Bathymetry Estimation from ICESat-2 in a Region Swamped by Mud: A Case Story from Moreton Bay

The bathymetry of coastal bay environments, such as Moreton Bay near Brisbane in eastern Australia, is constantly reworked because of changes in energy dispersal and related sediment transport pathways. Updated and accurate bathymetric models are a crucial component for scientific, environmental, and ship safety studies. NASA’s Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) is equipped with a laser detecting system (green light) that penetrates the air-water interface. Under optimal conditions, it can provide shallow water bathymetry (depths <40 m). We attempted to use ICESat-2 measurements to study bathymetry and possible bathymetry changes from repeated tracks across Moreton Bay. We found that the water turbidity in Moreton Bay varies with time. More than half of the water area is affected by suspended sediment, which makes ICESat-2 difficult to obtain bathymetric measurements. In other areas, repeated ICESat-2 tracks performed consistently on the 1-meter level. This means that ICESat-2 can be used to update existing bathymetry in the region. We also devised a method to determine bathymetry in the shallower parts of the zone affected by mud.<p></p>