A Novel Downward Continuation Method Based on Continued Fraction in Wavenumber Domain and Its Application on Aeromagnetic Data in the Xuanhua-Huailai Area, China

2022 ◽  
Author(s):  
Wenna Zhou ◽  
Chong Zhang ◽  
Dailei Zhang
Keyword(s):  
Continued Fraction ◽  
Continuation Method ◽  
Downward Continuation ◽  
Aeromagnetic Data ◽  
Wavenumber Domain

CONVOLUTION FILTERING OF GRAVITY AND MAGNETIC MAPS

Geophysics ◽  
1965 ◽  
Vol 30 (2) ◽  
pp. 281-283 ◽  
Author(s):  
P. Edward Byerly
Keyword(s):  
Downward Continuation ◽  
Filter Theory ◽  
Wavenumber Domain ◽  
Gravity And Magnetic ◽  
Single Ring ◽  
Low Pass ◽  
Convolution Filter

This note discusses some applications of convolution filter theory to gravity and magnetic maps. Sampling of the field is equivalent to a multiplication, and the corresponding convolution determines the sampling spectrum. If aliasing is acceptably small a specific filtering multiplication in the wavenumber domain corresponds to a convolution of a set of grid coefficients with gridded map values. The application of this theory to single‐ring residuals, certain vertical derivatives, downward continuation, and low‐pass filtering is discussed.

A novel method for computing the vertical gradients of the potential field: Application to downward continuation

2019 ◽  
Author(s):  
Kha Van Tran ◽  
Trung Nhu Nguyen
Keyword(s):  
Series Expansion ◽  
Taylor Series ◽  
Potential Field ◽  
Continuation Method ◽  
Taylor Series Expansion ◽  
Expansion Method ◽  
Downward Continuation ◽  
Source Distribution ◽  
Vertical Derivative ◽  
Series Expansion Method

Summary Downward continuation is a very useful technique in the interpretation of potential field data. It would enhance the short wavelength of the gravity anomalies or accentuate the details of the source distribution. Taylor series expansion method has been proposed to be one of the best downward continued methods. However, the method using high-order vertical derivatives leads to low accuracy and instability results in many cases. In this paper, we propose a new method using a combination of Taylor series expansion and upward continuation for computing vertical derivatives. This method has been tested on the gravitational anomaly of infinite horizontal cylinder in both cases with and without random noise for higher accurate and stable than Hilbert transform method and Laplace equation method, especially in the case of noise input data. This vertical derivative method is applied successfully to calculate the downward continuation according to Taylor series expansion method. The downward continuation is also tested on both complex synthetic models and real data in the East Vietnam Sea (South China Sea). The results reveal that by calculating this new vertical derivative, the downward continuation method gave higher accurate and stable than the previous downward continuation methods.

Analysis on Convergence of Iteration Method for Potential Fields Downward Continuation and Research on Robust Downward Continuation Method

2009 ◽  
Vol 52 (2) ◽  
pp. 511-518 ◽  
Author(s):  
Hui ZHANG ◽  
Long-Wei CHEN ◽  
Zhi-Xin REN ◽  
Mei-Ping WU ◽  
Shi-Tu LUO ◽  
...  
Keyword(s):  
Iteration Method ◽  
Continuation Method ◽  
Downward Continuation ◽  
Potential Fields

Interpretation Method of GATEM Data based on PID Controller Iteration Downward Continuation Method

2021 ◽  
Vol 36 (6) ◽  
pp. 622-631
Author(s):  
Shanshan Guan ◽  
Bingxuan Du ◽  
Dongsheng Li ◽  
Yuan Wang ◽  
Yu Zhu ◽  
...  
Keyword(s):  
Pid Controller ◽  
High Efficiency ◽  
Continuation Method ◽  
Synthetic Data ◽  
Downward Continuation ◽  
Shanxi Province ◽  
Electromagnetic Response ◽  
Ground Source ◽  
The Impact ◽  
Interpretation Method

The Ground-source Airborne Time-domain Electromagnetic (GATEM) system has advantages for high efficiency and complex areas such as mountainous zone. Because of ignoring the impact of flight height, the section interpretation method seriously affects the interpretation and imaging accuracy of shallow anomalies. The PID controller iteration downward continuation method is proposed. Based on the original iteration continuation method, the differential coefficient and integral coefficient are added. The result shows that the new method remarkably decreases the iteration number, and the accuracy are verified by comparison with the numerical integration solution. The PID controller iteration downward continuation method is applied to the interpretation of GATEM data. For synthetic data, the interpretation results of continued electromagnetic response are closer to the true model than the z = 30 m interpretation results. The method is also applied to GATEM field data in Yangquan City, Shanxi Province, China. The interpretation results perform reliability using PID controller iteration downward continuation method in a GATEM field.

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