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 towards an 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.