Basics
About
DEA Surface Reflectance (Landsat 7 ETM+) is part of a suite of Digital Earth Australia (DEA)’s Surface Reflectance datasets that represent the vast archive of images captured by the US Geological Survey (USGS) Landsat and European Space Agency (ESA) Sentinel-2 satellite programs, validated, calibrated, and adjusted for Australian conditions — ready for easy analysis.
Background
The United States Geological Survey's (USGS) Landsat satellite program has been capturing images of the Australian continent for more than 30 years. This data is highly useful for land and coastal mapping studies.
In particular, the light reflected from the Earth’s surface (surface reflectance) is important for monitoring environmental resources – such as agricultural production and mining activities – over time.
We need to make accurate comparisons of imagery acquired at different times, seasons and geographic locations. However, inconsistencies can arise due to variations in atmospheric conditions, sun position, sensor view angle, surface slope and surface aspect. These need to be reduced or removed to ensure the data is consistent and can be compared over time.
What this product offers
This product takes Landsat 7 Enhanced Thematic Mapper Plus (ETM+) imagery captured over the Australian continent and corrects for inconsistencies across land and coastal fringes. The result is accurate and standardised surface reflectance data, which is instrumental in identifying and quantifying environmental change.
This product is a single, cohesive Analysis Ready Data (ARD) package, which allows you to analyse surface reflectance data as is, without the need to apply additional corrections.
It contains three sub-products that provide corrections or attribution information:
- DEA Surface Reflectance NBAR (Landsat 7 ETM+)
- DEA Surface Reflectance NBART (Landsat 7 ETM+)
- DEA Surface Reflectance OA (Landsat 7 ETM+)
The resolution is a 30 m grid based on the USGS Landsat Collection 1 archive.
Applications
- The development of derivative products to monitor land, inland waterways and coastal features, such as:
- urban growth
- coastal habitats
- mining activities
- agricultural activity (e.g. pastoral, irrigated cropping, rain-fed cropping)
- water extent
- The development of refined information products, such as:
- areal units of detected surface water
- areal units of deforestation
- yield predictions of agricultural parcels
- Compliance surveys
- Emergency management
Related products
- DEA Surface Reflectance NBAR (Landsat 7 ETM+)
- DEA Surface Reflectance NBART (Landsat 7 ETM+)
- DEA Surface Reflectance OA (Landsat 7 ETM+)
Publications
- Li, F., Jupp, D. L. B., Reddy, S., Lymburner, L., Mueller, N., Tan, P., & Islam, A. (2010). An evaluation of the use of atmospheric and BRDF correction to standardize Landsat data. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 3(3), 257–270. https://doi.org/10.1109/JSTARS.2010.2042281
- Li, F., Jupp, D. L. B., Thankappan, M., Lymburner, L., Mueller, N., Lewis, A., & Held, A. (2012). A physics-based atmospheric and BRDF correction for Landsat data over mountainous terrain. Remote Sensing of Environment, 124, 756–770. https://doi.org/10.1016/j.rse.2012.06.018
Access
Data access
Link to data |
NCI - THREDDS Digital Earth Australia - Public Data |
---|---|
Code examples | Jupyter notebook |
eCat record | 132310 |
Product ID | ga_ls7e_ard_3 |
Open Data Cube product configuration | https://github.com/GeoscienceAustralia/dea-config/tree/master/dev_3-0-0/products/ga-landsat-ard-3-0-0 |
CMI RESTful node ID | 475 |
NCI project code | xu18 |
Security classification | Unclassified |
Update frequency | asNeeded |
Access notes
Open Data Cube
This product is contained in the Open Data Cube instance managed by Digital Earth Australia (DEA). This simplified process allows you to query data from its sub-products as part of a single query submitted to the database.
Details
Technical information
The Enhanced Thematic Mapper Plus (ETM+) sensor
The ETM+ instrument is a fixed ‘whisk broom’, eight-band, multispectral scanning radiometer capable of providing high-resolution imaging information of the Earth’s surface. It is an enhanced version of the Thematic Mapper (TM) sensor.
The Analysis Ready Data concept
The Analysis Ready Data (ARD) package allows you to get up and running with your analysis as quickly as possible with minimal data preparation and additional input. This makes it simpler for you to develop applications and for the database to execute queries.
The satellite data has been processed to a minimum set of requirements and organised into a form that allows immediate analysis and interoperability through time and with other datasets. It has been adapted from CEOS Analysis Ready Data (CARD4L).
The technical report containing the data summary for the Phase 1 DEA Surface Reflectance Validation is available.
ARD sub-products
1) DEA Surface Reflectance NBAR (Landsat 7 ETM+)
This sub-product produces standardised optical surface reflectance data using robust physical models which correct for variations and inconsistencies in image radiance values. Corrections are performed using Nadir corrected Bi-directional reflectance distribution function Adjusted Reflectance (NBAR).
2) DEA Surface Reflectance NBART (Landsat 7 ETM+)
This sub-product performs the same function as Surface Reflectance (Landsat 5 TM NBAR), but also applies terrain illumination correction.
3) DEA Surface Reflectance OA (Landsat 7 ETM+)
The NBAR and NBART sibling products depend upon the OA product to provide accurate and reliable contextual information about the Landsat data. This ‘data provenance’ provides a chain of information which allows the data to be replicated or utilised by derivative applications. It takes a number of different forms, including satellite, solar and surface geometry and classification attribution labels.
Accuracy and limitations
For detailed information on accuracy and limitations, refer to the sub-products' pages:
- DEA Surface Reflectance NBAR (Landsat 7 ETM+)
- DEA Surface Reflectance NBART (Landsat 7 ETM+)
- DEA Surface Reflectance OA (Landsat 7 ETM+)
Quality assurance
For detailed information on quality assurance, refer to the sub-products' pages:
- DEA Surface Reflectance NBAR (Landsat 7 ETM+)
- DEA Surface Reflectance NBART (Landsat 7 ETM+)
- DEA Surface Reflectance OA (Landsat 7 ETM+)
Software
Relevant websites
- Landsat Enhanced Thematic Mapper Plus
- MODIS BRDF
- Land Processes Distributed Active Archive Center (LP DAAC)
- Global ozone maps
- National Geospatial-Intelligence Agency
- NASA Shuttle Radar Topography Mission
- Earth Resources Observation and Science (EROS) Center
- USGS Landsat Collection 1
References
Berk, A., Conforti, P., Kennett, R., Perkins, T., Hawes, F., & van den Bosch, J. (2014, June 13). MODTRAN6: A major upgrade of the MODTRAN radiative transfer code (M. Velez-Reyes & F. A. Kruse, Eds.). https://doi.org/10.1117/12.2050433
Dymond, J. R., & Shepherd, J. D. (1999). Correction of the topographic effect in remote sensing. IEEE Transactions on Geoscience and Remote Sensing, 37(5), 2618–2619. https://doi.org/10.1109/36.789656
Hudson, S. R., Warren, S. G., Brandt, R. E., Grenfell, T. C., & Six, D. (2006). Spectral bidirectional reflectance of Antarctic snow: Measurements and parameterization. Journal of Geophysical Research, 111(D18), D18106. https://doi.org/10.1029/2006JD007290
Kalnay, E., Kanamitsu, M., Kistler, R., Collins, W., Deaven, D., & Gandin, L. et al. (1996). The NCEP/NCAR 40-Year Reanalysis Project. Bulletin Of The American Meteorological Society, 77(3), 437-471. https://doi.org/10.1175/1520-0477(1996)077<0437:tnyrp>2.0.co;2
Li, F., Jupp, D. L. B., Reddy, S., Lymburner, L., Mueller, N., Tan, P., & Islam, A. (2010). An evaluation of the use of atmospheric and brdf correction to standardize landsat data. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 3(3), 257–270. https://doi.org/10.1109/JSTARS.2010.2042281
Li, F., Jupp, D. L. B., Thankappan, M., Lymburner, L., Mueller, N., Lewis, A., & Held, A. (2012). A physics-based atmospheric and BRDF correction for Landsat data over mountainous terrain. Remote Sensing of Environment, 124, 756–770. https://doi.org/10.1016/j.rse.2012.06.018
Qin, Y., Mitchell, R., & Forgan, B. W. (2015). Characterizing the aerosol and surface reflectance over Australia using AATSR. IEEE Transactions on Geoscience and Remote Sensing, 53(11), 6163–6182. https://doi.org/10.1109/TGRS.2015.2433911
Schaaf, C., Gao, F., Strahler, A., Lucht, W., Li, X., & Tsang, T. et al. (2002). First operational BRDF, albedo nadir reflectance products from MODIS. Remote Sensing Of Environment, 83(1-2), 135-148. https://www.doi.org/10.1016/s0034-4257(02)00091-3
SZA. (2011). Retrieved May 2019, from http://sacs.aeronomie.be/info/sza.php
Zhu, Z., Wang, S., & Woodcock, C. (2015). Improvement and expansion of the Fmask algorithm: cloud, cloud shadow, and snow detection for Landsats 4–7, 8, and Sentinel 2 images. Remote Sensing Of Environment, 159, 269-277. https://doi.org/10.1016/j.rse.2014.12.014
Zhu, Z., & Woodcock, C. E. (2012). Object-based cloud and cloud shadow detection in Landsat imagery. Remote Sensing of Environment, 118, 83–94. https://doi.org/10.1016/j.rse.2011.10.028
Processing
Lineage
This product is derived from the USGS Landsat Collection 1 archive.
- The Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A1 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) Model Parameters dataset was provided by the National Aeronautics and Space Administration (NASA). It was produced daily using 16 days of Terra and Aqua MODIS data at 500 m resolution.
See USGS: MCD43A1, NASA: MODIS BRDF / Albedo Parameter, Schaaf et al. (2002)
- The ozone data was provided by Environment Canada.
See Environment Canada: Global Ozone Maps
- The Aerosol Optical Thickness data was provided by the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
See Qin et al. (2015)
- The Precipitable Water for Entire Atmosphere data was provided by the National Oceanic and Atmospheric Administration (NOAA) / Earth System Research Laboratory (ESRL) / Physical Sciences Division (PSD).
See Kalnay et al. (1996)
- The baseline Digital Surface Model (DSM) data produced from the Shuttle Radar Topography Mission (SRTM) was provided by the National Geospatial-Intelligence Agency (NGA).
See NGA: SRTM, NASA: SRTM
- Level 1 Collection 1 data was provided by the United States Geological Survey (USGS)'s Earth Resources Observation and Science (EROS) Center.
See USGS: EROS, USGS: Landsat Collection 1
Data sources
- DEA Surface Reflectance NBAR (Landsat 7 ETM+)
- DEA Surface Reflectance NBART (Landsat 7 ETM+)
- DEA Surface Reflectance OA (Landsat 7 ETM+)
Processing steps
- Longitude and Latitude Calculation
- Satellite and Solar Geometry Calculation
- Aerosol Optical Thickness Retrieval
- BRDF Shape Function Retrieval
- Ozone Retrieval
- Elevation Retrieval and Smoothing
- Slope and Aspect Calculation
- Incidence and Azimuthal Incident Angles Calculation
- Exiting and Azimuthal Exiting Angles Calculation
- Relative Slope Calculation
- Terrain Occlusion Mask
- MODTRAN
- Atmospheric Correction Coefficients Calculation
- Bilinear Interpolation of Atmospheric Correction Coefficients
- Surface Reflectance Calculation (NBAR)
- Surface Reflectance Calculation (NBAR + Terrain Illumination Correction)
- Function of Mask (Fmask)
- Contiguous Spectral Data Mask Calculation
Schema / spatial extent
Geoscience Australia Landsat Collection 3
Update frequency | asNeeded |
---|---|
Temporal extent | |
Coordinate reference system | Universal Transverse Mercator (variable) |
Cell size X | 30.00 |
Cell size Y | 30.00 |
Credits
Owner
Commonwealth of Australia (Geoscience Australia)Principal contributors
Fuqin Li, David Jupp, Joshua Sixsmith, Lan-Wei Wang, Passand Dorj, Alexander Vincent, Imam Alam, Jeremy Hooke, Simon Oliver, Medhavy ThankappanSubject matter experts
Fuqin Li, David Jupp, Joshua Sixsmith
License
CC BY Attribution 4.0 International LicenseRights statement
© Commonwealth of Australia (Geoscience Australia) 2020. Creative Commons Attribution 4.0 International License.
Acknowledgments
The authors would like to thank the following organisations:
- NASA
- Environment Canada
- CSIRO
- NOAA / ESRL / PSD
- NGA
- USGS / EROS Center
- Spectral Sciences, Inc.