Focused synthetic aperture radar processing of ice-sounder data collected over the Greenland ice sheet

We developed a synthetic aperture radar (SAR) processing algorithm for airborne/spaceborne ice-sounding radar systems and applied it to data collected in Greenland. By using focused SAR (phase-corrected coherent averaging), we improved along-track resolution by a factor of four and provided a 6-dB processing gain over unfocused SAR (coherent averaging without phase correction) based on a point-target analysis for a Greenland ice-sounding data set. Also, we demonstrated that the focused-SAR processing reduced clutter and enabled us to identify bedrock-interface returns buried in clutter. Using focused-SAR technique, we processed data collected over a key 360-km-long portion of the 2000-m contour line of southwest Greenland. To the best of our knowledge, these are the first high-quality radar ice thickness measurements over this key location. Moreover, these ice-thickness measurements have been used for improving mass-balance estimates of the Greenland ice sheet.