The GRACE and GO missions have revolutionised our understanding of mass movement at and below the surface of the Earth but the spatial and temporal resolution and instrument sensitivity limits our ability to resolve fundamental processes. In this presentation we focus on the advances and capabilities that the proposed Mass change And Geosciences International Constellation (MAGIC) mission will deliver for cryosphere and solid Earth applications and will also consider the potential it will have for studying the neutral atmosphere.
The time-varying gravity solutions from the current GRACE and GRACE-FO missions have an effective spatial resolution of ~300-400 km applying regularization or post-processing filters, which is larger than the scale of any glacier or ice cap and larger than most catchments on the Greenland Ice Sheet. Even over Antarctica, the limited spatial resolution is a major limitation for regions such as the Antarctic Peninsula. Tectonic processes, such as earthquakes, volcanic activity and even viscous mantle flow can take place on scales smaller than can be resolved currently. The target resolution and accuracy for MAGIC over ice is 170 km at 2.6 mm/yr EWH over the long term and 250 km at 5.5 mm EWH at monthly resolution plus lower accuracy daily to weekly capabilities. We consider here what this means for understanding and observing ice mass exchange with the oceans and improving our ability to measure the manometric contribution to sea level rise. Based on similar targets, we also explore the improvements this offers for monitoring different types of solid Earth processes such as the transient signals of tsunamis in the open ocean as well as other geohazard processes such as volcanic eruptions to slower steady motions. This includes the monitoring of the whole seismic cycle, from inter-seismic to post-seismic phases and the slow reshaping of the Earth's surface by active tectonics. We discuss potential improvements at larger spatial scales, in order to advance knowledge of deep interior properties and dynamics for instance from tidal forcing. We finally consider what contributions MAGIC will be able to make to observations of thermosphere neutral density and related atmospheric parameters.