Landsat Collection 2 Atmospheric Auxiliary Data
Landsat Collection 2 Level-2 surface reflectance and surface temperature data processing requires atmospheric auxiliary data from multiple external sources. The required data is extracted from the source and the components specific to generating a Collection 2 Level-2 product are repackaged and are available to download.
Return to Landsat Collection 2 Overview
These data are available for users wanting to generate custom Level-2 products using the Collection 2 surface reflectance and surface temperature algorithms. It is not necessary for users to download the atmospheric auxiliary data for use with Collection 2 Level-2 products.
Surface Reflectance
Landsat 4, Landsat 5, and Landsat 7 Surface Reflectance products are generated using the Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) algorithm developed through a National Aeronautics and Space Administration (NASA) Making Earth System Data Records for Use in Research Environments (MEaSUREs) grant by NASA Goddard Space Flight Center (GSFC) and the University of Maryland (Masek et al., 2006).
Landsat 8 and Landsat 9 Surface Reflectance products are generated using the Land Surface Reflectance Code (LaSRC), which makes use of the coastal aerosol band to perform aerosol inversion tests, uses auxiliary climate data from MODIS, and uses a radiative transfer model. (Vermote et al., 2016). The following versions of MODIS atmospheric characterization auxiliary data are used:
- February 2023 - present: MODIS Version 6.1
- February 2013 to February 17, 2023: MODIS Version 6.0
Surface Temperature
Landsat 4-9 Surface Temperature products are generated from Landsat Collection 2 Level-1 thermal infrared bands, Top of Atmosphere (TOA) reflectance, TOA Brightness Temperature, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Emissivity Database (GED) data, ASTER Normalized Difference Vegetation Index (NDVI) data, and atmospheric profiles of geopotential height, specific humidity, and air temperature extracted from the following inputs:
- January 1, 2024 to present: Goddard Earth Observing System (GEOS) for Instrument Teams (IT)
- January 1, 2000 to December 31, 2023: Forward Processing for Instrument Teams (FP-IT)
- August 22, 1982 to December 31, 1999: Modern Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2)
Collection 2 Atmospheric Auxiliary Data Inputs
The table below lists the atmospheric auxiliary dataset source, the corresponding algorithm/sensor, purpose, and the download location used in the generation of Collection 2 Level-2 products. Each dataset includes a link to more information described below.
Please refer to the Landsat Atmospheric Auxiliary Data Format Control Book for additional technical information and examples of auxiliary file structures.
Collection 2 Surface Reflectance Atmospheric Auxiliary Data Inputs
| Dataset Source |
Purpose Download Source |
|---|---|
| Earth Topography Five Minute Grid (ETOPO5) (CMGDEM) LEDAPS (Landsat 4-7), LaSRC (Landsat 8-9) More Information |
Calculate surface pressure Landsat Web Site (.hdf file) |
| Landsat 8-9 Ratio Map LaSRC (Landsat 8-9) More Information |
Retrieve aerosol Landsat Web Site (.hdf file) |
| Landsat Data Continuity Mission Look Up Tables (LDCMLUT-4 files) LaSRC (Landsat 8-9) More Information |
Atmospheric correction of a Lambertian surface Landsat Web Site (.zip file) |
| MODIS Fused: Daily Surface Reflectance and Daily Aerosol MODIS Climate Modeling Grids, Fused LaSRC (Landsat8-9) More Information *MODIS Fused is used for Landsat 8-9 data acquired between March 2013 (Landsat 8 commissioning) to 09/30/2023. |
Retrieve ozone and water vapor |
| Visible Infrared Imaging Radiometer Suite (VIIRS) Aerosol Daily Level 3 Global 0.05 Degree Climate Modeling Grid (CMG) from the LAADS DAAC. LaSRC (Landsat 8-9) VIIRS CMG is used for Landsat 8-9 data acquired from 10/01/2023 to the present. More Information |
Retrieve ozone and water vapor |
| National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis 1 LEDAPS (Landsat 4-7) More Information |
Retrieve surface pressure, precipitable water, air temperature |
| Total Ozone Mapping Spectrometer (TOMS) LEDAPS (Landsat 4-7) More Information |
Retrieve ozone EarthExplorer |
Collection 2 Surface Temperature Atmospheric Auxiliary Data Inputs
| Dataset Source |
Purpose Download Source |
Notes |
|---|---|---|
|
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Emissivity Data (GED) |
Calculate emissivity
|
|
| Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2) (Landsat 4-7) More Information |
Retrieve atmospheric profiles of geopotential height, specific humidity, and air temperature EarthExplorer |
Used for data acquired August 22, 1982 – 12/31/1999 |
| Goddard Earth Observing System (GEOS) Forward Processing for Instrument Teams (FP-IT) (Landsat 7-9) More Information |
Retrieve atmospheric profiles of geopotential height, specific humidity, and air temperature EarthExplorer |
Used for data acquired 01/01/2000 – 12/31/2023 |
|
Goddard Earth Observing System (GEOS) |
Retrieve atmospheric profiles of geopotential height, specific humidity, and air temperature EarthExplorer |
Used for data acquired 01/01/2024 - forward |
Collection 2 Surface Reflectance Atmospheric Auxiliary Data Inputs
Earth Topography Five Minute Grid (ETOPO5) (CMGDEM)
ETOPO5 (CMGDEM) is a gridded global elevation data model derived from several sources at a resolution of 5 minutes and is used in surface reflectance algorithms for Landsat 4-8 data. It is stored in Hierarchical Data Format Version 4 (HDF4) format. This file is only available from this page.
Landsat 8-9 Ratio Map
This file of band ratio averages is used by the LaSRC algorithm for aerosol retrieval calculation in Landsat 8 surface reflectance processing. It is derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data and gives an estimate of Normalized Difference Water Index (NDWI). This file is only available from this page.
Landsat Data Continuity Mission Look Up Tables (LDCMLUT)
The four look up tables contained in this file are used by the LaSRC algorithm in Landsat 8 surface reflectance processing. These files are only available from this page.
- ANGLE_NEW.hdf - contains scattering, view, and sun angles
- RES_LUT_V3.0-URBANCLEAN-V2.0.hdf - contains intrinsic reflectance information
- AERO_LUT_V3.0-URBANCLEAN-V2.0.ASCII - contains spherical albedo information
- TRANS_LUT_V3.0-URBANCLEAN-V2.0.ASCII - contains transmission information
MODIS Fused
Water vapor and ozone data are extracted from two MODIS Climate Modeling Grids for use in the surface reflectance algorithm for Landsat 8-9 data:
MODIS Aerosol Optical Thickness Daily Climate Modeling Grid (MOD09CMA.061 and MYD09CMA.061): Global products generated daily. Pixels with cloud cover or high solar zenith angles are excluded. These products are in geographic projection with a 0.05 degree spatial resolution. Water vapor data are extracted from these products.
MODIS SR Daily Climate Modeling Grid (MOD09CMG.061 and MYD09CMG.061): Global products generated daily. Pixels with cloud cover, high solar zenith angle, and high blue reflectance are excluded. These products are in geographic projection with a 0.05 degree spatial resolution. Ozone data is extracted from these products.
The data are combined to create a single daily Hierarchical Data Format (HDF) file that contains only water vapor and ozone values. MODIS Terra data are used, if available for both water vapor and ozone data. When MODIS Terra data are not available, MODIS Aqua data are used to fill in missing values (if available). If MODIS Terra or Aqua data are both unavailable, fill values are generated by interpolation. The generated file contains a Scientific Data Set (SDS) for ozone data (unsigned 8-bit integers), an SDS for water vapor data (unsigned 16-bit integers), and a "wherefrom" SDS (8-bit unsigned integers) to identify if the pixel is filled from Terra data, Aqua data, or "none" for interpolated values. The output file name is "L8ANC<yyyy><doy>.hdf_fused". MODIS Fused data are available to download from EarthExplorer. (https://doi.org/10.5066/P9ISIQC9).
VIIRS Aerosol Daily Climate Modeling Grid (CMG)
The VIIRS aerosol daily Level-3 Climate Modeling Grid (CMG) is used in Landsat 8-9 Surface Reflectance algorithm. The VIIRS CMG products are accessed from the Global daily level 3 retrieved from the NASA's Level 1 and Atmosphere Archive & Distribution System Distributed Active Archive Center (LAADS DAAC). The ozone and water vapor datasets are extracted, and gap filled for LaSRC processing.
Currently, two sources of VIIRS CMG data are public. NOAA-20 (designated as JPSS-1 prior to launch) CMG data (VJ104ANC) is currently the primary source. If NOAA-20 data is unavailable for specific day, Suomi National Polar-orbiting Partnership (Suomi-NPP) data (VNP04ANC) will be used instead. Once the data from recently launched NOAA-21 (designated as JPSS-2 prior to launch) becomes available (currently scheduled for late 2023/early 2024), the NOAA-21 data (VJ204ANC) will be the highest priority. If NOAA-21 data is unavailable for a day, then NOAA-20 and Suomi-NPP will be considered.
The VIIRS CMG ozone and water vapor datasets contain orbital gaps over polar regions and open ocean. The gaps are filled using precalculated full resolution monthly averages of the VIIRS datasets from the previous month, the current month of the previous year, and the next month of the previous year. The weight that each monthly average contributes to the final fill value is dependent on the day of the month, and whether the corresponding pixel in the monthly average files contain fill.
The gap filled ozone and water vapor datasets are compressed and archived in daily HDF5 files. These HDF5 files contain the “Coarse Resolution Ozone” SDS (unsigned 8-bit integers) and the “Coarse Resolution Water Vapor” SDS (unsigned 16-bit integers). The LocalGranuleID (e.g., ‘VJ104ANC.A2018005.002.2022256072652.h5’) and PlatformShortName (e.g., ‘JPSS-1’) are also carried over to the HDF5 file for data provenance.
National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis 1
The NOAA NCEP/NCAR Reanalysis 1 products are annual Network Common Data Form (netCDF) files, which contain the daily values for each surface pressure, precipitable water, and air temperature. NCEP data are used in the surface reflectance algorithm for Landsat 4-7 data. The NCEP products are repackaged into daily HDF files that contain SDS for surface pressure, precipitable water, and air temperature, stored as floating-point values. The output file name is "REANALYSIS_<yyyy><doy>.hdf". NCEP/NCAR Reanalysis 1 data are available to download from EarthExplorer. (https://doi.org/10.5066/P9Y9CG3P)
Total Ozone Mapping Spectrometer (TOMS)
Ozone data products are available for the Total Ozone Mapping Spectrometer (TOMS) instruments and for the Ozone Monitoring Instrument (OMI), and are used in the surface reflectance algorithm for Landsat 4-7 data.
Different sources are used for different date ranges, which are listed below. The source is recorded in the ‘Platform’ attribute of the repackaged file.
Nimbus7 TOMS: October 24, 1978 to May 6, 1993
Meteor3 TOMS: August 22, 1991 to Nov 24, 1994
Earth Probe TOMS: July 6, 1996 to Dec 14, 2005
Aura OMI: July 15, 2004 to present
The ozone products are repackaged into daily HDF files that contain ozone data stored as 16-bit integers. The output files are named TOMS_<yyyy><doy>.hdf. TOMS data are available to download from EarthExplorer. (https://doi.org/10.5066/P9KAACSP)
Collection 2 Surface Temperature Atmospheric Auxiliary Data Inputs
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Emissivity Data
ASTER is an instrument on the Terra satellite. ASTER Global Emissivity Dataset (GED) is a global, 90-meter spatial resolution emissivity map of the Earth’s non-frozen land surfaces at different wavelengths in the thermal infrared spectrum. ASTER GED bands 13, 14, and Normalized Difference Vegetation Index (NDVI) are used in the surface temperature algorithm for Landsat 4-8 data. ASTER Emissivity data are available to download from EarthExplorer. (https://doi.org/10.5066/P9ZQJ30Q)
Modern Era Retrospective analysis for Research and Applications Version 2 (MERRA-2)
MERRA-2 is a NASA atmospheric reanalysis that provides data beginning in 1980. MERRA-2 is the first long-term global reanalysis to assimilate space-based observations of aerosols and represent their interactions with other geophysical processes in the climate system. For surface temperature processing of the Landsat 4-7 data acquired between 1982 to December 31, 1999 the atmospheric characterization auxiliary data are retrieved from MERRA-2. MERRA-2 data are available to download from EarthExplorer. (https://doi.org/10.5066/P9HI8JTZ)
Goddard Earth Observing System Model (GEOS) Forward Processing for Instrument Teams (FP-IT) A system of models integrated using the Earth System Modeling Framework that begins in 2000. The GEOS FP-IT data are used in the surface temperature algorithm for Landsat 7-9 data acquired between January 1, 2000 to December 31, 2023. GEOS FP-IT data are updated every three hours and are delivered in 8 files per day. New files that contain the subset of the GEOS FP-IT data are created for Landsat Level-2 surface temperature processing. GEOS-5-FP-IT data are available to download from EarthExplorer. (https://doi.org/10.5066/P9NP30Z1)
Goddard Earth Observing System (GEOS) for Instrument Teams (IT)
The GEOS IT replaces the FP-IT with enhancements to the model and assimilation system which enables more realistic representations of moisture, temperature, land surface, etc. The GEOS FP-IT data are used for surface temperature processing of Landsat 8-9 data acquired on January 1, 2024 to present. The GEOS-IT retains many characteristics of FP-IT, including the three-hour intervals and 50-Km spatial resolution. The subset of GEOS-IT data that are used for Landsat Level-2 surface temperature processing are being made available via the EarthExplorer. (DOI will be available after January 17, 2024)
Documentation
The Landsat Atmospheric Auxiliary Data Data Format Control Book (DFCB) describes the atmospheric auxiliary data required to create surface reflectance and surface temperature data.