Ocean Optics and Biogeochemistry Protocols for Satellite Ocean Colour Sensor Validation, Volume 3.0: Protocols for Satellite Ocean Colour Data Validation: In Situ Optical Radiometry.

Abstract

This protocol document aims to support the ocean color community with protocols for the collection, processing and quality assurance of in situ measurements of the apparent optical properties of natural water for the validation of satellite radiometric products. In addition to a general introduction on Elements of Marine Optical Radiometry Data and Analysis (Chapter 1), the document addresses Radiometers Specifications (Chapter 2), Calibration and Characterization of Optical Radiometers (Chapter 3), In-water Radiometry Measurements and Data Analysis (Chapter 4), and Above-water Radiometry Measurements and Data Analysis (Chapter 5).

The overall structure and content of the various chapters are based on, and benefit from, the Ocean Optics Protocols promoted by the National Aeronautics and Space Administration within the framework of the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) and Sensor Intercomparison for Marine Biological and Interdisciplinary Ocean Studies (SIMBIOS) programs (Mueller and Austin 1995, Mueller et al. 2003a, Mueller et al. 2003b).

It is emphasized that, by recognizing optical radiometry can be heavily affected by the presence of clouds which will unavoidably challenge the quantification of measurement uncertainties, the protocols put emphasis only on measurements performed during clear sky conditions, which are those relevant for the validation of satellite ocean color data products.

Finally, it is anticipated that the chapters on in-water and above-water radiometry provide comprehensive details on those measurement methods sharing large consensus inside the community and whose application is strongly encouraged. Conversely, brief summaries are only provided for those methods already well represented by the previous ones or for those methods that may exhibit difficult implementation in a variety of measurement conditions.