【作者】 李增兵；

【导师】 张晓帆；

【作者基本信息】 新疆大学 ， 地球探测与信息技术， 2007， 硕士

【摘要】 重磁位场的空间分布特征,具有较强的直观性,是研究场源体的重要依据。目前,位场的向上延拓已有一套较为完整的方法,效果显著。向下延拓由于存在着高频振荡效应,是位场转换处理中最为困难的运算之一。但是,越靠近场源体,场的特征越能细致地反映场源体的特征,所以下延有着其他位场处理方法所不能取代的重要作用。因此,寻找一个比较合理的方法,消除或削弱位场下延过程中的高频振荡效应,实现位场精确、稳定下延是极为必要的。本文研究以频率域下延方法为核心,在前人研究的基础上提出一套稳定下延的方案。该方案以网格化、奇异值分解、数据扩充和匹配滤波为预处理部分;以补偿圆滑滤波下延法为核心部分,充分利用多种方法的优点和互补性实现了重力场下延的稳定计算。论文以优秀数字信号处理软件Matlab 7.0作为主要开发平台,编制程序(函数)20余个,对多种下延方法进行了实现。通过设计和正演模拟实测重力场的理论模型,对各种方法作了定性或定量的比较分析与评价。结果表明,稳定下延方案较单项的其他下延方法具有更高的精度和稳定性。东天山地区是当今矿产勘查的重点区域,仍然具有巨大的找矿潜力。实现东天山重力场的稳定下延对该区的地质研究和矿产勘查工作有着实际意义。将稳定下延方案实施于东天山重力场,实现了不同深度下延、深部重力异常信息的提取和重力场的垂向分离。各种处理结果能够为东天山的地质研究和矿产勘查提供更多的重力场信息,尤其能够得到各种深度的重力异常的细部信息,这充分证明了稳定下延的重要性和必要性。更多还原

【Abstract】 The spatial distribution characteristics of gravity and magnetic field are highly visible, so that they are the important basises of researching the field-source. Currently, Field’s upward continuation has been in a more complete way. On the contrary, downward continuation is one of the most difficult operations in conversion and processing of potential field, because of the high frequency oscillation effect. However, more near the field source, the characteristics of the field can reflect the characteristics of the field-source more particularly. So downward continuation plays an important part in potential field processing, that can not be replaced by other processing methods. Therefore, it is extremely necessary to search for a more reasonable method to eliminate or weaken the high frequency oscillation effect, in order to realize downward continuation accurately and stably.On the basis of the previous studyies, we put forward a stable downward continuation program. The program uses methods in frequency domain as the main methods and makes full use of the advantages and complement of many processing methods to realize the gravity field downward continuation stably. We use the outstanding digital signal processing software Matlab7.0 as the main development platform, and made procedures (functions) more than 20 to realize many downward continuation methods. Through designing and making a model which models the actural gravity field, we made quantitative or comparative analysises and evaluations to the various downward continuation methods. The results show that the stable downward continuation program has higher accuracy and stability than other single method.East Tianshan Mountain is the focus of mineral exploration region currently. It still has the tremendous exploration potential. It has practical significance on the geological studies and mineral prospecting work to realize the downward continuation of East Tianshan gravity field stably. Using the stable downward continuation program, we realized the different depths downward continuation, the acquisition of deep-abnormals’information and the separation of vertical field. Different processing results can provide more gravity information to the geological studies and mineral prospecting in East Tianshan. In particular, we can obtain the detail information of each depth of the gravity field. It’s fully proved that the stable downward continuation is important and necessary.更多还原