Harmful algal blooms are increasingly common in freshwater ecosystems such as rivers, lakes, ponds and reservoirs due to warm, nutrient-rich water conditions. NASA, the U.S. Environmental Protection Agency, the National Oceanic and Atmospheric Administration, and the U.S. Geological Survey have jointly launched the Cyanobacteria Assessment Network, a standardized method that uses satellite data and computer algorithms to assess cyanobacteria concentrations.The cyanobacteria index is based on satellite data collected by the Moderate Resolution Imaging Spectroradiometer on ESA's Envisat satellite and the Ocean and Land Color Instrument on ESA's Sentinel-3A and Sentinel-3B satellites to accurately identify cyanobacteria in water.
Above is a time series image of a blue algal bloom in Utah Lake captured by Sentinel-3A satellite OLCI data, along with true-color images of the bloom beginning and ending (green indicates high algae concentration).
On the left is the map of east-central Wisconsin, and on the right is the true color image generated by cyanobacteria assessment network (yellow indicates high algae concentration). Based on the data, the local government and relevant environmental protection departments can master the location the the algal blooms that had occurred and respond timely to the early bloom, which would help avoid the potential threat to humans, wildlife and the ecological environment constituted.
In China, the most common way to monitor water bodies is through remote sensing technology. Through the macroscopic view from the remote sensing data, multi-dimensional information regarding water environment monitoring and treatment can be provided. To see the current state of water quality of Taihu Lake after years of treatment, TerraQuanta has previously monitored its water quality in 2019. TerraQuanta’s lake eutrophication remote sensing monitoring technology measures and analyzes water samples within a certain band of radiation value for spectral characteristics, establish the corresponding water quality index inversion algorithms through researching the relationship between spectral reflectance characteristics and water quality parameters, and monitor and evaluate the eutrophicated water body by combining the relevant models of lake eutrophication.
Below is the monitoring results of TerraQuanta show the chlorophyll concentration, suspended particle size and water transparency of Taihu Lake in May 2019.