The SMAP Level-4 data sets, available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC), have been updated to Version 8. For all Level-4 data products, data from the entire time series (31 March 2015 to present) is now available. For each product, SMAP L-band brightness temperature data from descending and ascending half-orbit satellite passes (approximately 6:00 a.m. and 6:00 p.m. local solar time, respectively) are assimilated into a land surface model that is gridded using an Earth-fixed, global cylindrical 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) projection. Version 7 data products will be retired on 30 June 2025.
The NSIDC DAAC provides access to documentation and data from the following locations:
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update, Version 8
Data set DOI: https://doi.org/10.5067/02LGW4DGJYRX
SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data, Version 8
Data set DOI: https://doi.org/10.5067/T5RUATAQREF8
SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants, Version 8
Data set DOI: https://doi.org/10.5067/PXQIBL2ALDZD
SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 8
Data set DOI: https://doi.org/10.5067/U7SN8JDZL0UC