Diurnal variability of turbidity and light attenuation in the southern North Sea from the SEVIRI geostationary sensor

This study follows up on the successful feasibility study of Neukermans et al. (2009) for mapping suspended matter in turbid waters from the SEVIRI sensor on board the METEOSAT geostationary weather satellite platform. Previous methodology is extended to the mapping of turbidity, T, and vertical attenuation of photosynthetically active radiation (PAR), KPAR. The spatial resolution of the SEVIRI products is improved from 3 km × 6.5 km to 1 km × 2 km using the broad high resolution visual band. The previous atmospheric correction is further improved and the uncertainties on marine reflectance due to digitization are considered. Based on a two year archive of SEVIRI imagery, available every 15 min, the diurnal variability of T and KPAR is investigated during cloud free periods and validated using half-hourly T and KPAR data obtained from a system of moored buoys (SmartBuoys) in the southern North Sea. Based on numerous match-ups, 80% of SEVIRI derived T and KPAR are within 53% and 39% of SmartBuoy T and KPAR, respectively. Results further show that on cloud free days, the SEVIRI T and KPAR signals are in phase with the SmartBuoy data, with an average difference in the timing of the maximum T and KPAR of 11 min and 23 min, respectively. It is concluded that diurnal variability of T and KPAR can now be mapped by remote sensing offering new opportunities for improving ecosystem models and monitoring of turbidity. Limitations of the current SEVIRI sensor and perspectives for design of future geostationary sensors and synergy with polar orbiting satellites are discussed.

► First study on geostationary remote sensing of tidal variability of water turbidity.
► Assessment of atmospheric correction, digitization, and algorithm uncertainties.
► Validation of geostationary SEVIRI products using half-hourly moored buoy data.
► Good correspondence between SEVIRI remote sensing products and buoy data.