Comparative validation of the radar interferometry-based SYM12 Using ICESat-2 ATL03 and ground-based GPS measurements

This study evaluates the performance of the SYM12 digital surface model, derived from radar interferometry between 2011 and 2014, by comparing it with two reference datasets: the ICESat-2 ATL03 lidar altimeter (2018–2023) and 879 GPS ground control points measured in 2024. Relationships between SYM12, ICESat-2 ATL03, and GPS measurements were tested using root mean square error (RMSE), mean absolute error (MAE), and Pearson correlation coefficient analysis. Both unfiltered and interquartile range (IQR) filtered data were analyzed. Results indicate a strong correlation (R > 0.99) between SYM12, ICESat-2 ATL03, and GPS observations in low- and mid-elevation regions, while discrepancies increase in high-elevation and complex terrain areas. Filtering improved the performance of SYM12 relative to ATL03, reducing the RMSE from 35.54 m to 2.24 m and the MAE from 5.10 m to 1.60 m. Notably, RMSE and MAE values remained higher in high-altitude areas. For SYM12-GPS comparisons, the RMSE and MAE were 2.32 m and 1.56 m, respectively, while GPS-ATL03 comparisons yielded RMSE and MAE values of 0.60 m and 0.39 m, respectively. This study underscores the value of integrating newer lidar-based datasets, such as ATL03, to enhance the accuracy of DSMs derived from radar interferometry.