Solid Earth response to climate change in Svalbard and South America using geodetic observations of hydrological loading

Global warming and other climate change influences are leading to major changes in the global hydrological cycle. The response of the Solid Earth to water mass transfers causes crustal deformations and gravity field temporal variations that can be monitored by space geodesy. It is challenging to identify the climate change signature contained in the time series and to separate the different contributions from various spatial and temporal scales. In this study, we use more than 20 years of GNSS and GRACE time series to analyse hydrological loading signal in two different areas that are highly sensitive to climate change. The Svalbard archipelago in the Arctic is one of the fastest warming locations in the world. We use seasonal analysis and comparison with satellite altimetry and in-situ datasets to distinguish current ice melting from the solid Earth’s response to past events (GIA, LIA). South America and the Amazon basin, home to some of the world’s largest rivers, have recently experienced severe drought and extreme floods. The hydrological loading shows huge annual variations superimposed on interannual variations linked to extreme events. It is therefore essential to use high-performance analysis methods to separate the part of the observed signals associated with climate change from the well-known seasonal trends. To assess their reliability and interpretation, the results are discussed in relation to complementary datasets and models.