We are pleased to announce that the report from the IOCCG working group on In-flight Calibration of Satellite Ocean-Colour Sensors (IOCCG Report 14), chaired by Robert Frouin (Scripps), has been published. The report is currently being printed by JRC and will be mailed to subscribers on the IOCCG mailing list within a few months. A PDF version of the report can be downloaded from the IOCCG website at:
The report provides a comprehensive review of techniques for radiometric calibration of ocean-colour sensors while they operate in orbit. It also provides concrete recommendations on how to proceed with the radiometric calibration of ocean-colour sensors during operational phase, in order to generate and maintain quality retrievals of water-leaving radiance during mission lifetime, including selection of calibration sites, requirements for in situ measurements, and sensor inter-calibration.
The 19th IOCCG Committee meeting took place in Cape Town, South Africa from 28-30 January 2014. It was hosted by the South African National Space Agency (SANSA), the Council for Scientific and Industrial Research (CSIR) and the University of Cape Town which are gratefully acknowledged.
IOCCG-19 participants (click on image to enlarge).
A number of important issues were addressed during the meeting including implementation of the CEOS Ocean Colour Radiometry-Virtual Constellation (OCR-VC), arrangements for the 2014 IOCCG Summer Lecture Series and tentative plans for the second IOCS meeting, scheduled to take place in the USA in 2015. In addition, the status of the various IOCCG scientific working groups was addressed. Notably, the report from the WG on "Phytoplankton Functional Types" is nearing completion, as is the report from the WG on "Ocean Colour Remote Sensing in Polar Seas". A workshop from the new IOCCG WG on "Atmospheric correction in coastal waters" is scheduled to take place this year, and a proposal for a new WG on "Earth observations in support of global water quality monitoring" was accepted by the IOCCG Executive Committee. This WG aims to provide a strategic plan for incorporating current and future EO information into water quality monitoring efforts globally.
At the end of the meeting, the IOCCG Chairmanship was transferred from David Antoine (LOV, France) to Stewart Bernard (CSIR, South Africa), who is warmly welcomed. David Antoine was congratulated on his tremendous tenure as Chair of the IOCCG Committee, having started many new initiatives which are proving to be critical to the ocean-colour community. The full minutes of the meeting will be available on the IOCCG website shortly.
Applications are still being accepted for the Second IOCCG Summer Lecture Series, which will take place in Villefranche-sur-Mer, France from 21 July to 2 August 2014. This course is dedicated to lectures and in-depth discussions on cutting edge research conducted by a number of distinguished scientists. Further information about the course can be found at: www.ioccg.org/training/SLS_2014.html. The deadline for applications is 14 March 2014.
A significant outcome of the first International Ocean Colour Science (IOCS) meeting was a number of recommendations from the various splinter sessions for follow up workshops. The first of these took place at ESA/ESRIN, Italy from 2-3 December 2013. Presentations from the workshop on "Ocean Colour System Vicarious Calibration for Science and Operational Missions", chaired by Ewa Kwiatkowska (EUMETSAT), are available on the IOCCG website at: ioccg.org/groups/vical.html. Gerhard Meister (NASA GSFC) chaired a second workshop on "Satellite Instrument Pre- and Post-Launch Calibration". Presentations from this workshop are available at: ioccg.org/groups/inst_cal.html.
The 2014 Ocean Sciences Meeting (with AGU, TOS) will take place in Honolulu, Hawaii (23 - 28 February 2014), and the EGU General Assembly 2014 will take place from 27 April - 02 May 2014 in Vienna, Austria. Special sessions include "Application of Ocean Color Products & Use for Resource Management (OS4.5)", and "Ocean Remote Sensing" (OS4.2). The 6th IEEE/OES Baltic Symposium 2014 will take place in Tallinn, Estonia from 26-29, May 2014, with a symposium theme of Measuring and modeling of multi-scale interactions in the marine environment. Other meetings include the IMBER Open Science Conference 2014, Bergen, Norway, 23-27 June 2014 and Ocean Optics XXII, Portland, Maine, USA, 26-31 Oct 2014.
Cornell Summer Satellite Remote Sensing Training Course, May 30 - June 13, 2014, Cornell University, Ithaca New York. A two-week summer satellite remote sensing training course is being offered once again to marine scientists who have modest or no prior experience with satellite remote sensing techniques. For more information and application instructions visit: www.geo.cornell.edu/ocean/satellite.
The European Space Agency (ESA) recently announced that free and open access to Sentinel satellite data will become available during the Copernicus operational phase. Copernicus is an Earth observation program operated by a partnership of the European Commission (EC), ESA, EUMETSAT and the European Environment Agency (EEA). The European Delegated Act on Copernicus data and information policy provides for free, full and open access to users for data and information generated inside the Copernicus program, which will include Sentinel mission data (the first of Sentinels is set for launch later this year) as well as service information provided by Copernicus services.
Following the release of the MERIS Level-1 Full Resolution Full Swath data online via FTP (ftp://merisfrs-ftp-ds.eo.esa.int), the products are now also retrievable via HTTP through the MERIS MERCI server (http://merisfrs-merci-ds.eo.esa.int/merci). The MERIS MERCI catalogue and inventory provides services for accessing the MERIS FRS Level-1 data products allowing area and time extraction as well as visualisation of the list of available products including related quick looks. The MERCI file archive contains all available MERIS Full Resolution data acquired throughout the entire mission (17 May 2002 to 8 April 2012). For new users, access to the bulk processed FRS Level-1 dataset via HTTP and FTP is provided upon registration. Systematic processing of ESA's MERIS FRS mission archive into Level-2 products is also under preparation and will be completed in the first half of 2014.
Shirley Jeffrey, one of the world's foremost authorities on phytoplankton pigments, passed away peacefully in Hobart, Australia, on 4 January 2014 after a highly successful research career spanning more than 50 years. She received many awards in recognition of her work and published numerous classic papers in algal phylogeny, chemotaxonomy and pigment-based analysis of ocean phytoplankton communities, including co-editing the state-of-the-art SCOR UNESCO Monograph on Phytoplankton Pigments in Oceanography (Jeffrey et al. 1997), which provides a comprehensive review of methods for estimating chlorophylls and carotenoids in water samples. For further details see CSIRO's obituary for Shirley Jeffrey.
Several new publications have been added to the IOCCG Recent References list, including a paper by Singh and Shanmugam (2014) entitled "A novel method for estimation of aerosol radiance and its extrapolation in the atmospheric correction of satellite data over optically complex oceanic waters". The authors developed a new aerosol correction scheme to make satellite ocean colour data provide unrivalled utility in optically-complex oceanic waters.
Chlorophyll-a from the ABI algorithm using MODIS-Aqua nLw(λ) data derived from the new method and from the NIR scheme.
The new scheme retrieves water-leaving radiances nearly comparable to those of the NIR scheme for extremely clear waters. Further evaluation of the performance of the new method with NIR and NIR-SWIR switching schemes using in situ data and MODIS-Aqua data showed that the new method yields physically realistic water-leaving radiances in all visible bands, in contrast to the later two schemes which showed large distortions in water-leaving radiance structures with large negative values across the visible bands. The new method will have important implications for satellite remote sensing of optically-complex waters, since the accuracy of bio-geophysical products derived from such data depends mainly on the water-leaving radiance products delivered by the atmospheric correction algorithm.
In another new paper by Eleveld et al. (2014) entitled "Estuarine suspended particulate matter concentrations from sun-synchronous satellite remote sensing", the authors quantify how sun-synchronous data acquisition of optical data impacts derived water quality parameters, and how retrieved suspended particulate matter concentrations are biased by tidal aliasing and sampling under clear sky conditions. This is complementary to recent publications that demonstrate the value of ocean-colour observations from geostationary platforms. It also supports the idea of having identical ocean-colour sensors on two platforms in the same orbit, such as is anticipated for Sentinel-3A and B.
In a paper by Chuanmin Hu et al. (2013) looking at "Uncertainties of SeaWiFS and MODIS remote sensing reflectance" the authors avoid the use of in situ Rrs data (which themselves may contain substantial uncertainties) but use a spectral-curvature constraint to find the highest-quality image pixels, and use those pixels as the "truth" to gauges Rrs uncertainties from all other pixels. This is the first time that satellite-derived Rrs data are shown to have uncertainties meeting the mission goals (<5% for blue bands over clear waters). All previous field-based validations showed uncertainties > 10% due to inherent uncertainties in the field-measured Rrs.
Lastly, in a study of "Climate-driven chlorophyll a changes in a turbid estuary" Chengfeng Le et al. (2013) highlight a new chlorophyll algorithm for a moderate-sized estuary (Tampa Bay, 1000 km2) where Chl typically ranges between 1 and 50 mg m-3. They also show that a long-term chlorophyll time series (1998 - 2012, combination of SeaWiFS and MODIS) appears to be weather (climate) driven. This type of study has been rare in the literature due to algorithm difficulties (nearly all published algorithm papers for estuaries use only several examples, but not long-term time series).
Material for possible inclusion in the IOCCG Newsletter should be submitted to the Project Scientist, Dr. Venetia Stuart
Subscription to the IOCCG Mailing List.
Participants receive a brief summary of the IOCCG Newsletter by e-mail (quarterly), as well as hard copies of IOCCG Reports as, and when, they become available.