Ellipsoidal Vertical Deflections: Regional, Continental, Global Maps of the Horizontal Derivative of the Incremental Gravity Potential

2004 ◽  
pp. 252-259 ◽  
Author(s):  
G. Finn ◽  
E. W. Grafarend
Keyword(s):  
Gravity Potential ◽  
Horizontal Derivative

scholarly journals The surface layer integral method for the modelling of the radial gravity gradient component over sea surface

2019 ◽  
Vol 9 (1) ◽  
pp. 127-132
Author(s):  
D. Zhao ◽  
Z. Gong ◽  
J. Feng
Keyword(s):  
Surface Layer ◽  
Integral Method ◽  
Integral Formula ◽  
Radial Component ◽  
Second Order ◽  
Sea Surface ◽  
Gravity Potential ◽  
Gravity Gradient ◽  
Disturbing Potential ◽  
Gradient Component

Abstract For the modelling and determination of the Earth’s external gravity potential as well as its second-order radial derivatives in the space near sea surface, the surface layer integral method was discussed in the paper. The reasons for the applicability of the method over sea surface were discussed. From the original integral formula of disturbing potential based on the surface layer method, the expression of the radial component of the gravity gradient tensor was derived. Furthermore, an identity relation was introduced to modify the formula in order to reduce the singularity problem. Numerical experiments carried out over the marine area of China show that, the modi-fied surface layer integral method effectively improves the accuracy and reliability of the calculation of the second-order radial gradient component of the disturbing potential near sea surface.

scholarly journals Review of Environmental and Geological Microgravity Applications and Feasibility of Its Employment at Archaeological Sites in Israel

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Lev V. Eppelbaum
Keyword(s):  
Gravity Anomalies ◽  
Gravity Potential ◽  
Archaeological Sites ◽  
Useful Signal ◽  
Geometric Size ◽  
Archaeological Models ◽  
Vertical Gravity ◽  
Transformation Methods ◽  
Derivatives Of ◽  
Archaeological Objects

Microgravity investigations are widely applied at present for solving various environmental and geological problems. Unfortunately, microgravity survey is comparatively rarely used for searching for hidden ancient targets. It is caused mainly by small geometric size of the desired archaeological objects and various types of noise complicating the observed useful signal. At the same time, development of modern generation of field gravimetric equipment allows to register promptly and digitally microGal (10-8 m/s2) anomalies that offer a new challenge in this direction. An advanced methodology of gravity anomalies analysis and modern 3D modeling, intended for ancient targets delineation, is briefly presented. It is supposed to apply in archaeological microgravity the developed original methods for the surrounding terrain relief computing. Calculating second and third derivatives of gravity potential are useful for revealing some closed peculiarities of the different Physical-Archaeological Models (PAMs). It is underlined that physical measurement of vertical gravity derivatives in archaeological studying has a significant importance and cannot be replaced by any transformation methods. Archaeological targets in Israel have been ranged by their density/geometrical characteristics in several groups. The performed model computations indicate that microgravity investigations might be successfully applied at least in 20–25% of archaeological sites in Israel.

A Calculation Method of Magnetic Anomaly Field Distribution of Ellipsoid with Arbitrary Posture

2021 ◽  
Author(s):  
Song-tong Han ◽  
Bo Zhang ◽  
Xiao-li Rong ◽  
Lei-xiang Bian ◽  
Guo-kai Zhang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Anomaly ◽  
Field Distribution ◽  
Calculation Method ◽  
Gravity Potential ◽  
Anomaly Field ◽  
Finite Element Software ◽  
Wide Range ◽  
Distribution Equation

The ellipsoidal magnetization model has a wide range of application scenarios. For example, in aviation magnetic field prospecting, mineral prospecting, seabed prospecting, and UXO (unexploded ordnance) detection. However, because the existing ellipsoid magnetization formula is relatively complicated, the detection model is usually replaced by a dipole. Such a model increases the error probability and poses a significant challenge for subsequent imaging and pattern recognition. Based on the distribution of ellipsoid gravity potential and magnetic potential, the magnetic anomaly field distribution equation generated by the ellipsoid is deduced by changing the aspect ratio, making the ellipsoid equivalent to a sphere. The result of formula derivation shows that the two magnetic anomaly fields are consistent. This paper uses COMSOL finite element software to model UXO, ellipsoids, and spheres and analyzes magnetic anomalies. The conclusion shows that the ellipsoid model can completely replace the UXO model when the error range of 1nT is satisfied. Finally, we established two sets of ellipsoids and calculated the magnetic anomalous field distributions on different planes using deduction formulas and finite element software. We compared the experimental results and found that the relative error of the two sets of data was within [Formula: see text]‰. Error analysis found that the error distribution is standardized and conforms to the normal distribution. The above mathematical analysis and finite element simulation prove that the calculation method is simple and reliable and provides a magnetic field distribution equation for subsequent UXO inversion.

scholarly journals Pemodelan Inversi 3D Daerah Panas Bumi Berbasis Data Anomali Magnetik di Kota Agung dan Sekitarnya, Provinsi Lampung

PRISMA FISIKA ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 71
Author(s):  
Sepbriyan Rizky Saputra ◽  
Yoga Satria Putra ◽  
Aji Suteja ◽  
Muhardi Muhardi
Keyword(s):  
Horizontal Derivative

Penelitian tentang pemodelan 3 Dimensi berbasis data anomali magnetik untuk mengetahui struktur bawah permukaan telah dilakukan di Kabupaten Tanggamus dan Kabupaten Lampung Barat. Data yang digunakan adalah data sekunder yang diambil dengan cara mendigitasi peta anomali magnet total. Pemisahan anomali regional, analisis turunan mendatar pertama (First Horizontal Derivative), dan pemodelan inversi 3D telah dilakukan untuk mencapai tujuan dari penelitian ini. Hasil penelitian menunjukkan bahwa daerah penelitian memiliki potensi panas bumi yang cukup besar di sekitar Kota Agung dan Gunung Sermaun dengan Sebaran nilai anomali magnetik dari -362,7 nT hingga 602,4 nT. Hasil analisis turunan mendatar pertama menunjukkan adanya beberapa patahan yang diduga sebagai jalur bagi fluida panas untuk mengalir ke permukaan. Hasil pemodelan inversi 3D menunjukkan struktur lapisan bawah permukaan Kota Agung bahwa reservoir panas bumi terdapat pada kedalaman 3000 meter, berupa batu pasir, batu lempung, batu lanau, dan batuan yang mengandung mineral non magnetik dengan rentang nilai -0,005 SI hingga -0,002 SI.

Determining gravity potential difference via VLBI time comparisons

2021 ◽  
Author(s):  
Yifan Wu ◽  
Wen-Bin Shen
Keyword(s):  
High Reliability ◽  
Space Station ◽  
Potential Difference ◽  
Gravity Potential ◽  
Atomic Clocks ◽  
Height System ◽  
Celestial Bodies ◽  
Excellent Work ◽  
Present Simulation ◽  
Comparison Technique

<p>VLBI technique plays important role in both astronomy and geodesy due its fantastic ability to determine the position of celestial bodies and the length of baseline on Earth. Moreover it also presents excellent work on time comparisons between atomic clocks located in remote positions where optical fiber links are not accessible. Due to its high reliability and stability, the information of Earth’s gravity field can be extracted from VLBI time comparisons in the framework of general relativity. In this study, we provide a formulation to determine the gravity potential difference by VLBI time comparisons. In fact the precision of the estimated gravity potential depends on the performance of participated clocks and the accuracy of time comparison technique. Thus we present simulation experiments using clocks with 10<sup>-16</sup>@1d stability and broadband VLBI observation and determine gravity potential difference within a VLBI network around world with 10 m<sup>2</sup>/s<sup>2 </sup>precision which is equivalent to 1 m in height. The results could be greatly improved using optical atomic clocks with much higher stabilities. Furthermore it can be applied to height transfer across oceans and unifying the height system. This study is supported by the National Natural Science Foundations of China (NSFC) under Grants 42030105, 41721003, 41804012, 41631072, 41874023, and Space Station Project (2020)228.</p>

Sign in / Sign up

Export Citation Format

Share Document