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SEASAT/SIR-A DIGITAL REGISTRATION OVER ALGERIA 
Ph. REBILLARD*, C. ELACHI, M. NARAGHI, J. SOHA, W. STROMBERG 
Jet Propulsion Laboratory 
MS 183-701 
4800 Oak Grove Drive 
Pasadena, CA 91109, USA 
*National Research Council Research Associate 
ABSTRACT 
Seasat Synthetic Aperture Radar (SAR) and Shuttle Imaging Radar 
(SIR-A) data over northeastern Algeria have been studied using digital 
registration. 
Preliminary results of this work show that: (1) both radars delineate 
in the same way the same features on the ground, (2) the Seasat image shows a 
strong difference between the Chott Melrhir and its environment, not seen in 
the same way by SIR-A, and (3) SIR-A data enhance more details on the floor of 
the Chotts, presumably due to the look angle or due to flooding conditions 
which may have occurred prior to the SIR-A experiment (November 12-14,1981). 
DATA LOCATION 
Few places outside the U.S. were covered by both Seasat and SIR-A. 
Among them the Chott Merouane and the Chott Melrhir (northeastern Algeria) are 
intersected by Seasat Rev 791 and SIR-A data take 32-33 (Fio. 1). Seasat 
Synthetic Aperture Radar data were acquired on August 21, 1978 and Shuttle 
Imaging Radar (SIR-A) data take 32-33 were taken during the second flight of 
Columbia (Nov. 12-14, 1981). Goals and first results of the imaging radar 
mission are given by Elachi, 1982. 
The Chott Merouane and the Chott Melrhir are located on the 
northeastern boundary of the Algerian Sahara, 100 Km south of the town of 
Biskra, center coordinates of the area are 6° 30’ East and 34° 10’ North. 
        
      
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Figure 1: 
Seasat SAR and SIR-A ocverages over 
northeastern Algeria. An: Annaba, 
Ba: Batna, Be: Bejaia, Bi: Biskra, 
Co: Constantine, Se: Setif. Chotts: 
1, El Honda; 2, Merouane; 3, Melrhir; 
4, El Rharsa; 5, Djerid. Seasat 
coverage in solid lines and SIR-A 
data take in dots. 
ALGIERS 
ALGERIA 7 
  
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