Evaluation of historic and operational satellite radar altimetry missions for constructing consistent long-term lake water level records

Abstract. A total of 13 satellite missions have been launched since 1985, with different types radar altimeters on board. This study intends to make a comprehensive evaluation historic and currently operational altimetry for lake water level retrieval over the same set lakes develop strategy constructing consistent long-term records inland at global scale. The estimates produced by retracking algorithms (retrackers) were compared gauge measurements 12 in four countries. performance each retracker was assessed terms data missing rate, correlation coefficient r, bias, root mean square error (RMSE) between altimetry-derived concurrent measurements. results show that model-free retrackers (e.g., OCOG/Ice-1/Ice) outperform model-based most missions, particularly small lakes. Among Sentinel-3 gave best results, followed SARAL. ENVISAT has slightly better than Jason-1 Jason-2, but its rate is higher. For lakes, ERS-1 ERS-2 provided more accurate TOPEX/Poseidon mission. In contrast, large option due lower shorter repeat cycle. GeoSat Follow-On (GFO) both an extremely high estimates. Although several contemporary provide GFO, sole mission, 1985 1990, With full consideration duration, should be two-step bias correction normalization procedure. first step, use Jason-2 as initial reference estimate systematic biases TOPEX/Poseidon, Jason-1, Jason-3 then normalize them form TOPEX/Poseidon–Jason series. Then, series remove other construct ungauged