Optical remote sensing of marine and inland waters (BELCOLOUR-2)

RUDDICK, K.; ASTORECA, R.; BORGES, A.; DEKKER, A.; DOGLIOTTI, A.I.; DOXARAN, D.; HARLAY, J.; KNAEPS, E.; LANCELOT, C.; NECHAD, B.; NEUKERMANS, G.; PARK, Y.; RAYMAEKERS, D.; ROUSSEAU, V.; SCHROEDER, T.; STERCKX, S.; TOTE, C.; VANHELLEMONT, Q.

Encuentro; Belgian Earth Observation Day 2011; 2011

The general objective of the BELCOLOUR-2 project was to improve the quality of existing optical remote sensing products for marine and inland waters based on new knowledge and to develop new products (including primary production and partial pressure of CO2) for key applications such as aquaculture support and air-sea CO2 flux estimation. Key issues studied in BELCOLOUR-2 include suspended matter and chlorophyll estimation, automated data quality control, validation, phytoplankton optical properties and taxonomic groups, atmospheric correction, primary production, air-sea CO2 flux estimation and the preparation of new technologies including future satellite-based hyperspectral sensors, geostationary sensors and unmanned airborne vehicules. Key results of the BELCOLOUR-2 project that have already been published can be found at: http://www.mumm.ac.be/BELCOLOUR/EN/Publications/index.php Other results are in various stages of publication and will appear there when completed. Significant progress has been made in improving the understanding of the optical properties of marine particles, both algal and non-algal, and of coloured dissolved organic matter, all of which affect the spectral reflectance of water bodies, as perceived by optical remote sensors. Algorithms for retrieval of water quality parameters such as chlorophyll a concentration (CHL) or total suspended matter (TSM) concentration, therefore, depend on knowledge of the relationship between these parameters and the corresponding optical properties. On the one hand, variability of mass-specific optical properties is a key source of uncertainty for remote sensing products. On the other hand, better exploitation of optical properties, such as the spectral absorption of different algal species, may enable new products to be developed from optical remote sensing, such as phytoplankton functional types or suspended particle size distribution. Based on this theoretical work, algorithms for new products are in various stages of maturity (concept design, prototype implementation on in situ or satellite data ... standard processing for a complete satellite data archive). Such algorithms include the detection of Phaeocystis globosa and Noctiluca scintillans plankton species, estimation of the partial pressure of dissolved CO2 and of primary production, detection of bottom vegetation/substrate, annual algal bloom timing, annual 90 percentile chlorophyll a concentration (as required by the European Union Water Framework Directive), diffuse attenuation coefficient and euphotic depth, wavelength of maximally transmitted underwater light, etc. Progress has also been made in the atmospheric correction of data from satellite (MODIS, MERIS, SEVIRI) and airborne sensors. Atmospheric correction is particularly critical for aquatic studies and original algorithms have been developed for detection and correction of adjacency effects (airborne, MERIS) and for correction of aerosol effects (SEVIRI). Various algorithms have been compared for MODIS data.  Large satellite data archives have been processed for MODIS, MERIS and SEVIRI sensors and data is supplied to various marine scientists for applications in ecosystem modelling, sediment transport modelling and marine biology.