SMAP provides global measurements of soil moisture and its freeze/thaw state. In September 2015, mission managers determined that the SMAP radar instrument active mode failed on July 7 (see NASA news story). SMAP receive-only radar data are available subsequent to July 7 on an experimental basis.
The SMAP instrument incorporates an L-band radar (VV, HH, and HV polarizations) and an L-band radiometer (V, H, and 3rd and 4th Stokes parameter polarizations). The Level 1 radar data products is archived and distributed by the Alaska Satellite Facility, and the radiometer and Level 2-4 data products is archived and distributed by the National Snow and Ice Data Center.
The SMAP orbit is a 685-km altitude, near-polar, sun-synchronous 6 a.m./6 p.m., 8-day, exact repeat, frozen orbit.
To obtain high spatial resolution, the radar employs range and Doppler discrimination. Unfocused SAR (synthetic aperture radar) processing yields spatial resolution that varies from 1 km to 3 km over the outer 70% of the swath ('high-resolution' radar).
The data products will conform to the HDF-EOS5 standard, and metadata will conform to the ISO 19115 standard.
Citing SMAP Level 1 Datasets
Cite datasets in publications such as journal papers, articles, presentations, posters, and websites. Each SMAP Level 1 dataset has an assigned DOI. Please also send a copy of publications that cite datasets or tools obtained through ASF to firstname.lastname@example.org.
|SMAP data [year of data acquisition] (NASA). Dataset: [name of dataset]. Retrieved from ASF [add URL if print publication: www.asf.alaska.edu] DAAC [day month year of data access]. DOI: [doi]||click for list of SMAP Level 1 datasets and their DOIs.|
Crediting SMAP Imagery
Include appropriate credit with each image shown in publications such as journal papers, articles, presentations, posters, and websites. For more information, see NASA guidelines.
|Imagery, primary or altered||Credit: NASA data [year of data acquisition].||Credit: NASA data 2014.|
|Imagery, derivative||Credit: [Name of image creator or institution, as appropriate], [year of image creation], contains NASA data [year of data acquisition].|
Credit: Jones, D., 2015, contains NASA data 2015.
SMAP Level 1 Datasets and DOIs
Data Service Name: Vertex
Data Service Description: Search, visualize, subset, and download data in HDF5
Data Service Access URL: https://vertex.daac.asf.alaska.edu
Data Service Name: Alaska Satellite Facility Application Programming Interface (API)
Data Service Access URL: https://www.asf.alaska.edu/get-data/api/
Data Service Name: Earthdata Search
Data Service Description: This application allows you to search, discover, visualize, refine, and access NASA Earth Observation data.
Data Service Access URL: https://search.earthdata.nasa.gov/search
Short Name(s): SPL1AAV2
Spatial Coverage: (90.0 N to -90.0 S; 180.0 E to -180.0 W)
Temporal Coverage: 15 April 2015 to 7 July 2015
See NASA news story about cessation of radar.
Latitude Resolution: 1-3 km
Longitude Resolution: 30 km
Temporal Resolution: 3 days