Dr. Charles R. McClain
NASA/Goddard Space Flight Center
Code 614.8, Greenbelt, MD 20771, USA

Dr. Gerhard Meister
NASA/Goddard Space Flight Center
Ocean Biology Processing Group, USA

Dr. Paula Bontempi
NASA/Goddard Space Flight Center
Code 614.8, Greenbelt, MD 20771, USA

In terms of Level 1 requirements for ocean-colour sensors, perspectives have changed dramatically over the past decade since publication of of the first IOCCG report on “Minimum Requirements for an Operational Ocean Colour Sensor for the Open Ocean” (IOCCG Report 1, 1998). It is now possible to measure more complex ocean variables, as well as physiological features of phytoplankton using ocean-colour radiometry. For ocean biology, the minimum requirements have changed and the new generation of ocean radiometers will require many more bands, and more stringent pre-launch and on-orbit calibration procedures. This working group will develop a consensus for the minimum requirements for ocean-colour sensors that meet a broad range of user needs, and identify options to sustain long-term, global, climate research quality ocean-colour radiometry (OCR) time series from space. The IOCCG monograph on “Ocean Colour Level-1 Requirements” will be published by the IOCCG and will include observational requirements (spectral bands, data quality (cal/val), format, and reprocessing) for future OCR missions based on new research and operational needs, and gap analysis to the current situation. This report will address CEOS-GEO action number AR-09-02a_33 (Area: Architecture, Overarching Task: Interoperable Systems for GEOSS, Sub-task: Virtual Constellations).

Terms of Reference

The working group will address the following:

  • Survey, delineate, and quantify the minimum current research and operational observational needs regarding ocean-colour product suites, and the associated global ocean-colour sensor and high-level system requirements (e.g., radiance accuracy, signal-to-noise ratio, etc.) for a sustained, systematic capability to estimate ocean-colour radiances and derived products from space;
  • Review the capability, to the extent possible based on available information, of current national and international sensors in meeting sensor requirements;
  • Identify and assess the observational gaps between current and planned sensor capabilities, identifying appropriate timelines to launch for future missions and sensors to ensure a sustained observational capability globally;
  • Survey, delineate, and quantify the desired observational requirements for future ocean-colour sensors based on anticipated future oceanographic research and operational needs (across a spectrum of scales from basin to synoptic to local process studies), including high-level system requirements (e.g., radiance accuracy, signal-to-noise ratio, etc.);
  • Identify and quantify minimum requirements for all aspects of satellite ocean-colour sensors, including on-board calibration options and requirements, vicarious calibration requirements, and field data validation efforts, which incorporate a mix of measurement platforms (e.g., satellites, aircraft, and in situ platforms including but not limited to ships and buoys);
  • Identify minimum requirements for a sustained rigorous on-orbit sensor inter-calibration and data validation; data processing, re-processing, distribution and archiving.

Working Group Documents:


Charles McClain NASA/Goddard Space Flight Center, USA
Gerhard Meister NASA/Goddard Space Flight Center, USA
Paula Bontempi NASA/Goddard Space Flight Center, USA
Steven Delwart ESA/ESTEC, The Netherlands
Yu-Hwan Ahn KORDI, South Korea
Hiroshi Murakami JAXA, Japan
Bertrand Fougnie CNES, France

Terms of Reference

  1. To define precisely the parameters required for Cal/Val activities and biogeochemical studies (e.g. modelling), with their significance and limitations;
  2. To evaluate the technical specifications for optical sensors (passive and active), and the adaptations required for long-term, autonomous missions onboard a drifting float:
    • miniaturisation, buoyancy
    • consumption, energy constraints
    • sensitivity, accuracy and precision, acquisition rate;
  3. To evaluate the complementarities with other chemical sensors (O2, nutrients);
  4. To evaluate the optimal placement of bio-optical devices on the floats
    • shadowing effects
    • quality control issues: life time and bio-fouling, stability /drift over 2-4 years of deployment, parking depths and measurements at parking depths;
  5. To provide recommendations for deployment strategy of the equipped floats:
    • adhering to the standard protocol adopted for physical S-T parameters, vs using another specific, and more flexible, protocol (e.g. higher profiling frequency, shallower casts, near-surface cast at noon for matchup), or a combination of both approaches,
    • evaluation of the various communication devices (ARGOS, ARGOS 3, Iridium; two-way (adaptative sampling) vs one-way communication,
    • data acquisition frequency over the profile and related issues of sensor consumption;
  6. To recommend unified processing techniques for meaningful comparisons of the data, and ultimately for merging them;
  7. To make recommendations regarding organization of data storage, quality control and archiving capacities;
  8. To elaborate on recommendations for the policy in terms of data distribution (real-time and quality controlled, delayed time data) and access for ensuring the best and unselfish use of these data, at international, and inter-Agencies, levels;
  9. To provide recommendations for pilot studies before large scale implementation;
  10. To implement links with space agencies about the capacity of such a deployment, and its cost;
  11. To produce a white paper to promote the addition of bio-optical sensors to the international Argo float program.

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