On the Validation of Satellite-Derived Products for Land Applications

SUMMARYRigorous validation of the accuracy and consistency of satellite-derived products representing surface biophysical variables is at the heart of the success of Earth observation as a practical tool. Such validation ensures that the derived products meet the claimed specifications and thus results produced with their use can be viewed with confidence. As part of an overall quality control, which is involved in most production processes, validation is especially important for products derived from remote sensing data because the information is inferred and because the signal to noise ratio in the measurements is frequently low. In this paper, the validation of remote sensing products is considered in two phases: initial validation which establishes the soundness of a product; and continuing validation which ensures the ongoing quality and reliability of such a product. The discussion is focused on optical satellite data and their terrestrial applications, primarily in the boreal environment. Examples are given for land products derived from satellite data, including the practical difficulties in the initial validation. Several strategies are suggested to make the validation process more efficient and effective.