Landsat Science Products

Landsat Surface Reflectance

Landsat Surface Reflectance measures the fraction of incoming solar radiation that is reflected from Earth's surface to the Landsat sensor. 

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Landsat 8 Level-1 (right) and Surface Reflectance (right) Image Comparison

Landsat image mosaics over the conterminous United States created using Landsat 8 Level-1 data (left) and Landsat 8 Surface Reflectance data (right). Images were created in December 2014.

Surface reflectance (SR) improves comparison between multiple images over the same region by accounting for atmospheric effects such as aerosol scattering and thin clouds, which can help in the detection and characterization of Earth surface change. Surface reflectance is the amount of light reflected by the surface of the Earth. It is a ratio of surface radiance to surface irradiance, and as such is unitless, with values between 0 and 1.

Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+)

Landsat 4-5 TM and Landsat 7 ETM+ Surface Reflectance are generated using the Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) algorithm, a specialized software originally 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).

The software applies Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric correction routines to Level-1 data products. Water vapor, ozone, geopotential height, aerosol optical thickness, and digital elevation are input with Landsat data to the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) radiative transfer models to generate top of atmosphere (TOA) reflectance, surface reflectance, TOA brightness temperature, and masks for clouds, cloud shadows, adjacent clouds, land, and water.

The Landsat 4-7 Surface Reflectance Product Guide contains details about the LEDAPS algorithm and the Surface Reflectance data products created from it. 

Landsat 8 Operational Land Imager (OLI)

Landsat 8 OLI Surface Reflectance are generated using the Landsat 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 unique radiative transfer model.  (Vermote et al., 2016).

LaSRC hardcodes the view zenith angle to “0”, and the solar zenith and view zenith angles are used for calculations as part of the atmospheric correction. 

The Landsat 8 Surface Reflectance Code (LaSRC) Product Guide contains details about the LaSRC algorithm and the Surface Reflectance data products created from it. 

Differences in Surface Reflectance Processing Algorithms

While both the LEDAPS and LaSRC algorithms produce similar SR products, the inputs and methods to do so differ between them.  The table below displays each algorithm.   

Parameter Landsat 4-5, Landsat 7
(LEDAPS)
Landsat 8
(LaSRC)
(Original) research grant NASA GSFC, MEaSUREs (Masek) NASA GSFC (Vermote)
Global Coverage Yes Yes
TOA Reflectance Visible (Bands 1–5,7) Visible (Bands 1–7, 9 OLI)
TOA Brightness Temperature Thermal (Band 6) Thermal (Bands 10 & 11 TIRS)
SR Visible (Bands 1-5, Band 7) Visible (Bandsat 1-7) (OLI only)
Thermal bands used in Surface Reflectance processing?  Yes
(Brightness temperature Band 6 is used in cloud estimation)
No
Radiative transfer model 6S Internal algorithm
Thermal correction level TOA only TOA only
Thermal band units Kelvin Kelvin
Pressure NCEP Grid Surface pressure is calculated internally based on the elevation
Water vapor NCEP Grid MODIS CMA
Air temperature NCEP Grid MODIS CMA
DEM GTOPO5  GTOPO5 
Ozone OMI/TOMS MODIS CMG Coarse resolution ozone
AOT Correlation between chlorophyll absorption
and bound water absorption of scene
MODIS CMA
Sun angle Scene center from input metadata Scene center from input metadata
View zenith angle From input metadata Hard-coded to "0"
Undesirable zenith angle correction SR not processed when solar zenith angle
> 76 degrees
SR not processed when solar zenith angle > 76 degrees
Pan band processed? No No
XML metadata?  Yes Yes
Top of Atmosphere
Brightness Temperature calculated
Yes (Band 6 TM/ETM+) Yes (Band 10 & 11 TIRS)
Cloud mask CFMask CFMask
Data format INT16 INT16
Fill values -9999 -9999
QA bands Cloud
Adjacent cloud
Cloud shadow
DDV
Fill
Land water
Snow
Atmospheric opacity
Cloud
Adjacent cloud
Cloud shadow
Aerosols
Cirrus
Aerosol Interpolation

6S Second Simulation of a Satellite Signal in the Solar Spectrum, AOT Aerosol Optical Thickness, CFmask C Version of Function Of Mask, CMA Climate Modeling Grid - Aerosol, CMG Climate Modeling Grid, DDV Dark Dense Vegetation, DEM Digital Elevation Model, ETM+ Enhanced Thematic Mapper Plus, GSFC Goddard Space Flight Center, INT Integer, MEaSUREs Making Earth Science Data Records for Use in Research Environments, MODIS Moderate Resolution Imaging Spectroradiometer, N/A Not Applicable, NASA National Aeronautics and Space Administration, NCEP National Centers for Environmental Prediction, OLI Operational Land Imager, OMI Ozone Monitoring Instrument, QA Quality Assessment, SR Surface Reflectance, TIRS Thermal Infrared Sensor, TM Thematic Mapper, TOA Top of Atmosphere Reflectance, TOMS Total Ozone Mapping Spectrometer, XML Extensible Markup Language

Contraints and Caveats 

Most day-lit (descending) Landsat 4-8 scenes in the USGS archive can be processed to Surface Reflectance. Newly-collected Landsat 8 and Landsat 7 Real-Time scenes become suitable for processing within a few days of data acquisition. Please note the following caveats:

1. Due to missing auxiliary input data and/or necessary thermal data, Surface Reflectance processing cannot be applied to data acquired during the dates listed below.

Landsat 8

2016:  February 19 to February 27 (DOY 50 to 58) **

Landsat 7

2016: May 30 to June 12 (DOY 151 to 164) **
2017: March 12 to March 17 (DOY 71 to 76)**

** Auxiliary data needed to produce Surface Reflectance data is unavailable. 

2. The efficacy of land surface reflectance correction is likely to be reduced in hyper-arid or snow-covered regions, areas with low sun angle conditions, coastal regions where land area is small, relative to adjacent water, or areas with extensive cloud contamination.

Corrections may not be accurate to data acquired over high latitudes (> 65 degrees North or South). Landsat 7 ETM+ inputs are not gap-filled in the surface reflectance production. Users can refer to the Quality Assessment(QA) band for pixel-level condition and validity flags.

3. Landsat atmospheric correction and surface reflectance retrieval algorithms are not ideal for water bodies due to the inherently low level of water leaving radiance, and the consequential very low signal to noise ratio. Similarly, surface reflectance values greater than 1.0 can be encountered over bright targets such as snow and playas. These are known computational artifacts in the Landsat surface reflectance products.  

Quantitative remote sensing retrievals of water column constituents requires different algorithms, which are being considered for integration into future Landsat surface reflectance products.

Data Access

Scene-based Surface Reflectance data (on-demand): Processing requests for scene-based Landsat Surface Reflectance data can be submitted from EarthExplorer. The data are located under the Landsat category, Landsat Collection 1 Level-2 (On-Demand)subcategory, with Landsat 8, Landsat 7, and Landsat 4-5 TM listed as individual datasets. These requests are sent to the ESPA On-Demand Interface for processing and data delivery.

The USGS Earth Resources Observation and Science (EROS) Center Science Processing Architecture (ESPA) On Demand Interface (ESPA) can also be used to submit lists of Landsat Level-1 scenes or granules from select MODIS collections to request Level-2 Surface Reflectance processing, Surface Reflectance-based spectral indices, customize output options, and request output product statistics and plots. 

Tile-based Surface Reflectance data: Tile-based Surface Reflectance data are available for immediate download; the data are located under the Landsat category, Landsat Analysis Ready Data (ARD) subcategory, and listed as U.S. Landsat 4-8 ARD.

Visit the Landsat Data Access web page for information about bulk download options.  

Data Manipulation Tools

Data manipulation tools that function with Moderate Resolution Imaging Spectroradiometer (MODIS) Land products are likely to work with Landsat surface reflectance data products as well. The public domain tools listed below are suggested for format conversion, science data set extraction, bit extraction (for top of atmosphere reflectance, saturation values only), and reprojection.

HDF-EOS To GeoTIFF Conversion Tool (HEG): Allows a user to reformat, re-project and perform stitching/mosaicing and subsetting operations on HDF-EOS objects. It can also reformats and re-project some SMAP, VIIRS and SRTM products. The output GeoTIFF file is ingestible into commonly used GIS applications. HEG will also write to HDF-EOS Grid & SWATH formats (i.e for Subsetting purposes) and native (or raw) binary. 

Landsat Quality Assessment (QA) ToolsDeveloped by the MODIS land quality assessment group to work specifically with Landsat Surface Reflectance data. 

Documentation

Landsat 4-7 Surface Reflectance Product Guide

Landsat 8 Surface Reflectance Code (LaSRC) Product Guide

Landsat 8 OLI/TIRS Surface Reflectance Digital Object Identifier (DOI): doi.org/10.5066/F78S4MZJ

Landsat 7 ETM+ Surface Reflectance Digital Object Identifier (DOI): doi.org/10.5066/F7Q52MNK

Landsat 4-5 TM Surface Reflectance Digital Object Identifier (DOI): doi.org/10.5066/F7KD1VZ9

ESPA on-Demand Interface User Guide

Contacts