New IOCCG Report on Algorithms
Most of the algorithms used in ocean-colour remote sensing attempt to derive chlorophyll concentration. However, recent studies have emphasized the importance of understanding and retrieving the inherent optical properties (IOPs), i.e., the scattering and absorption characteristics of water and its constituents (the dissolved and suspended material). In this report, the performance of various algorithms developed to derive inherent optical properties (IOPs) from water-leaving radiance are assessed through application to synthetic and in situ data sets developed by the working group. These data sets, as well as software for several of the algorithms tested, are also available on the Ocean Colour Algorithms website.
All members on the IOCCG Mailing List will receive a copy of the report, via surface mail. A PDF version of the report can be downloaded from the IOCCG Website, and copies can also be requested online.
The IOCCG, with support from the Canadian Space Agency, will be conducting an intensive training course on the Analysis and Applications of Satellite-derived Ocean-Colour Data, at Memorial University, St. John's, Newfoundland from 7-11 May 2007. The course will consist of lectures by specialists, hands-on practical sessions in the analysis of satellite data, and small projects executed by the participants. The course will provide an overview of remote sensing of ocean colour with special emphasis on applications of ocean colour relevant to Canadian waters.
The course is targeted at postgraduate students as well as professional researchers working in the area of marine science and coastal-zone management in Canadian institutes, although applications from advanced undergraduates may also be considered.
Further information about the course, as well as application details can be found on the on Training and Education section of the IOCCG website.
An international workshop was hosted by the Plymouth Marine Laboratory (PML) from 18-22 September 2006 to initiate a global network of chlorophyll observations using in situ and remote-sensing techniques, for operational applications. The workshop was sponsored by the Group on Earth Observations (GEO), the Global Ocean Observing System (GOOS), the Partnership for Observation of the Global Oceans (POGO), PML and the IOCCG, and was attended by 33 scientists from 20 different countries around the world.
This primary goal of the workshop was to discuss strategies to establish a number of regional networks to effectively monitor marine chlorophyll levels in support of local and regional needs (forecasting harmful algal blooms and aiding in fishing operations, fisheries management, and coastal zone management). It was envisaged that each network would have two components, one for satellite data and the other related to in situ time series observations (to provide regional calibrations for the satellite data and to extend the observations to other variables not directly observable through satellites). Workshop participants were thus divided into two groups: one discussed the operational archiving of satellite ocean-colour imagery, while the other addressed methodological issues for measuring in situ chlorophyll concentrations. The workshop concluded with a detailed report of recommendations on the mechanisms for practical operation of the chlorophyll network and the next stages of the study.
Recently, the IOCCG supported Dr. Trevor Platt to attend a Global Ecosystems Classification Workshop in Paraguay (9-12 October 2006), as part of the Ecosystems Classification Advisory Group of GEOSS (Global Earth Observation System of Systems). The aim of the group is to establish a viable classification framework for terrestrial, freshwater, and marine environments in support of GEOSS.
Participants at the workshop focused on the classification of global ecosystems at the meso-scale (on the order of 10 to 103 km2) and adopted a biophysical stratification approach for terrestrial, freshwater, and marine ecosystem delineation. They discussed the best approach and data sets for each domain to include in the classification and mapping. For the oceans, Dr. Platt recommended the approach adopted by the IOCCG Global Ecological Provinces working group.
The classification framework developed at the workshop will be delivered to GEO for their consideration and subsequent mapping. This work, commissioned by GEO, is likely to have a large impact on global resource management and monitoring in the coming years. The subsequent mapping of global ecosystems using this classification scheme will represent a longer term GEO task.
New scholarships and fellowships have recently been announced by The International Institute for Applied Systems Analysis (IIASA) and the Institute for Global Environmental Strategies (IGES). See the Training and Education section of the IOCCG webpage for further details.
Chinese scientists plan to put into orbit the Haiyang 1-B oceanic satellite, developed by CAST (Chinese Academy of Space Technology) and sponsored by the State Ocean Administration (SOA), China, by the end of this year. The new satellite will succeed the HY-1A satellite which operated from 2002-2004, and will provide images of the entire Earth's surface every 24 hours (as compared with 72 hours for HY-1A). Like its precursor, the HY-1B is also an ocean-colour monitoring satellite, but it will provide improved quality ocean colour and SST data, and will also monitor pollution and aid in mitigating disasters. The satellite's operational life is expected to reach three years, one year more than that of Haiyang 1-A.
The SeaWiFS 8-day data interface in Giovanni has been updated. It is now possible to use the 8-day interface to define the region and time-period of interest, generate analytical visualizations and ASCII data, and then to access the Ocean Biology Processing Group (OBPG) data browser with the submitted criteria. This procedure will generate a data order in the OBPG browser for the requested time period, using the regional coordinates to subset the Level 1A and Level 2 data. The data order would then be submitted and processed using the OBPG data browser interface.
The monthly output from the NASA Ocean Biogeochemical Model (NOBM) has also just been added to ocean color Giovanni. NOBM features total assimilated chlorophyll, four phytoplankton functional groups, nitrate concentrations, and mixed layer depth. This should be a very helpful research tool. Note that this is output from a model based on remote-sensing data output, not actual remotely-sensed parameters.
Lastly, now that nine years of SeaWiFS data are available for every month of the year, the current SeaWiFS climatology baseline in Giovanni (used to calculated chlorophyll anomalies) has been updated. The new baseline will run from September 1997 to August 2006 (the old baseline extended to May 2005).
Under a collaborative program sponsored through the NASA ReaSON CAN, the Ocean Biology
Processing Group just completed a reprocessing of the Coastal Zone Color Scanner (CZCS)
and NASDA Ocean Color and Temperature Scanner (OCTS) mission data sets. These CZCS and
OCTS products are being distributed through the Level-1-2 and Level-3 browsers of the
OceanColor Web and the associated Oceans ftp site. Potential users of these data sets
should realize that both data sets have significant uncertainties related to the sensor
characterization, spectral and temporal stability, and, in the case of CZCS, significant
temporal and spatial limitations in coverage. Complete descriptions of the instruments
and mission histories, the CZCS temporal and spatial coverage, the processing algorithms
and methodologies (calibration, atmospheric correction, etc.) used can be
The Journal of Applied Remote Sensing (JARS) is a new journal of interest to the ocean-colour community. JARS is an online-only, multimedia journal published in the SPIE Digital Library. The e-journal format provides numerous advantages, including:
JARS is currently accepting submissions for its launch in January 2007. All manuscripts will be peer-reviewed and refereed. The journal will cover the concepts, information, and progress of the remote sensing community. Topics include remote sensing science and remote sensing applications in the atmosphere and oceans. Detailed information about the journal and author guidelines are available at the following website: http://spie.org/jars/.
Papers from the ocean-colour remote sensing community are welcome, and will be handled by. Dr. Robert Frouin (Scripps Institution of Oceanography), a member of the JARS Editorial Board.
Several new references have been added to the Recent Ocean Colour References section of the IOCCG website including a publication by Hubert Loisel et al., entitled "Spectral dependency of optical backscattering by marine particles from satellite remote sensing of the global ocean" (Journal of Geophysical Research, Vol. 111, No. C9).
In this paper the authors demonstrate that the spectral dependence, γ, of the particulate backscattering coefficient can be assessed from satellite observations of ocean colour. Because γ is sensitive to particle size distribution, this information opens new ways for advancing remote assessment of biogeochemical processes such as the link between oceanic primary production and carbon export into the deep ocean. The authors applied their algorithm to SeaWiFS satellite data of ocean colour to derive global distributions of γ (Figure above). The spatio-temporal patterns of γ were shown to differ from those of the chlorophyll-a concentration and particulate backscattering coefficient. These results were interpreted in terms of processes that modify the composition of particulate assemblages and physiology of phytoplankton in response to environmental forcing. The changes in γ are clearly related to variations in the mixed layer depth and photosynthetic available radiation.
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