Home - News RSS feed - UNN scientists develop a satellite system for monitoring water quality of inland water bodies

sputnikovuyu sistemu monitoringa kachestva vody vnutrennih vodoyomov razrabatyvayut uchyonye nngu

Scientists from Lobachevsky University’s Laboratory for Reservoir Hydrology and Ecology together with their colleagues from the Shirshov Oceanology Institute of the Russian Academy of Sciences (Moscow) and the Marine Hydrophysical Institute of the Russian Academy of Sciences (Sevastopol) have developed an efficient algorithm for atmospheric correction of satellite images of various water bodies. It will be used in the remote sensing method of water quality assessment.

Satellite images make it possible to estimate the content of impurities, chlorophyll or mineral particles in water bodies. However, the brightness of the water surface on space images is severely distorted by atmospheric aerosol due to light absorption and scattering.

Atmospheric image correction helps to eliminate interference, but the existing methods do not work well for images of freshwater bodies and coastal areas of seas, where the determination of the water brightness using a satellite image is hindered by the impurities in the upper water layer, such as algae. Abroad, this problem is solved by using the atmospheric information from the measuring posts making part of an extensive monitoring network. In Russia with its vast territory, no such option exists.

Nizhny Novgorod scientists have proposed an atmospheric correction algorithm with aerosol parameters that are fixed over the reservoir, such parameters being determined by the pixels with the clearest water.

"From April to October 2022, we carried out measurements of the optical transparency of the atmosphere over the Gorky Reservoir. The obtained values were compared with satellite data. It turned out that the proposed algorithm makes it possible to eliminate the influence of the atmosphere with an accuracy of 65% to 95%," explains Alexander Molkov, Head of the Laboratory for Reservoir Hydrology and Ecology at the UNN Radiophysics Faculty.

sputnikovuyu sistemu monitoringa kachestva vody vnutrennih vodoyomov razrabatyvayut uchyonye nngu 1

The next step for Lobachevsky University researchers will be to develop a regional model for assessing water quality in the Gorky Reservoir using satellite imagery.

"The results of our research will make it possible to create a GIS system and to monitor changes in the reservoir over time, which will help to detect pollution, determine the temperature of water in the near-surface layer, study currents and the transport of impurities, thus predicting and identifying potential risks," says Alexander Molkov.

The results of the study have been published in the journal Remote Sensing. The research is conducted as part of the federal Priority 2030 programme.