CDOM determines the ALB capability on the shallow water

The monitoring of the water bottom topography by the airborne laser bathymetry  (ALB) may have a significant contribution to forecast and to mitigate the disasters like river flooding or high tide along the coast related to the bottom topography and the geographic signatures. The ALB has the capability to monitor the broad area instantaneously and precisely relative to the traditional monitoring method using acoustics. The ALB was experimentally deployed over the rivers and the river mouths in Japan to evaluate the capability of monitoring the bottom topography with in-situ measurements. As the results, the colored dissolved organic matter (CDOM) was extracted as the principal factor to determine the capability of topography measurement rather than suspended solids or chlorophyll as the proxy of phytoplankton. The CDOM may absorb the laser pulse emitted from ALB and reflected from the bottom of water, which may have more significant optical contributions than scattering particles.