摘要
重力场向上延拓是稳定且收敛的过程,而向下延拓是不稳定且发散的过程。为此,本文提出一种重力场向下延拓新方法。首先,对重力场及其垂向一阶导数向上延拓,得到不同高度的重力场垂向导数;然后,基于求解微分方程的三阶Adams-Bashforth多步法,推导出稳定的向下延拓公式;最后,为验证本文方法,将其分别应用于模型数据和实际数据。理论模型试验及误差曲线表明,相对于经典下延方法——傅里叶变换下延法和积分迭代下延法,新方法三阶Adams-Bashforth公式法下延过程稳定,边界效应不明显,下延深度可达5倍点距,下延结果与真实值的相对误差更小,结果更准确。将本文方法应用于加拿大某区实测航空重力数据,得到有效且准确的下延结果,能够识别和圈定一些细小异常特征。
Upward continuation of gravity field is considered to be a stable and convergence process, but downward continuation is not. This paper presents a new method of downward continuation of gravity field. Firstly, the gravity field and its vertical first-order derivatives are continued upward to different height. Secondly, the authors derive with the stable downward continuation based on multistep method of Adams-Bashforth formula of third-order of the differential equation. Finally, the method is applied to the synthetic model data and the real data. Compared with the classical downward continuation methods which are the Fourier transform method and integral-iteration method, the synthetic results show that the new method, which is Adams-Bashforth formula of third-order, is more stable, less edge effect, the depth of downward continuation is 5 intervals, the relative error of the downward result and the real value is smaller, and the result is more accurate. The method is applied to the measured airborne gravity data in Canada, .and the results obtained are valid and accurate. Small sources are identified and delineated.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2017年第5期1533-1542,共10页
Journal of Jilin University：Earth Science Edition
基金
国家深部探测技术与实验研究专项项目SinoPrbe-09-01(201311192)
国家高技术研究发展计划("863"计划)项目(2014AA06A613)~~
