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I drift from ENVISAT ASAR WSM data Danish National Space Center, DTU

I drift from ENVISAT ASAR WSM data Danish National Space Center, DTU. Leif Toudal Pedersen & Roberto Saldo Danish National Space Center Technical University of Denmark. Outline. Method Background – GMM mode images NRT Ice drift from WSM images High resolution ice drift Ice deformation.

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I drift from ENVISAT ASAR WSM data Danish National Space Center, DTU

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  1. I drift from ENVISAT ASAR WSM dataDanish National Space Center, DTU Leif Toudal Pedersen & Roberto Saldo Danish National Space Center Technical University of Denmark

  2. Outline • Method • Background – GMM mode images • NRT Ice drift from WSM images • High resolution ice drift • Ice deformation DNSC sea ice | Oct 2007 | Ltp| side 2

  3. Method - Cross correlation • area of reference • correlation area • distance between vectors • sampling DNSC sea ice | Oct 2007 | Ltp| side 3

  4. GMM+WSM 3-day ice drift October 16-19, 2007 Spatial resolution 35 km (GMM) Temporal resolution (3-day – GMM) DNSC sea ice | Oct 2007 | Ltp| side 4

  5. Spatial resolution 10 km (WSM) Temporal resolution (1-day – WSM) WSM 1-day ice drift October 18-19, 2007 Spatial resolution 35 km (GMM) or 10 km (WSM) DNSC sea ice | Oct 2007 | Ltp| side 5

  6. Accurate start and end time • Drift is calculated from swath data • All swaths from day 0 is correlated with all swaths from day 1 (or day 3 for 3-day drift) • Enables accurate start and end time contrary to using daily mosaics DNSC sea ice | Oct 2007 | Ltp| side 6

  7. New DTU dataset available from June 1, 2007 • Daily drift vectors from all available ENVISAT ASAR WSM data • 1-day drift (12-36 hours) • 10 kilometer resolution (correlation of a circular area r=5km) • 10 kilometer grid (drift vector every 10 kilometers) • Arctic and Antarctic • Examples: (Only daily average displacements are shown) DNSC sea ice | Oct 2007 | Ltp| side 7

  8. 20070628 DNSC sea ice | Oct 2007 | Ltp| side 8

  9. 20070629 DNSC sea ice | Oct 2007 | Ltp| side 9

  10. 20070630 DNSC sea ice | Oct 2007 | Ltp| side 10

  11. 20070701 DNSC sea ice | Oct 2007 | Ltp| side 11

  12. 20070702 DNSC sea ice | Oct 2007 | Ltp| side 12

  13. 20070703 DNSC sea ice | Oct 2007 | Ltp| side 13

  14. 20070704 DNSC sea ice | Oct 2007 | Ltp| side 14

  15. 20070705 DNSC sea ice | Oct 2007 | Ltp| side 15

  16. 20070706 DNSC sea ice | Oct 2007 | Ltp| side 16

  17. Ice drift and deformation from SAR • Application • Ice deformation (1-day, WSM, 3km resolution) • The method is applied to WSM data fro the area north of Greenland • The 10 kilometer vectors are used as seed points • A new dataset of 3km resolution is derived (3km radius of correlation area) • The ice drift field is differentiated and divergence is calculated • Divergence corresponds to opening • Convergence corresponds to ridging DNSC sea ice | Oct 2007 | Ltp| side 17

  18. Ice deformation ENVISAT ASAR Sept 03 2007 Drift Sept 2-3 DNSC sea ice | Oct 2007 | Ltp| side 18

  19. Ice deformation ENVISAT ASAR Sept 2-3 2007 Divergence September 2-3, 2007 Black is opening, white is ridging DNSC sea ice | Oct 2007 | Ltp| side 19

  20. Validation • Validation with buoy data: • RMS difference to AOBP buoy drifts 750m/day for the 1-day WSM drift at 10 kilometer resolution • Movement of fast ice off East Greenland: • RMS: 80m/day for the high res ice motion (2000 obs) DNSC sea ice | Oct 2007 | Ltp| side 20

  21. Ice drift and deformation from SAR • Displacement NOT velocity • integrated quantity • In data assimilation: don’t assimilate velocities! DNSC sea ice | Oct 2007 | Ltp| side 21

  22. Lincoln Sea 2007 animation ENVISAT ASAR WSM animation by DTU December 27 (2006) to June 8 (2007) DNSC sea ice | Oct 2007 | Ltp| side 22

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