Validation of Satellite-Derived Ocean Color: Theory and Practice

Satellite validation is the process of determining the spatial and temporal errors of a given biological or geophysical data product, including the development of match-up data sets, i.e., field observations and satellite data coincident in time and location. The primary objective of NASA's Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project is identifying biases between similar products generated by various ocean color missions. The utility of satellite- derived ocean color data is strongly dependent upon the validation of these data. The temporal and spatial scales of the phenomena being measured by a satellite borne sensor, along with the resolution of the sensor, must be considered when trying to validate a data product using a single point in situ measurement. To facilitate this validation process, the SIMBIOS project in conjunction with the SeaWiFS Project have developed a database of radiometric, phytoplankton pigment, and other oceanographic and atmospheric data: the SeaWiFS Biooptical Archive and Storage System (SeaBASS). A theoretical framework and practial application of satellite valiation is discussed.