利用重力异常数据构建重力梯度场的方法比较

Comparison of Methods to Model Gravity Gradient Field Using Gravity Anomaly Data

为实现大范围、高精度基准重力梯度数据库的构建,考虑到重力梯度场对地形质量的敏感效应,一般利用恒密度数字高程模型来求取重力梯度值,从而忽略了地形密度变化以及水准面以下密度异常对重力梯度的影响。根据重力位理论中求解边值问题的数值应用方法,直接利用重力异常数据求取重力梯度场,弥补了密度变化和密度异常在重力梯度上的反映。根据模型算例和实测重力异常数据求取了剖面重力梯度值,结果表明,限于重力数据空间分辨率的影响,利用重力异常数据可恢复中长波段重力梯度场。该方法与地形数据求取重力梯度和卫星重力梯度测量等方法技术相结合,对重力梯度数据库的建设具有实际应用价值。

Considering the gravity gradient field is sensitive to the terrain mass,to construct a wide range,high precision gravity gradient database,most of the methods calculate the gravity gradient using digital elevation model with constant density,which ignores the influence of the terrain density variation and density anomalies below geoid to the gravity gradients.Based on the numerical analysis of boundary value problems in gravitational potential theory,this paper presents methods which directly use gravity anomaly data to calculate the gravity gradient field and remedy the density variation and abnormal density reflection on the gravity gradients.According to a synthetic model and the measured gravity anomaly data,we calculate the profile gravity gradients.The results show that based on the limited spatial resolution gravity anomaly data,these methods can recover long and medium waveband gravity gradient field.Combining with gravity gradient derived from terrain data and satellite gravimetry,these methods are beneficial for gravity gradient database construction.