Alaska Satellite Facility DAAC (ASF DAAC)
Photo: This 30-m digital elevation model of the Delta Junction area was created from ERS-1 and ERS-2 tandem mission data. The colors reflect varying elevations, with green representing the lowest elevations and white the highest. The coverage area is approximately 130 by 100 km. Note: Granite Mountain shown in the SAR image below. The scale, coverage, and orientation of the two images differ.
The ASF DAAC is located in the Geophysical Institute at the
University of Alaska Fairbanks. The DAAC is supported by NASA to
acquire, process, archive, and distribute Synthetic Aperture Radar (SAR)
data from polar-orbiting satellites to advance polar research and Earth
science.
Available Data
ASF provides users with several types of SAR data from nearly raw (Level 0) to higher level derived products. ASF is actively archiving SAR data from the Canadian RADARSAT-1 and European Remote Sensing Satellite-2 (ERS-2). In addition, the ASF archive contains SAR data from the ERS-1 and Japanese Earth Resources Satellite-1 (JERS-1).
The majority of available data is considered restricted and available only to NASA-approved researchers.
Unrestricted derived products are available for order. Products can be ordered from the Web; some are available via FTP or through the EOS Data Gateway (EDG) [+ more].
Unrestricted Data
- Antarctic Mosaic
(Resolution: 125 m | Availability: October 1997 | Coverage: Antarctica)The first, most complete and detailed views of the Antarctic continent were obtained by RADARSAT-1 during October 1997. The RADARSAT-1 SAR Mosaic of Antarctica was produced by the RADARSAT-1 Antarctic Mapping Project (RAMP). The mosaic is available by FTP at a resolution of 125 meters and requires visualization software.
- Boreal Forest Mosaics
(Resolution: 100 m to 2 km | Availability: 1997 and 1998 | Coverage: North America boreal forest)JERS-1 SAR mosaics of boreal North America (Alaska and Canada) are now available on DVD. Winter and summer mosaics were assembled under the North American component of the Global Boreal Forest Mapping (GBFM) project. The DVD includes imagery extending from northern Alaska to the northeastern United States. Backscatter and texture products are provided as complete summer and winter mosaics at both 500-meter and 2-kilometer resolution. Backscatter data at 100-meter resolution are also provided as tiles of about 50 JERS-1 scenes each.
- Capturing a Dynamic Planet
Capturing a Dynamic Planet: Using Synthetic Aperture Radar to View the Earth, an outreach and informal education CD-ROM, provides an introduction to the use of Synthetic Aperature Radar (SAR) data for imaging the Earth's surface. Included on the CD are an image gallery with explanations on the possible applications of the images, and explanations of basic SAR and interferometric SAR concepts.
- Geophysical Sea Ice Products
(Availability: ERS-1 GPS, 1991 to 1993; RGPS, 1997 to 2000 | Coverage: Arctic region)SAR imagery provides a detailed view of sea ice, which has a key role in the global climate system. From sequential data, sea ice features can be tracked over time. Ice motion data derived from ERS-1 SAR imagery and produced with the Geophysical Processor System (GPS) for the period from 1991 to 1993 is available for order via the EDG. In 1996, ASF began collecting and archiving RADARSAT-1 data of the entire Arctic Ocean every 3 to 6 days. The RADARSAT Geophysical Processor System (RGPS) produces a variety of ice motion data products, including new-ice thickness.
- Glacier Power
Glacier Power, a multimedia Earth sciences curriculum CD-ROM for use on Macintosh computers, was created primarily for middle school teachers. Glacier Power uses SAR data to lay a foundation in the subject of glacier dynamics through the use of imagery and cartoon characters.
- Rain Forest Mosaics
(Resolution: 100m | Availability: Central America, 1996; South America, 1995 and 1996; Africa, 1996 and 1997; South-East Asia, 1997 and 1998 | Coverage: Major rain forests)The goal of the Global Rain Forest Mapping (GRFM) project is to acquire contiguous SAR data sets of the Earth's major rain forests using the JERS-1 satellite. ASF has available complete GRFM-produced mosaics of the Amazon, Central America, Africa, Pantanal region, and South-East Asia. The mosaics are available on CD-ROM.
Restricted Data
- RADARSAT-1 C-Band SAR System
(Resolution: 10 to 600 m | Availability: February 1996 to present | Coverage: Within a circle of 3,000-km radius centered on ASF and McMurdo Station (Antarctica), more limited elsewhere in the world)The side-looking radar has a range of incidence angles from approximately 20 to 60 degrees. Swath widths range from approximately 50 to 500 kilometers. Significant coverage outside the ASF and McMurdo Station masks is also available. New acquisitions are available both within and outside the ASF and McMurdo Station masks. RADARSAT-1 data are the property of the Canadian Space Agency (CSA).
- RADARSAT-1 SAR Mosaic of Antarctica
This 25-meter resolution product of the RAMP is available as a 15-DVD set. - ERS-1 and ERS-2 C-Band SAR Systems
(Resolution: 30 to 240 m | Availability: ERS-1, August 1991 to June 1996; ERS-2, October 1995 to present | Coverage: Within a circle of 3,000-km radius centered on ASF and McMurdo Station)The side-looking radar has an incidence angle of 23 degrees and a 100-kilometer swath width. ERS-2 is a current mission, and new acquisitions are available within the stated coverage. ERS-1 and ERS-2 data are the property of the European Space Agency (ESA).
- JERS-1 L-Band SAR System
(Resolution: 30 to 240 m | Availability: May 1992 to October 1998 | Coverage: Extensive within a circle of 2,600-km radius centered on ASF and over Central and South America)The side-looking radar has an incidence angle of 35 degrees and a 75-kilometer swath width. Limited coverage outside the ASF mask, including extensive rain forest and boreal forest data, is also available. JERS-1 data are the property of the Japan Aerospace Exploration Agency (JAXA).
Data Tools
The ASF software tools are designed to make it easier for users to process ASF data products and translate them into a variety of other formats. The tools support all ASF satellite SAR data sources (ERS 1/2, JERS-1, and RADARSAT-1).
The tools can ingest most Level 1 ASF products, and produce geocoded (or ungeocoded) GeoTIFF, TIFF, JPEG, or portable pixel map images. A graphical user interface exists which guides the user through the process of ingesting, geocoding, and exporting datasets. The SAR interferometric (InSAR) tools that deal with Level 0 data as input are currently under revision. An old version of the InSAR tool set is still available, but using it effectively may require assistance from ASF personnel. Distribution of Level 0 processing binaries is restricted by U.S. export laws. Source code is available by cooperative agreement only.
Data Access
Online access to ASF DAAC data is available through the EDG data
search-and-order system.
For assistance or additional information, contact:
ASF DAAC User Services
Alaska Satellite Facility
University of Alaska Fairbanks
Phone: +1 907-474-6166
Fax: +1 907-474-2665
E-mail: asf@eos.nasa.gov or uso@asf.alaska.edu