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A sensor invariant Atmospheric Correction (SIAC)

Feng Yin

Department of Geography, UCL

ucfafyi@ucl.ac.uk

PyPI version conda py version Docker Image Size (latest by date) Documentation Status Lisence DOI

This atmospheric correction method uses MODIS MCD43 BRDF product to get a coarse resolution simulation of earth surface. A model based on MODIS PSF is built to deal with the scale differences between MODIS and Sentinel 2 / Landsat 8. We uses the ECMWF CAMS prediction as a prior for the atmospheric states, coupling with 6S model to solve for the atmospheric parameters. We do not have topography correction and homogeneous surface is used without considering the BRDF effects.

:whale: Docker:

Please refer to the SIAC Docker usage instruction inside Docker folder.

Citation:

Yin, F., Lewis, P. E., and Gómez-Dans, J. L.: Bayesian atmospheric correction over land: Sentinel-2/MSI and Landsat 8/OLI, Geosci. Model Dev., 15, 7933–7976, https://doi.org/10.5194/gmd-15-7933-2022, 2022.

Auxiliary data needed (Automatically downloaded by SIAC):

Installation:

You will need to have gdal and Lightgbm installed, and it is suggested to install them with:

Then you can install SIAC:

<!-- 1. Using PyPI ```bash pip install SIAC ``` 3. Using anaconda ```bash conda install -c f0xy -c conda-forge siac ``` -->

GEE authenticate:

If you have not used GEE python API before, you will need to authenticate to GEE first after you installed SIAC:

Usage:

The typical usage of SIAC for and Landsat 8&9:

Outputs from SIAC_S2

All the outputs from SIAC are specified in the siac_output.json within the original S2 L1C folder:

An example of the siac_output.json

The following table specifies a list of the outputs from SIAC and their corresponding meanings:

AbbreviationDescriptionScaleComments
siacLogSiac log fileN/A
toaOvrsToa reflectance RGB overviewsN/A
boaOvrsSurface reflectance RGB overviewsN/A
toaOvrFullToa reflectance RGB overview full resolutionN/A
boaOvrFullSurface reflectance RGB overviewsN/A
viewAnglesView angles for each band0.012 bands GeoTiff: B1 view azimuth, B2 view zenith
sunAnglesSun angles for each band0.012 bands GeoTiff: B1 sun azimuth, B2 sun zenith
SurfaceReflectanceSurface reflectance for each band0.0001
SurfaceReflectanceUncertaintySurface reflectance uncertainty for each band0.0001
atmoParasAtmospheric parametersN/Aaerosol optical depth[-], total column of water vapour [ $g/cm^2$ ] and total column of ozone [ $cm-atm$ ]
atmoParasUncsAtmospheric parameter uncertaintiesN/A
Cloud probabilityCloud0.01
VersionVersion of the SIAC softwareN/A
CleanPixelPercentageClean pixel percentageN/A
ValidPixelPercentageValid pixel percentageN/A

Outputs from SIAC_L8

All the outputs from SIAC are within the original L8/L9 L1C folder.

Examples and Map:

A page shows some correction samples.

A map for comparison between TOA and BOA.

LICENSE

GNU GENERAL PUBLIC LICENSE V3