Spatial correlation between GRACE-based total water level fluctuation and GNSS-derived dilatation rate of peatland area in Kalimantan, Indonesia

Borneo Island is home to the world’s largest peatland with relatively straightforward tectonics movement. Those nature would be beneficial to illuminate the hydrological cycle of the Earth-surface processes. We analyzed the total water storage changes deduced from the Gravity Recovery and Climate Experiment (GRACE) satellite where the Global Navigation Satellite System (GNSS) network may detect its deformation. High-frequency data in GNSS observation might benefit the hydrological cycle real-time monitoring. We investigate the spatial correlation of GRACE-based total water storage changes and the GNSS-derived horizontal dilatational strain rate. We found that the dilatational strain rate based on GNSS data negatively correlates to the Equivalent Water Height (EWH) change observed from GRACE data. Hence, the extensional dilatation rate (> 20 nanostrain/yr) is observed exactly in the decreased EWH region (<-13 mm), while the compressional dilatational region (< -20 nanostrain/yr) is observed in the increased EWH (> 20 mm) trend. Finally, we highlighted that GNSS observation’s precise horizontal dilatation rate in Borneo Island is reliable for detecting seasonal total water storage changes. © The Author(s), under exclusive licence to Società Italiana di Fotogrammetria e Topografia (SIFET) 2025.