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Ice Sheet Elevations from ICESat Evolving Precision and Accuracy plus Examples

Detailed analysis of ICEsat elevation data accuracy with examples, including polar elevation data and laser energy plots.

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Ice Sheet Elevations from ICESat Evolving Precision and Accuracy plus Examples

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  1. Ice Sheet Elevations from ICESatEvolving Precision and Accuracy plus Examples Christopher A. Shuman and Vijay P. Suchdeo (with help from many others, thank you!)

  2. 2003-2006* Operations Periods(*sorry, no guarantees)

  3. ICESat GLAS Energy Plots - Lasers 1 and 2

  4. ICESat GLAS Energy Plots - Laser 3 so far

  5. Polar Elevation Data - Laser 1 S. Hemisphere Summer and N. Hemisphere Winter

  6. Polar Elevation Data - Laser 2a S. Hemisphere Spring and N. Hemisphere Fall

  7. Polar Elevation Data - Laser 2b S. Hemisphere Summer and N. Hemisphere Winter

  8. Polar Elevation Data - Laser 2c S. Hemisphere Fall and N. Hemisphere Spring

  9. Polar Elevation Data - Laser 3a S. Hemisphere Spring and N. Hemisphere Fall

  10. Polar Elevation Data - Laser 3b S. Hemisphere Summer and N. Hemisphere Winter

  11. Polar Elevation Data - Laser 3c S. Hemisphere Fall and N. Hemisphere Spring

  12. ICESat - More Than Precise ElevationsLots of great data for many science applications S. Hemisphere Spring and N. Hemisphere Fall(whiter areas indicate data gaps, in part due to clouds)

  13. ICESat Laser 2a Elevation Map Pulses Emitted ~20,000,000 Pulses Received ~17,000,000

  14. Laser 2a Xover Map - With RTWs, TC Crossovers (total) ~210,000

  15. Laser 2a Xover Map - With RTWs, No TC

  16. Laser 2a Xover Map - No RTWs or TC

  17. Laser 2a Xover Map - No RTWs, Ice Shelves Tidal areas, steep slopes, off-nadir tracks, and cloud tops can be > ±1.1 m

  18. Laser 2a Crossover Map - No RTWs or TC by slope class (slopes from GFSC Radar DEM) The best (so far) operational period has a relative accuracy (i.e. ICESat to ICESat) of ~14 cm as measured by crossover standard deviations after 3 sigma editing of ‘best’ data (i.e. no off-nadir data and no tidal areas). For low slope (< 0.25°) and short interval crossovers (< 8 days), this improves to ~10 cm but some issues are not yet resolved (more on this later) so this should get better.

  19. Crossover Closeup - L2a A-D Vostok 150 km diameter

  20. Repeats of Track 0071 Vostok - L2a and L3a (with saturation correction)

  21. L2a 0071 Vostok - Precision/Saturation Correction

  22. Cloud Impacts - L2a Track 091 - Case 1

  23. Cloud Impacts - L2a Track 091 - Case 1

  24. L2a 091 C28 Cloud Impacts - L2a Track 091 - Case 1 L2a 091 C29

  25. Cloud Impacts - L2a Track 091 - Case 1 Note slope impact (sensitive to cross track alignment)

  26. Cloud Impacts - L2a Track 091 - Case 2

  27. Cloud Impacts - L2a Track 091 - Case 2

  28. L2a 091 C28 Cloud Impacts - L2a Track 091 - Case 2 L2a 091 C29

  29. Cloud Impacts - L2a Track 091 - Case 2 Note slope impact (sensitive to cross track alignment)

  30. Antarctic DEM - ICESat Only Shaded relief image of DEM (~500 m) J. DiMarzio GSFC

  31. ICESat vs. Radar ICESat shot-to-shot variability over low slopes is ~2cm; data is acquired even from steep slopes ICESat to ICESat accuracy from East Antarctic crossovers is ±14cm Ice sheet model coverage extends to ~86°S (limit for ICESat not shown) vs. radar to ~81.5°S (lower) but ICESat data ‘density’ is a function of latitude Additional data acquisition for enhanced DEMs will continue with Laser 3e, including completing the 91-day pattern Release of the DEM by Fall AGU (?) J. DiMarzio, GSFC

  32. ICESat is an exceptional tool for exploration of the Earth Development of an Advanced ICESat follow-on is underway

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