On Wednesday, February 23rd from 9:30 to 10:30 a.m. (USA Mountain Time), the following data collections may not be available due to planned system maintenance: AMSR-E, Aquarius, High Mountain Asia, IceBridge, ICESat/GLAS, ICESat-2, MEaSUREs, MODIS, NISE, SMAP, SnowEx, and VIIRS.

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Data for new versions of SMAP Level-4 data sets are currently available from 31 March 2015 through present. Data prior to 27 August 2020 are being reprocessed with the latest version of input data and will become available as they are completed.
Antenna scan angle (ASA) errors affected a large number of data files between 05 Oct and 23 Nov 2019, as well as a handful of dates within 2020 (04 and 05 Feb, 09 Apr, 30 May, and 18 Jun). The bad data are not currently identified by data quality flags. The ASA errors disrupt the proper geolocation of half-orbits, which may be off by as much as 99 km in the along scan direction. The affected half-orbits are in the Version 5 SPL1BTB product (specifically half-orbits 24977.5 - 25691, 26765 - 26781, 27709 - 27713, 28458~28459, and 28733.5 – 28739.5), but upstream products are similarly impacted. The cause of the ASA errors has been identified and the affected data files will be reprocessed. This reprocessing is scheduled to begin in March, 2021 and the Level 4 (Vv5030 and Vv5040) reprocessing will pause until it is complete.
Data Set ID: 
SPL4CMDL

SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 5

The Level-4 (L4) carbon product (SPL4CMDL) provides global gridded daily estimates of net ecosystem carbon (CO2) exchange derived using a satellite data based terrestrial carbon flux model informed by the following: Soil Moisture Active Passive (SMAP) L-band microwave observations, land cover and vegetation inputs from the Moderate Resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), and the Goddard Earth Observing System Model, Version 5 (GEOS-5) land model assimilation system. Parameters are computed using an Earth-fixed, global cylindrical 9 km Equal-Area Scalable Earth Grid, Version 2.0 (EASE-Grid 2.0) projection.

This is the most recent version of these data.

Version Summary: 

Changes to this version primarily represent changes to the model inputs and model Biome Properties Look-up Table (BPLUT) calibration rather than changes to the internal model structure or code. The Version 5 product accuracy and performance is largely consistent with Version 4. Specific changes include:
- Revised Level-4 carbon global model calibration and soil organic carbon (SOC) initialization using the latest SMAP Nature Run (NRv8.3) soil moisture and soil temperature data, and MERRA-2 surface meteorology.
- The carbon model BPLUT has been recalibrated using a FLUXNET2015 global tower site record that includes 329 sites representing all major global plant functional type (PFT) classes.
- Implemented minor changes to spatial weighting of FLUXNET2015 tower sites in the Level-4 carbon model BPLUT calibration. Northern (≥ 45°N) tower sites now have greater impact in defining global PFT response characteristics; whereby, the adjusted weighting is designed to enhance product performance in boreal-arctic biomes. It also incorporated a more detailed set of PFT realistic range constraints for the BPLUT parameters prior to the model calibration and optimization.
- Enhanced an attribute in the legend_carbon_model_bitflag data field to include descriptions of the bit values.

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

COMPREHENSIVE Level of Service

Data: Data integrity and usability verified; data customization services available for select data

Documentation: Key metadata and comprehensive user guide available

User Support: Assistance with data access and usage; guidance on use of data in tools and data customization services

See All Level of Service Details

Parameter(s):
  • SOILS > SOIL PRODUCTIVITY > GROSS PRIMARY PRODUCTION (GPP)
  • SOILS > SOIL RESPIRATION > HETEROTROPHIC RESPIRATION (Rh)
  • SOILS > CARBON > NET ECOSYSTEM CO2 EXCHANGE (NEE)
  • SOILS > CARBON > SOIL ORGANIC CARBON (SOC)
Data Format(s):
  • HDF5
Spatial Coverage:
N: 85.044, 
S: -85.044, 
E: 180, 
W: -180
Platform(s):Aqua, GEOS-5, L4_C, SMAP, SUOMI-NPP, Terra
Spatial Resolution:
  • 9 km x 9 km
Sensor(s):MODIS, NOT APPLICABLE, SMAP L-BAND RADIOMETER, VIIRS
Temporal Coverage:
  • 31 March 2015
Version(s):V5
Temporal Resolution1 dayMetadata XML:View Metadata Record
Data Contributor(s):Kimball, J. S., L. A. Jones, A. Endsley, T. Kundig, and R. Reichle.

Geographic Coverage
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Download Via HTTPS: An Earthdata Login account is required to access these data.

Once you have logged in, you will be able to click and download files via a Web browser. There are also options for downloading via a command line or client. For more detailed instructions, please see Options Available for Bulk Downloading Data from HTTPS with Earthdata Login.

Earthdata Search: This application allows you to search, visualize, and access data across thousands of Earth science data sets. Additional customization services are available for select data sets, including subsetting, reformatting, and reprojection.

Worldview: This application allows you to interactively browse global satellite imagery within hours of it being acquired. You can also save it, share it, and download the underlying data.

Subscription Service: Subscribe to have new data automatically delivered to you as they become available at NSIDC. Subscriptions apply only to future data as they are delivered to NSIDC; they cannot be used to receive data already in NSIDC's archive.

As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Kimball, J. S., L. A. Jones, A. Endsley, T. Kundig, and R. Reichle. 2020. SMAP L4 Global Daily 9 km EASE-Grid Carbon Net Ecosystem Exchange, Version 5. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/9IKKQ4BL3PK8. [Date Accessed].

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How To

Programmatic Data Access Guide
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 or through our Application Programming Interface (API). Our API offers you the ability to order data using specific temporal and spatial filters... read more
How to import and geolocate SMAP Level-3 and Level-4 data in ENVI
The following are instructions on how to import and geolocate SMAP Level-3 Radiometer Soil Moisture HDF5 data in ENVI. Testing notes Software: ENVI Software version: 5.3 Platform: Windows 7 Data set: SMAP L3 Radiometer Global Daily 36 km EASE-Grid Soil... read more
How to Import SMAP HDF Data Into ArcGIS
Selected SMAP L4, Version 4 HDF data (SPL4SMAU, SPL4SMGP, & SPL4SMLM) can be added to ArcGIS with a simple drag/drop or using the 'Add Data' function. These data can be imported and visualized but not geolocated. In order to import, project, and scale these data and other SMAP L3 and L4 HDF... read more
How do I access data using OPeNDAP?
Data can be programmatically accessed using NSIDC’s OPeNDAP Hyrax server, allowing you to reformat and subset data based on parameter and array index. For more information on OPeNDAP, including supported data sets and known issues, please see our OPeNDAP documentation: ... read more
How to learn more about SMAP ancillary data
SMAP Ancillary data sets are used to produce SMAP Level-1, -2, -3, and -4 standard data products. Several of these ancillary data sets are produced by external organizations, such as NOAA, the NASA Global Modeling and Assimilation... read more
How to extract point and area data samples using AppEEARS
This step-by-step tutorial demonstrates how to access MODIS and SMAP data using the Application for Extracting and Exploring Analysis Ready Samples (AppEEARS). AppEEARS allows users to access, explore, and download point and area data with spatial, temporal, and parameter subsets. Interactive... read more
Visualize NSIDC data as WMS layers with ArcGIS and Google Earth
NASA's Global Imagery Browse Services (GIBS) provides up to date, full resolution imagery for selected NSIDC DAAC data sets. ... read more
Search, order, and customize NSIDC DAAC data with NASA Earthdata Search
NASA Earthdata Search is a map-based interface where a user can search for Earth science data, filter results based on spatial and temporal constraints, and order data with customizations including re-formatting, re-projecting, and spatial and parameter subsetting. Thousands of Earth science data... read more
Filter and order from a data set web page
Many NSIDC data set web pages provide the ability to search and filter data with spatial and temporal contstraints using a map-based interface. This article outlines how to order NSIDC DAAC data using advanced searching and filtering.  Step 1: Go to a data set web page This article will use the... read more
Visualize and download NSIDC DAAC data with NASA Worldview
NASA Worldview uses the Global Imagery Browse Service (GIBS) to provide up to date, full resolution imagery for select NSIDC DAAC data sets (see attachments below). The map interface allows users to... read more

FAQ

What are the latencies for SMAP radiometer data sets?
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. Short name Title Latency Required Actual (mean1) SPL1AP SMAP L1A... read more
What data subsetting, reformatting, and reprojection services are available for SMAP data?
The following table describes the data subsetting, reformatting, and reprojection services that are currently available for SMAP data via the NASA Earthdata Search tool and a Data Subscription... read more
How do I convert an HDF5/HDF-EOS5 file into binary format?
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. Full instructions for installing and using h5dump on Mac/Unix and... read more
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NSIDC User Services
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