First Meeting of the PFT Working Group

The IOCCG working group on Phytoplankton Functional Types (PFTs) met for the first time on 6-7 July 2006 at the CNES Headquarters in Paris. The meeting was chaired by Dr. Cyril Moulin (LSCE/IPSL, France) and was attended by a number of specialists in the field. By definition, PFTs are groups of phytoplankton species that have a specific function in common with respect to the scientific question being addressed. However, for biologists working on marine ecosystems at both global and regional scales, phytoplankton are often classified by pigment composition and not by function. The definition of PFTs thus depends on the type of application, and is also susceptible to change (e.g. with the increasing complexity of biogeochemical models). Retrieval of information on PFTs from space by various analytical and empirical approaches was also discussed at length. Further information about this meeting and the PFT working group can be found under the IOCCG Working Groups section of the IOCCG website.

Publications by IOCCG Fellowship Students

Over the past few years, the IOCCG has provided fellowships to a number of young scientists to travel to foreign institutes to work with experts in the field. These exchanges have been extremely successful and have lead to advanced training in specific areas and, recently, to the publication of the research carried out during these exchanges.

Fellowship student Caiyun Zhang from Xiamen University (China) worked with Dr. Chuanmin Hu at the University of South Florida to complete a study on ocean-colour data product validation and comparison over the northern South China Sea and Taiwan Strait using a time-series of MODIS and SeaWiFS high resolution data as well as in situ data. Their finding were recently published in Remote Sensing of Environment 102: 250-263 (2006). They found that MODIS and SeaWiFS Chl data were comparable for most of the waters in the Taiwan Strait and northern South China Sea, with no significant bias in either data set. The difference between MODIS and SeaWiFS Chl data was less than between satellite and in situ data. The authors concluded that it would be possible to continue the time-series using only one sensor such as MODIS, in the eventual absence of SeaWiFS.

Another fellowship student, Aurea Ciotti (University of Sao Paulo, Brazil), worked with Dr. Annick Bricaud at Laboratoire d'Océanographie de Villefranche (France) on retrieving information on phytoplankton cell size and light absorption by coloured detrital material (CDM) from satellite data. Their paper was recently accepted for publication in L&O: Methods (July 2006). They presented two procedures to retrieve simultaneously the magnitudes and spectral shapes for both light absorption by CDM and phytoplankton, along with a size parameter for phytoplankton.

South Korean Fellowship student, SeungHyun Son, worked with Dr. Shubha Sathyendranath at the Bedford Institute of Oceanography (Canada), and recently published a paper entitled Primary production in the Yellow Sea determined by ocean color remote sensing (Mar. Ecol. Prog. Ser. 303: 91-103). They used the primary production algorithm of Platt & Sathyendranath (1988) to estimate primary production in the Yellow Sea to provide the first synoptic views of primary production in this area.

WATeRS: A portal for water quality information products from operational remote sensing

The Institute for Environmental Studies of the Vrije Universiteit of Amsterdam has developed a generic method to convert MODIS-Aqua satellite data to information in GIS format. The information is provided in near-real time and is freely available on the Internet via the customised WATeRS web portal. This is an innovative ArcIMS-application with a WMS ArcIMS-OGC connector which enables users to interactively explore remote-sensing products, and to seamlessly combine the data with other data with a geographic component. The service has been created for the North Sea only, but the procedure could be adapted for other regions, and also other algorithms and sensors.

Training Course in Vietnam

A training course entitled "A comprehensive hands-on course in satellite oceanography with emphasis on ocean colour, SST and HAB" funded by POGO was held from 7-13 May 2006 in Nha Trang, Vietnam. The course took place at the Institute of Oceanography, Nha Trang. Visiting professors were Prof. Joji Ishizaka (Nagasaki University) and Dr. Mati Kahru (Scripps Institution of Oceanography). The trainees came from a variety of institutions in Vietnam, such as the Institute of Oceanography Nha Trang, Institute of Marine Environment and Resources, Hai Phong, Institute of Physics, Hanoi, the National University of Ho Chi Minh City, as well as local government offices of various provinces. Over the course of one week 29 trainees (including 9 observers) received lectures and hands-on training in analysing data from various satellites using different methods. Students used software contributed by WimSoft throughout the course.

News from NASA

Another Year of SeaWiFS Data

NOAA, working in partnership with NASA, recently announced that it is enabling continued access to satellite ocean data from SeaWiFS onboard the OrbView-2 satellite (operated by GeoEye Corporation). Through existing agreements with GeoEye and NASA, NOAA will, for the first time, provide funds to continue the collection of SeaWiFS data, including global coverage at 4-km, and contiguous U.S. coverage at 1-km. NASA will continue to support mission operations and science data analysis of the SeaWiFS data, as well as provide access to resulting data products for Earth science research. NOAA support will extend access to higher resolution SeaWiFS data for local U.S. waters until September 2006, and global data until April 2007.

Chlorophyll Anomaly Product

NASA has started producing a very useful chlorophyll-a anomaly product, which is derived for each year, season, and month of the SeaWiFS mission, based on nearly 9-years of SeaWiFS data (starting September 1997). These products are produced by subtracting the climatological averages for each time period from the averages for just the period under consideration. The differences, with respect to the climatology (in mg m-3), are logarithmically scaled and assigned colours on the positive- or negative-anomaly portion of the colour scale. The anomaly products can be reached directly at:

Giovanni and LOCUS

NASA's Giovanni (GES-DISC Interactive Online Visualization and ANalysis Infrastructure) interface provides users with an easy-to-use, Web-based interface for visualization and analysis of several different types of earth science data (including ocean-colour data). Giovanni also includes a climatological anomaly analysis function, based on the SeaWiFS climatology base period from September 1997 - May 2005. Use of the single base period makes this climatological anomaly analysis different from that produced by the OBPG (see above), which is updated monthly with a new base period. Chlorophyll anomaly analysis is an exciting new way to look at the data, and it allows discovery of features and phenomena that may have been difficult to detect previously.

Researchers are also encouraged to use NASA's Laboratory for Ocean Color Users (LOCUS) which can provide an insight into the data analysis that Giovanni provides. LOCUS is for researchers who are interested in applying remotely-sensed ocean-colour data to research questions.

GlobCOLOUR CDR meeting

ESA's GlobCOLOUR Project, which aims to develop a 10-year global ocean-colour data set by merging together information from four satellite sensors (SeaWiFS, MODIS-Aqua, MERIS and tentatively Parasol/POLDER) recently held their Critical Design Review meeting in Paris (10-11 July 2006). The in-situ characterisation of MERIS, MODIS and SeaWiFS was reviewed, amongst other items on the agenda. The in situ characterisation for chlorophyll and the diffuse attenuation coefficient produced some useable results but the in situ nLw characterization will undergo additional work. The sensor cross characterization showed that this changes with the different acquisition situations (observation conditions, seasonal variations and regional sensitivity). A final merging method for the GlobCOLOUR project will be decided upon shortly, with the following pre-selection methods:

  • weighted averaging
  • GSM01 (Garver-Siegel-Maritorena, version 1)
  • Optimal interpolation

The first GlobCOLOUR user workshop will be held in Villefranche, France (tentative dates Dec. 4-7, 2006) to get feedback from a wider community than those directly involved in the project.

New References

Several new references have been added to the Recent Ocean Colour References (2004-2006) section of the IOCCG website including a publication by Chuanmin Hu et al., which appeared in the April 2006 issue of IEEE Geoscience and Remote Sensing Letters entitled "Ocean color reveals phase shift between marine plants and yellow substance". Using high temporal and spatial resolution SeaWiFS data (1998-2003) from an oligotrophic gyre centre, the authors demonstrate that there is a phase shift (time lag) between the absorption coefficient of phytoplankton pigment and that of coloured dissolved organic matter (CDOM), with CDOM peaks lagging ~2 weeks behind phytoplankton peaks and CDOM troughs lagging by ~4 weeks.

This phase shift provides indirect evidence that CDOM in the gyre is produced by phytoplankton growth, grazing, and degradation, and that the common assumption of linear co-variation between phytoplankton and CDOM (the basis for the band-ratio chlorophyll algorithms) may need to be revisited, even for the clearest waters. If Chl is linearly proportional to phytoplankton absorption, the phase shift suggests that the bio-optical band-ratio algorithm may lead to an overestimate in the magnitude of the spring bloom, and an underestimate of Chl in the fall. These observations were only possible through use of synoptic, precise, accurate, and frequent measurements afforded by space-based sensors. In situ technologies cannot provide the required sensitivity or synoptic coverage to observe these natural phenomena.

Special Session AGU Fall Meeting

A special AGU session OS05 (AGU Fall Meeting, San Francisco, 11-15 December 2006) entitled "Ocean Phytoplankton from Sea, Space, and Computers" is being convened by Watson Gregg (GSFC/NASA, USA) and Cyril Moulin (LSCE/IPSL, France). They look forward to receiving your abstracts and having an exciting session with your participation.

Ocean phytoplankton are important contributors to ecology, carbon cycling, fisheries, and biodiversity. In particular, evaluation of Phytoplankton Functional Types (PFTs) is an emerging field in biological oceanography. New algorithms are being developed to detect certain PFTs from space. In parallel, biogeochemical modellers are increasingly incorporating PFTs for more realistic simulations. Both modeling and algorithm developments require in situ data observations for evaluation. Methods for discriminating in situ phytoplankton groups are also varied in the scientific literature. This session solicits research emphasizing phytoplankton identification, characterization, simulation, and data analysis. They would like to bring together scientists working on various aspects of ocean phytoplankton to promote advances in this emerging field. For further details of the meeting see

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