Validation of Altimetry Derived Water Levels for Mekong River

Monitoring water bodies using satellite radar altimetry is an advanced and cost-effective technique with high accuracy. The method is effective for monitoring water level changes in lakes, rivers, and reservoirs. This study selected two locations near Vientiane over the Mekong River in Laos. Two sentinel 3-B (S-3B) tracks are selected for this study-the first one crosses the Mekong River 17km upstream while the second track passes 35km downstream of the Vientiane gauge station. The root mean square error between satellite-driven and in-situ water levels for upstream and downstream stations were 0.43m and 2.62m, respectively, while the correlation coefficient (R) values for these stations were 0.9 and 0.5, respectively. The water levels from the in-situ gauge and sentinel 3-B (S-3B) show a significant correlation between upstream virtual station (VSs) than the downstream virtual station (VSs). The downstream sentinel 3-3B virtual station (S3B-VSs) are crossing the river after a meander at around 35km distance from the gauge located in Vientiane. The possible reason for the difference in validation may be due to the difference in location of virtual stations and in-situ gauge station.