{ "culture": "en-US", "name": "sentinel1_flood", "guid": "50B8C611-66FB-4891-904C-2EBD22AFC310", "catalogPath": "", "snippet": "Flood Detection using Sentinel-1 Synthetic Aperture Radar in semiarid areas in New Mexico.", "description": "

Date of Images:<\/span><\/p>

Post-Event: Jun 26, 2025 at 00:59 UTC (about 6:59PM MT)<\/span>

Pre-Event: Jun 20, 2025<\/span><\/p>

Date of Next Image:<\/span><\/p>

July 2, 2025<\/span><\/p>

Summary:<\/span><\/p>

We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1\u2019s 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>

To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post \u2013 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>

Suggested Use:<\/span><\/p>

The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color).<\/span><\/p>

Satellite/Sensor:<\/span><\/p>

Sentinel-1 /Synthetic Aperture Radar (SAR)<\/span><\/p>

Resolution:<\/span><\/p>

10 meters<\/span><\/p>

Credits:<\/span><\/p>

Dr. Khuong H. Tran (<\/span>Khuong.tran@nasa.gov<\/a>)<\/span><\/p>

Esri REST Endpoint:<\/span><\/p>

See URL section on right side of page<\/span><\/p>

WMS Endpoint:<\/span><\/span><\/span><\/p>

https://maps.disasters.nasa.gov/ags03/services/NM_FIre_202506/sentinel1_flood/MapServer/WMSServer<\/a>

Data Download:<\/span><\/p>

https://maps.disasters.nasa.gov/download/gis_products/event_specific/2025/newmexico_wildfires_202506/sentinel1_flood/<\/a><\/span><\/p><\/div>", "summary": "Flood Detection using Sentinel-1 Synthetic Aperture Radar in semiarid areas in New Mexico.", "title": "Flood Detection using Sentinel-1 Synthetic Aperture Radar in semiarid areas in New Mexico", "tags": [ "Sentinel-1", "USA", "New Mexico", "NASA", "NASA Disasters Program", "ESA", "SAR", "Synthetic Aperture Radar", "Copernicus", "Roswell" ], "type": "Map Service", "typeKeywords": [ "Data", "Service", "Map Service", "ArcGIS Server" ], "thumbnail": "thumbnail/thumbnail.png", "url": "", "extent": [ [ -105.354057195424, 32.5187437905414 ], [ -103.509726085598, 34.0888192441255 ] ], "minScale": 0, "maxScale": 1.7976931348623157E308, "spatialReference": "GCS_WGS_1984", "accessInformation": "Dr. Khuong H. Tran (Khuong.tran@nasa.gov)", "licenseInfo": "

The threshold-based approach may lack robustness when delineating flooded areas due to noisy Sentinel-1 backscatter signals and terrain-induced effects.<\/SPAN><\/P>

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. Use of this product should include: \"Contains modified Copernicus Sentinel data (2025) processed by ESA\".<\/SPAN><\/P>

<\/P><\/DIV><\/DIV>" }