In situ optical and biogeochemical in- and above-water measurements are critical for calibration and validation of satellite ocean colour radiometry data products, and for refinement of ocean colour algorithms. During the SeaWiFS era, NASA commissioned the development of a series of ocean optical measurement protocols (see NASA Ocean Optics Protocols for Satellite Ocean Color Sensor Validation) which have served as international reference standards ever since, and have promoted the collection and assembly of climate quality, ocean optical datasets by the global ocean colour community. Since publication of the last revision in 2004, there have been major advances in instrumentation and observing capability, so these community-vetted protocols need to be revised to account for new, emerging, and planned capabilities and modes of deployment.

Over the past few years NASA has sponsored several international workshops with experts (including breakout workshops at the International Ocean Colour Science meetings), to update and develop new community consensus protocols for ocean colour sensor validation. The newly drafted protocols will be made available to the international user community on this webpage for a period of time for testing, public comment and review, before they are accepted as international reference standards. Once accepted, the protocols will receive a publication date and version number (e.g., v1.0), and will also have a digital object identifier (doi). These revised protocols will be revisited periodically to determine if enough changes have taken place to warrant a significant update, in which case a new version number will be assigned.

IOP Measurements and Protocols: Absorption Coefficient

The comment and review period for the protocol document entitled Inherent Optical Property Measurements and Protocols:  Absorption Coefficient is now closed. The final  document will be posted on this website in the near future.


IOP Measurements and Protocols: Best Practices for the Collection and Processing of Ship-Based Underway Flow-Through Optical Data

The protocol document entitled “Inherent Optical Property Measurements and Protocols: Best practices for the collection and processing of ship-based underway flow-through optical data”  is now available for a 60-day public comment and review period  before being accepted as the international reference standard.  After this period, the document will be revised based on comments received, formatted, and a final pdf document will be posted onto this website.  Once accepted, the protocols will receive a publication date and version number (e.g., v1.0), and will also have a digital object identifier (doi).  Please email  comments  on the document to:  inline-iop_comments@oceancolor.gsfc.nasa.gov before 28 February 2018.


Protocols for Satellite Ocean Color Data Validation: In situ Optical Radiometry

The protocol document entitled “Protocols for Satellite Ocean Color Data Validation: In situ Optical Radiometry”  is now available for a 60-day public comment and review period  before being accepted as the international reference standard.  After this period, the document will be revised based on comments received, formatted, and a final pdf document will be posted onto this website.  Once accepted, the protocols will receive a publication date and version number (e.g., v1.0), and will also have a digital object identifier (doi).  Please email  comments  on the document to: aop_comments@oceancolor.gsfc.nasa.gov  before 5  November 2018.

This 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.


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