Challenges and opportunities for geostationary remote sensing – the next ocean colour revolution
Ruddick, K.; Neukermans, G.; Shang, S.; Vanhellemont, Q. (2012). Challenges and opportunities for geostationary remote sensing – the next ocean colour revolution, in: 44th international Liège colloquium on ocean dynamics "Remote sensing of colour, temperature and salinity – new challenges and opportunities" - May 7-11, 2012. pp. 1 In: (2012). 44th international Liège colloquium on ocean dynamics "Remote sensing of colour, temperature and salinity – new challenges and opportunities" - May 7-11, 2012. GHER, Université de Liège: Liège. 126 pp., more |
| Authors | | Top | - Ruddick, K., more
- Neukermans, G., more
- Shang, S.
- Vanhellemont, Q., more
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| Abstract | What new information can we get from geostationary ocean colour? Is geostationary ocean colour “just” more frequent data? What new algorithms are required to exploit this data?Optical remote sensing of marine processes from polar-orbiting sensors such as MODIS-AQUA and Envisat/MERIS has become quite well-established over the last decade. Products such as chlorophyll a and Total Suspended Matter concentration are widely used as support for marine science and water quality monitoring. However, the sampling frequency, typically once per day, is too slow for resolving tidal and diurnal processes and the presence of clouds is a big limitation to data availability. The geostationary orbit offers a vastly improved sampling frequency, typically one image per hour or more, and hence the possibility to resolve new processes with tidal and diurnal variability. The probability of obtaining data during periods of scattered clouds is also greatly enhanced. However, the advantages go beyond simply obtaining more data. The exploitation of temporal coherency of natural processes over the timescales resolved by geostationary sensors may offer entirely new ways of processing data – instead of pure pixel-by-pixel processing, information from adjacent pixels in time may allow better constraint of the ocean colour inversion problem or provide new opportunities for data quality control via temporal outlier detection of retrieved marine or atmospheric parameters. Multiple geostationary sensors at different longitudes give extra information on the bidirectional reflectance of the ocean-atmosphere system.This presentation will identify new opportunities inherent to high frequency data from geostationary ocean colour sensors and possibilities for new algorithms. On the other hand, the atmospheric correction for high viewing zenith and high sun zenith angles will be a more critical issue for geostationary sensors and the related challenges will also be addressed. Examples will be presented from the SEVIRI sensor over the North Sea and from the GOCI sensor over the Bohai Sea.The presentation will conclude with a provocative question for the conference participants: If we have in the future geostationary ocean colour sensors, what rôles/niches are still available for polar-orbiting ocean colour sensors? |
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