Bathymetry from space: technologies and applications

Bathymetry from space describes the use of satellite reconnaissance of oceans and coastal regions to map the topography of the bottom. Space-based technologies for acquiring bathymetry have the potential to fill important knowledge gaps and shorten huge data collection backlogs held by ongoing ship and aircraft hydrographic surveys. Satellite altimeter technologies indirectly measure open ocean bathymetry by observing sea surface height. The bottom topography strongly correlates to gravity-induced anomalies in sea surface height. Data processing eliminates wave, tide, and thermal effects from the signal, revealing the sea floor topography. The primary benefit of this technique is globally uniform data within a time and cost that is unachievable with shipboard surveys. Hyperspectral sensor technologies measure shallow water (< 50 m) bathymetry by observing the scattering of visible light from the ocean bottom at selected wavelengths. The primary benefit of this technique is ubiquitous access to global coastal areas where national sovereignty and security issues or geographic constraints frustrate conventional technologies. This paper introduces the concept of ocean bathymetry from space-based sensors, the related technologies, and illustrates impacts on civil and military applications that depend on bathymetric information.