Amazon Hydrology From Space: Scientific Advances and Future Challenges

Abstract

As the largest river basin on Earth, the Amazon is of major importance to the world's climate and water resources. Over the past decades, advances in satellite‐based remote sensing (RS) have brought our understanding of its terrestrial water cycle and the associated hydrological processes to a new era. Here, we review major studies and the various techniques using satellite RS in the Amazon. We show how RS played a major role in supporting new research and key findings regarding the Amazon water cycle, and how the region became a laboratory for groundbreaking investigations of new satellite retrievals and analyses. At the basin‐scale, the understanding of several hydrological processes was only possible with the advent of RS observations, such as the characterization of "rainfall hotspots" in the Andes‐Amazon transition, evapotranspiration rates, and variations of surface waters and groundwater storage. These results strongly contribute to the recent advances of hydrological models and to our new understanding of the Amazon water budget and aquatic environments. In the context of upcoming hydrology‐oriented satellite missions, which will offer the opportunity for new synergies and new observations with finer space‐time resolution, this review aims to guide future research agenda toward integrated monitoring and understanding of the Amazon water from space. Integrated multidisciplinary studies, fostered by international collaborations, set up future directions to tackle the great challenges the Amazon is currently facing, from climate change to increased anthropogenic pressure.

Evaluation of Paralytic Shellfish Toxins in Marine Oyster Farming and Microalgae in the Atlantic Amazon Evidences Safety but Highlights Potential Risks of Shellfish Poisoning

“…Seasonality, especially precipitation, is the main variable that influences the dynamics of microalgae and physicochemical properties of water in the microregion known as “Salgado Paraense”. Precipitation is widely recognized as the most important climatological variable in the tropical region, including the Amazonian coastal region [ 29 ], which has the Amazon basin as the main promoter of the hydrological cycle of the entire region [ 30 ].…”

Tropical deforestation causes large reductions in observed precipitation

“…A comparison of station-based precipitation datasets revealed higher levels of uncertainty in the tropics, including the Amazon 19 . In regions of sparse data such as tropical forests 20 , interpolation methods may mask precipitation changes driven by forest loss. Reanalysis products, which are numerical models constrained by empirical data, are also expected to be less reliable in regions where in situ data are limited 21 .…”

Estimation of the Madeira floodplain dynamics from 2008 to 2018

“…The delineation of the floodplain is based on the method of slope thresholds described in Rathjens et al (2015). The SRTM DEM is a global topographic data set widely used in hydraulic simulations and geomorphologic characterization of the Amazon floodplains but these data are affected by vegetation cover, speckle, and stripe noise (Fassoni-Andrade et al, 2021). In first approximation, these data are adequate to delineate the floodplains in the SWAT model regarding the study area, the model discretisation, and the aim of simplifying the processes.…”