Tommy Lindell

Ecological effects of waste water

Part I. General Concepts of Aquatic Ecology: 1. Aquatic ecosystems and management 2. Standing crop and productivity 3. Hydrographic characteristics 4. Population growth 5. Limitation, tolerance, and adaptation 6. Nutrient cycles Part II. The Effect of Waste on Populations: 7. Phytoplankton and controlling factors 8. Zooplankton 9. Periphyton 10. Macrophytes 11. Benthic macroinvertebrates 12. Fish Appendices Index.

Mapping of the water quality of Lake Erken, Sweden, from Imaging Spectrometry and Landsat Thematic Mapper

Hyperspectral data have been collected by the Compact Airborne Spectrographic Imager (CASI) and multispectral data by the Landsat Thematic Mapper (TM) instrument for the purpose of mapping lake water quality. Field campaigns have been performed on Lake Erken in Sweden during the summer of 1997. Water samples have been collected and analysed in laboratory. Continuously measured variables from a boat have added a spatial dimension to the ground truth dataset. The data have been used to construct algorithms, based on remotely sensed data, for the retrieval of water quality parameters. The correlation between the continuous data and the collected CASI data has been investigated. Algorithms using both the point sampling results and the continuous data have been developed. Maps based on data from each instrument, showing the distribution of chlorophyll, are presented. Problems of having few water sampling stations, and the potential of using sub-water optics models are addressed as well. Tests were performed on MERIS bands and found useful for mapping chlorophyll and turbidity, and algorithms have been suggested for future use with MERIS.

Bio-optical modelling combined with remote sensing to assess water quality

A simple bio-optical model, with parameter values derived from measurements of the inherent optical properties (IOPs) and optically active substances that are known to influence the IOPs, has been developed. A large historical dataset of measurements of the concentration of chlorophyll a and phaeophytine a (Chl), suspended particulate inorganic material (SPIM) and the absorption coefficient of Coloured Dissolved Organic Matter (CDOM), spanning more than 25 years, has been used together with the model to develop algorithms for the retrieval of these water quality parameters, for a site in Lake Malaren, Sweden. The model takes as input the optically active substances and outputs a reflectance spectrum just above the water surface. From the modelled reflectance, algorithms were derived for Chl, SPIM and CDOM absorption at 420 nm. The algorithms were applied to atmospherically corrected remote sensing data, which were collected by the Compact Airborne Spectrographic Imager, CASI. The radiative transfer code 6S was used for the atmospheric correction of the data. Distribution maps for the three retrieved parameters were constructed and Chl and SPIM were validated by continuous field measurements of fluorescence and beam attenuation. The continuous data were calibrated with water analysis results from nine water samples. The time lag between the image acquisition and the ground data measurements was never more than 3 hours. Even though the model parameter values were collected at different times from that of the CASI over-flight, and from a larger geographic region of Lake Malaren than that used for the CASI measurements, the independently developed algorithms predicted the concentrations of the optically active substances within a reasonable level of accuracy, allowing spatial variations in the substances to be predicted.

Industrial plume detection in hyperspectral remote sensing data

Industrial and river outlet plumes are characterized by high concentrations of dissolved and suspended substances. The optical properties of these waters have been investigated in laboratory and in remotely sensed data in order to establish characteristics that could be used to locate and map discharges from paper and pulp industries. Water samples from the outlet of one paper‐pulp industry in the investigated area around Norrsundet, Sweden, have been analysed in the laboratory. An increase in absorption by dissolved substances was found around 550 nm, compared to waters unaffected by industrial outlets. Airborne hyperspectral remote sensing data from the corresponding area have also been investigated and spectral differences between industrial and riverine outlets were found in the interval between 450 nm and 550 nm. The remotely sensed data have been used to create reference spectra for different types of water. These spectra served as input to the Spectral Angle Mapper (SAM) algorithm to classify additional remotely sensed data from the region in order to estimate the possibility of using these type of data for industrial plume detection.