The GGMPlus Global Gravity Data from the Geophysical Exploration Perspective

Abstract The recently available maps and data provided by the global gravity model with its GGMPlus product are highly praised for their apparent high-resolution characteristics (∼200 m). Researchers, mostly from Indonesia consider that the data from GGMPlus are equivalent to the gravity data in terms of geophysical exploration such that they can be directly used to infer the subsurface density distribution. The latter is obtained from semi-qualitative derivative analysis as well as more quantitative 2D or 3D modeling. In fact, the composite GGMPlus model incorporates information from various sources, i.e. from satellite-derived gravity data at very large scales to a very high-resolution topographic gravity effect based on SRTM data. This study aims to provide a new perspective on understanding the GGMPlus data in the context of geophysical exploration. In this paper, we emphasize that the apparent detailed anomalies from GGMPlus are essentially from the calculated or modeled gravity effect of topography that should be corrected to obtain the geological signal describing the subsurface. We compare gravity anomalies from satellite-derived data and observed ground gravity data with those from GGMPlus that have undergone proper adjustments or corrections. The results reveal that GGMPlus have a similar resolution to global gravity data, from which the GGMPlus was derived. Based on the basic principles that (i) models are only approximations of reality and (ii) data can only be measured, they cannot be created, the GGMPlus derived data cannot surpass excessively the resolution of the actually measured satellite gravity data. Therefore, proper processing and use of data from the GGMPlus model should be encouraged.