The Earth's Core Nutation from VLBI Data Analysis
Transactions of IAA RAS, issue 20, 142–149 (2009)
Keywords: радиоинтерферометрия со сверхдлинными базами, остаточные колебания небесного полюса CIP (Celestial Intermediate Pole), обратная свободная нутация земного ядра (RFCN Retrograde Free Core Nutation), амплитуда нутации, частота нутации, резонансные эффекты в разложениях лунно-солнечной нутации
Abstract
A new combined series of the Celestial Intermediate Pole (CIP) coordinates is obtained by join their estimates during 1984-2009 at 11 individual VLBI analysis centers of IERS. The new series gvs_comb is received exceed in accuracy and uniformity official series EOP IERS 05 C04 and NEOS. The amplitude-and-phase analysis of gvs_comb series has shown that the amplitude and period of Retrograde Free Core Nutation (RFCN) changes in time. The first change of the period is noted in the beginning of 1992. In 1999 there was an actual damping and shift in phase of the CIP oscillation process. After 2000 the amplitude began to increase, and the period has increased almost for 20 days. As free core nutation creates resonances in the Earth's tides and forced luni-solar nutation the instability of RFCN period should lead to instability of these resonances. The received results say about existence of so significant perturbation of core nutation that hardly it is possible to name it "free".
Citation
V. Gubanov. The Earth's Core Nutation from VLBI Data Analysis // Transactions of IAA RAS. — 2009. — Issue 20. — P. 142–149.
@article{gubanov2009,
abstract = {A new combined series of the Celestial Intermediate Pole (CIP) coordinates is obtained by join their estimates during 1984-2009 at 11 individual VLBI analysis centers of IERS. The new series gvs_comb is received exceed in accuracy and uniformity official series EOP IERS 05 C04 and NEOS.
The amplitude-and-phase analysis of gvs_comb series has shown that the amplitude and period of Retrograde Free Core Nutation (RFCN) changes in time. The first change of the period is noted in the beginning of 1992. In 1999 there was an actual damping and shift in phase of the CIP oscillation process. After 2000 the amplitude began to increase, and the period has increased almost for 20 days. As free core nutation creates resonances in the Earth's tides and forced luni-solar nutation the instability of RFCN period should lead to instability of these resonances.
The received results say about existence of so significant perturbation of core nutation that hardly it is possible to name it "free".},
author = {V. Gubanov},
issue = {20},
journal = {Transactions of IAA RAS},
keyword = {радиоинтерферометрия со сверхдлинными базами, остаточные колебания небесного полюса CIP (Celestial Intermediate Pole), обратная свободная нутация земного ядра (RFCN Retrograde Free Core Nutation), амплитуда нутации, частота нутации, резонансные эффекты в разложениях лунно-солнечной нутации},
pages = {142--149},
title = {The Earth's Core Nutation from VLBI Data Analysis},
url = {http://iaaras.ru/en/library/paper/619/},
year = {2009}
}
TY - JOUR
TI - The Earth's Core Nutation from VLBI Data Analysis
AU - Gubanov, V.
PY - 2009
T2 - Transactions of IAA RAS
IS - 20
SP - 142
AB - A new combined series of the Celestial Intermediate Pole (CIP)
coordinates is obtained by join their estimates during 1984-2009 at
11 individual VLBI analysis centers of IERS. The new series gvs_comb
is received exceed in accuracy and uniformity official series EOP
IERS 05 C04 and NEOS. The amplitude-and-phase analysis of gvs_comb
series has shown that the amplitude and period of Retrograde Free
Core Nutation (RFCN) changes in time. The first change of the period
is noted in the beginning of 1992. In 1999 there was an actual
damping and shift in phase of the CIP oscillation process. After 2000
the amplitude began to increase, and the period has increased almost
for 20 days. As free core nutation creates resonances in the Earth's
tides and forced luni-solar nutation the instability of RFCN period
should lead to instability of these resonances. The received
results say about existence of so significant perturbation of core
nutation that hardly it is possible to name it "free".
UR - http://iaaras.ru/en/library/paper/619/
ER -