The Validated (Version 2) SMAP Level 4 Carbon Product Suite (L4_C)
The primary science objectives of the SMAP Level 4 Carbon (L4_C) product
are to:
• Determine Net Ecosystem CO2 Exchange (NEE) regional patterns and temporal (daily, seasonal, and annual) behavior to within the accuracy range of in situ tower eddy covariance measurements of these processes;
• Link NEE estimates with component carbon fluxes including Gross Primary Productivity (GPP) and heterotrophic respiration (RH), surface soil organic carbon stocks and the primary environmental constraints (EC) to these processes.
Fig 1 (left): Overview of the SMAP L4_C product elements.
Fig 2 (right): L4_C estimated surface (< 10 cm depth) soil organic carbon (SOC, kg C m-2) stocks for April 21, 2016 from the SMAP Level 4 Carbon (L4_C) operational data record. The SOC estimates are derived at a daily time step and 1-km spatial resolution as highlighted for selected Yucatan and Kenya sub-regions; the L4_C product is posted to a 9-km resolution global grid, while preserving sub-grid scale SOC metrics from 1-km processing for up to eight global plant functional types within each 9-km grid cell. Non-vegetated areas (in white) are screened from L4_C processing, while red lines denote political boundaries.
L4_C algorithm
Satellite data driven Terrestrial Carbon Flux (TCF) model developed at the University of Montana
Primary model inputs:
- NASA SMAP L4_SM surface and root zone soil moisture, and soil temperature
- Daily surface meteorological data from the NASA GEOS-5 Forward Processing system
- MODIS Land cover and FPAR (MOD12Q1, MOD15A2)
References
Entekhabi, D. et al. 2014. SMAP Handbook–Soil Moisture Active Passive: Mapping Soil Moisture and Freeze/Thaw from Space. Pasadena, CA USA: SMAP Project, JPL CL#14-2285, Jet Propulsion Laboratory.
Glassy, J., J.S. Kimball, L. Jones, R. H., Reichle, R. A. Lucchesi, J. V. Ardizzone, G.-K. Kim, E. B. Smith, and B. H. Weiss, 2016: Soil Moisture Active Passive (SMAP) Mission Level 4 Carbon (L4_C) Product Specification Document. GMAO Office Note No. 11 (Version 2.0), 69 pp, NASA Goddard Space Flight Center, Greenbelt, MD, USA. Available from http://gmao.gsfc.nasa.gov/pubs/office_notes/.
Kimball, J. S., L. A. Jones, J. Glassy, E. N. Stavros, N. Madani, R. H. Reichle, T. Jackson, and A. Colliander, 2016: Soil Moisture Active Passive (SMAP) Mission Assessment Report for the Version 2 Validated Release L4_C Data Product. GMAO Office Note No. 13 (Version 1.0), 37 pp, NASA Goddard Space Flight Center, Greenbelt, MD, USA. Available from http://gmao.gsfc.nasa.gov/pubs/office_notes.
Kimball, J. S., L. A. Jones, J. P. Glassy, and R. Reichle. 2014. SMAP Algorithm Theoretical Basis Document, Release A: L4 Carbon Product. SMAP Project, JPL D-66484, Jet Propulsion Laboratory, Pasadena CA. 76 pp. (https://nsidc.org/sites/nsidc.org/files/files/271_L4_C_RevA_web.pdf, 2.7 MB)
Kimball, J. S., L. A. Jones, J. Glassy, E. N. Stavros, N. Madani, R. H. Reichle, T. Jackson, and A. Colliander, 2015. Soil Moisture Active Passive (SMAP) Project Calibration and Validation for the L4_C Beta-Release Data Product. NASA/TM–2015-104606, Vol. 42, 37 pp. Document (13765 kB).
Kimball, J., L. A. Jones, J. P. Glassy, and R. Reichle. 2016. SMAP L4 Global Daily 9 km Carbon Net Ecosystem Exchange. Version 2. Boulder, Colorado USA: NASA National Snow and Ice Data Center Distributed Active Archive Center. http://dx.doi.org/10.5067/UBKO5ZUI7I5V. Accessed 29 April 2016.
