Abstract
Abstract. The characterization of estuarine hydrodynamics primarily depends on knowledge of the bathymetry and topography. Here, we present the first comprehensive, high-resolution dataset of the topography and bathymetry of the Amazon River estuary, the world's largest estuary. Our product is based on an innovative approach combining spaceborne remote sensing data, an extensive and processed river depth dataset, and auxiliary data. Our goal with this mapping is to promote the database usage in studies that require this information, such as hydrodynamic modeling or geomorphological assessments. Our twofold approach considered 500 000 sounding points digitized from 19 nautical charts for bathymetry estimation, in conjunction with a state-of-the-art topographic dataset based on remote sensing, encompassing intertidal flats, riverbanks, and adjacent floodplains. Finally, our estimate can be accessed in a unified 30 m resolution regular grid referenced to the Earth Gravitational Model 2008 (EGM08), complemented both landward and seaward by land (Multi-Error-Removed Improved-Terrain digital elevation model, MERIT DEM) and ocean (General Bathymetric Chart of the Oceans version 2020, GEBCO_2020) topographic data. Extensive validation against independent and spatially distributed data, from an airborne lidar survey, from ICESat-2 altimetric satellite data, and from various in situ surveys, shows a typical vertical accuracy of 7.2 m (riverbed) and 1.2 m (non-vegetated intertidal floodplains). The dataset is available at https://doi.org/10.17632/3g6b5ynrdb.2 (Fassoni-Andrade et al., 2021).
Highlights
The Amazon River exports the largest discharge of freshwater (205 000 m3 s−1; Callède et al, 2010) and the largest sedimentary supply (5–13 × 108 t yr−1; Filizola et al, 2011) worldwide
Downstream of the downstream-most tidal stations, the SYZ level was calculated using a combination of the mean sea surface height provided by the ocean general circulation model of Ruault et al (2020) and of a proxy of the syzygy level estimated by the FES2014 tidal atlas (Carrère et al, 2016; available at https://www.aviso.altimetry.fr/ en/data/products/auxiliary-products/global-tide-fes.html, last access: 1 November 2020)
In the intertidal zone and floodplains along the Amazon River, water surface elevations (WSEs) records from limnigraphic and tidal stations were considered over the period from 2015 to 2018 (Tables A2 and A3) for consistency with the imagery period covered by the flood frequency map
Summary
The Amazon River exports the largest discharge of freshwater (205 000 m3 s−1; Callède et al, 2010) and the largest sedimentary supply (5–13 × 108 t yr−1; Filizola et al, 2011) worldwide. The Amazon estuary extends from the continental shelf up to Óbidos city, corresponding to the longest tidally influenced reach in the world, extending over 800–910 km (Kosuth et al, 2009; Nittrouer et al, 2021; Fig. 1) This river flow is drained downstream towards the ocean through the main channel until the confluence with the Xingu River, around 300 km upstream of the mouth, where it is divided into two long channels, hereafter called “South Channel” (locally named Gurupá Channel) and “North Channel” (Fig. 1). Our dataset is regularly gridded at a 30 m resolution and elevations are referenced to the Earth Gravitational Model 2008 (EGM08; Pavlis et al, 2012) The remainder of the paper is structured as follows: Sect. 2 presents the data sources and the methods used to build the dataset; Sect. 3 presents the validation against independent databases; Sect. 4 shows the topographic mapping and cross section along the river and floodplain; Sect. 5 discusses the significance and caveats of the dataset; and Sect. 6 explains the access to the various forms of our dataset
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