Water Quality Parameters |
Chlorophyll-a (Chl-a) is a pigment found in all plants and algae. In coastal productive waters, Chl-a is an important water quality parameter (measured in micro gram per liter, µg/l) which provides food to aquatic life. It also indicates pollution from high nutrient inputs from land drainage. Of these, phosphorus and nitrogen are the main factors which enhance the growth of algae and ultimately reduces oxygen availability for marine organisms. In extreme cases eutrophication leads to the formation of algal blooms. Therefore, measuring Chl-a as an indicator of algal biomass can help in assessment of water quality and serve as a health indicator of the marine system.
Suspended Solids (SS) are defined as the particles larger than 2 microns, found in water column and mostly comprise inorganic materials. Measured in milligrams per liter of water (mg/l), suspended solid concentrations and total suspended solid readings are based on filtered and dried water samples. The main difference between total suspended solid and suspended solid concentrations is in the amount of water sample analyzed. After filtering a water sample with a 2 µm filter, the particles are dried and weighed to determine suspended solids. When an entire sample is filtered, dried and weighed, the American Society for Testing of Materials (ASTM) considers the measurement to be the suspended solid concentration. If a water sample is further sub-sampled, the subsequent mass measurement will be the total suspended solids measurement.
Nazeer, M., and Nichol, J.E. (2015), Combining Landsat TM/ETM+ and HJ-1 A/B CCD Sensors for Monitoring Coastal Water Quality in Hong Kong . IEEE Geosciences and Remote Sensing Letters, 12 (9), 1898-1902. doi: 10.1109/LGRS.2015.2436899
Nazeer, M., and Nichol, J.E. (submitted), Development and application of a remote sensing-based Chlorophyll-a concentration prediction model for complex coastal waters of Hong Kong. Journal of Hydrology.