| snippet:
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Flood detection and impact assessment using Sentinel-1 Synthetic Aperture Radar for the Washington Atmospheric River December 2025. |
| summary:
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Flood detection and impact assessment using Sentinel-1 Synthetic Aperture Radar for the Washington Atmospheric River December 2025. |
| extent:
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[[-124.429587703668,45.8504363455406],[-120.655765195081,49.0025348459876]] |
| accessInformation:
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Dr. Khuong H. Tran (Khuong.tran@nasa.gov) |
| thumbnail:
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thumbnail/thumbnail.png |
| maxScale:
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1.7976931348623157E308 |
| typeKeywords:
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["ArcGIS","ArcGIS Server","Data","Map Service","Service"] |
| description:
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<div style='text-align:Left;'><p style='margin:0 0 11 0;'><b>Dates of Images:</b></p><p style='margin:0 0 11 0;'><i>Post-Event: </i>Dec 10, 2025<span><span></span></span></p><p style='margin:0 0 11 0;'><span><span><i>Pre-Event:</i> Dec 7, 2025</span></span></p><p><span style='font-weight:bold;'>Date of Next Image:</span></p><p style='margin:0 0 11 0;'><span><span>Dec 11, 2025</span></span></p><p><span style='font-weight:bold;'>Summary:</span></p><p><span>We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1’s SAR backscatter characteristics are particularly effective for detecting surface water: water surfaces typically exhibit low backscatter, whereas non-water areas show higher backscatter. Leveraging this physical property, we distinguished between water and non-water surfaces from both pre- and post-flood observations.</span></p><p><span>To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post – VV_pre). This change detection technique enhances the visibility of newly inundated areas. We then applied a simple threshold to the dVV image to separate flooded from non-flooded areas.</span></p><p><span style='font-weight:bold;'>Suggested Use:</span></p><p><span>The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color).</span></p><p><span>A permanent water body layer and a binary layer incorporating land cover are also included.</span></p><p><span style='font-weight:bold;'>Satellite/Sensor:</span></p><p><span>Sentinel-1 /Synthetic Aperture Radar (SAR)</span></p><p><span><b>Resolution:</b></span></p><p><span>10 meters</span></p><p><span><b>Credits:</b></span></p><p><span>Dr. Khuong H. Tran (Khuong.tran@nasa.gov)</span></p><p><span><b>Esri REST Endpoint:</b></span></p><p><span>See URL section on right side of page</span></p><p><span><b>WMS Endpoint:</b></span></p><p><a href='https://gis.earthdata.nasa.gov/gis05/services/DISASTERS_202512_FLOOD_WA/sentinel1_FloodDetection/MapServer/WMSServer' target='_blank'>https://gis.earthdata.nasa.gov/gis05/services/DISASTERS_202512_FLOOD_WA/sentinel1_FloodDetection/MapServer/WMSServer</a></p></div> |
| licenseInfo:
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<div style='text-align:Left;'><div><div><p><span>NASA data and products are freely available to federal, state, public, non-profit and commercial users. This information can be experimental- or research-grade data products and may not be appropriate for operational use. These NASA data products, services, and the Disasters Mapping Portal are intended to aid decision makers and enhance situational awareness, but these data are not guaranteed to be consistently available or routinely updated.</span></p></div></div></div> |
| catalogPath:
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| title:
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Flood detection and impact assessment using Sentinel-1 Synthetic Aperture Radar for the Washington Atmospheric River December 2025 |
| type:
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Map Service |
| url:
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|
| tags:
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["Sentinel-1","USA","Washington","NASA","NASA Disasters Program","ESA","SAR","Syntehtic Aperture Radar","Copernicus","Flood","Atmospheric River"] |
| culture:
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en-US |
| portalUrl:
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|
| name:
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sentinel1_FloodDetection |
| guid:
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E13DF4D2-30C5-4484-B2F1-5536EE3E38EA |
| minScale:
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0 |
| spatialReference:
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GCS_WGS_1984 |