• In mid-April 2025, the “Order Files” option of NSIDC DAAC’s Data Access Tool will be retired and replaced with Earthdata Download. Earthdata Download is a native desktop application that enables efficient direct download for orders of any size. To use this new download option, you must install the new version release of Earthdata Download (v1.0.4) available here: https://nasa.github.io/earthdata-download/.
    Additionally, the “Order History” page (https://nsidc.org/order-history) will also be removed two weeks after this update, at the end of April 2025.

Data Access Tool

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Selected Data Set Information

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Data Set:
SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants, Version 7
Data Set ID:
SPL4SMLM
Data Set Summary:
SMAP Level-4 (L4) surface and root zone soil moisture data are provided in three products: * SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Geophysical Data (SPL4SMGP, DOI: 10.5067/EVKPQZ4AFC4D) * SMAP L4 Global 3-hourly 9 km EASE-Grid Surface and Root Zone Soil Moisture Analysis Update (SPL4SMAU, DOI: 10.5067/LWJ6TF5SZRG3) * SMAP L4 Global 9 km EASE-Grid Surface and Root Zone Soil Moisture Land Model Constants (SPL4SMLM, DOI: 10.5067/KN96XNPZM4EG). 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.