Enhancing Sea Surface Height Monitoring and Depth Datum Assessment Using GNSS/IMU Buoy Systems: A Case Study of Taiwan

Accurate monitoring of sea level variations is crucial for understanding climate change impacts and supporting coastal management. However, traditional methods like tide gauges and satellite altimetry face limitations in coverage and precision. This research explores the capabilities of GNSS/IMU buoy systems for enhancing sea surface height measurements and depth datum assessments. By deploying GNSS/IMU buoys near 34 tide gauge stations across Taiwan, a comparative analysis was conducted to examine the reliability and precision of these innovative tools against conventional tide gauge data. Utilizing advanced loosely coupled GNSS/IMU integration of GNSS and IMU data, the study achieves centimeter-level accuracy in dynamic marine conditions. Results reveal that while most tide gauges are consistent with the buoy data, significant discrepancies are observed at a few stations, particularly in subsidence areas and offshore islands. This study underscores the potential of GNSS/IMU buoy systems as a cost-effective and flexible solution to complement tide gauges, especially in regions affected by vertical land motion. The findings advocate for broader adoption of GNSS/IMU technologies to improve coastal and offshore hydrographic observations under changing environmental conditions.