SMAP Level-4 soil moisture and carbon data have been updated to Version 3 and are available at the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) via the following product pages: SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP), Version 3 Data set DOI: https://doi.org/10.5067/B59DT1D5UMB4 SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update (SPL4SMAU), Version 3 Data set DOI: https://doi.org/10.5067/20ULJH6EZKFJ SMAP L4 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants (SPL4SMLM), Version 3 Data set DOI: https://doi.org/10.5067/4IYTBSUKM57Q SMAP L4 Global Daily 9 km Carbon Net Ecosystem Exchange (SPL4CMDL), Version 3 Data set DOI: https://doi.org/10.5067/O4HAQJEWWUU8 Primary changes to SMAP Level-4 soil moisture data include:
- SMAP observations are now assimilated in Eastern Europe, the Middle East, and East Asia due to expanded coverage of the brightness temperature scaling parameters. The latter are based on two years of SMAP Version 3 brightness temperature observations where the SMOS climatology is unavailable due to RFI.
- An improved version of the model-only Nature Run (NRv4.1) simulation is used to derive the brightness temperature scaling parameters, the model soil moisture initial conditions, and the soil moisture climatology.
- Model now uses dynamic 8-day fPAR inputs obtained from the latest (Collection 6) MODIS fPAR record at 500 m resolution.
- Updated and recalibrated ancillary Biome Properties Look-Up Table (BPLUT) and re-initialized model initial global soil organic carbon (SOC) pools to reflect new MODIS Collection 6 fPAR inputs.