Synthetic Aperture RADAR (SAR) Remote Sensing Basics and Applications

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.

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 time an d energy of the return pulse received by the antenna.


Synthetic Aperature Radar (SAR) Tutorials

  1. A Tutorial on Synthetic Aperture RADAR – ESA (PDF )  (PDF) (Radiometric Calibration of SAR Image)
  2. 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.
  3. 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.
  4. Synthetic Aperture RADARs Imaging Basics (PDF)
  5. NOAA SAR Manual (PDF)
  6. Synthetic-aperture imaging from high-Doppler-resolution measurements (PDF)
  7. A Mathematical Tutorial on Synthetic Aperture RADAR (PDF)
  8. Remote sensed ground control points with TerraSAR-X and TanDEM-X (PDF)

Synthetic Aperature Radar (SAR) Applications

  1. Infrastructure Monitoring with Spaceborne SAR Sensors (Link)
  2. Soil Moisture Measurements by SAR (PDF)
  3. Marine applications: Sea Ice (Link), Marine Winds (PDF), Oil Pollution (PDF)
  4. Land deformation (Link)
  5. Flood Mapping (PDF) (PDF)

Detecting rainfall from the bottom up: SM2RAIN

SM2RAIN is a simple algorithm for estimating rainfall from soil moisture data.

The SM2RAIN code and the soil moisture derived rainfall data sets are freely available and can be downloaded here. The description of SM2RAIN and of its performance can be found in Brocca et al. (2013) and Brocca et al., 2014. (also here at IRPI-CNR website)


Here you can find two recent TALKS (IPWG 2016SMAP 2016) showing the latest results with the applications of SM2RAIN to multiple satellite soil moisture products (ASCAT, QUIKSCAT, RAPIDSCAT, AMSR-E, AMSR2, SMOS, and SMAP). In the paper by Massari et al. (2014) it is shown that SM2RAIN-derived rainfall from in-situ soil moisture observations even improves flood modelling (see also here, Italian media). In this paper by Brocca et al. (2015) the application of SM2RAIN to synthetic and in situ observations at several sites in Europe further underlines the robustness of the method. In Ciabatta et al. (2015) the integration of SM2RAIN with state-of-the-art products has provided significant improvements for rainfall estimation over the whole Italian territory. The latest application of SM2RAIN is for irrigation assessment, see here the project and a first overview paper.
Other scientist are using SM2RAIN in Mexico, in the Tibet Pleateau, and on a global scale. Click on the image below for the current list (PDF) of SM2RAIN papers with link to full text.