Pre-processed Sentinel-1 SAR of the Madeira River, Brazil

This dataset provides seven Sentinel-1 Synthetic Aperture Radar (SAR) scenes covering a portion of the Madeira River in Brazil from Porto Velho to Abuna. Each scene has been pre-processed for the use of detecting artisanal and small-scale mining (ASM) riverine dredges. The scenes were collected from the ASF search vertex (https://search.asf.alaska.edu/#/) as L1 Detected High-Res Dual-Pol (GRD-HD) products. They were acquired using a C-band SAR with the Interferometric Wide Swath (IW) mode, VV and VH polarizations, and a temporal resolution of 6 days. Each SAR acquisition covers a 250 km swath; however, these have been clipped to the study area. They have a 20 m x 22 m (ground range x azimuth) resolution, a 10 m x 10 m pixel spacing, and an Equivalent Number of Looks (ENL) of 4.4. The data is collected in ascending and descending passes; although, only descending passes were available in the study area. Four of the dates (20190604, 20190616, 20190628, and 20190710) required two scenes to be mosaicked together after pre-processing in order to cover the study area. The SAR data is pre-processed using the Sentinel Applications Platform (SNAP) software by following the steps: apply orbit file, thermal noise removal, border noise removal, calibration, and range doppler terrain correction. The commonly applied speckle filtering step is not applied as it reduces small spatial structures in the data, impacting the potential detection of the potentially small features produced by backscatter from ASM riverine dredges. Each scene contains the VH polarization in band 1 and the VV polarization in band 2, and should be displayed using the stretch type: standard deviation.

                                            [
  "010:12"
]
                                        

                                            {
  "fn": "Marissa A Alessi",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:malessi@usgs.gov"
}
                                        

                                            [
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                                            [
  "Mining and Mineral Extraction",
  "SAR",
  "USGS:655388a5d34ee4b6e05c3d89",
  "gold",
  "placer deposit mining",
  "radar imaging",
  "remote sensing"
]
                                        

                                            {
  "name": "U.S. Geological Survey",
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                                            [
  "Geospatial"
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