航空伽玛能谱数据地形改正方法对比研究及其应用  

The comparative study to terrain correction method of airborne gamma-ray spectrometry and its application

作　　者：万建华[1,2] 熊盛青[2] 范正国[2] 

机构地区：[1]中国地质大学(北京),北京100083 [2]中国国土资源航空物探遥感中心,北京100083

出　　处：《地球物理学进展》2011年第2期641-646,共6页Progress in Geophysics

基　　金：863计划重大项目"航空地球物理勘查技术系统"(2006AA06A200)资助

摘　　要：在地形高度变化较大的复杂地形区由于探测立本角难于近似满足2π条件,造成航空伽玛能谱测量数据高度改正结果失真,在山谷区立体角大于2π条件,改正结果偏高,在山峰区立体角小于2π条件,改正结果偏低,即地形的变化影响了高度改正的效果.本文对现有两类四种航空伽玛能谱测量数据地形改正方法进行理论分析和效果对比研究,优选出适用于航空伽玛能谱数据处理的方法.理论模型数据对比分析结果表明,地形影响系数法能有效地降低地形的影响.在白云鄂博一最大地形高差约100 m地区根据空中测量航迹开展了地面同步测量,以航空测量作用带范围为窗口对地面数据作光滑处理,对比分析表明地面测量结果与地形影响系统法改正结果相吻合.对白云鄂博矿区的航空伽玛能谱数据进行地形影响改正应用结果表明,该区地形通常能在总道引起±5Ur的误差,局部地区高达50Ur,地形改正结果有效地提高了该区天然辐射水平评价的准确性.The airborne gamma-ray survey result is distortional by the height correction in the complex terrain area where the terrain height changes in a large range. The existing results show that the height-corrected outcomes are greater than the real value in the valley conditions while the height-corrected results are less than the real value in the peak conditions due to the aerial survey solid angle was not meet 2π condition. Based on the theoretical analysis and the comparative study of two different types of the four existing terrain correction methods to airborne gamma-ray spectrometry, the suited method is optimized in this paper. The theoretical analysis based on the given terrain models shows that the terrain-influence-coefficient method can effectively reduce the impact of the terrain in the best way. In the area of Bayan Obo with a maximum height difference about 100m, a ground-based survey is carried out following the aerial survey with a space 20 m and measuring time 120 s. Smoothed the ground-based date with a window as large as the aerial survey affected zone （about 500 m）, then the aerial-ground comparison results show that the terrain-corrected results by terrain-influence-coefficient method are the same with the ground-based ones. Applied the optimized terrain-influence-coefficient method to the airborne gamma-ray survey carried out for environmental evaluation in the area of Bayan Obo where the maximum height difference is about 150 m, and the results show that the terrain can cause an error range form - 5Ur to 5Ur for Total window, even up to 50Ur in some areas. The terrain-corrected method effectively improves the accuracy of the evaluation of natural radiation level.

关 键 词：航空伽玛能谱测量 地形改正 地形影响系数 

分 类 号：P631[天文地球—地质矿产勘探]