NSIDC IceBridge Value Added Data Products

Ted Scambos, Bruce Raup, Susan Rogers, Mary-Jo Brodzik

IceBridge Value Added Data Products from NSIDC

• NSIDC was asked to include production of value added, science-targeted products in its data management proposal.

• We are working on two basic types of products:

–updates to ice sheet gridded data sets, such as ice surface elevation and bed topography.

–flightline along-track profile data sets, combining instrument data sets for specific studies.

• These value-added products will be produced in conjunction with the Ice Bridge ScienceTeam members, Instrument Team members, and the SWG

• The first products we are developing aremulti-data-set DEM for Greenland, dH/dt for Greenland (w/B. Csatho),

and two along-flight profile data sets: ice sheet ice dynamics and surface properties

Gridded Product: Rapid Update of Greenland Multi-instrument DEM and dH/dt

• B. Csatho and G. Babonis (SUNY Buffalo) have been developing dH/dt relationship for all ICESat-1 cross-over and ATM-ICESat cross-over points (6000 points). Elevations at the crossovers are fit to a 3rd-order polynomial.

-this will be updated with each IceBridge campaign

• A time-corrected ‘best’ DEM will be produced, as well as a means of rapid updating of the DEM, by NSIDC/Csatho, e.g. an ice-sheet wide elevation grid referenced to 2005(mid ICESat-1 –time) or 2011 (latest available).

• Both the dH/dt grid and the merged corrected DEM will be distributed by NSIDC underIceBridge

• B. Raup will create a merged Greenland DEM using Bamber DEM, ASTER photogrammetric elevation grids, and MODIS-derived photoclinometry of the Greenlandinterior (T. Haran). B. Raup will also develop a rapid re-gridding tool.

Along-Track Products:Ice Sheet, Sea Ice, and Surface Properties Multi-instrument ‘Tables’

• We will combine groups of measurements from the instruments for science-topic specific applications. In assembling the data, we propose cross-checking, quality control and derived product generation.

• Along-flight-track data format will be (eventually) ‘meta-tables’:Embedded links and images, etc.

• Two NSIDC Along-Track Products at present: (all are based on the NASA P-3 or DC-8 platforms)

– Ice Sheet Data Product Set: ATM Nadir Elevation and Slope, MCORDS Bed Elev, Ice Thickness, Bed Refl. Strength, radar traces, SANDER Free Air Gravity, DMS images, stereo DEM

– Surface Properties Data Product Set: ATM Swath Elev, Slope, Roughness, Snow Radar, DMS images, stereo DEM, Surface Skin Temp

– Sea Ice Data Product Set (Laura Koenig et al., NASA GSFC): ATM Elevation, RMS Roughness, Ku Radar, DMS images, Surface Skin Temp( )

Gridded Product: Greenland Multi-instrument DEM and dH/dt

NASA PARCA/Polar Research Meeting Pasedena, CA January 29-31, 2007

Scambos DEM (upper left) + interpolated ICESat residual (lower left) = new DEM (right)

Gridded Product: Greenland Multi-instrument DEM and dH/dt

Gridded Products: Improvements to bedrock maps

• Create similar system for updating gridded bed elevation data;

• Mass continuity: surface topography (DEM) and ice flow speed (MEaSURES data) to infer topography

• Use gravimeter data to extend/refine ice thickness measurements from radar;

Along-Flight Track Data Set Ice Sheet Product ProfileOIB 10.18.2009 Antarctica TSK1 Mission

ATM Input

Gravity Input

Currently assembling the tables, assessing offsets, errors, quality parameters

MCORDS Input

A/C Orientation

Along-Flight Track Data Set Ice Sheet Product ProfileOIB 10.18.2009 Antarctica TSK1 Mission

MCORDS Input, data source

DMS Image link

The ATM data sample rate is 0.25 seconds and the GRAV data is 0.5 seconds. The Table requires that the minimum absolute value of the time error between ATM and Gravimeter data to be less than 0.25 seconds.

The MCoRDS data does not have a static sample rate; it varies near 0.17 seconds. The Table requires that the minimum absolute value of the time error between ATM and MCoRDS data to be less than 0.17 seconds.

LAT/

LON

TIM

E

IGGRV1B & ILATM2 IRMCR2 & ILATM2

200 km

Where to take the along-track data sets next?– Ice Sheet Data Product Set: ATM Nadir Elevation and Slope, MCORDS Ice Thickness, and Radar Traces, SANDER Free Air Gravity, DMS images, stereo DEM

•Combine ATM/DMS slope (at ~2 km avg) and ice thickness and report local driving stress;

•Combine MCORDS Ice Thickness and Gravity and report nominal near-surf. bedrock density;(or quality control MCORDS bedrock elevation/ice thickness pick)

– Sea Ice Data Product Set: ATM Freeboard Elev, Surface Roughness*, Ku Radar, DMS images, stereo DEM, Surface Skin Temp

•Re-calculate Qfit (ATM) and/or DMS stereo DEM elevation statistics for ice type information;

– Surface Properties Data Product Set: ATM Swath Elev, Slope, Roughness*, Snow Radar, DMS images, stereo DEM; Surface Skin Temperature

•surface snow grain size (from DMS w/modifications);

•combine gridded products (outside IceBridge), radar, others to infer accumulation rate.

NSIDC IceBridge Gridded Product Projection Selections:

Arctic/GreenlandPolar Stereographic

70°N plane of projection 135°E up, 45°W down

WGS84 ellipsoid

AntarcticaPolar Stereographic

71°S plane of projection0° up, 180°downWGS84 ellipsoid

100 m SAR Radarsat-1 mosaic (Kwok)MODIS Mosaic of Greenland (MOG, shown above)

MEaSURES InSAR ice velocity data sets1-km ICESat Greenland DEM (Zwally)

5km Radar Altimetry Greenland DEM (y=39°N)NSIDC Passive Microwave Data (Hughes ellip.)

25 m RAMP and MAMM Radarsat products (Jezek)MODIS Mosaic of Antarctica (MOA, shown above)

MEaSURES InSAR ice velocity data sets1-km ICESat+Radar Alt DEM (Bamber)

AVHRR and LIMA mosaics (USGS, Bindschdlr)

ICESat 500m DEM (70°S, Hughes Ellips.)NSIDC Passive Microwave Data (70°S, Hughes ellip.)