User notice: Upcoming changes to SMAP Level-2 and Level-3 radiometer soil moisture products

The SMAP Level-2 and Level-3 standard and enhanced radiometer soil moisture products from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) are being updated in summer 2019. The Level-2 updates will introduce an improved version of the existing Dual Channel Algorithm, DCA (option 3). The new version, known as M-DCA, achieves better retrieval performance by modeling the mixing of vertically and horizontally polarized brightness temperature channels and using new estimates of single-scattering albedo and roughness coefficients. M-DCA (option 3) will supersede optional algorithms MPRA (option 4) and E-DCA (option 5), so the following data fields will be removed from the SMAP Level-2 standard and enhanced radiometer soil moisture products: soil_moisture_option4 vegetation_opacity_option4 retrieval_qual_flag_option4 soil_moisture_option5 vegetation_opacity_option5 retrieval_qual_flag_option5 In addition, a clay fraction field and a bulk density field will be added to both the Level-2 and Level-3 products. The baseline retrieval algorithm remains SCA-V, which is unchanged from the previous release. Access to each data set and related documentation can be found at: SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 5 DOI: https://doi.org/10.5067/SODMLCE6LGLL SMAP Enhanced L2 Radiometer Half-Orbit 9 km EASE-Grid Soil Moisture, Version 2 DOI: https://doi.org/10.5067/K4A1SNL5DLON SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil Moisture, Version 5 DOI: https://doi.org/10.5067/ZX7YX2Y2LHEB SMAP Enhanced L3 Radiometer Global Daily 9 km EASE-Grid Soil Moisture, Version 2 DOI: https://doi.org/10.5067/RFKIZ5QY5ABN