This enhanced Level-2 (L2) product contains calibrated, geolocated, brightness temperatures acquired by the Soil Moisture Active Passive (SMAP) radiometer during 6:00 a.m. descending and 6:00 p.m. ascending half-orbit passes. This product is derived from SMAP Level-1B (L1B) interpolated antenna temperatures. Backus-Gilbert optimal interpolation techniques are used to extract maximum information from SMAP antenna temperatures and convert them to brightness temperatures, which are posted to the 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) in a global cylindrical projection [available as the SPl1CTB_E product]. As of 2021, the data are also posted to the Northern Hemisphere EASE-Grid 2.0, an azimuthal equal-area projection. These 9-km brightness temperatures are then used to retrieve surface soil moisture posted on the 9-km grid [this SPL2SMP_E product].
SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 5
This is the most recent version of these data.
Changes to this version include:
- Dual Channel Algorithm (DCA) replaces Single Channel Algorithm – Vertical (SCA-V) as baseline algorithm.
- Addition of north-polar grid soil moisture retrievals which are intended to mitigate the distortion of global-grid cells at high northern latitudes (> 50N). These are presented in the products in the new Soil_Moisture_Retrieval_Data_Polar data group.
- Addition of the soil texture elements organic_content and sand_fraction in both global and polar grid groups.
- Bulk_density maximum value changed from 1 to 2.65.
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Data: Data integrity and usability verified; data customization services available for select data
Documentation: Key metadata and comprehensive user guide available
User Support: Assistance with data access and usage; guidance on use of data in tools and data customization services
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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.
O'Neill, P. E., S. Chan, E. G. Njoku, T. Jackson, R. Bindlish, J. Chaubell, and A. Colliander. 2021. SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 5. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/LOT311EZHH8S. [Date Accessed].Literature Citation
As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.
Chan, S., R. Bindlish, P. E. O'Neill, T. Jackson, E. G. Njoku, S. Dunbar, J. Chaubell, J. R. Piepmeier, S. Yueh, D. Entekhabi, A. Colliander, F. Chen, M. Cosh, T. Caldwell, J. Walker, A. Berg, H. McNairn, M. Thibeault, J. Martinez-Fernandez, F. Uldall, M. Seyfried, D. Bosch, P. Starks, C. Holifield -Collins, J. Prueger, R. Van der Velde, J. Asanuma, M. Palecki, E. E. Small, M. Zreda, J. Calvet, W. T. Crow, and Y. Kerr. 2018. Development and assessment of the SMAP enhanced passive soil moisture product, Remote Sensing of the Environment. 204. 931–941. https://doi.org/10.1016/j.rse.2017.08.025