The performance of CryoSat-2 fully-focussed SAR for inland water-level estimation

Details

• Journal Title:
  Remote Sensing of Environment
• Personal Author:
  Kleinherenbrink, Marcel ; Naeije, Marc ; Slobbe, Cornelis ; Egido, Alejandro ; Smith, Walter
• NOAA Program & Office:
  STAR (Center for Satellite Applications and Research) ; NESDIS (National Environmental Satellite, Data, and Information Service)
• Description:
  This paper applies the Fully-Focussed SAR (FF-SAR) algorithm to CryoSat-2 full-bit-rate data to measure water levels of lakes and canals in the Netherlands, and validates these measurements by comparing them to heights measured by gauges. Over Lake IJssel, a medium-sized lake, the FF-SAR height is biased about 6 cm below the gauge height, and a similar bias is found at six sites where CryoSat-2 crosses rivers and canals. The precision of the FF-SAR measurements depends on the extent of multi-looking (incoherent averaging along-track) applied. Over Lake IJssel the precision varies from 4 to 11 cm, decreasing as multi-looking increases. The precision of FF-SAR with 100 m of multi-looking is equivalent to that of the standard delay/Doppler processing, which has an along-track resolution of about 300 m. The width and orientation of rivers and canals limits the maximum available multi-looking. After removing the 6 cm bias, FF-SAR heights of rivers and canals have an accuracy between 2 cm and several decimeters, primarily depending on the presence of other water bodies lying within the cross-track measurement footprint, as these contaminate the waveform. We demonstrate that FF-SAR processing is able to resolve and measure small ditches only a few meters in width. The visibility of these signals depends on the angle at which CryoSat-2 crosses the ditch and on whether or not the ditch remains straight within CryoSat-2’s field of view. In the best-case scenario, straight ditches at nearly 90° to the CryoSat-2 ground track, the ditch signal has high enough signal-to-noise to allow sub-decimeter accuracy of FF-SAR height measurement.
• Keywords:
  Computers In Earth Sciences Geology Soil Science Computers In Earth Sciences Computers In Earth Sciences
• Source:
  Remote Sensing of Environment, 237, 111589
• DOI:
  https://doi.org/10.1016/j.rse.2019.111589
• ISSN:
  0034-4257
• Format:
  PDF
• Publisher:
  Elsevier BV
• Document Type:
  Journal Article
• Rights Information:
  Accepted Manuscript
• Compliance:
  Library
• Main Document Checksum:
  urn:sha-512:c287249526fa6aa6e8637eb23469b9e4318217a565f580119c5e6ec4393ae523f2712a84b4960ae902d5a1dbeb08636a92918fe0d92f40472708ee97800aeff4
• Download URL:
  https://repository.library.noaa.gov/view/noaa/64518/noaa_64518_DS1.pdf
• File Type:
  [PDF - 9.75 MB ]