• Data is currently available for this data set from 04 Dec 2023 onward. Data since 31 March 2015 will become available as they are reprocessed.

SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures, Version 6
Data set id:
DOI: 10.5067/GWYQTF307Y9Y
This is the most recent version of these data.
Version Summary
Changes to this version include:
• A new 1-km land-water mask based on the MODIS44w V6 data is used to determine land-water Tb corrections. The mask:
o more accurately portrays current coastal and inland water body boundaries
o adds an ice shelf type to determine an ice shelf fraction for a given footprint or grid cell, reflected in new data elements ice_shelf_fraction_h and ice_shelf_fraction_v
• The maximum Tb threshold has been reduced from 340K to 310K to further remove RFI contamination

For the full major and minor version history, go to https://nsidc.org/data/smap/version-history


This Level-1B (L1B) product provides calibrated estimates of time-ordered geolocated brightness temperatures measured by the Soil Moisture Active Passive (SMAP) passive microwave radiometer. SMAP L-band brightness temperatures are referenced to the Earth's surface with undesired and erroneous radiometric sources removed.
Data Format(s):
Temporal Coverage:
31 March 2015 to present
Temporal Resolution:
  • 49 minute
Spatial Resolution:
  • 47 km
  • 36 km
Spatial Reference System(s):
WGS 84
Spatial Coverage:
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.

Data Access & Tools

A free NASA Earthdata Login account is required to access these data. Learn More

Help Articles

General Questions & FAQs

SMAP Ancillary data sets are used to produce SMAP Level-1, -2, -3, and -4 standard data products.
The following table describes both the required and actual latencies for the different SMAP radiometer data sets. Latency is defined as the time (# days, hh:mm:ss) from data acquisition to product generation.

How to Articles

Many NSIDC DAAC data sets can be accessed using the NSIDC DAAC's Data Access Tool. This tool provides the ability to search and filter data with spatial and temporal constraints using a map-based interface.Users have the option to
To convert HDF5 files into binary format you will need to use the h5dump utility, which is part of the HDF5 distribution available from the HDF Group. How you install HDF5 depends on your operating system.
Data subscriptions are available for select NSIDC DAAC data collections. Once signed up, the subscription service automatically sends you new data as they are delivered from active NASA satellite missions.
All data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system, using wget or curl. Basic command line instructions are provided in the article below. 
NASA Worldview is a map interface that allows users to interactively browse imagery, create visualizations, and download the underlying data.
NASA's Global Imagery Browse Services (GIBS) provides up to date, full resolution imagery for selected NSIDC DAAC data sets.