scholarly journals Airborne Measurements of Natural Source EM Induction Responses to Study Shallow Sursurface Features – Results From 3-D Numerical Calculations

2007 ◽  
Vol 2007 (1) ◽  
pp. 1-1
Author(s):  
JOHN JOSEPH
Keyword(s):  
Natural Source ◽  
Numerical Calculations ◽  
Airborne Measurements ◽  
Em Induction

Principles of probability tomography for natural‐source electromagnetic induction fields

Geophysics ◽  
1999 ◽  
Vol 64 (5) ◽  
pp. 1403-1417 ◽  
Author(s):  
Paolo Mauriello ◽  
Domenico Patella
Keyword(s):  
Electric Charge ◽  
Probability Function ◽  
Ground Surface ◽  
Magnetic Surface ◽  
Natural Source ◽  
Occurrence Probability ◽  
Suitable Parameter ◽  
Em Induction ◽  
Em Field ◽  
Induced Charge

The 3-D interpretation problem of natural‐source electromagnetic (EM) induction field data collected over a flat air‐earth boundary is dealt with using the concept of probability tomography. This paper presents a method to recognize the most probable localization of the induced electric charge accumulations across resistivity discontinuities and current channeling inside conductive bodies. We begin by writing the solutions for the electric (magnetic) ground surface EM field components in the frequency domain as a sum of elementary contributions, each resulting from a single induced‐charge (dipole) element. Then we express the total electric (magnetic) power associated with each EM field component as a sum of crosscorrelation integrals between the measured component and the homologous synthetic expression resulting from each causative induced‐charge (dipole) element. The synthetic component takes the key role of scanner function in the new imaging procedure. Moreover, using the crosscorrelation bounding inequality we introduce the concept of EM induction occurrence probability as a suitable parameter for the tomographic representation of the induced‐charge and dipole distributions underground. For each electric and magnetic surface component we define the corresponding occurrence probability function as the crosscorrelation product of the observed component and the relative scanning function, divided by the square root of the product of the respective variances. In the space domain, the 3-D tomographic procedure consists of scanning the half‐space below the survey area by the unit strength charge or dipole element, which is given a regular grid of space coordinates within the volume. At each node of the grid, the occurrence probability function is calculated. We use the complete set of calculated grid values to single out the zones of highest occurrence probability of electric charge accumulations and current channeling elements. The physical reliability of the proposed tomography is tested on synthetic and field examples.

COMPARISON BETWEEN EXPERIMENTS AND NUMERICAL CALCULATIONS ON S = 1/2 HEISENBERG-XY FERROMAGNETIC CHAINS

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1451-C8-1452 ◽  
Author(s):  
K. Kopinga ◽  
J. Emmen ◽  
G. C. de Vries ◽  
L. F. Lemmens ◽  
G. Kamieniarz
Keyword(s):  
Numerical Calculations

Airborne measurements of Space Shuttle exhaust constituents

1983 ◽  
Author(s):  
W. COFER, III ◽  
R. BENDURA ◽  
D. SEBACHER ◽  
G. PELLETT ◽  
G. GREGORY ◽  
...  
Keyword(s):  
Space Shuttle ◽  
Airborne Measurements

The Feasibility of Numerical Calculations of Vias Using the Matrix-Penciled Moment Method

PIERS Online ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Hailiang Li ◽  
Yu Tian ◽  
Tong Ling
Keyword(s):  
Moment Method ◽  
Numerical Calculations ◽  
The Matrix

Normal form method in search for periodic solutions of ordinary differential equations. Case of the fourth order

2018 ◽  
pp. 24-34
Author(s):  
V. F. Edneral ◽  
O. D. Timofeevskaya
Keyword(s):  
Normal Form ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Periodic Solutions ◽  
Fourth Order ◽  
Numerical Solutions ◽  
Numerical Calculations ◽  
Computational Time ◽  
Resonant Normal Form ◽  
Normal Form Method

Introduction:The method of resonant normal form is based on reducing a system of nonlinear ordinary differential equations to a simpler form, easier to explore. Moreover, for a number of autonomous nonlinear problems, it is possible to obtain explicit formulas which approximate numerical calculations of families of their periodic solutions. Replacing numerical calculations with their precalculated formulas leads to significant savings in computational time. Similar calculations were made earlier, but their accuracy was insufficient, and their complexity was very high.Purpose:Application of the resonant normal form method and a software package developed for these purposes to fourth-order systems in order to increase the calculation speed.Results:It has been shown that with the help of a single algorithm it is possible to study equations of high orders (4th and higher). Comparing the tabulation of the obtained formulas with the numerical solutions of the corresponding equations shows good quantitative agreement. Moreover, the speed of calculation by prepared approximating formulas is orders of magnitude greater than the numerical calculation speed. The obtained approximations can also be successfully applied to unstable solutions. For example, in the Henon — Heyles system, periodic solutions are surrounded by chaotic solutions and, when numerically integrated, the algorithms are often unstable on them.Practical relevance:The developed approach can be used in the simulation of physical and biological systems.

Vertical profiles of biospheric and fossil fuel-derived CO2and fossil fuel CO2: CO ratios from airborne measurements of Δ14C, CO2and CO above Colorado, USA

Tellus B ◽  
2009 ◽  
Vol 61 (3) ◽  
Author(s):  
Heather D. Graven ◽  
Britton B. Stephens ◽  
Thomas P. Guilderson ◽  
Teresa L. Campos ◽  
David S. Schimel ◽  
...  
Keyword(s):  
Fossil Fuel ◽  
Vertical Profiles ◽  
Airborne Measurements

Airborne measurements of dust layer properties, particle size distribution and mixing state of Saharan dust during SAMUM 2006

Tellus B ◽  
2009 ◽  
Vol 61 (1) ◽  
Author(s):  
Bernadett Weinzierl ◽  
Andreas Petzold ◽  
Michael Esselborn ◽  
Martin Wirth ◽  
Katharina Rasp ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Saharan Dust ◽  
Mixing State ◽  
Dust Layer ◽  
Airborne Measurements

Aeromagnetic survey in central West Greenland: project Aeromag 2001

2002 ◽  
pp. 67-72 ◽  
Author(s):  
Thorkild M. Rasmussen
Keyword(s):  
High Resolution ◽  
Magnetic Measurements ◽  
Geophysical Data ◽  
High Quality ◽  
Aeromagnetic Survey ◽  
Original Series ◽  
West Greenland ◽  
Airborne Measurements ◽  
Geophysical Surveys ◽  
Airborne Geophysical Data

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article. Rasmussen, T. M. (1). Aeromagnetic survey in central West Greenland: project Aeromag 2001. Geology of Greenland Survey Bulletin, 191, 67-72. https://doi.org/10.34194/ggub.v191.5130 The series of government-funded geophysical surveys in Greenland was continued during the spring and summer of 2001 with a regional aeromagnetic survey north of Uummannaq, project Aeromag 2001 (Fig. 1). The survey added about 70 000 line kilometres of high-quality magnetic measurements to the existing database of modern airborne geophysical data from Greenland. This database includes both regional high-resolution aeromagnetic surveys and detailed surveys with combined electromagnetic and magnetic airborne measurements.

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