Basics

The basic technological approach that is adopted is summarised in the following flowchart.

• The starting point for MERIS validation, algorithm development and product validation is the collection of high quality, complete and validated historic and actual data.
  
• These data will be used to parameterise a bio-optical model, which will subsequently be used to model water leaving radiance or a derived parameter such as subsurface irradiance reflectance.
  
• Modelled water leaving radiance will be compared to in-situ measured water leaving radiance to calibrate and validate the bio-optical model.
  
• If model prediction of water leaving radiance is successful, the bio-optical model will be inverted into an algorithm using state of the art analytical techniques such as Neural networks inversion and/or Matrix inversion techniques.
  
• The algorithm will be inserted into the MERIS processor chain to produce regional maps of CHL concentration. These maps will be validated using selected in situ observations.
  
• An important step in the calibration of the bio-optical model is the understanding, measurement and parameterisation of optical properties such as phytoplankton and suspended matter absorption and backscattering, and absorption by coloured dissolved organic matter.