Amazon hydrology: Advances and perspectives in monitoring by remote sensing

ABSTRACT: The Amazon Basin harbors one of the most vital ecosystems globally. It plays a crucial role in climate  regulation and rainfall patterns across South America. However, the Amazon faces severe threats from anthropogenic  pressures such as deforestation, human-induced fires, dam construction, and illegal mining. Additionally, climate  change exacerbates these threats, with increasing floods, and droughts, endangering the aquatic environment. While  monitoring the Amazon is essential, in-situ methods are limited due to its vast size and remote areas. Remote sensing  offers an alternative to providing comprehensive, high-resolution spatiotemporal data critical for understanding the  basin's hydrological processes. Recent advancements in Earth Observation missions, including passive sensors  (Sentinel-2/MSI, Sentinel-3/OLCI, EnMAP, PRISMA, PACE, Landsat-8/9, PlanetScope SuperDove) and active  sensors (Sentinel-1, SWOT, IceEYE) have significantly expanded the capabilities for detecting and monitoring the  Amazon's water quantity and quality. This section has a twofold objective: highlight how remote sensing has been  crucial to studying the Amazon Basin's hydrology and to explore new applications of remote sensing data, particularly  in the context of climate change, thereby contributing to the sustainable management and preservation of this critical  ecosystem.