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GLAS/ICESat L2 Sea Ice Altimetry Data (HDF5), Version 34
GLAH06 is used in conjunction with GLAH05 to create the Level-2 altimetry products. Level-2 altimetry data provide surface elevations for ice sheets (GLAH12), sea ice (GLAH13), land (GLAH14), and oceans (GLAH15). Data also include the laser footprint geolocation and reflectance, as well as geodetic, instrument, and atmospheric corrections for range measurements. The Level-2 elevation products, are regional products archived at 14 orbits per granule, starting and stopping at the same demarcation (± 50° latitude) as GLAH05 and GLAH06. Each regional product is processed with algorithms specific to that surface type. Surface type masks define which data are written to each of the products. If any data within a given record fall within a specific mask, the entire record is written to the product. Masks can overlap: for example, non-land data in the sea ice region may be written to the sea ice and ocean products. This means that an algorithm may write the same data to more than one Level-2 product. In this case, different algorithms calculate the elevations in their respective products. The surface type masks are versioned and archived at NSIDC, so users can tell which data to expect in each product. Each data granule has an associated browse product.
Release 34 incorporates fixes for several data issues that were determined to exist in the GLAS Release 33 data products.
|Temporal Resolution:||1288 minute|
|Data Contributor(s):||H. Zwally, Robert Schutz, John Dimarzio|
|Metadata XML:||View Metadata Record|
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.Zwally, H. J., R. Schutz, D. Hancock, and J. Dimarzio. 2014. GLAS/ICESat L2 Sea Ice Altimetry Data (HDF5), Version 34. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: http://dx.doi.org/10.5067/ICESAT/GLAS/DATA210. [Date Accessed].
The elevation data is relative to the ellipsoid.
The data also have a parameter indicating the geoid height which is the height of the geoid above the ellipsoid for the first and last shot in the record.
Yes, it is an element of: GLA06 (GLAH06), GLA12 (GLAH12), GLA13 (GLAH13), GLA14 (GLAH14), GLA15 (GLAH15).
The Multiple Scattering Warning Flag, i_cld1_mswf (cld1_mswf_flg) is based on the total... read more
The standard 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 fitting is meant to capture up to six peaks. More peaks are necessary for more complex waveforms over land, vegetated... read more
Yes, surface type flags are never purely sea ice; ocean is always combined with sea ice. Since GLA13 is a sea ice product, if the sea ice bit is not turned on in "surfType," it will not be in the product. This explains why there are no "pure land" returns. Also, the mask resolution is sufficient... read more
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.