Two New Methods Based on Implicit Expressions and Corresponding Predictor-Correctors for Gravity Anomaly Downward Continuation and Their Comparison

Downward continuation is a key technique for processing and interpreting gravity anomalies, as it has major role in reducing values to horizontal planes identifying small shallow sources. However, can be unstable inaccurate, particularly when depth increases. While the Milne Adams–Bashforth methods based on numerical solutions of mean-value theorem have partly addressed these problems, more accurate realistic need presented enhance results. To address challenges, we present two new methods, Milne–Simpson Adams–Bashforth–Moulton, implicit expressions their predictor-correctors. We test validity by applying them synthetic models real data, obtain stability, accuracy, large (eight times intervals) downward continuation. facilitate wider applications, use calculated vertical derivatives (of first order) integrated second (ISVD) method replace theoretical ones from forward calculations observations, obtaining reasonable continuations. further understand effect introduced calculation factors, also compare previous under different conditions, such with purely anomalies at heights calculations, non-measurement above observation upward continuation, ISVD measurement height, noise. sometimes outperforms newly predictor-corrector Adams–Bashforth–Moulton generally better results compared methods.