Mapping aquatic systems with a physically based process chain

Kurzfassung

Mapping the submersed vegetation can give significant information about the actual state of shoreline vegetation in inland waters. It is of prime importance for the ecological valuation of the entire lake. Remote sensing techniques can accomplish an efficient tool for mapping tasks, if the processing methods are universally valid. The Modular Inversion Program (MIP) follows this concept. It is a processing tool designed for the recovery of hydro-biological parameters from multi- and hyper-spectral remote sensing data. The architecture of the program consists of physical inversion schemes that derive bio-physical parameters from the measured radiance signal at the sensor. Program modules exist for the retrieval of aerosols, sun glitter correction, atmosphere- and water surface corrections, retrieval of water constituents, primary production in optically deep waters and the classification of substrates such as macrophytes and bottom sediments amongst others. For the purpose of mapping the bottom coverage in optically shallow waters, two modules have been added to MIP: The first module calculates the bottom reflectance using the subsurface reflectance, the depth and an approximation of the water constituent concentrations as input. The second module fractionalizes the bottom reflectance to three endmembers of specific reflectance spectra by linear unmixing. The three endmembers are specific reflectance spectra of bottom sediments, small growing macrophytes (Characeae) and tall macrophytes (here: mainly Potamogeton perfoliatus & P. pectinatus). The processing system has been tested with data collected from the multi-spectral airborne scanner Daedalus AADS1268 at Lake Constance, Germany, for multi- temporal analysis.