Code Cryospheric Sciences Branch Christopher A. Shuman and Vijay P. Suchdeo (with help from many others, thank you!) Ice Sheet Elevations from ICESat Evolving Precision and Accuracy plus Examples

Code Cryospheric Sciences Branch * Operations Periods (*sorry, no guarantees)

Code Cryospheric Sciences Branch ICESat GLAS Energy Plots - Lasers 1 and 2

Code Cryospheric Sciences Branch ICESat GLAS Energy Plots - Laser 3 so far

Code Cryospheric Sciences Branch S. Hemisphere Summer and N. Hemisphere Winter Polar Elevation Data - Laser 1

Code Cryospheric Sciences Branch S. Hemisphere Spring and N. Hemisphere Fall Polar Elevation Data - Laser 2a

Code Cryospheric Sciences Branch S. Hemisphere Summer and N. Hemisphere Winter Polar Elevation Data - Laser 2b

Code Cryospheric Sciences Branch S. Hemisphere Fall and N. Hemisphere Spring Polar Elevation Data - Laser 2c

Code Cryospheric Sciences Branch S. Hemisphere Spring and N. Hemisphere Fall Polar Elevation Data - Laser 3a

Code Cryospheric Sciences Branch S. Hemisphere Summer and N. Hemisphere Winter Polar Elevation Data - Laser 3b

Code Cryospheric Sciences Branch S. Hemisphere Fall and N. Hemisphere Spring Polar Elevation Data - Laser 3c

Code Cryospheric Sciences Branch ICESat - More Than Precise Elevations Lots of great data for many science applications S. Hemisphere Spring and N. Hemisphere Fall (whiter areas indicate data gaps, in part due to clouds)

Code Cryospheric Sciences Branch ICESat Laser 2a Elevation Map Pulses Emitted ~20,000,000 Pulses Received ~17,000,000

Code Cryospheric Sciences Branch Laser 2a Xover Map - With RTWs, TC Crossovers (total) ~210,000

Code Cryospheric Sciences Branch Laser 2a Xover Map - With RTWs, No TC

Code Cryospheric Sciences Branch Laser 2a Xover Map - No RTWs or TC

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

Code Cryospheric Sciences Branch 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.

Code Cryospheric Sciences Branch Crossover Closeup - L2a A-D Vostok 150 km diameter

Code Cryospheric Sciences Branch Repeats of Track 0071 Vostok - L2a and L3a (with saturation correction)

Code Cryospheric Sciences Branch L2a 0071 Vostok - Precision/Saturation Correction

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 1

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 1

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 1 L2a091C28 L2a091C29

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 1 Note slope impact (sensitive to cross track alignment)

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 2

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 2

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 2 L2a091C28 L2a091C29

Code Cryospheric Sciences Branch Cloud Impacts - L2a Track Case 2 Note slope impact (sensitive to cross track alignment)

Code Cryospheric Sciences Branch Antarctic DEM - ICESat Only Shaded relief image of DEM (~500 m) J. DiMarzio GSFC

Code Cryospheric Sciences Branch 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

Code Cryospheric Sciences Branch ICESat is an exceptional tool for exploration of the Earth Development of an Advanced ICESat follow-on is underway