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J/A+AS/116/473 Nutation modeling and VLBI observations (Souchay+, 1996)
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Precise modeling of nutation and VLBI observations
Souchay J., Feissel M., Ma C.
<Astron. Astrophys. Suppl. Ser. 116, 473 (1996)>
=1996A&AS..116..473S (SIMBAD/NED BibCode)
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ADC_Keywords: VLBI ; Earth
Keywords: Reference systems - Earth
Description:
Using geodetic and astrometric VLBI acquired between 1984-1994, we
have determined coefficients in the nutation series with uncertainties
of 10microarcseconds. This level of accuracy is quite sufficient to
differentiate between alternate theories of nutation. We show that
small terms predicted using the Kinoshita & Souchay (1990) rigid Earth
theory of nutation revised by Souchay & Kinoshita (1996), agree well
with the VLBI results at periods where the non rigid Earth corrections
are reliable. These terms are different or absent from the Kinoshita
(1977) theory that is the basis for the standard IAU 1980 model. We
propose a nutation series based on the Kinoshita & Souchay theory
using the Wahr (1979) transformation for a non rigid Earth that can be
useful where the physical interpretation of the smaller terms is
important. This series, called VKSNRE95.1, includes corrections to the
nine largest terms derived from VLBI observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 106 382 *VKSNRE95.1, a nutation series for a nonrigid
Earth: lunisolar and planetary contributions
(unit: 0.001")
table3 130 42 Correction to 42 nutation terms
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Note on table2: Expression in longitude or in obliquity
Si=1.377[(Ai+Ai'*t)sin(Argument)+(Bi+Bi'*t)cos(Argument)],
where t is in Julian centuries from epoch J2000.0
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See also:
J/A+A/312/1017: Coefficients of rigid Earth nutation. I. (Souchay+, 1996)
Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 3 I3 --- No Sequential number
5- 6 I2 --- l Coefficient of "l"
8- 9 I2 --- l' Coefficient of "l'"
11- 12 I2 --- F Coefficient of "F"
14- 15 I2 --- D Coefficient of "D"
17- 18 I2 --- Omega Coefficient of "Omega"
20- 21 I2 --- Lv Coefficient of "Lv"
23- 25 I3 --- Le Coefficient of "Le"
27- 28 I2 --- Lm Coefficient of "Lm"
30- 31 I2 --- Lj Coefficient of "Lj"
33- 34 I2 --- Ls Coefficient of "Ls"
36- 37 I2 --- pA Coefficient of "pA"
39- 40 I2 --- phi Coefficient of "phi"
42- 49 F8.2 --- Period Period (in years or days, see x_Period)
50 A1 --- x_Period Unit in which the period is expressed
(y for years, d for days)
52- 61 F10.3 --- AiL Amplitude delta(PSI)/sine (Longitude)
63- 69 F7.3 --- Ai'L []? Amplitude delta(PSI)/t*sine (Longitude)
71- 76 F6.3 --- BiL []? Amplitude delta(PSI)/cosine (Longitude)
79- 84 F6.3 --- AiO []? Amplitude delta(EPS)/sine (Obliquity)
86- 93 F8.3 --- BiO Amplitude delta(EPS)/cosine (Obliquity)
95-100 F6.3 --- Bi'O []? Amplitude delta(EPS)/t*cosine (Obliquity)
102-105 A4 --- Type Origin (1)
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Note (1): LS Lunisolar term existing in the 1980 IAU Theory of Nutation
LS+ Lunisolar term not existing in the 1980 IAU Theory of Nutation
P Planetary term not existing in the 1980 IAU Theory of Nutation
VLBI Estimated on the basis of VLBI observations
Geo Based on geophysical considerations
J3 Term due to the J3 coefficient in the Earth's potential
TR Term due to the triaxiality of the Earth
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Byte-by-byte Description of file: table3
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Bytes Format Units Label Explanations
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2- 3 I2 --- l Coefficient of "l"
5- 6 I2 --- l' Coefficient of "l'"
8- 9 I2 --- F Coefficient of "F"
11- 12 I2 --- D Coefficient of "D"
14- 15 I2 --- Omega Coefficient of "Omega"
17- 18 I2 --- Lv Coefficient of "Lv"
20- 21 I2 --- Le Coefficient of "Le"
23- 24 I2 --- Lm Coefficient of "Lm"
26- 27 I2 --- Lj Coefficient of "Lj"
29- 30 I2 --- Ls Coefficient of "Ls"
32- 33 I2 --- pA Coefficient of "pA"
35- 40 F6.2 d Period Period
42- 47 F6.3 --- dPSIs IAU amplitude delta(PSI)/sine (1)
49- 54 F6.3 --- dPSIc []? IAU amplitude delta(PSI)/cosine (1)
56- 61 F6.3 --- dEPSs []? IAU amplitude delta(EPS)/sine (1)
63- 68 F6.3 --- dEPSc IAU amplitude delta(EPS)/cosine (1)
71- 73 A3 --- Type Type of the terms(2)
75- 80 F6.3 --- dPSIs2 VLBI amplitude delta(PSI)/sine (3)
82- 87 F6.3 --- dPSIc2 VLBI amplitude delta(PSI)/cosine (3)
89- 94 F6.3 --- dEPSs2 VLBI amplitude delta(EPS)/sine (3)
96-101 F6.3 --- dEPSc2 VLBI amplitude delta(EPS)/cosine (3)
105-109 F5.3 --- e_dPSIs2 rms uncertainty on dPSIs2 (3)
112-116 F5.3 --- e_dPSIc2 rms uncertainty on dPSIc2 (3)
119-123 F5.3 --- e_dEPSs2 rms uncertainty on dEPSs2 (3)
126-130 F5.3 --- e_dEPSc2 rms uncertainty on dEPSc2 (3)
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Note (1): Values for VKSNRE95.1-IAU 1980
Note (2): The lunisolar terms in the IAU 1980 Theory of Nutation are marked IAU.
The planetary terms are marked Pl.
Note (3): Values for VKSNRE95.1-VLBI (estimation)
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Table1:
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Argument Signification
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l mean anomaly of the Moon
l' mean anomaly of the Sun
Omega longitude of the node of the Moon
F mean longitude of the Moon - Omega
D mean longitude of the Moon - mean longitude of the Sun
LV mean longitude of Venus
LE mean longitude of the Earth
LM mean longitude of Mars
LJ mean longitude of Jupiter
LS mean longitude of Saturne
PA general precession in longitude
phi angle of rotation
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Courtesy: J. Souchay <Jean.Souchay@obspm.fr>
References:
Kinoshita H., 1977, Celest. Mech. 26, 296
Kinoshita H. & Souchay J., 1990, Celest. Mech. 48, 187
Souchay J. & Kinoshita H., 1996, A&A (in press)
Wahr J.M., 1979, Ph.D. Thesis, University of Boulder, Colorado, USA
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(End) Patricia Bauer [CDS] 16-Jan-1996