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What's hot in the news around climate and sea ice and what are scientists talking about now? SMAP Level 4 soil moisture products will version up in December 2021. Should you have questions, please contact user services at nsidc@nsidc.org. Thank you for your patience while we update the data.
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
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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].How To
Programmatic Data Access Guide
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Testing notes
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Software version: 5.3
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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
# days hh:mm:ss
Actual (... read more
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The following table describes the data subsetting, reformatting, and reprojection services that are currently available for SMAP data via the NASA Earthdata Search, a Data Subscription, and Programmatic Access.
Short name
Title
Subsetting
Reformatting... read more
