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SUMMARY:Radar Instrumentation for Polar Research: Status and Future  - S. 
 Gogineni\, The Center for Remote Sensing of Ice Sheets\, The University of
  Kansas
DTSTART:20130903T100000Z
DTEND:20130903T110000Z
UID:TALK46914@talks.cam.ac.uk
CONTACT:Rosie Williams
DESCRIPTION:Satellites provide long time series of measurements to support
  scientific and operational studies of polar regions. The sensors on these
  satellites have revealed the speed-up and retreat of glaciers\, the break
 -up of ice shelves\, and the reduction of sea ice thickness and extent in 
 the Arctic. However\, satellite observations alone are not sufficient to u
 nderstand the processes causing glacier speed-up and retreat and sea ice r
 etreat. Airborne and in-situ measurements are also required to interpret s
 atellite data sets and to understand the processes causing the observed ch
 anges. For example\, we need deeper knowledge of bed topography and basal 
 conditions to obtain both an improved understanding of the processes causi
 ng glacier retreat and speed-up and incorporate this knowledge into next-g
 eneration ice-sheet models.  Sea ice thickness is a key variable in modeli
 ng ice-ocean-atmosphere interactions\, and it is one of the most difficult
  variables to measure over large areas. Additional information on snow thi
 ckness is required to convert satellite altimeter-measured free-board meas
 urements of snow and ice into sea-ice thickness.\n \nWe developed radar in
 strumentation for polar research that is being operated on both long-range
  and short-range aircraft in conjunction with other sensors. The instrumen
 tation include radars operating over a frequency range of about 14 MHz to 
 18 GHz.  These are: (1) a radar depth sounder/imager that operates at a ce
 nter frequency of 195 MHz to sound ice and image the ice-bed interface\; (
 2) an ultra-wideband radar that operates over a frequency range of 600 -90
 0 MHz to map near-surface internal layers in polar firn and ice\; (3) an u
 ltra-wideband microwave radar that operates over a frequency range of 2-8 
 GHz to measure the thickness of snow cover over sea ice and map near-surfa
 ce internal layers in polar firn with fine range resolution of about 3 cm\
 ; and (4) a radar altimeter that operates over a frequency range of 12-18 
 GHz for high-precision surface elevation measurements. These radars are be
 ing used to collect data as a part of NASA Operation Ice Bridge (OIB) and 
 CReSIS field activities over the Antarctic and Greenland ice sheets\, as w
 ell as over Arctic and Antarctic sea ice.  \n\nIn this talk\, I will discu
 ss the scientific and technical requirements for radar sounding and imagin
 g of the ice sheets\, mapping near-surface internal layers\, and measuring
  snow thickness over sea ice. I will also discuss the technical challenges
  associated with sounding fast-flowing glaciers and ice-sheet margins\, as
  well as our solutions to these challenges. I will present the way in whic
 h ice-core measurements and radar data can be combined to generate unambig
 uous determinations of basal conditions\, and I will show sample results o
 btained with advanced signal processing techniques to identify undisturbed
  internal layers for selecting optimum drill sites for future ice core col
 lection. Finally\, I will discuss the recent technical advances in radar\,
  antenna and signal-processing technologies and the potential development 
 of ultra-wideband radars that can be operated from aircraft for sounding s
 ea ice and sounding and imaging ice sheets and mapping internal layers fro
 m the surface to the bed with fine resolution.\n
LOCATION:British Antarctic Survey\, Room 187
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