Using Hyperspectral Imagery for Ocean Process Studies in Monterey Bay, California

Hyperspectral remotely sensed imagery is promising technology for coastal marine science. High-resolution snapshots from airborne platforms reveal detailed ocean structure, from which information on the processes that shape the coastal marine environment can be derived. The Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor was flown aboard the ER-2 aircraft over Monterey Bay on October 13, 2000. Upwelling radiance and downwelling irradiance were measured just above the surface of the water during the overflight. CTD casts, inherent optical property (absorption and attenuation) measurements at CTD stations, and continuous underway sea surface temperature, salinity, fluorescence, attenuation and absorption measurements were also taken. The 5 AVIRIS flight lines, consisting of 33 scenes, were mosaicked into a composite image of Monterey Bay and the adjacent ocean. The image was radiometrically corrected and transformed into map space. FLAASH, a commercial release software, was used for atmospheric correction and optimized for use over water. Spectra in the atmospherically corrected image were compared with in situ measurements. Surface chlorophyll estimates, derived from reflectance values of the composite image, reveal fine scale coastal ocean structure. The imagery, combined with in situ data, illustrate the dynamic processes that shape the coastal marine environment of Monterey Bay. Future considerations in adapting hyperspectral imagery to ocean process studies are also addressed.