Participation in the absolute gravity comparison with a compact cold atom gravimeter

2019 ◽  
Vol 17 (1) ◽  
pp. 011204 ◽  
Author(s):  
Zhijie Fu Zhijie Fu ◽  
Qiyu Wang Qiyu Wang ◽  
Zhaoying Wang Zhaoying Wang ◽  
Bin Wu Bin Wu ◽  
Bing Cheng Bing Cheng ◽  
...  
Keyword(s):  
Cold Atom ◽  
Absolute Gravity ◽  
The Absolute

scholarly journals The significance of determination of the absolute value of gravity in geodesy

Tehnika ◽  
2021 ◽  
Vol 76 (1) ◽  
pp. 17-24
Author(s):  
Sofija Naod
Keyword(s):  
Theoretical Basis ◽  
Absolute Gravity ◽  
Reference Systems ◽  
Global Knowledge ◽  
Earth’S Gravity Field ◽  
Absolute Value ◽  
Reference Networks ◽  
The Absolute ◽  
Gravimetric System

The gravity is used to solve geodesy's primary tasks, such as determining geoid and defining the height and gravimetric reference networks of different scales, from national to global. Knowledge of gravity is of great importance for both metrology and geodetic metrology. In addition to the historical overview of absolute gravimeters, this paper presents the theoretical basis of the most commonly used method for determining the absolute value of gravity. The principle of operation of the absolute gravimeter FG5 and the importance of international comparison of absolute gravimeters are briefly presented. An overview of the gravimetric reference systems is given, emphasizing the establishment of the International Reference Gravimetric System. The previous works concerning the absolute determination of acceleration due to Earth's gravity field in Serbia are presented. Finally, the importance of determining the absolute value of gravity from the geodetic and metrological perspective is pointed out. Both national and international significance of determining absolute gravity in defining gravimetric reference systems and the importance of absolute gravity in monitoring global phenomena are emphasized.

scholarly journals Measurement of absolute gravity acceleration in Firenze

2011 ◽  
Vol 3 (1) ◽  
pp. 43-64
Author(s):  
M. de Angelis ◽  
F. Greco ◽  
A. Pistorio ◽  
N. Poli ◽  
M. Prevedelli ◽  
...  
Keyword(s):  
Absolute Gravity ◽  
Noise Condition ◽  
Study Region ◽  
Gravity Measurements ◽  
European Laboratory ◽  
The Absolute ◽  
Gravity Network ◽  
Acceleration Of Gravity ◽  
Newtonian Constant ◽  
Gravity Acceleration

Abstract. This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

AN ABSOLUTE MEASUREMENT OF THE ACCELERATION DUE TO GRAVITY AT OTTAWA

1960 ◽  
Vol 38 (6) ◽  
pp. 824-852 ◽  
Author(s):  
H. Preston-Thomas ◽  
L. G. Turnbull ◽  
E. Green ◽  
T. M. Dauphinee ◽  
S. N. Kalra
Keyword(s):  
Stainless Steel ◽  
Discrete Time ◽  
Absolute Measurement ◽  
Absolute Gravity ◽  
Time Intervals ◽  
Absolute Value ◽  
Gravity Station ◽  
A Value ◽  
The Absolute

An apparatus for determining the absolute value of gravity by measuring the distances through which a rule falls in discrete time intervals is described. From the data associated with 64 drops with two non-magnetic stainless steel rules in vacuum, a value of g at the absolute gravity station at Ottawa of 980.6132 cm sec−2 with a possible error of ± 0.0015 cm sec−2 has been obtained. This value is 13.7 ± 2.0 milligal less than the Potsdam value at that position.

Gravity changes before and after the 2015 Mw7.8 Nepal earthquake

2020 ◽  
Author(s):  
Weimin Xu ◽  
Shi Chen ◽  
Hongyan Lu
Keyword(s):  
Source Region ◽  
Absolute Gravity ◽  
Nepal Earthquake ◽  
Source Regions ◽  
Gravity Changes ◽  
Seismogenic Source ◽  
Before And After ◽  
Gravity Measurements ◽  
The Absolute ◽  
Regional Gravity

<p>Based on the absolute gravity measurements of 4 gravimetric stations (Shigatse, Zhongba, Lhasa and Naqu) in southern Tibet surveyed from 2010 to 2013, we modeled the source region as a disk of 580 km in diameter by Hypocentroid model, shown that the gravity increase at these stations may be related to mass changes in the source region of the 2015 Mw7.8 Nepal earthquake. We analyzed the characteristics of gravity variations from the repeated regional gravity network, which including the 4 absolute gravimetric stations and 13 relative gravimetric stations from 2010 to 2019, to study the characteristics of gravity changes before and after the earthquake.</p><p>We firstly estimated the reliability of the absolute gravity measurements by the errors of each station, and considered the effect of vertical displacement, denudation of surface mass, GIA correction and the secular and background gravity changes. Secondly we employed the Bayesian adjustment method for the relative gravimetric network data analysis, which was more robust and adaptive for solving problems caused by irregular nonlinear drift of different gravimeters, and then carried out error analysis for the repeated relative gravity measurements. Furthermore, we took the Shigatse station as example, which covered absolute and relative measurements and was most close to the Hypocenter of the inversion Hypocentroid model, the hydrologic effects of the Shigatse station was modeled exactly, and the results shown that the secular and background gravity changes were much smaller than the observed gravity changes. Lastly we studied the characteristics of gravity changes before and after the earthquake through the Hypocentroid model, we found the coincident gravity increase both in absolute and repeated regional gravity results before the earthquake, and gravity decreased after the earthquake, which suggested that the pre-earthquake gravity increase may be caused by strain and mass (fluid) transfer in broad seismogenic source regions of the earthquake. Moreover, the study indicated that high-precision ground gravity measurements (absolute and relative) may provide a useful method for monitoring mass changes in the source regions of potential large earthquakes.</p><p> </p><p><strong>Acknowledgment: </strong>This research is supported by National Key R&D Program of China (Grant No.2018YFC1503806 and No.2017YFC1500503) and National Natural Science Foundation of China (Grant No.U1939205 and No.41774090).</p>

scholarly journals Measurement of absolute gravity based on cold atom gravimeter at large tilt angle

2018 ◽  
Vol 67 (19) ◽  
pp. 190302
Author(s):  
Wu Bin ◽  
Cheng Bing ◽  
Fu Zhi-Jie ◽  
Zhu Dong ◽  
Zhou Yin ◽  
...  
Keyword(s):  
Tilt Angle ◽  
Cold Atom ◽  
Absolute Gravity

scholarly journals Experiment on dynamic absolute gravity measurement based on cold atom gravimeter

2022 ◽  
Vol 71 (2) ◽  
pp. 026701-026701
Author(s):  
Cheng Bing ◽  
◽  
Chen Pei-Jun ◽  
Zhou Yin ◽  
Wang Kai-Nan ◽  
...  
Keyword(s):  
Cold Atom ◽  
Gravity Measurement ◽  
Absolute Gravity ◽  
Absolute Gravity Measurement

THE GRAVITY METER AS A GEODETIC INSTRUMENT

Geophysics ◽  
1950 ◽  
Vol 15 (1) ◽  
pp. 1-29 ◽  
Author(s):  
George Prior Woollard
Keyword(s):  
National Physical Laboratory ◽  
Base Stations ◽  
Absolute Gravity ◽  
Naval Research ◽  
Absolute Value ◽  
Office Of Naval Research ◽  
Physical Laboratory ◽  
The World ◽  
Before And After ◽  
The Absolute

A special Worden temperature compensated gravity meter having a range of 5,500 mgals, and a reading sensitivity of 0.1 mgal was used to tie together various primary gravity base stations around the world and to establish new stations. Air transport was used and in a 3 month period over 80,000 miles were flown. Thirty‐three pendulum stations were reoccupied involving a change in gravity of 3,800 mgals, and 125 gravity stations were established. The investigation demonstrated that this instrument could be used satisfactorily for long range geodetic work and the results appear to be the equal of good pendulum observations. Drift was corrected for on the basis of the drift rate established immediately before and after flights. Closures after correcting for drift averaged less than 0.4 mgals, and the closure for the world girdling loop was 0.33 mgals. The probable error based upon the gravity values at the reoccupied pendulum station was ±0.5 mgals. Reoccupation of the absolute gravity stations at the U. S. Bureau of Standards in Washington, D. C. and the National Physical Laboratory in Teddington, England, indicated an approximate 5 mgal error in these pendulum determinations. Indirect ties to the absolute gravity base in Potsdam, Germany, through the primary national gravity bases tied to it, indicated a 15 to 19 mgal error in the Potsdam absolute value. Most of the primary national gravity bases tied directly to Potsdam were found to agree among themselves to within 1 mgal, and the U. S. Bureau of Standards Absolute Base in Washington, D. C. to have a perfect connection within the limits of accuracy of the present measurements. This investigation was made under the auspices of the Office of Naval Research.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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