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ICESat/GLAS

Ice, Cloud, and land Elevation / Geoscience Laser Altimeter System

Help Articles

Getting started

The elevation data are relative to the ellipsoid. The data also have a parameter indicating the geoid height, which is the height of the EGM2008 geoid above the TOPEX/Poseidon ellipsoid for the first and last shot in the record:
"Freeboard" is a measure of the height of sea ice above the ocean surface.
Analysis of altimetric data acquired by the GLAS instrument requires accurate determination of the laser spot location on the Earth's surface (ice, land, water, clouds) or geolocation of the laser spot.
In short, the elevation of the surface at each laser footprint is the height of the spacecraft minus the measured distance to the surface.
Yes, it is an element of GLAH06, GLAH12, GLAH13, GLAH14, and GLAH15. 
The following table describes the data subsetting and reformatting services that are currently available for ICESat/GLAS HDF5 data via the NASA Earthdata Search tool.
There are 40 laser shots in one second which are associated with the transmit pulses. The first shot is from the laser, the last shot is the 40th record of that transmitted pulse.
Surface roughness greatly affects the elevation measurement accuracy. Over most of the ice sheets, the accuracy of each elevation measurement is 15 cm.
The standard waveform fit is optimized for "ice sheet-like" returns. The majority of these are single-peaked, narrow waveforms. The standard fit allows for only two peaks. Alternate waveform fitting is meant to capture up to six peaks.
Several parameters help quantify the shape of the GLAS laser footprint, which change slightly for each campaign. These parameters are:

How To

The HDF Group has example code for access and visualization of MODIS, GLAS HDF5, AMSR-E, and NISE data in MATLAB, IDL, Python, and NCL.
To convert HDF5 files into binary format you will need to use the h5dump utility, which is part of the HDF5 distribution available from the HDF Group. How you install HDF5 depends on your operating system.
The following steps outline the process for visualizing the GLAS/ICESat 500m DEM in ArcGIS. At the time of writing, these instructions are relevant to ArcMap 10.4
NASA Earthdata Search is a map-based search and order tool, allowing you to search for ICESat/GLAS data based on spatial and temporal constraints.
The instructions below will describe how to extract elevation in text format from GLAS HDF5 Altimetry data using the free open source tool HDFView.
This guide will provide an overview of the altimetry measurements and data sets across the missions, as well as a guide for accessing the data through NASA Earthdata Search and programmatically using an Application Programming Interface (API).
  Data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system or through our Application Programming Interface (API).
NASA Earthdata Search is a map-based interface where a user can search for Earth science data, filter results based on spatial and temporal constraints, and order data with customizations including re-formatting, re-projecting, and spatial and parameter subsetting.
HDFView https://support.hdfgroup.org/products/java/hdfview/ When you first open HDFView, the HDFView window appears with an empty tree and data panel.