New Long-Term Data Record Products Available from LAADS DAAC

NASA's Level-1 and Atmosphere Archive & Distribution System Distributed Active Archive Center (LAADS DAAC) released, new Long-Term Data Record Products (LTDR) -- Version 6 -- using data from the Advanced Very-High-Resolution Radiometer (AVHRR). Data users will notice updates to the LTDR product pages, user guide, and tables related to accessing the 24 available LTDR Products.

Updates in Version 6 include:

1. The use of National Centers for Environmental Prediction (NCEP) reanalysis data (NCEP/NWS/NOAA, 1994) for water vapor, surface pressure and surface temperature ancillary data, and TOMS ozone for ozone ancillary data, for all processing prior to the availability of Global Data Assimilation System (GDAS) ancillary data (prior to 2000).
2. Constraint of relative azimuth data in outputs to between +/- 180 degrees.
3. New calibration coefficients for all NOAA-11 processing.
4. Product availability in the NetCDF4 format.
5. Stratospheric aerosol correction performed for all data acquired between 1981 to 1992.

The LTDR project produces, validates, and distributes a global land surface climate data record that uses both mature and well-tested algorithms in concert with the best-available polar-orbiting satellite data from past to the present. The LAADS DAAC hosts the LTDR collections that include top-of-atmosphere reflectance, surface reflectance, and vegetation index products. LTDR draws from the following eight AVHRR missions: MetOp-B, NOAA-19, NOAA-18, NOAA-16, NOAA-14, NOAA-11, NOAA-09, and NOAA-07, to create three data products (Atmospherically Corrected NDVI Daily L3 Global, Atmospherically Corrected Reflectance Daily L3 Global, and Top-of-Atmosphere Reflectance Daily L3 Global) per mission, resulting in 24 data products.

The LTDR project leverages over four decades of institutional knowledge to render AVHRR data products spectrally and temporally consistent with MODIS through reliable and consistent calibration across the different NOAA platforms, bidirectional reflectance distribution function (BRDF) corrections, and MODIS algorithms-driven aerosol retrieval and atmospheric correction processes. Therefore, the LTDR project's promotes coincidence between AVHRR and MODIS, helping improve the AVHRR products and their accuracy, and producing and distributing a validated surface reflectance FCDR and NDVI TCDR, as important Essential Climate Variables (ECV) for climate-change research.