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.

SAR Links & Resources:

Latest Updates

September 21, 2020
Map showing likely damaged areas in Angeles National Forest on September 7th, 8th, 13th, and 14th
As fires continue to rage in California and across the western U.S., NASA’s Earth Applied Sciences Disasters Program is aiding local agencies by using satellite and airborne instruments to help track the burned areas and map damage to infrastructure and the environment.  Map showing likely damaged areas in Angeles National Forest on September 7th, 8th, 13th, and 14th. Credits: Sentinel-1 data were accessed through the Copernicus Open Access Hub and the NASA mirror...
April 27, 2020
ARIA Damage Proxy Map (DPM) showing potentially damaged structures from Cyclone Harold in red and yellow in Luganville, the second largest city in Vanuatu,. Credit: NASA ARIA, EOS, Google, Copyright contains modified Copernicus Sentinel data 2020, process
ARIA Damage Proxy Map (DPM) showing potentially damaged structures from Cyclone Harold in red and yellow in Luganville, the second largest city in Vanuatu,. Credit: NASA ARIA, EOS, Google, Copyright contains modified Copernicus Sentinel data 2020, processed by ESA Tropical Cyclone Harold developed from a low-pressure system that was observed to the east of Papua New Guinea, and tracked to the southeast where it peaked as a Category 5 cyclone on April 6th, 2020. The cyclone brought...
January 15, 2020
Preliminary map of co-landslides caused by the Mw6.4 earthquake. The image shows the location of 120 landslides with the USGS Peak Ground Acceleration Contours that shows the areas of greatest shaking (available here).
The NASA Earth Applied Sciences Disasters Program has activated a “Tier 1” response to the earthquakes in Puerto Rico, which entails collecting information and coordinating with stakeholders and university partners. The program is participating in inter-agency calls with federal agencies leading the response effort including the Federal Emergency Management Agency (FEMA), the United States Geological Survey (USGS) and the U.S. Department of Health and Human Services (HHS), along with the Earthquake Engineering Research Institute, to provide NASA Earth-observing data in support of the response...
January 13, 2020
This map shows ground changes, or displacement, on the eastern two-thirds of Puerto Rico following a 6.4-magnitude earthquake. The ground shifted up to 5.5 inches (14 centimeters) in a downward and slightly west direction. Credit: NASA/JPL-Caltech, ESA, U
NASA scientists are using satellite data to help federal and local agencies identify areas with potential damage. Earthquakes cause permanent changes to the ground surface. By comparing interferometric synthetic aperture radar (InSAR) data acquired on Jan. 9, 2020, with data acquired on Dec. 28, 2019, from the Copernicus Sentinel-1A satellite, the scientists were able to map where, how much and in what direction those changes occurred.
September 6, 2019
Screenshot of SAR flood map from Hurricane Dorian on 9/2/19.
Powerful Category 5 Hurricane Dorian struck the northern parts of the Bahamas on Sunday, September 1. Dorian first pummeled the Abaco Islands before stalling and battering Grand Bahama Island more than 40 hours with heavy rain and catastrophic storm surge. The National Oceanic and Atmospheric Administration’s (NOAA) GOES East satellite provided rapid, highly detailed imaging so that forecasters would have critical information about the storm’s movement. In the evening hours of September 2, the European Space Agency’s Sentinel-1A satellite also passed over the Bahamas, with a synthetic...
September 5, 2019
A damage assessment map derived from satellite data shows conditions on one island in the Bahamas on Sept. 2. Red and yellow areas are likely the most damaged. Credit: NASA-JPL, Caltech, Earth Observatory of Singapore. 
A damage assessment map derived from satellite data shows conditions on one island in the Bahamas on Sept. 2. Red and yellow areas are likely the most damaged. Credit: NASA-JPL, Caltech, Earth Observatory of Singapore. Copyright contains modified Copernicus Sentinel data (2019), processed by ESA Versión en español NASA has created and provided to emergency response...
September 3, 2019
 NASA's ARIA team used satellite data acquired on Sept. 2, 2019, to map flooding in the Bahamas in the wake of Hurricane Dorian. Credits: NASA/JPL-Caltech, ESA
NASA's ARIA team used satellite data acquired on Sept. 2, 2019, to map flooding in the Bahamas in the wake of Hurricane Dorian. Credits: NASA/JPL-Caltech, ESA While many NASA missions are tracking Hurricane Dorian as the storm makes its way toward the United States, some researchers are looking at what Dorian has already left behind.  The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, used synthetic aperture radar data from the...
June 21, 2019
This map shows water extent along the Missouri River and surrounding regions on May 29th, 2019. Areas with likely flooding detected are shown in red.
The NASA Disasters Program responded to a request from the USDA National Agricultural Statistics Service (NASS) to provide water extent maps for the regions affected by the recent flooding rainfall in the central U.S. Maps were generated using Sentinel 1A/B satellite overpasses of the central U.S. from 5/22/19 to 6/17/19...
October 30, 2018
ARIA DPM Imagery of Northern Mariana Islands Devastated by Super Typhoon Yutu
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 Northern Mariana Islands that are likely damaged (shown by red and yellow pixels) as a result of Super Typhoon Yutu. The map is derived from synthetic aperture radar (SAR) images from the Copernicus Sentinel-1 satellites, operated by the European Space Agency (ESA). The pre-event images were taken before (October 4, 2017...
September 18, 2018
ARIA damage proxy map derived from images taken before (September 02, 2016) and 12 hours after the hurricane's landfall (September 14, 2018 7:06 PM local time).
UPDATE 9/18/18:ARIA damage proxy map derived from images taken before (September 02, 2016) and 12 hours after the hurricane's landfall (September 14, 2018 7:06 PM local time). The ARIA team has created a flood extent map from Sentinel-1 SAR data acquired from Track 4, 12 hours after the landfall of Hurricane Florence. The map was pushed to the FEMA's SFTP server and is available to download from  ...
September 15, 2018
Sentinel 1A overpass of coastal North and South Carolina from 9/14/18. Contains modified Copernicus Sentinel data (2017), processed by ESA. 
Sentinel 1A overpass of coastal North and South Carolina from 9/14/18. Contains modified Copernicus Sentinel data (2018), processed by ESA.  Mission description: Sentinel 1A/B is a two satellite synthetic aperture radar constellation operated by the European Space Agency. The backscattered microwave energy from the ground can be used to map flooded areas, and estimate wind speeds over the ocean. Both satellites have a 12-day repeat cycle, providing imagery at about 20m resolution every 6...
August 19, 2018
ARIA Damage Proxy Map (DPM) comparing JAXA ALOS-2 SAR data from May 13, 2018  vs. August 19, 2018.
ARIA Damage Proxy Map (DPM) comparing JAXA ALOS-2 SAR data from May 13, 2018  vs. August 19, 2018. The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas in the northeastern part of Lombok Island, Indonesia, that are likely damaged (shown by red and yellow pixels) as a result of the major earthquake sequence (including the M6.4 July 29...
August 18, 2018
Flood map for Kerala
In the maximum observed flooding map, areas in RED are flooding mapped from Copernicus Sentinel 1 SAR data provided by the European Space Agency. Areas in PURPLE are currently flooded and also flooded in previous years. Areas in BLUE are covered by a reference normal water extent. Areas in LIGHT GRAY are all previously mapped flooding, since 1999. The...
August 7, 2018
Satellite-Derived Map of Ground Deformation from Earthquake beneath Lombok, Indonesia
Scientists with the Advanced Rapid Imaging and Analysis project (ARIA), a collaboration between NASA’s Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, using synthetic aperture radar (SAR) data from the European Union’s Copernicus Sentinel-1A and -1B satellites, operated by the European Space Agency, generated a map of the deformation of Earth’s surface caused by the Aug. 5, 2018 magnitude 6.9 earthquake under Lombok island, Indonesia. The deformation map is produced from automated interferometric processing of the SAR...
July 27, 2018
LAOS Dam failure
On July 25, 2018, the Sentinel-1 satellite from the European Space Agency (ESA) Copernicus program captured a clear image of the collapsed Xe-Pian Xe-Namnoy dam and resulting floods. The imagery within the map viewer shows a drastic drop in the reservoir level, the impacts of which were felt on villages downstream.  NASA and SERVIR-Mekong processed satellite imagery to estimate the extent of the flooded areas, particularly along the Xe Pian River and village of Sanamxai along the Xe Khong River in Attapeu province. Since the dam failure on July 23, cloudy skies have...
June 11, 2018
JAXA ALOS-2 SARS data
ALOS-2 interferogram comparing data from 1/30/18 vs. 5/8/18.  The above map shows ALOS-2 SAR scenes acquired in January 2018 and May 8, 2018 and shows the early opening of the lower East Rift Zone before May 8. In this first map there is a zone approximately 1.5 km wide where there is little motion of the surface, indicating that the magma injection is primarily around 1-2 km below the surface in this early stage.  In both maps, I overlaid in green...
June 7, 2018
ARIA damage proxy map of Fuego volcano
The Advanced Rapid Imaging and Analysis (ARIA) team at NASA's Jet Propulsion Laboratory in Pasadena, California, and Caltech, also in Pasadena, created this Damage Proxy Map (DPM) depicting areas around Fuego volcano, Guatemala, that are likely damaged (shown by red and yellow pixels) as a result of pyroclastic flows and heavy ash spewed by Fuego volcano. The map is derived from synthetic aperture radar (SAR) images from the Copernicus Sentinel-1 satellites, operated by the...
May 26, 2018
ALOS-2 interferogram from June 23rd, 2018 acquisition relative to June 9th, 2018.
The Advanced Land Observing Satellite-2 (ALOS-2), a Japanese Aerospace Exploration Agency (JAXA) satellite, is a follow-on mission from the "DAICHI", which contributed to cartography, regional observation, disaster monitoring, and resource surveys. ALOS-2 will succeed this mission with enhanced capabilities. Specifically, JAXA is conducting research and development activities to improve wide and high-resolution observation technologies developed for DAICHI in order to further fulfill social needs. Each interferometric synthetic aperature radar (InSAR) image, or interferogram, shows the amount...
May 4, 2018
Sentinel 1B 12-day interferogram: April 23, 2018, 4:15 p.m. UTC to May 5, 2018, 4:15 p.m. UTC
Sentinel 1B image from May 5th, 2018. Sentinel 1B 12-day interferogram: April 23, 2018, 4:15 p.m. UTC to May 5, 2018, 4:15 p.m. UTC The ESA Sentinal 1 mission has produced a series of interferograms for the recent volcanic eruption and earthquake that have occurred at the Kilauea volcano on...
February 17, 2018
Motion towards satellite (up and west) in radar line-of-sight direction.
Interferogram from modified Copernicus Sentinel-1 SAR data acquired 2018/02/17 and 02/05 shows earthquake fault slip on subduction megathrust beneath coast caused up to 40 cm of uplift of the ground surface. Interferometric SAR (InSAR) analysis was automatically performed by Caltech-JPL ARIA data system. Main image shows motion towards satellite (up and west) in radar line-of-sight direction. Additional images show motion contoured with 9 cm (image 2) and 2.8 cm (image 3) color contours, also known as fringes, displayed in Google Earth. Symbols show preliminary USGS and Mexican seismic...

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