Prediction of gravity anomalies over the South China and Philippine Seas from multi-satellite altimeter sea surface heights

Abstract

Gravity anomalies on a 2.5 x 2.5 arc-minute grid in a non-tidal system were derived over the South China and Philippine Seas from multi-satellite altimetry data. North and east components of deflections of the vertical were computed from altimeter-derived sea surface heights at crossover locations, and gridded onto a 2.5 x 2.5 arc-minute resolution grid.EGM96-derived components of deflections of the vertical and gravity anomalies gridded into 2.5 x 2.5 arc-minute resolutions were then used as reference global geopotential model quantities in a remove-restore procedure to implement the Inverse Vening Meinesz formula via the 1D-FFT technique to predict the gravity anomalies over the South China and Philippine Seas from the gridded altimeter-derived components of deflections of the vertical. Statistical comparisons between the altimeter-derived and the shipboard gravity anomalies showed that there is a root-mean-square agreement of 5.7 mgals between them.

Assessment of HY-2A GM data by deriving the gravity field and bathymetry over the Gulf of Guinea

“…Due to the variety of its applications, various countries and economic blocs have launched their respective altimeter satellites, which has since 1991 provided the geoscience community with significant volume of sea surface height (SSH) data. The SSH data are then used to recover marine gravity anomalies (Andersen and Knudsen 1998;Hwang 1998;Soltanpour et al 2007;Dadzie et al 2008;Sandwell et al 2014Sandwell et al , 2019Zhang et al 2016). Comparatively, satellite altimetry is less time-consuming; and has been proven by Sandwell et al (2013) to yield comparable marine gravity models to existing governmental shipborne gravity data.…”

“…For instance: Soltanpour et al (2007) modeled the gravity field of Norway's maritime waters using data from ERS-1, ERS-2 and ENVISAT satellites. Dadzie et al (2008) used combined data to derive a 2.5′ × 2.5′ gravity field of the south China and Philippine seas. Recently, Zhang et al (2016) and Zhu et al (2020) have separately constructed 1′ × 1′ marine gravity models over the south China seas.…”