REMOTE SENSING

Remote sensing involves the use of electromagnetic or acoustic radiation for observing various geophysical processes from aircraft, satellite, or underwater vehicles. Research is being conducted toward the development and application of remote sensing techniques in the marine, coastal, and Great Lakes environments. In addition, basic research is being carried out in related areas such as surface wave dynamics and electromagnetic scattering, the results of which have application to the understanding and interpretation of remote sensing data.

Specific remote sensing techniques are being developed for synthetic aperture radar (SAR) sensors and sonar. SAR systems are being used for observing ocean fronts and for measuring surface currents. Improved sonar techniques are being investigated for three-dimensional imaging of underwater objects.

Related research areas include laboratory studies of capillary wave generation and turbulence/free-surface interactions, as well as numerical and experimental investigations of radar backscatter from steep and breaking waves. A High Resolution Surface Slope Imager (HRSSI), an optical device, has been developed and is capable of measuring the slope of the water surface in two dimensions at very high temporal rates (330 frames per second). From this data, the three-dimensional shape of the water surface can be deduced. This facility is currently being used for detailed investigations into the physics of water drops interacting with the ocean surface, and the resulting radar backscatter signatures.

An example of the current vectors estimated by tracking surface features on SAR images collected near the edge of the Gulf Stream.