Flood Monitoring from Space – ESA’s Sentinel-1

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:

 

 

Advertisements

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.

sar_satellite_missions.png

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)

ERS SAR data available via ESA On-The-Fly service – Content – Earth Online – ESA

ESA is pleased to announce that SAR data from the ERS-1 and the ERS-2 missions have been made available for direct download via the (A)SAR On-The-Fly (OTF) service.

With this release, users now have access to (A)SAR level 1 products from both ERS missions and from Envisat, covering Image Mode (IMS, IMP), Wide Swath (WSS) and Alternating Polarisation (APP, APS). All data are delivered as standard scenes in Envisat format.

Processing and download of the generated “standard scene” Level 1 products is performed directly through the EOLI-SA user interface. A user manual and FAQ page are available to get started.

 

Source: ERS SAR data available via ESA On-The-Fly service – Content – Earth Online – ESA

The evolution of the Sentinel Collaborative Ground Segment – News – Sentinel Online

The evolution of the Sentinel Collaborative Ground Segment

12 January 2017

ESA and its Member States created the Sentinel Collaborative Ground Segment (CollGS) to further enhance the Sentinel missions exploitation in various areas. Today, the cooperation is also open to all European countries and Copernicus Participating States.

Besides the challenging task of building and launching a satellite, a key indicator of the success of an Earth observation mission relies on ensuring that the data gathered are of good quality and made easily available to users.

These functions are all ensured by the Copernicus Space Component (CSC) Ground Segment.

The Sentinel Collaborative Ground Segment complements the Copernicus Ground Segment. This entails additional elements for specialised solutions in different technological areas, such as data acquisition, complementary production and dissemination.

But what does the CollGS do, exactly?

  • National entities can build-up their own mirror data archive and base operational services on Sentinel data. Participating countries then redistribute the Sentinel data and/or value added products from their “mirror sites”, to institutional, commercial and science users.
  • Many mirror sites in place are now also adding hosted processing to their services.
  • If technically required to meet data timeliness obligations, local ground stations are configured to listen-in as Sentinel data is downlinked to core ground stations. This allows for quasi-real time product generation as, for instance, in supporting marine surveillance activities in the Baltic Sea.
  • Furthermore, in the frame of the CollGS, national initiatives carry out the development of innovative tools and applications.

Canada, which is an associate ESA Member State, operates extremely important land and maritime monitoring activities, with C-CORE and other organisations. Having established a CollGS agreement, they can access the Sentinel products via a data hub operated by ESA and dedicated to collaborative partners.

Shahid Khurshid, Physical Scientist at Meteorological Service of Canada, and Matt Arkett, Acting Manager of Earth Observation and Geomatics, at Environment and Climate Change Canada, said: “Environment and Climate Change Canada’s Operational National SAR Winds (NSW) system provides near real-time delivery of marine wind measurements derived from spaceborne synthetic aperture Radars (SAR) to support marine forecasters & other applications.

“The programme has been operational since 2013, ingesting SAR data from the RADARSAT-1 and RADARSAT-2 missions. The NSW system began to generate operational surface wind maps using Sentinel-1A data in April 2016 and Sentinel-1B in September 2016.
“Access to Sentinel-1 data has significantly increased the temporal and spatial frequency of marine wind speed information being delivered to our operational marine forecasters.

Continue reading