Statistical Analysis of the Results of 20 Years of Activity of the International VLBI Service for Geodesy and Astrometry

Malkin, Zinovy

doi:10.1134/s1063772920020043

Cited by 7 publications

(5 citation statements)

References 42 publications

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“…The two FCN models, ZM3 and SB, are compared in Figure 3. One can see that two models are very close except for the period before 2002 (start of the R1 and R4 IVS observing programs [10]) and the very end of the series. One of the main reasons between the discrepancies of the SB and ZM3 FCN models are the differences between the IERS C04 and IVS CPO series shown in Figure 4.…”

Section: Fcn Series: Computation and Analysismentioning

confidence: 84%

“…Figure 1 shows the ZM2 CPO model along with the underlying IVS CPO series. Two epochs of abrupt improvement in the accuracy of the VLBI-based EOP series can be noticed in May 1993, when the NEOS-A observing program started, and in the beginning of 2002, when the IVS observing programs R1 and R4 started [10]. The second FCN model used in this study, called "SB", was constructed in a similar way to the ZM3 model with a few exceptions [11,12]: (a) SB FCN series is based on the IERS C04 EOP series (https://datacenter.iers.org/eop.…”

Section: Fcn Series: Computation and Analysismentioning

confidence: 99%

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Detection of a New Large Free Core Nutation Phase Jump

Malkin

Belda

Modiri

2022

Sensors

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We announce the detection of a new large jump in the phase of the free core nutation (FCN). This is only the second such large FCN phase jump in more than thirty years of FCN monitoring by means of a very long baseline interferometry (VLBI) technique. The new event was revealed and confirmed by analyzing two FCN models derived from a long-time series of VLBI observations. The jump started in 2021 and is expected to last until the late fall of 2022. The amplitude of the phase jump is expected to be approximately 3 rad, which is as much as 1.5 times larger than the first phase jump in 1999–2000. A connection of the new FCN phase jump with the recent geomagnetic jerk started in 2020 is suggested.

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Section: Fcn Series: Computation and Analysismentioning

confidence: 84%

Section: Fcn Series: Computation and Analysismentioning

confidence: 99%

Detection of a New Large Free Core Nutation Phase Jump

Malkin

Belda

Modiri

2022

Sensors

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“…These series substantially differ at the beginning of the interval due to the low accuracy and instability of the CPO observations in this period. The most reliable CPO data begins in May 1993 [19] .…”

Section: Free Core Nutationmentioning

confidence: 99%

Revisiting Recent Amplitude and Phase Variations of the Chandler Wobble and Free Core Nutation

Malkin

2023

eps

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The paper is devoted to the analysis of two components of the Earth’s rotation, Chandler wobble (CW) and free core nutation (FCN). They are oscillations with near-constant periods but variable amplitude and phase. The variations of the amplitude and phase of the CW and FCN have already been considered in the literature, and both showed similar behavior such as a recent significant decrease of the amplitude and large phase change. However, the CW and FCN amplitude and phase variations are, to a large extent, predicted for the current epochs, and their today’s variations need regular updates with obtaining new observations. In this work, the CW and FCN parameters have been re-computed using the latest data and compared with the data published earlier. It was found that the currently obtained amplitude and phase variations generally agreed with the data published earlier. The main difference is that the epochs of the current minimum of amplitude and phase jump or both CW and FCN happened somewhat later than was predicted in previous publications. The delay is about two years for the CW relative to the prediction made in 2010 and about one year for the FCN with respect to the prediction made in 2022.

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“…VLBI is the only method that can access the absolute UT1 information. It is classically determined weekly by the International VLBI Service (IVS) R1 and R4 sessions with an error of the order of 2 − 3 s (microsecond), as well as via daily one-hour intensive sessions at the level of ∼ 20 s accuracy (Malkin 2020).…”

Section: Modelling and Observationsmentioning

confidence: 99%

Earth’s Rotation: Observations and Relation to Deep Interior

et al. 2021

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Observation of the variations in the Earth's rotation at time scales ranging from subdiurnal to multidecadal allows us to learn about its deep interior structure. We review all three types of motion of the Earth's rotation axis: polar motion (PM), length of day variations ( ΔLOD ) and nutations, with particular attention to how the combination of geodetic, magnetic and gravity observations provides insight into the dynamics of the liquid core, including its interactions with the mantle. Models of the Earth's PM are able to explain most of the observed signal with the exception of the so-called Markowitz wobble. In addition, whereas the quasi-six year oscillations (SYO) observed in both ΔLOD and PM can be explained as the result of Atmosphere, Oceans and Hydrosphere Forcing (AOH) for PM, this is not true for ΔLOD where the subtraction of the AOH leads to an amplified signal. This points to a missing-possibly common-interpretation related to deep interior dynamics, the latter being also the most likely explanation of other oscillations in ΔLOD on interannual timescales. Deep Earth's structure and dynamics also have an impact on the nutations reflected in the values of the Basic Earth Parameters (BEP). We give a brief review of recent works aiming to independently evaluate the BEP and their implications for the study of deep interior dynamics. Article Highlights• Review of observations of the three components of Earth's rotation using magnetic, gravimetric and geodetic measurements. • Discussion of the implications for the dynamics of the Earth's liquid core.• Perspective on future theoretical and experimental development.

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Statistical Analysis of the Results of 20 Years of Activity of the International VLBI Service for Geodesy and Astrometry

Cited by 7 publications

References 42 publications

Detection of a New Large Free Core Nutation Phase Jump

Detection of a New Large Free Core Nutation Phase Jump

Revisiting Recent Amplitude and Phase Variations of the Chandler Wobble and Free Core Nutation

Earth’s Rotation: Observations and Relation to Deep Interior

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