 806SST(via forams)

    96100 M2MG2

    cooling (C) in ~3,6062,384 kyr

    0.12 0.47

    0.62 0.29

    1.0 0.5

    0.85 0.17

    Mudelsee M, Raymo ME (submitted)

    NHG amplitudes: ice volume

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    p

    Temperature calibration: 18OT/T= 0.234 0.003 /C (Chen 1994; own errordetermination)

    Salinity calibration: 18OS/T= 0.05 /C (Whitman and Berger1992)

    DSDP 572 p 18OT= 0.03 0.12 18OS= 0.01 18OI= 0.34 0.13

    DSDP 607 b 18OT= 0.15 0.07 18OS= 0.03 18OI= 0.41 0.09

    ODP 806 b 18OT= 0.24 0.12 18OS= 0.05 18OI= 0.25 0.13

    ODP 806 p 18OT= 0.20 0.04 18OS= 0.04 18OI= 0.43 0.06

    (DSDP 1085 b cooling by 1 C18

    OI= 0.35 )

    Average 18OI= 0.39 0.04