Definition of the normal gravity field including the constant part of tides

1987 ◽  
Vol 31 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Antonín Zeman ◽  
Z. Šimon
Keyword(s):  
Gravity Field ◽  
Normal Gravity ◽  
Constant Part ◽  
Definition Of

Clarification of the geophysical definition of a gravity field

Geophysics ◽  
2004 ◽  
Vol 69 (5) ◽  
pp. 1252-1254 ◽  
Author(s):  
Hualin Zeng ◽  
Tianfeng Wan
Keyword(s):  
Gravity Field ◽  
Definition Of

Reply to the Comment on ‘Evaluation of the local value of the Earth gravity field in the context of the new definition of the kilogram’

Metrologia ◽  
2010 ◽  
Vol 47 (3) ◽  
pp. 341-342
Author(s):  
H Baumann ◽  
E E Klingelé ◽  
A L Eichenberger ◽  
B Jeckelmann ◽  
P Richard
Keyword(s):  
Gravity Field ◽  
Earth Gravity Field ◽  
Earth Gravity ◽  
The Earth ◽  
Definition Of ◽  
Local Value

scholarly journals Relativistic effects in geodynamics

1986 ◽  
Vol 114 ◽  
pp. 241-253 ◽  
Author(s):  
C. Boucher
Keyword(s):  
Gravity Field ◽  
Reference Frame ◽  
Relativistic Effects ◽  
Terrestrial Reference Frame ◽  
The Earth ◽  
Lunar Laser ◽  
Time Variations ◽  
Satisfactory Answer ◽  
Definition Of ◽  
Theories Of Gravitation

Geodesy has now reached such an accuracy in both measuring and modelling that time variations of the size, shape and gravity field of the Earth must be basically considered under the name of Geodynamics. The objective is therefore the description of point positions and gravity field functions in a terrestrial reference frame, together with their time variations.For this purpose, relativistic effects must be taken into account in models. Currently viable theories of gravitation such as Einstein's General Relativity can be expressed in the solar system into the parametrized post-newtonian (PPN) formalism. Basic problems such as the motion of a test particle give a satisfactory answer to the relativistic modelling in Geodynamics.The relativistic effects occur in the definition of a terrestrial reference frame and gravity field. They also appear widely into terrestrial (gravimetry, inertial techniques) and space (satellite laser, Lunar laser, VLBI, satellite radioelectric tracking …) measurements.

Tensor Invariants for Gravitational Curvatures

2021 ◽  
Author(s):  
Xiao-Le Deng ◽  
Wen-Bin Shen ◽  
Meng Yang ◽  
Jiangjun Ran
Keyword(s):  
Gravity Field ◽  
Gravity Gradient ◽  
Additional Information ◽  
Tensor Invariants ◽  
Global Gravity ◽  
Potential Applications ◽  
Gravitational Curvatures ◽  
Definition Of ◽  
Elemental Mass ◽  
Derivatives Of

<p>The tensor invariants (or invariants of tensors) for gravity gradient tensors (GGT, the second-order derivatives of the gravitational potential (GP)) have the advantage of not changing with the rotation of the corresponding coordinate system, which were widely applied in the study of gravity field (e.g., recovery of global gravity field, geophysical exploration, and gravity matching for navigation and positioning). With the advent of gravitational curvatures (GC, the third-order derivatives of the GP), the new definition of tensor invariants for gravitational curvatures can be proposed. In this contribution, the general expressions for the principal and main invariants of gravitational curvatures (PIGC and MIGC denoted as I and J systems) are presented. Taking the tesseroid, rectangular prism, sphere, and spherical shell as examples, the detailed expressions for the PIGC and MIGC are derived for these elemental mass bodies. Simulated numerical experiments based on these new expressions are performed compared to other gravity field parameters (e.g., GP, gravity vector (GV), GGT, GC, and tensor invariants for the GGT). Numerical results show that the PIGC and MIGC can provide additional information for the GC. Furthermore, the potential applications for the PIGC and MIGC are discussed both in spatial and spectral domains for the gravity field.</p>

The GGOS Bureau of Products and Standards

2020 ◽  
Author(s):  
Detlef Angermann ◽  
Thomas Gruber ◽  
Michael Gerstl ◽  
Urs Hugentobler ◽  
Laura Sanchez ◽  
...  
Keyword(s):  
Organizational Structure ◽  
Gravity Field ◽  
Working Group ◽  
System Modeling ◽  
Earth System ◽  
Earth System Modeling ◽  
The Earth ◽  
External Stakeholders ◽  
Definition Of

<p>The Bureau of Products and Standards (BPS) supports GGOS in its goal to obtain consistent products describing the geometry, rotation and gravity field of the Earth. A key objective of the BPS is to keep track of adopted geodetic standards and conventions across all IAG components as a fundamental basis for the generation of consistent geometric and gravimetric products. This poster gives an overview about the organizational structure, the objectives and activities of the BPS. In its present structure, the two Committees “Earth System Modeling” and “Essential Geodetic Variables” as well as the newly established Working Group “Towards a consistent set of parameters for the definition of a new GRS” are associated to the BPS. Recently the updated 2<sup>nd</sup> version of the BPS inventory on standards and conventions used for the generation of IAG products has been compiled. Other activities of the Bureau include the integration of geometric and gravimetric observations towards the development of integrated products (e.g., GGRF, IHRF, atmosphere products) in cooperation with the IAG Services and the GGOS Focus Areas, the contribution to the re-writing of the IERS Conventions as Chapter Expert for Chapter 1 “General definitions and numerical standards”, the interaction with external stakeholders regarding standards and conventions (e.g., ISO, IAU, BIPM, CODATA) as well as contributions to the Working Group “Data Sharing and Development of Geodetic Standards” within the UN GGIM Subcommittee on Geodesy.</p>

scholarly journals A novel electro-catalytic degradation method of phenol wastewater with Ti/IrO2-Ta2O5 anodes in high-gravity fields

2017 ◽  
Vol 76 (3) ◽  
pp. 662-670 ◽  
Author(s):  
Jing Gao ◽  
Junjuan Yan ◽  
Youzhi Liu ◽  
Jiacheng Zhang ◽  
Zhiyuan Guo
Keyword(s):  
Energy Consumption ◽  
Gravity Field ◽  
Normal Gravity ◽  
Catalytic Degradation ◽  
Degradation Efficiency ◽  
High Gravity ◽  
Electrolysis Time ◽  
Removal Efficiencies ◽  
High Gravity Field ◽  
Phenol Wastewater

In the electro-catalytic degradation process of phenol wastewater, bubbles and mass transfer limitation will result in the decrease in wastewater degradation efficiency, a long electrolysis time and a high energy consumption. Self-made Ti/IrO2-Ta2O5 anodes and a high-gravity electro-catalytic reactor were used to improve them. The Ti/IrO2-Ta2O5 anode was prepared with a thermal decomposition method and characterized by scanning electron microscopy (SEM). Under optimum conditions, the removal efficiencies of phenol, total organic carbon (TOC) and chemical oxygen demand (COD) respectively reached 94.77%, 50.96% and 41.2% after 2 h electrolysis in the high-gravity field, which were respectively 10.93%, 16.72% and 24.84% higher than those in the normal gravity field. For about the same removal efficiencies, the electrolysis time and energy consumed in the high-gravity field were 33.3% and 15.4% lower than those consumed in the normal gravity field, respectively. The degradation pathway of phenol detected by high performance liquid chromatography (HPLC) was unchanged in the high-gravity field, but the degradation rate of phenol increased. The Ti/IrO2-Ta2O5 anode provided good stability because the removal efficiencies of phenol and TOC decreased slightly and the surface morphology of the coating was almost unchanged when it had been used in electrolysis for 11 months, about 1,200 h, in the high-gravity field. Results indicated that the phenol wastewater degradation efficiency was improved, the time was shortened, and the energy consumption was reduced in the high-gravity field.

The normal vertical gradient of gravity

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 1011-1013 ◽  
Author(s):  
John H. Karl
Keyword(s):  
Gravity Field ◽  
Potential Field ◽  
Large Scale ◽  
Normal Gravity ◽  
Vertical Gradient ◽  
Original Model ◽  
Field Methods ◽  
The Earth ◽  
Vertical Gradient Of Gravity

Most gravity surveys are conducted to estimate subsurface density contrasts for one application or another. From large‐scale crustal studies to relatively small exploration surveys, it is necessary to determine in some way what the normal gravity field should be in order to identify anomalous features. The anomalies then represent deviations to be interpreted in light of the original model. It is a central limitation of potential field methods that this model, sometimes representing a so‐called “regional” field, is not unique. In the case of gravity, this model has traditionally involved geometrical approximations. It is generally assumed that variations in station elevations are small compared with the radius of the earth—an obviously excellent approximation, but one needs to be mathematically consistent.

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