Brief description
Background:This is a sub-product of DEA Surface Reflectance (Sentinel-2A MSI) - Geoscience Australia Sentinel-2A MSI Analysis Ready Data Collection 3. See the parent product for more information.
Reflectance data at top of atmosphere (TOA) collected by Sentinel-2A MSI sensors can be affected by atmospheric conditions, sun position, sensor view angle, surface slope and surface aspect.
Surfaces with varying terrain can introduce inconsistencies to optical satellite images through irradiance and bidirectional reflectance distribution function (BRDF) effects. For example, slopes facing the sun appear brighter compared with those facing away from the sun. Likewise, many surfaces on Earth are anisotropic in nature, so the signal picked up by a satellite sensor may differ depending on the sensor’s position.
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 Sentinel-2A MSI imagery captured over the Australian continent and corrects the inconsistencies across the land and coastal fringe. It achieves this using Nadir corrected Bi-directional reflectance distribution function Adjusted Reflectance (NBAR).
In addition, this product applies terrain illumination correction to correct for varying terrain.
The resolution is a 10/20/60 m grid based on the the ESA level 1C 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
Lineage
Maintenance and Update Frequency: asNeeded
Statement: Data sources:
- SRTM DSM/DEM data
- Ephemeris Data
- Aerosol Optical Depth
- Precipitable Water for Entire Atmosphere
MCD43A1 Collection 6
- Kuruzc 2005 TOA Solar Irradiance
- Ozone data
- Sentinel-2 level 1C
Processing steps:
1. Longitude and Latitude Calculation
2. Satellite and Solar Geometry Calculation
3. Aerosol Optical Thickness Retrieval
4. BRDF Shape Function Retrieval
5. Ozone Retrieval
6. Elevation Retrieval and Smoothing
7. Slope and Aspect Calculation
8. Incidence and Azimuthal Incident Angles Calculation
9. Exiting and Azimuthal Exiting Angles Calculation
10. Relative Slope Calculation
11. Terrain Occlusion Mask
12. MODTRAN
13. Atmospheric Correction Coefficients Calculation
14. Bilinear Interpolation of Atmospheric Correction Coefficients
15. Surface Reflectance Calculation (NBAR)
- SRTM DSM/DEM data
- Ephemeris Data
- Aerosol Optical Depth
- Precipitable Water for Entire Atmosphere
MCD43A1 Collection 6
- Kuruzc 2005 TOA Solar Irradiance
- Ozone data
- Sentinel-2 level 1C
Processing steps:
1. Longitude and Latitude Calculation
2. Satellite and Solar Geometry Calculation
3. Aerosol Optical Thickness Retrieval
4. BRDF Shape Function Retrieval
5. Ozone Retrieval
6. Elevation Retrieval and Smoothing
7. Slope and Aspect Calculation
8. Incidence and Azimuthal Incident Angles Calculation
9. Exiting and Azimuthal Exiting Angles Calculation
10. Relative Slope Calculation
11. Terrain Occlusion Mask
12. MODTRAN
13. Atmospheric Correction Coefficients Calculation
14. Bilinear Interpolation of Atmospheric Correction Coefficients
15. Surface Reflectance Calculation (NBAR)
Notes
PurposeThis product represents standardised optical surface reflectance using robust physical models to correct for variations and inconsistencies in image radiance values. It delivers modelled surface reflectance from Sentinel-2A MSI data using physical rather than empirical models. This ensures that the reflective value differences between imagery acquired at different times by different sensors will be primarily due to on-ground changes in biophysical parameters rather than artefacts of the imaging environment. This product is created using a physics-based, coupled Bidirectional Reflectance Distribution Function (BRDF) and atmospheric correction model that can be applied to both flat and inclined surfaces (Li et al. 2012). The resulting surface reflectance values are comparable both within individual images and between images acquired at different times.
Created: 13 09 2021
Issued: 11 05 2022
text: westlimit=112; southlimit=-44.00; eastlimit=154; northlimit=-9.00
Subjects
EARTH SCIENCES |
Earth observation |
Published_External |
Sentinel-2 |
analysis ready data |
geoscientificInformation |
satellite images |
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Identifiers
- DOI : 10.26186/146571
- URI : pid.geoscience.gov.au/dataset/ga/146571
- global : 45499ffc-3ca7-450a-a786-7423870b6032