Monitoring and Accuracy Assessment of Urban Lake Level From Jason-3 Altimeter Data: A Case Study of East Lake in Wuhan City

Urban lakes play a critical role in urban ecosystems, providing essential services such as water supply, flood control, and recreational spaces. However, monitoring urban lake levels using traditional in situ methods is often challenging due to high costs, data continuity issues, and restricted access. Satellite altimetry has emerged as a promising alternative, offering global coverage and consistent measurements. Despite its success in monitoring large inland water bodies, applying satellite altimetry to urban lakes remains challenging due to their small size, shallow depth, and complex surrounding environments, which seriously distort altimeter waveforms. This study evaluates the performance of Jason-3 satellite altimetry data for monitoring urban lake levels, focusing on East Lake in Wuhan, China. We propose a novel waveform retracking method, the three major peaks (MP3) retracker, designed to address the complexities of urban lake environments by analyzing the first three maximum peaks in the waveform. The MP3 retracker is compared with traditional retracking algorithms, including ICE, Offset Center of Gravity (OCOG), and the 50% threshold method, using in situ gauge data for validation. Results show that the MP3 retracker significantly outperforms traditional methods, achieving a root mean square error (RMSE) of 7.21 cm and a correlation coefficient (CC) of 0.94, with a valid data rate exceeding 70%. In contrast, traditional retrackers exhibited lower accuracy and higher rates of invalid data. This study demonstrates the potential of satellite altimetry, combined with advanced retracking techniques, for accurate and reliable monitoring of urban lake levels, contributing to improved water resource management and environmental conservation in urban settings.