ICESat/GLAS Tools at NSIDC Melinda Marquis NSIDC Product Team Lead, AMSR-E and GLAS Feb. 16, 2005

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, Outline: ICESat/GLAS Tools GLAS on ICESat. Graphic is courtesy of Ball Aerospace. IDL Visualizer NSIDC GLAS Altimetry elevation extractor Tool (NGAT) IDL Readers Fortran 90 Readers IDL Ellipsoid Conversion tool ICESat/GLAS Subsetter GLAS Tools Page at

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Visualizer  Reads data from an ICESat/GLAS file and views graphical summaries of variables.  A quick-start tutorial is available on-line to help users get started viewing ICESat/GLAS data.  SCF responded to NSIDC’s request that this package be made to work with the free IDL Virtual Machine (Jan. 2005).  Developed by the GLAS SCF.

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Visualizer

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Visualizer

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, NSIDC GLAS Altimetry elevation extractor Tool (NGAT)  Extracts elevation and geoid data from GLAS altimetry products (GLA06 and GLA12-15) and outputs latitude, longitude, elevation, and geoid in ASCII columns.  The NGAT runs under IDL (6.0 or greater) or the free IDL Virtual Machine (IDLVM) available from Research Systems Inc.  Developed by NSIDC (Matt Savoie).

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, NSIDC GLAS Altimetry elevation extractor Tool (NGAT) /07/ :31: /07/ :31: /07/ :31: /07/ :31: /07/ :31: /07/ :31: Record No. Date Time Lat. (deg.) Long. (deg.) Elevation (m) Geoid (m)

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Readers  Read data from an ICESat/GLAS file and prints all the variables in ASCII format.  The readers run under IDL (6.0 or greater) or the free IDL Virtual Machine (IDLVM) available from Research Systems, Inc.  Developed by the GLAS SCF.

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Readers

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, Fortran 90 Readers  This set of programs reads data from an ICESat/GLAS file and prints all the variables in ASCII format (identical output as IDL reader).  This is sample code to help users develop their own applications.  There is a separate program for each product type ("read_glaxx_file") where xx is the product number.

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, Fortran 90 Readers  The programs are written in Fortan 90 and developed in a HP/UX 11.x runtime environment.  A relatively modern Fortran 90 compiler is required.  Runs on only HP/UX and some Sun platforms.  Developed by the GLAS SCF.

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, IDL Ellipsoid Conversion tool Converts between the ICESat/GLAS and WGS-84 ellipsoids. ICESat/GLAS geolocated products are given in terms of geodetic latitude, longitude, and height (elevation) above the TOPEX/Poseidon ellipsoid. Three programs convert latitudes and elevations between the WGS-84 and the TOPEX/Poseidon ellipsoids. Developed by NSIDC (Terry Haran).

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, ICESat/GLAS Subsetter  User enters bounding coordinates and temporal range of interest in a web form on NSIDC’s site.  NSIDC provides the spatially subsetted data.  Developed by NSIDC (Matt Savoie), in conjunction with the GLAS SCF.  NSIDC uses our rSCF (with code dev’d by main SCF) to perform subsetting.

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, Summary NSIDC has worked with the ICESat/GLAS science team, SCF and SIPS to provide needed tools to the broad user community.  Readers  Visualization tools  Subsetter This collaborative effort benefits users and facilitates use of the ICESat/GLAS data. Thanks go to the science team, SCF, SIPS and NSIDC programmers and staff: John DiMarzio Kris Barbieri Jeff Guerber Jay Zwally David Hancock Anita Brenner Matt Savoie Terry Haran Siri Jodha Singh Khalsa

Polar DAAC Advisory Group Melinda Marquis, NSIDC DAACFeb. 16, GLAS Data Products ShortName Longname Received # of Granules Ingested GLA01L1A Global Altimetry Data X 206 GLA02L1A Global Atmosphere Data X 26 GLA03L1A Global Engineering Data X 22 GLA04L1A Global Laser Pointing Data X 22 GLA05L1B Global Waveform-based Range Corrections X 95 GLA06L1B Global Elevation Data X131 GLA07L1B Global Backscatter Data X 6 GLA08L2 Global PBL & Elevated Aerosol Layer Heights X 3 GLA09 L2 Global Cloud Heights for Multi-layer Clouds X 3 GLA10L2 Global Aerosol Vertical Structure Data X 2 GLA11L2 Global Thin Cloud/Aerosol Optical Depths Data X 2 GLA12L2 Global Antarctic & Greenland Ice Sheet Alt. X 2 GLA13L2 Sea Ice Altimetry Data X 2 GLA14L2 Global Land Surface Altimetry Data X 2 GLA15L2 Ocean Altimetry Data X 2 GLA16 is not fully developed