Advancing marine gravity anomaly modeling from multi-mission altimetry in the Banda Sea: preprocessing strategies, spectral diagnostics, and bathymetric consistency
Abstract
Abstract This study proposes a comprehensive framework for gravity anomaly modeling from multi-mission satellite altimetry, introducing a novel preprocessing strategy based on the Neighbor Gradient Anomaly Detection (NGAD) method. The approach integrates datasets from Jason-1 GM, Jason-2 GM, and Cryosat-2, combining systematic preprocessing, computation of vertical deflections, and gravity anomaly derivation using the inverse Vening Meinesz method through one-dimensional Fast Fourier Transform (1D FFT). Unlike conventional statistical approaches, the NGAD-based method effectively suppresses noise while preserving short-wavelength geophysical signals essential for high-resolution gravity field reconstruction. Validation against independent shipborne gravity data demonstrates strong agreement in spatial patterns, with correlation values comparable to state-of-the-art global models (DTU21, SIO V33). Following track segmentation, NGAD-based outlier removal, Gaussian filtering, and exclusion of low SNR (<10 dB) data, the results show consistent RMSE values across missions, with differences of 1.98–2.36 mGal relative to EGM2008. These differences are linked to enhanced sensitivity to short-wavelength variability rather than reduced model performance. Spectral analysis confirms reliable signal recovery within the 10–20 km wavelength band, while shorter wavelengths remain partially unresolved. The model achieves an average accuracy of 4.77 mGal in deep-water regions (>2,000 m), consistent with previous studies, while accuracy decreases to ∼14 mGal in shallow regions, highlighting bathymetric influence. The proposed framework provides a robust foundation for gravity modeling in the Banda Sea, with significant potential for geophysical exploration in tectonically complex archipelagic regions. No comprehensive gravity anomaly studies have previously been conducted in the Banda Sea, underscoring the novelty and contribution of this work.