Radar images from TerraSAR-X

DLR provides satellite data for Hurricane Harvey

Radarsatellit TerraSAR-X

30 August 2017

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  • Radarsatellit TerraSAR%2dX
    TerraSAR-X radar satellite

    TerraSAR-X orbits Earth in a polar orbit at an altitude of 514 kilometres. DLR has provided real-time data that enabled a detailed analysis of the flooded regions.

  • Überflutungsgebiete bei Houston / Texas (USA)
    Flooded regions in Houston, Texas (USA)

    Interactive map of the flooded regions in Houston, Texas (USA). TerraSAR-X image acquired on 28 August 2017.

  • Gebiet Corpus Christi mit markierten Hochwasserflächen
    Marked high-water areas in Corpus Christi flooded region

    TerraSAR-X satellite image in wide-scan mode from 28 August 2017 superimposed with high-water areas (light blue) and water courses (dark blue).

  • Überflutungsgebiet Corpus Christi vor Harvey
    Corpus Christi area before Harvey hit

    TerraSAR-X satellite image before the hurricane

  • Überflutungsgebiet Houston mit markierten Hochwasserflächen
    Flooded regions of Houston with marked high-water areas

    TerraSAR-X recordings of 29 August 2017 showing high-water areas (light-blue) and water courses (dark blue).

  • Überflutungsgebiet Houston vor Harvey
    Houston area before Harvey hit

    Recording of the flooded region in Houston in wide-scan mode before the hurricane hit.

  • German Aerospace Center (DLR) provides real-time recordings and archive data of the German radar satellite TerraSAR-X.
  • DLR supports hurricane disaster management in Texas, USA.
  • Focus: Space, climate change, disaster and disaster management, Earth observation

In anticipation of the catastrophic hurricane Harvey, the International Charter 'Space and Major Disasters' was activated early on the evening of 24 August 2017. This was initiated by the Charter member United States Geological Survey (USGS) on behalf of the Texas Emergency Management Council. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) provided real-time recordings and archive data from the German radar satellite TerraSAR-X, which enabled a detailed analysis and an overview of the flood situation. Using these and other satellite data provided by 16 Charter members, the Center for Space Research at the University of Texas is currently working on providing assistance and information to disaster relief personnel on the ground.

"The various recording modes of the German radar satellite TerraSAR-X make it possible to react very flexibly to individual crisis situations," explains André Twele, who, as an Emergency On-Call Officer (ECO) of the Charter at DLR, was tasked with preparing an acquisition plan using available satellite resources in the first hours of activation. "The challenge herein lies in determining possible disaster areas as early as possible from the initially still rough forecast of the hurricane's path to be able to plan the satellite recordings effectively."

Through the clouds with radar

DLR's Earth Observation Center (EOC) delivered the data acquired by the satellite as quickly as possible. The particularly wide swath mode of the TerraSAR-X recordings made it possible to precisely depict the extent of the catastrophe shortly after the hurricane made landfall. A decisive advantage is the weather-independent nature of radar imaging. While optical satellites are limited to imaging cloud surfaces on an overcast day, the radar instrument on the German satellite is able to penetrate cloud cover to 'scan' the surface and receive the reflected ‘echo’. Radar satellites are the first choice in large-scale flood disasters, because the backscattered signal from water bodies stands out from non-flooded surfaces.

The Charter allows its Authorised Users (AU) – usually national disaster management authorities – to activate the Charter already in anticipation of an imminent emergency. This was the case here. “Therefore, we were able to program our satellites at an early stage so that the images could be taken shortly after the hurricane made landfall," explains Jens Danzeglocke from the DLR Space Administration, who coordinates the Charter activities in Germany.

The flood maps derived from the satellite data help to coordinate emergency procedures, for example to identify particularly affected areas, assess damage to infrastructure and traffic routes, or plan evacuation centres.  

About the International Charter 'Space and Major Disasters'

DLR’s membership in the Charter is carried out by the DLR Space Administration and the DLR Earth Observation Center (EOC). The International Charter ‘Space and Major Disasters’ is comprised of space agencies and satellite operators with the aim of providing a uniform system for the quick acquisition and delivery of satellite data in the event of a disaster. The members of the Charter thus make free satellite data available to authorised users in the event of a disaster, usually disaster management and civil protection organisations, in support of assistance measures in case of major technical or natural catastrophes. The Charter data will be used by the Authorised Users directly or will be analysed by associated Value Adders, like the Centre for Satellite Based Crisis Information (ZKI). The results are provided to the Authorised Users, requesting authorities and also to the public.

Last modified:
30/08/2017 19:03:40



Miriam Poetter
German Aerospace Center (DLR)

Communications Oberpfaffenhofen

Tel.: +49 8153 28-2297

Fax: +49 8153 28-1243
Dr.rer.nat. Torsten Riedlinger
German Aerospace Center (DLR)

German Remote Sensing Data Center, Civil Crisis Information and Geo Risks

Tel.: +49 8153 28-3674

Fax: +49 8153 28-1445
Jens Danzeglocke
German Aerospace Center (DLR)

Space Administration, Earth Observation

Tel.: +49 228 447-215

Fax: +49 228 447-747