Evaluation of the Performances of Radar and Lidar Altimetry Missions for Water Level Retrievals in Mountainous Environment: The Case of the Swiss Lakes

Radar altimetry is now commonly used to provide long-term monitoring of inland water levels in complement or for replacing disappearing situ networks gauge stations. Recent improvements tracking and acquisition modes improved the quality retrievals. The newly implemented Open Loop mode likely increase number monitored bodies owing use an a priori elevation, especially hilly mountainous areas. novelty this study comprehensive evaluation performances past current radar missions according their (Low Resolution Mode Synthetic Aperture Radar) (close open loop) modes, frequency (Ku Ka) area where losses signal are occur, as well recently launched ICESat-2 GEDI lidar missions. To do so, we evaluate level retrievals from most after 1995 over eight lakes Switzerland, using developed ALtimetry Time Series software, compare new also impact used. combination with on SENTINEL-3A B outperforms classical Low other lake observability greater than 95%, almost constant bias (?0.17 ± 0.04) m, RMSE generally lower 0.07 m R times higher 0.85 when compared records. that can be temporal sampling retrievals, data acquired by were considered. Very accurate results obtained 0.06 0.95 levels. An (0.42 0.03) was observed. More contrasted GEDI. As these available shorter time period, more analyses necessary determine potential retrieving