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

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.