SAR

Overview

Synthetic Aperture Radar (SAR) refers to a technique for producing fine resolution images from an intrinsically resolution-limited radar system. The wavelengths, λ, that are used for radar remote sensing of the earth’s surface are typically in the range of a few to tens of centimeters. At these wavelengths, the energy radiated from a radar antenna of dimension D disperses quickly at a rate that is equivalent to the beam width λ/D of the antenna. For a typical spaceborne SAR configuration with wavelengths of ~10 cm and an antenna of 10 m size, this beam width is 1/100 radians, or about 0.6 degrees. If we are in space observing the Earth 1000 km below, the beam size on the ground is then 1000 λ/D = 10 km. This intrinsic resolution of the radar system is insufficient for many applications and practical solutions for improving the resolution needed to be found.

Learn more: http://nisar.jpl.nasa.gov/technology/sar/

Latest Updates

September 14, 2017
Image Credit: NASA/JPL-Caltech/Copernicus
NASA and its partners are contributing important observations and expertise to the ongoing response to the September 7, 2017 (local time), magnitude 8.1 Oaxaca-Chiapas earthquake in Mexico. This earthquake was the strongest over a century for Mexico. It has caused a significant humanitarian crisis with widespread building damage and triggered landslides throughout the region. Scientists with the Advanced Rapid Imaging and Analysis project (ARIA), a collaboration...
January 11, 2017
 ARIA Flood Proxy Map for the floods in Northern California and Nevada on January 8th, 2017.
 ARIA Flood Proxy Map for the floods in Northern California and Nevada on January 8th, 2017.  Flood Proxy Map (FPM) covering an area of 155-by-224 miles (250-by-360 km), derived from Sentinel-1's pre- (2016-12-15 6 PM PST) and during-the-event (2017-01-08 6 PM PST) Synthetic Aperture Radar (SAR) amplitude images. The colored pixels represent areas of potential flood (Red: flooded vegetation, Blue: open water flood). Different irrigation conditions on the two data...
April 17, 2017
SAR flood extent map for Aukland New Zealand.
Following a Sentinel-1 acquisition over eastern North Island, covering Auckland on April 14, 2017 at 17:37h UTC, a synthetic aperture radar (SAR) flood proxy map (FPM)  was developed as a KMZ overlay (available for download here) This FPM covers an area of 175-by-500 km, derived from Sentinel-1's pre- (2016-04-02) and post-event (2017-04-14) SAR amplitude images. The colored pixels...
April 12, 2017
Sentinel-1 Comparison of 2017 New Zealand floods.
Change detection map of recent flooding in New Zealand 3/11/17 vs. 4/11/17 using Sentinel-1 data. Red areas indicate flooding.  Please ignore the change detection that is observed over the open ocean - the product does not incorporate a water mask at this time. 
April 4, 2017
Sentinel-1 flood map from Australia.
The NASA SPoRT team provided change detection products that highlight recent flood waters in Australia from Tropical Cyclone Debbie using Sentinel-1 data. These products were developed in conjunction with colleagues at the Alaska Satellite Facility (https://www.asf.alaska.edu/). The change detection is a simple algorithm is based detecting change that is consistent with flooding using a pre- and post-event scene. The product’s final...
April 4, 2017
Change detection map that highlights flood waters in Peru using Sentinel-1 data
The NASA SPoRT team provided change detection products that highlight recent flood waters in Peru using Sentinel-1 data. These products were developed in conjunction with colleagues at the Alaska Satellite Facility (https://www.asf.alaska.edu/). The change detection is a simple algorithm is based detecting change that is consistent with flooding using a pre- and post-event scene. The product’s final form is a binary geotiffs and a simple training...
September 12, 2017
ARIA Damage Proxy Map of Southern Florida from Hurricane Irma
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, created this Damage Proxy Map (DPM) depicting areas of Southwestern Florida, including Key West and Naples, that are likely damaged as a result of Hurricane Irma (Category 4 at landfall in Florida), shown by red and yellow pixels. The map is derived from synthetic aperture radar (SAR) images from the European Space Agency's (ESA) Sentinel-1...
April 13, 2017
SAR flood maps of 2017 New Zealand floods.
Below are images of a SAR Flood Map derived from ESA Sentinel-1 data for April 4, 2017. Flood regions were detected by measuring the difference in radar images acquired on April 4 and March 11 by Sentinel-1. Newer products will be developed when the data becomes available from ESA. On the KML file, red areas indicate flood presence. The point of contact for this data is: robert.brakenridge@colorado.edu Layers, top to bottom: Light Blue is reference water extent mapped via NASA 90 m (spatial resolution) SWBD. Red is flood water...
June 22, 2017
SAR map for 2017 Uruguay Flooding. Credit: Batuhan Osmanoglu (GSFC) and Rashied (JPL).
On May 24, 2017, a series of extreme rainfall events began impacting the west and northwest regions or Uruguay. These rains caused severe flooding in the Departments of Salto, Paysandú and Artigas.  SAR floods maps. The dates and locations depicted in these images are as follows: Upper left: Salto - 6/14/2017 Upper Right: Itaqui - 6/9/2017 Lower Left: Colón - 6/14/2017 Lower Right: closeup for Itaqui - 6/9/2017
January 7, 2016
This map highlights preliminary remote sensing priority areas for collection.
In anticipation of severe flooding likely to occur across portions of the central U.S., FEMA requires access to unclassified commercial Synthetic Aperture Radar (SAR) to ascertain flood extents. It is estimated that flooding will likely occur through this weekend (January 3, 2016). In addition, FEMA requests access to the raw SAR data collected as part of this effort in order for us (FEMA) to provide value-added analysis/flood extent delineation. 

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