http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Evaluation of the potential of the NOAA-n AVHRR reflective data in oceanography
A need exists in oceanography for synoptic detection and delineation of various organic and physical features at the ocean surface because assessment of such features may provide insight into the complex interactions of the various processes governing the ocean. This study investigates the capabilities of the reflective data of the NOAA-n Advanced Very High Resolution Radiometer (AVHRR) to detect and map features associated with phytoplankton concentrations at the ocean surface. Considering the capabilities of satellite observation for this problem, the more accessible data sets from the NOAA-n AVHRR are examined, and techniques designed to exploit the full sensitivity of the instrument are introduced. These procedures include an editing technique that maintains the full resolution in the low albedoes pertaining to ocean targets and a normalizing procedure to account for atmospheric contributions to the signal. The atmospheric effects are treated as functions of the amount of water vapor in the atmosphere and the position of the individual pixels along the swath width of the instrument. These techniques permit the refinement of the reflective data to 0.1% albedo and the expansion of acceptable data to at least 512 pixels on either side of nadir. Data obtained with these methodologies are compared with near-simultaneous and pigment calibrated Coastal Zone Color Scanner (CZCS) data. These two sets of data are segmented using a mathematical classification technique and then compared to determine similarity of spatio-temporal features. To verify the AVHRR findings, these data are compared to concurrent in-situ data from two red tide incidents in the eastern and western coasts of the Gulf of Mexico during 1983 and 1986, respectively. Comparisons are also made between AVHRR reflective and emittive data to investigate possible relationships existing between the circulation patterns and phytoplankton distributions.