Multichannel Wideband Synthetic Aperture Radar for Ice Sheet Remote Sensing: Development and the First Deployment in Antarctica

We developed a multichannel wideband synthetic aperture radar (SAR) that operates over a frequency range of 190-450 MHz for measurements over the ice sheets in Antarctica and Greenland. The antenna-array, which consists of eight elements housed in a certified external structure for a BASLER aircraft, was used for measurements during the 2013-2014 Antarctic field season. We performed measurements with this system in conjunction with two ultra-wideband radars operating over a frequency range of 2-8 GHz and 12-18 GHz on Siple Coast ice streams in West Antarctica during December 2013 and January 2014. We sounded ice thicker than 2 km with a signal-to-noise ratio (SNR) of more than 20 dB in an area with two-way ice loss of about 27 dB/km. The same system also simultaneously mapped near-surface internal layers with submeter resolution from the ice-surface to a depth of about 1100 for 1200 m thick ice. In this paper, we provide a detailed overview of the radar instrumentation and signal processing algorithms and present a few sample results. The radar will be operated over a frequency range of 150-550 MHz with a 24-element antenna-array for wide-ranging measurements over the Greenland and Antarctic ice sheets, starting around August 2015.

[1]  Charles R. Bentley,et al.  Timing of stagnation of Ice Stream C, West Antarctica, from short-pulse radar studies of buried surface crevasses , 1993, Journal of Glaciology.

[2]  Jonathan L. Bamber,et al.  A comparison of basal reflectivity and ice velocity in East Antarctica , 2010 .

[3]  Chung-Chi Lin,et al.  Radio Echo Sounding of Pine Island Glacier, West Antarctica: Aperture Synthesis Processing and Analysis of Feasibility From Space , 2007, IEEE Transactions on Geoscience and Remote Sensing.

[4]  Hermann Engelhardt,et al.  Bed reflectivity beneath inactive ice streams in West Antarctica , 2003, Annals of Glaciology.

[5]  Kristine L. Bell,et al.  A unified method for measurement and tracking of contacts from an array of sensors , 2001, IEEE Trans. Signal Process..

[6]  M. E. Peters,et al.  Along-Track Focusing of Airborne Radar Sounding Data From West Antarctica for Improving Basal Reflection Analysis and Layer Detection , 2007, IEEE Transactions on Geoscience and Remote Sensing.

[7]  Prasad Gogineni,et al.  Ice-sheet bed 3-D tomography , 2010, Journal of Glaciology.

[8]  Torry L. Akins,et al.  Focused synthetic aperture radar processing of ice-sounder data collected over the Greenland ice sheet , 2001, IEEE Trans. Geosci. Remote. Sens..

[9]  D. Gomez-Garcia,et al.  Measurements of In-Flight Cross-Track Antenna Patterns of Radar Depth Sounder/Imager , 2012, IEEE Transactions on Antennas and Propagation.

[10]  Eric Rignot,et al.  A Reconciled Estimate of Ice-Sheet Mass Balance , 2012, Science.

[11]  Xiaoqing Wu,et al.  Ice Sheet Bed Mapping With Airborne SAR Tomography , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[12]  Robert W. Jacobel,et al.  A time marker at 17.5 kyr BP detected throughout West Antarctica , 2005, Annals of Glaciology.

[13]  Richard D. Hale,et al.  Ultra-Wideband Radar for Measurements over Ice Sheets in Antarc-tica and Greenland , 2014 .

[14]  Frank Pattyn,et al.  Predicting radar attenuation within the Antarctic ice sheet , 2012 .

[15]  Sivaprasad Gogineni,et al.  SAR processing of radar echo sounder data , 2000, IGARSS 2000. IEEE 2000 International Geoscience and Remote Sensing Symposium. Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Environment. Proceedings (Cat. No.00CH37120).

[16]  David Braaten,et al.  Advanced Multifrequency Radar Instrumentation for Polar Research , 2014, IEEE Transactions on Geoscience and Remote Sensing.

[17]  S. J. Schmidt,et al.  Gross Errors in Height Indication from Pulsed Radar Altimeters Operating over Thick Ice or Snow , 1962, Proceedings of the IRE.

[18]  Dale P. Winebrenner,et al.  Modeling Englacial Radar Attenuation at Siple Dome, West Antarctica, Using Ice Chemistry and Temperature Data , 2006 .

[19]  Richard D. Hale,et al.  High-Altitude Radar Measurements of Ice Thickness Over the Antarctic and Greenland Ice Sheets as a Part of Operation IceBridge , 2013, IEEE Transactions on Geoscience and Remote Sensing.

[20]  Xiaoqing Wu,et al.  Two-Frequency Radar Experiments for Sounding Glacier Ice and Mapping the Topography of the Glacier Bed , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[21]  C. Bentley,et al.  Radar reflections reveal a wet bed beneath stagnant Ice Stream C and a frozen bed beneath ridge BC, West Antarctica , 1998 .

[22]  Richard D. Hale,et al.  Sounding and imaging of fast flowing glaciers and ice-sheet margins , 2012 .

[23]  S. A. Seguin,et al.  Antarctic ice depthsounding radar instrumentation for the NASA DC-8 , 2012, IEEE Aerospace and Electronic Systems Magazine.

[24]  Kenneth C. Jezek,et al.  Field studies of bottom crevasses in the Ross Ice Shelf, Antarctica , 1983 .

[25]  Sivaprasad Gogineni,et al.  Bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica , 2014 .

[26]  Ian Joughin,et al.  Tides of the Ross Sea and Ross Ice Shelf cavity , 2003, Antarctic Science.

[27]  D. J. Drewry,et al.  International Studies of Ice Sheet and Bedrock , 1977 .

[28]  Frank Pattyn,et al.  Spatial variation of englacial radar attenuation: Modeling approach and application to the Vostok flowline , 2012 .

[29]  Douglas R. Macayeal,et al.  The Ross Ice Shelf Geophysical and Glaciological Survey (RIGGS) : introduction and summary of measurements performed . Glaciological studies on the Ross Ice Shelf, Antarctica, 1973-1978 , 2013 .

[30]  N. Skou,et al.  ESA'S POLarimetric Airborne Radar Ice Sounder (POLARIS): design and first results , 2010 .

[31]  Sivaprasad Gogineni,et al.  Airborne‐radar and ice‐core observations of annual snow accumulation over Thwaites Glacier, West Antarctica confirm the spatiotemporal variability of global and regional atmospheric models , 2013 .