Satellite altimeters measure the distance between satellite and sea surface using radar or laser systems. This way, they provide precise observations of the sea surface with respect to a well-defined global references system. By using a cross-calibrated long-term multi-mission data record, changes of the ocean surface can be determined in high spatial and temporal resolution. These measurements are foundational for monitoring and understanding ocean dynamics and global change processes, and they are of high relevance for geodesy and various disciplines of the Earth sciences.
DGFI-TUM analyses altimetry observations to determine sea level changes on global scale and within regional studies. The resulting sea level variations are applied to create empirical ocean tide models, the dynamic ocean topography and time series of geostrophic surface currents. Furthermore, DGFI-TUM is working on improved methods to quantify the sea state, i.e. the condition of the ocean due to the action of wind, waves and swell, where a specific focus is on the determination of significant wave heights (SWH). A central topic of DGFI-TUM's research in the context of sea surface observations is the development of advanced analysis methods of radar echoes to accurately determine water levels and SWH in the open ocean, in coastal, shelf and polar areas.