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FRINGE scientists use radar vision to see the Earth move   The juxtaposition of old and new data shows the change. An aerial or satellite picture of Venice (black and white) is overlaid with the current data of the earth reconnaissance satellite (colored). The space data show that part of Venice is sinking millimetre by millimetre into the sea - more in the red and violet areas than in the blue and green. Such details help concentrate structural protection measures in the places where they are most needed. Credits: GAMMA/ESA  Speakers at the December 2003 FRINGE workshop for advances in Synthetic Aperture Radar (SAR) Interferometry derived from ERS and Envisat, taking place at ESRIN in Frascati, Italy. Precise views of changing landscapes  Prof. Fabio Rocca of the Politecnico di Milano, an authority on InSAR techniques.  More than 150 ERS images acquired between 1992 and 2000 were combined by the British Geological Survey to produce this InSAR-based depiction of crustal movement around Hamamatsu-Yaizu on Japan's south coast. It measures the annual average line of sight velocity in millimetres per year of 'permanent scatterer' fixed points. Light blue indicates 1 to 3 mm, green 1 to -1 mm, yellow -1 to -3 mm, orange -3 to -5 mm, and red greater than -5 mm. Applications of the data include geological risk assessment for the insurance industry and exploring links between ground movement and gas pipe failure. Watching over a 'breathing' volcano  Animation showing terrain displacement of Mount Etna, 1992-2000. Click to begin animation.  Paul Lundgren of JPL attending the 2003 FRINGE workshop at ESRIN. Lundgren has been using InSAR to monitor ground movement on Mount Etna in Italy. A lost world sealed off under tonnes of ice  Envisat wide-swath radar image of ice above the sub-glacial Lake Vostok, acquired 13 March 2003. The freshwater lake's full extent was first mapped using ERS-1 data in the early 90s, because the ice floating over the lake has a smoother surface than the ground-based ice surrounding it. More recently, ERS InSAR results have comfirmed its waters are influenced by tides.  Relief map of the Antarctic ice sheet derived from ERS-1 data. Lake Vostok shows up as an unusually smooth area of ice (highlighted). The main surface features such as ice divides, domes, ice stream outflow and drainage basins are well defined. Over 20 million height estimates were used to generate a 10 km Digital Elevation Model of the ice sheet which is accurate to better than 1 m for slopes less than 0.5 degrees. South of the latitudinal limit of the satellite (81.5degrees) a terrestrially derived dataset was used with a substantial reduction in both the accuracy and short wavelength detail (as can be seen in the diagram). Missions to come  Colour composite of airborne radar images acquired at three different frequencies (L-, C- and X-band) by the DLR E-SAR system during the ESA TerraSARSIM campaign in Barrax, Spain, in April 2003. The aim of the campaign was to investigate the effect of different acquisition times for each frequency on the combined information content of the three frequencies in support of the ESA TerraSAR L project.
The circular fields in the image are typical of pivot irrigation systems installed in the area. The light green slice in the circular field located in the upper right of the image illustrates the enhanced radar return due to the wet soil conditions after the pivot boom had passed over the area.  Dr Richard Bamler of the German Aerospace Centre DLR Release date: 11 June 2004 |