DOWNLOADING DATA VIA HTTPS
To learn more about Earthdata Login and register for an account, please see How to Register with Earthdata Login. Once you have logged in, data can be downloaded via a Web browser, command line, or client. For help with downloading data, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.
DOWNLOADING DATA VIA FTP
Data can be downloaded through a Web browser or command line via FTP. When using a Web browser, the FTP link first directs you to an Optional Registration Form that if filled out, will allow you to receive notifications about updates or processing changes related to that specific data set. After completing the Optional Registration Form, the FTP directory becomes available. For additional help downloading data through an FTP client, go to the How to access data using an FTP client support page.
Seasat and GEOSAT Altimetry for the Antarctic and Greenland Ice Sheets, Version 1
Note: This data set is now on FTP so references to CD-ROM are historic and no longer applicable.
The Ice Altimetry System (IAS) data seet contains surface elevations of
the Antarctic and Greenland ice sheets derived from Seasat and GEOSAT
radar altimetry data. The Seasat data were collected for a continuous
90 days in 1978, at latitudes between 72 degrees South and 72 degrees
North. GEOSAT was launched in 1985 and placed in a nearly identical
orbit to Seasat, also at latitudes of between 72 degrees South and 72
degrees North. The orbit was designed to provide high-density
measurements over the Earth's surface, at a maximum grid spacing of 2.7 kilometers at the equator and much denser spacing over polar ice
sheets. Data were acquired between April 1985 and September 1986.
Initially acquired by the Johns Hopkins APL (Applied Physics Lab)
satellite tracking facility, the raw altimetry satellite data from
Seasat and GEOSAT were passed on to NASA, via the US Navy. NASA
developed slope correction routines for the higher slopes over the ice
sheets, relative to ocean surfaces. The data are height profile Level
3 data and gridded height Level 4 data provided by the Oceans and Ice
branch of the Laboratory for Hydrospheric Physics of Goddard Space
Flight Center. Elevations from the full data rate (i.e., one
measurement every 662.5 m) are provided in georeferenced databases.
These elevations are relative to the WGS-84 ellipsoid. Gridded
elevations at 10-kilometer and 20-kilometer spacing are provided in
the gridded data sets created from the GEOSAT and Seasat data,
respectively. Software to extract and browse subsets of these data is
included. The IAS software also allows the user to view
contours created from the gridded data and groundtracks of the
|Spatial Resolution:||Not Specified|
|Temporal Resolution:||Not specified|
|Data Contributor(s):||H. Zwally, Anita Brenner|
|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, J. and A. Brenner 1997. Seasat and GEOSAT Altimetry for the Antarctic and Greenland Ice Sheets, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.5067/MTIF60G86H86. [Date Accessed].