Yavor Chapanov 1, Jan Vondrák 2, Cyril Ron 21National Institute of Geophysics, Geodesy and Geografy – Bulgarian Academy of Sciences2Astronomical Institute – Academy of Sciences of Czech Republic

OBJECTIVESDetermination of centennial oscillations of Earth rotation, solar indices, climatic parameters and

mean sea level

Investigation of possible connection between these oscillations and centennial cycles of the

solar activity

USED DATAUT1-TT for the period 1623-2005

Smoothed Wolf’s numbers for the period 1700-2010

Total solar Irradiance TSI: (1610-2010); (843-1961); 9Kyr series

Local temperature and precipitation variations: 1-2Kyr series

Mean sea level at Stockholm for the period 1770-2001

METHODSFourier approximation + Method of Least Squares

Averaging and Vondrak’s filtration

Cubic spline interpolation

FFT spectrograms

RESULTSThe best model of centennial cycles of the solar activity and Earth rotation is based on 210a

oscillations

The appropriative model of centennial cycles should combine 180a, 210a and 230a oscillations

and their harmonics

UT1 and LOD variations for 1623 - 2005

1650 1700 1750 1800 1850 1900 1950 2000Epoch-60-40-20

0204060

UT

1-T

T [

s]

-10

-5

0

5

LOD

[m

s]

1650 1700 1750 1800 1850 1900 1950 2000

UT1-TT

Polynomial part

LOD

Linear trend

DATA

Mean Sea Level variations at Stockholm

1770-2001

DATA

1750 1800 1850 1900 1950 2000Epoch-50.0-40.0-30.0-20.0-10.0

0.010.020.030.040.050.060.0

MS

L [c

m]

1750 1800 1850 1900 1950 2000Epoch-10.0

-5.0

0.0

5.0

10.0

MS

L [c

m]

Raw detrended data

Long term variations > 5a

Solar IndicesDATA

1700 1750 1800 1850 1900 1950 2000Epoch0.0

50.0

100.0

150.0

200.0

250.0

Wn

Smoothed Wolf’s numbers

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch1364.01365.01366.01367.01368.01369.0

TS

I [W

/m**

2]

TSI variations

800 1000 1200 1400 1600 1800 2000Epoch-3.0-2.0-1.00.01.02.0

TS

I [W

/m**

2]

(Lean)

(Bard)

Climatic Indices

DATA

-400 -200 0 200 400 600 800 1000 1200 1400 1600 1800 2000Epoch13.0

14.0

15.0

16.0

17.0

18.0

T [d

egre

e]

Local temperature variations – N. Am.

400 600 800 1000 1200 1400 1600 1800 2000Epoch10.0

20.0

30.0

40.0

50.0

60.0

P [c

m]

Local precipitation variations – N. Am.

TIME SERIES SPECTRA

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3

10 100 1000Periods [a]

0.00

0.05

0.10A

m. T

SI [

W/m

**2]

2 3 4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 310 100 1000

4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3 4 5

100 1000Periods [a]

0.0

0.1

0.2

0.3

Am

pl. P

[cm

]

4 5 6 7 8 9 2 3 4 5 6 7 8 9 2 3 4 5100 1000

Harmonics of the

Hallstatt cycle

Signature of 2300a

Hallstatt cycle

TIME SERIES SPECTRA

100 120 140 160 180 200 220 240 260 280 300Periods [a]

0.00

0.05

0.10

Am

. TS

I W/m

**2]

100 120 140 160 180 200 220 240 260 280 300

0.00

0.10

0.20

Am

pl. P

[cm

]

Hallstatt cycle harmonics:No 10 – 230a period (Suess cycle);No 11 – 210a period (de Vries cycle);

Planetary periods:178.8a period (Jose cycle, Jupiter/Saturn syn. p.);171.4a period (Uranus/Neptune synodic period).

170a-180a MODELS

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-20.0

0.0

20.0

UT

1

-0.4

0.0

0.4

TS

I [w

/m**

2]

1600 1650 1700 1750 1800 1850 1900 1950 2000

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-10.0

-5.0

0.0

5.0

10.0

UT

1

-0.4

-0.2

0.0

0.2

0.4

TS

I [w

/m**

2]

1600 1650 1700 1750 1800 1850 1900 1950 2000

PARTIAL NEGATIVE CORRELATON

Partial agreement

Poor agreement

170a

178.8a

210a-230a MODELs

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-10

0

10

20

UT

1-T

T [s

]

-1.0

-0.5

0.0

0.5

1.0

TS

I [w

/m**

2]

1600 1650 1700 1750 1800 1850 1900 1950 2000

210aBest agreement

NEGATIVE CORRELATON

PHASE DISCREPANCY

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-20.0

-10.0

0.0

10.0

20.0

UT

1 [s

]

-1.0

-0.5

0.0

0.5

1.0

TS

I [w

/m**

2]

1600 1650 1700 1750 1800 1850 1900 1950 2000

230a

Similar behavior,

but -20a or +40a lag

UT1, MSL and icethickness variations

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-15.0-10.0-5.00.05.0

10.015.0

UT

1

-3.0

-2.0

-1.0

0.0

1.0

2.0

MS

L [c

m]

1600 1650 1700 1750 1800 1850 1900 1950 2000

-0.2

-0.1

0.0

0.1

0.2

ICE

[m]

Relatively good agreement between thecentennial cycles of UT1, MSL and icethickness

230a

1600 1650 1700 1750 1800 1850 1900 1950 2000Epoch-10.0

-5.00.05.0

10.015.020.0

UT

1

-4.0

-2.0

0.0

2.0

MS

L [c

m]

1600 1650 1700 1750 1800 1850 1900 1950 2000

-0.2

0.0

0.2

ICE

[m]210a

CONCLUSIONSThe best agreement between the centennial cycles of the TSI and UT1 is achieved by 210a model.Partial correlation exists between the 180- and 230- year cycles of the time series of solar and climatic ind ices, UT1 and LOD, so the appropriative model the centenn ial cycles of the Earth rotation should combine 180a, 2 10a, 230a oscillations and their harmonics.The dependence between the TSI and UT1 centennial variations is negative, so the Earth rotation accel eration is connected with the decrease of the MSL, due to cooling effects of solar grand minima and corresponding increasing of the polar ice thickness .