Constraints on the Rheology of the Earth's Deep Mantle from Decadal Observations of the Earth's Figure Axis and Rotation Pole

2020 ◽  
Author(s):  
Alexandre Couhert ◽  
Christian Bizouard ◽  
Flavien Mercier ◽  
Kristel Chanard ◽  
Marianne Greff ◽  
...  
Keyword(s):  
Time Scales ◽  
Global Constraints ◽  
Geological Time ◽  
Rotation Pole ◽  
The Earth ◽  
Vlbi Data ◽  
Data Yield ◽  
External Forces ◽  
Short Time

<p>The over four decades long record of Satellite Laser Ranging (SLR) observations to a variety of historical geodetic spherical satellites makes it possible to directly observe the long-term (seasonal to decadal time scales) displacement of the Earth’s mean axis of maximum inertia, namely its principal figure axis, with respect to the crust, through the determination of the degree-2 order-1 geopotential coefficients over the 34-year period 1984—2017.</p><p>On the other hand, the pole coordinate time series (mainly from GPS and VLBI data), yield the motion of the rotation pole with even a greater accuracy.</p><p>The time-dependent nature of the response of the Earth’s mantle to external forces, where it behaves either elastically on short time scales (seconds) or like a viscous fluid over geological time scales (millions of years), is poorly constrained at decadal periods. Here we propose to relate oscillations of the figure axis to those of the Earth’s rotation pole (through the Euler-Liouville equations) to study the mass-related excitation of polar motion and provide global constraints on the rheological properties of the deep Earth.</p>

scholarly journals VLBI studies of the nutations of the earth

1988 ◽  
Vol 129 ◽  
pp. 371-375
Author(s):  
T. A. Herring
Keyword(s):  
Truncation Error ◽  
Very Long Baseline Interferometry ◽  
Long Baseline ◽  
The Earth ◽  
Vlbi Data ◽  
One Year ◽  
Nutation Series ◽  
Theoretical Considerations ◽  
Active Investigation

The application of very–long–baseline interferometry (VLBI) to the study of the nutations of the earth has yielded unprecedented accuracy for the experimental determination of the coefficients of the nutation series. The analysis of six years of VLBI data has yielded corrections to the coefficients of the seven largest terms in the IAU 1980 nutation series with periods of one year or less, with accuracies approaching the truncation error of this nutation series (0.1 mas). The nutation series coefficients computed from the VLBI data, and those obtained from theoretical considerations (the IAU 1980 nutation series), are in excellent agreement. The largest corrections are to the coefficients of the retrograde annual nutation [2.0 ± 0.1 mas], the prograde semiannual nutation [(0.5 - ι 0.4) ±0.1 mas], and the prograde 13.7 day nutation [−0.4 ± 0.1 mas]. (The imaginary term for the semiannual nutation represents a term 90° out–of–phase with the arguments of the nutation series.) The geophysical implications of these results are currently under active investigation. We discuss the methods used to extract the nutation information from the VLBI data, the calculations of the uncertainties of the resultant corrections to the coefficients of the nutation series, and the current research into the nutations of the earth.

scholarly journals Radar determination of the Astronomical Unit

1965 ◽  
Vol 21 ◽  
pp. 177-215
Author(s):  
Irwin Shapiro
Keyword(s):  
Time Delay ◽  
Astronomical Unit ◽  
Speed Of Light ◽  
Comprehensive Review ◽  
A Value ◽  
The Earth ◽  
Lincoln Laboratory ◽  
Data Yield ◽  
Shift Data

A comprehensive review is given of the Earth-Venus measurements made with the Lincoln Laboratory Millstone radar in 1959 and 1961. The time-delay and Doppler shift data yield a value for the Astronomical Unit of 499.0052 ± 0.001 light-sec. Using 299 792.5 km/s for the speed of light leads to an AU of 149 598 000 ± 300 km. With the radius of Earth taken as 6 378.15 km, the solar parallax then becomes 8″.79416 ± 0″.00002. This value is consistent with measurements made at various other laboratories to about one part in 105.

scholarly journals Determination of the Long Period Nutation Terms from Optical Astrometry and VLBI Data

2000 ◽  
Vol 178 ◽  
pp. 607-612
Author(s):  
P. Yaya ◽  
C. Bizouard ◽  
C. Ron
Keyword(s):  
Linear Trend ◽  
Earth Orientation Parameters ◽  
Earth Orientation ◽  
Long Period ◽  
The Earth ◽  
Vlbi Data ◽  
Orientation Parameters

AbstractA 100-year long optical astrometric series of the Earth Orientation Parameters produced by a Czech team (Vondrák et al., 1998) has been analysed in order to determine components of nutation. Our interest is mostly focused on the long periodic terms: 18.6-year term, 9.3-year term and linear trend, still correlated in VLBI series which cover only the last 20 years. A comparison has been made with the corresponding values determined from the VLBI series.

scholarly journals Proposals for an Improved Nutation Formula

1990 ◽  
Vol 141 ◽  
pp. 148-148
Author(s):  
E. Groten ◽  
S. Y. Zhu
Keyword(s):  
Gravity Field ◽  
Ocean Tide ◽  
Combined Model ◽  
Earth Gravity ◽  
The Earth ◽  
Low Degree ◽  
Vlbi Data ◽  
Nutation Series ◽  
New Formula

There are a variety of reasons why in geodesy an improved formula for nutation is needed; related topics of interest are the determination of time-dependences in low degree zonals of the earth gravity field, ocean tide modeling, determination of odd harmonics of gravity field etc. in satellite geodesy. A combined model of deterministic and stochastic components is used in order to evaluate two new nutation series where, in an adjustment, mainly VLBI data (IRIS, GSFC, IERS) have been applied. Contrary to earlier revisions of the present nutation formula, not only the five significantly affected waves (annual, semi-annual, FCN etc.) are corrected but rather all constituents are revised in such a way that white noise residuals result from the adjusted observations, based on the new formula. Still remaining problems (such as the separation of long-period terms from precession etc.) are outlined.

HADIS KURAIB DALAM KONSEP RUKYATUL HILAL

1970 ◽  
Vol 13 (2) ◽  
Author(s):  
Muslih Husein
Keyword(s):  
The West ◽  
The Earth ◽  
New Moon ◽  
The Republic

Hisab dan rukyat, hakikatnya, adalah cara untuk mengetahui pergantian bulan. Kajian ini memperlihatkan beberapa temuan. Pertama, korelasi antara hadis Kuraib dan terjadinya perbedaan penetapan awal Ramadan, Syawal, dan Dzul Hijjah di Indonesia. Kementerian Agama Republik Indonesia telah menetapkan bahwa Indonesia secara keseluruhan menjadi satu wilayah hukum (wilayatul hukmi). Kedua, tentang keberhasilan rukyat al-hilal di satu kawasan yang diberlakukan bagi kawasan lain di muka bumi. Perlu diketahui bersama bahwa visibilitas pertama hilal tidak meliputi seluruh muka bumi pada hari yang sama, melainkan membelahnya menjadi dua bagian: (1) bagian sebelah Barat yang dapat melihat hilal dan (2) bagian sebelah Timur yang tidak dapat melihat hilal.Hisab and rukyat is a way to know the turn of the month. This study shows several findings. First is the correlation between Kuraib traditions and differences in the determination of the beginning of Ramadan, Shawwal, and Dhul-Hijjah in Indonesia. Ministry of Religious Affairs of the Republic of Indonesia has stated that Indonesia as a whole into a single jurisdiction (wilayatul hukmi). Second, on the success rukyat alhilal in one area that applied to other regions of earth. Important to know that the first visibility of the new moon does not cover the entire face of the earth on the same day, but splitting it into two parts: (1) part of the West to see the new moon, and (2) part of the East were not able to see the new moon.

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

Forecasting the fl ood situation using space images in the city of Tavda Sverdlovsk region

2018 ◽  
Vol 934 (4) ◽  
pp. 46-52
Author(s):  
A.S. Bruskova ◽  
T.I. Levitskaya ◽  
D.M. Haydukova
Keyword(s):  
Water Levels ◽  
Economic Damage ◽  
Geoinformation System ◽  
Space Images ◽  
Geoinformation Systems ◽  
Emergency Situations ◽  
The Earth ◽  
Maximum Water ◽  
The City

Flooding is a dangerous phenomenon, causing emergency situations and causing material damage, capable of damaging health, and even death of people. To reduce the risk and economic damage from flooding, it is necessary to forecast flooding areas. An effective method of forecasting emergency situations due to flooding is the method of remote sensing of the Earth with integration into geoinformation systems. With the help of satellite imagery, a model of flooding was determined based on the example of Tavda, the Sverdlovsk Region. Space images are loaded into the geoinformation system and on their basis a series of thematic layers is created, which contains information about the zones of possible flooding at given water level marks. The determination of the area of flooding is based on the calculation of the availability of maximum water levels at hydrological stations. According to the calculated security data, for each hydrological post, flood zones are constructed by interpolation between pre-calculated flood zones of standard security. The results of the work can be used by the Main Directorate of the Ministry for Emergency Situations of Russia for the Sverdlovsk Region.

Carbonation possibilities of Steel slags -- a review

2021 ◽  
Author(s):  
Raghavendra Ragipani ◽  
Sankar Bhattacharya ◽  
Akkihebbal K. Suresh
Keyword(s):  
Carbon Dioxide ◽  
Time Scales ◽  
Carbon Dioxide Sequestration ◽  
Mineral Carbonation ◽  
Geological Time ◽  
The Stability ◽  
Significant Attention

Research pertaining to carbon dioxide sequestration via mineral carbonation has gained significant attention, primarily due to the stability of sequestered \ce{CO2} over geological time scales. Use of industry-derived alkaline wastes...

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