Karachi, the largest city of Pakistan received heavy monsoon rain August 30, 2017. The flood in Karachi due to heavy rains is the continuation of the similar monsoon related flooding crisis in the South East Asia region (India, Bangladesh etc.).The Flood map below is derived (subset of Karachi city ) from European Space Agency (ESA)’s Copernicus Program SENTINEL-1 Synthetic Aperture RADAR (SAR) image acquired on September 01, 2017. The green color in the map shows the flooded region.
The total rainfall derived from satellite data (GPM IMERG) for Karachi from August 29-31, 2017 is shown in Figure below:
This post will provide an overview of the basics of Synthetic Aperture RADAR (SAR) and applications. The main topics discussed in the listed documents include: SAR basics, backscatter, geometry, interferometry, polarimetry, SAR data, data acquisition, available data sets/access to data, data analysis tools, future missions and SAR applications. Please do check Part 2 for more details.
What is RADAR? – RAdio Detection And Ranging
What is SAR? – Synthetic Aperture Radar – Synthetic Aperture Radar (SAR) is an active remote sensing technology that uses microwave energy to illuminate the surface. The system records the elapsed timeand energy of the return pulse received by the antenna (PDF).
The Canada Centre for Mapping and Earth Observation (CCMEO) is considered an international leader in the development and use of synthetic aperture radar or SAR sensors. From space, SAR can image the Earth’s surface through clouds and in total darkness. This makes it a tremendously useful sensor for monitoring Canada’s changing landmass and coastal zones. CCMEO scientists have worked with the Canadian Space Agency in the development of both RADARSAT 1 and RADARSAT 2 satellite missions. Their research has led to improved data quality through enhanced sensor design and post-launch calibration and validation activities.
This training manual introduces and explains Interferometric Synthetic Aperture Radar (InSAR), including applications for data from the Envisat ASAR sensor and how to combine Envisat and ERS images to produce interferograms and differential interferograms.
Active Microwave Remote Sensing provides cloud penetration and day-night imaging capability. These unique characteristics of C-band (5.35GHz) Synthetic Aperture Radar enable applications in agriculture, particularly paddy monitoring in kharif season and management of natural disasters like flood and cyclone.
Terra SAR-X / TanDEM-X
Launched in 2007/10, X-band quad polirzation, DLR/Astrium, Germany
Terra SAR-X (TSX) mission overview, spacecraft, references (Link) (Link to documents)
JAXA conducted research and development activities for ALOS-2 to improve wide and high-resolution observation technologies developed for ALOS in order to further fulfill social needs. These social needs include: 1) Disaster monitoring of damage areas, both in considerable detail, and when these areas may be large 2) Continuous updating of data archives related to national land and infrastructure information 3) Effective monitoring of cultivated areas 4) Global monitoring of tropical rain forests to identify carbon sinks.
Launched in 2007/10, 4 Satellites X-band dual polirzation, ASI/Italy
COSMO SkyMed offers high resolution X‐Band SAR (synthetic aperture radar) images. Despite its enormous potential, research investigating the possible uses in archaeology is still very scarce, especially of one which works solely with single date analysis starting with a single SAR scene (PDF).
Launched in 2013, S-band (HH or VV) polarization CRESDA/CAST/NRSCC, China
HJ-1A/B/C corresponding to environment and disaster monitoring and forecasting small satellite constellation A/B/C include two optical satellites – HJ-1A/B and one radar satellite HJ-1C, which can carry out large-scale, all-weather and 24h dynamic monitoring for ecological environment and disaster (Link).
Launched in 2014, X-band quad polarization, Ministry of Defense, Spain
PAZ is a Spanish radar technology satellite designed to address not only security and defense requirements, but also others of civilian nature. It is capable of daily taking more than 100 images of up to 25 cm resolution, both day and night, and independently of weather conditions (Link).
Launched in 2013, X-band dual polarization, KARI, Korea
The Argentina National Space Activities Commission (CONAE) launched a new Earth observationsatellite that will support disaster management efforts. SAOCOM 1A is the first of a constellation of two radar satellites. The remote sensing mission aims to provide timely information for disaster management as well as monitoring services for agriculture, mining and ocean applications.
The launch of the first dual-frequency synthetic aperture radar (SAR). The data collected by the L-band (produced by NASA) and S-band (produced by ISRO) SAR systems aboard the NISAR satellite and processed into cloud-free, ultra-sharp imagery will facilitate cutting-edge research into some of the planet’s most complex processes, including ecosystem disturbances, ice-sheet dynamics, earthquakes, tsunamis, volcanoes, and landslides.
RADARSAT Constellation Mission (RCM)
Will launch in 2019 three satellites, C-band quad compact polirzation, Canadian Space Agency (CSA) (Link)