Short Course 26: Water quality monitoring using remote sensing data: principles and applications

Traditionally, water quality monitoring is performed by collecting water samples at a few points for in situ or laboratory water body water quality variables' determinations. However, this type of monitoring is difficult to perform in countries with continental dimensions, such as Brazil, and remote regions due to the high cost, which limits the water body's necessary spatial and temporal water properties representation. Then, remote sensing presents an alternative for estimating water quality parameters that interact with electromagnetic radiation, providing synoptic view and high spatiotemporal coverage. In recent years, sensors such as Landsat-8/OLI, Sentinel-2/MSI, and CBERS-04/MUX and WFI, Sentinel-3/OLCI, PRISMA and PACE have shown highly satisfactory results in this monitoring. However, there are still limitations and difficulties, mainly in understanding the interaction of light with the aquatic environment and, due to the low signal from water, in its accurate estimation via orbital remote sensors. Thus, this course aims to present the basic concepts of hydrological optics (interaction of light with water, spectral behavior of constituents) and image processing (atmospheric corrections, specular effect) necessary for the correct use of RS for aquatic applications.