Validation Strategy - In Brief

The goal of any validation activity is to compare a product with a designated truth. In the case of satellite ocean color validation, the goal is to validate satellite derived products using coincidentally measured in situ observations.

There are a number of benefits realized with a satellite validation activity:

1. Provide a measure of accuracy to satellite derived products to lend confidence in their scientific usefulness.
2. Identify conditions, either oceanic, atmospheric or satellite specific, for which satellite derived products are invalid. This may lead to improved algorithms or processing strategies.
3. Provide a consistency check to ensure that satellite calibration is correct and monitor long-term stability of satellite measurements.

The theoretical basis of satellite validation is quite simple. A satellite-based remote sensor images the earth, derived products are produced, and comparisons are made between the derived products and coincident in situ measurements. There are a number of considerations that must taken into account in order to bring this simple concept into a viable reality, not the least of which is a well defined set of exclusion criteria. Below is a flow chart depicting the strategy employed by the SeaWiFS project for calibration and validation purposes.