This tab pane (Figure 4.7) consists of four subpanels.
- 'Output products directory': In this text field, the user shall specify the directory where both the intermediate (after downscaling and after AE correction) and the final product will be written.
-
'Output product type': With this radio button group (toggle button), the user can specify
what kind of output he wants to write into the target product:
- 'Downscale source product to AE correction grid': The input L1 radiance product will be downscaled to the AE correction grid.
- 'Compute AE corrected product on AE correction grid': The AE correction will be done on the AE correction grid.
- 'Upscale AE corrected product to original grid': The AE corrected product will be upscaled to the original resolution of the input product.
- 'AE correction grid resolution': With this radio button group (toggle button), the user can specify if the LANDSAT TM AE correction shall be performed with a 300m (MERIS FR) or a 1200m (MERIS RR) resolution.
After setting the output products directory and cloud/land flag parameters (see below), the AE correction process of a Landsat TM or ETM+ product MUST be carried out in three subsequent steps:
- Select 'Downscale source product to AE correction grid', click 'Run': The downscaling subprocess will be done, an intermediate product with prefix 'L1N_' and suffix '_downscaled' will be written.
- Select 'Compute AE corrected product on AE correction grid', click 'Run': The AE correction subprocess will be done, an intermediate product with prefix 'L1N_' and suffix '_downscaled_corrected' will be written.
- Select 'Upscale AE corrected product to original grid', then select the name of the output product on the I/O parameters pane, then click 'Run': The upscaling subprocess will be done, the final product will be written.
- 'Ozone content (cm atm):' : A text field to enter the ozone content value to be used by the AE correction algorithm. The default is 0.32 cm atm, the valid interval is [0.01, 1.0].
- 'Surface pressure (hPa):' : A text field to enter the surface pressure value to be used by the AE correction algorithm. The default is 1013.0 hPa, the valid interval is [300.0, 1060.0].
- 'Surface TM apparent temperature (K):' : A text field to enter the ozone content value to be used by the AE correction algorithm. The default is 300 K, the valid interval is [200.0, 320.0].
-
With the checkboxes in this subpanel, the user can select subsequent tests
(see alsoSection 3.2.2)
to finally define a cloud flag:
If all selected tests are passed, the given pixel is considered and flagged as 'cloudy'.
- Brightness test ('passed' if TM3 < BT)
- NDVI test ('passed' if NDVI < NDVIT_CLOUD, with NDVI = (TM4 - TM3)/(TM4 + TM3))
- NDSI test ('passed' if NDSI < NDSIT, with NDSI = (TM2 - TM5)/(TM2 + TM5))
- Temperature test ('passed' if TM6 < TM6T_CLOUD)
-
With the textfields in this subpanel, the user can specify distinct thresholds for the tests above:
- Brightness threshold BT: The default is 0.3, the valid interval is [0.0, 1.0]
- NDVI threshold NDVIT_CLOUD: The default is 0.2, the valid interval is [0.0, 1.0]
- NDSI threshold NDSIT: The default is 3.0, the valid interval is [0.0, 10.0]
- Temperature threshold TM6T_CLOUD: The default is 300.0, the valid interval is [200.0, 320.0]
-
With the checkboxes in this subpanel, the user can select subsequent tests
(see alsoSection 3.2.2)
to finally define a land flag:
If all selected tests are passed, the given pixel is considered and flagged as 'land'.
- NDVI test ('passed' if NDVI < NDVIT_LAND, with NDVI = (TM4 - TM3)/(TM4 + TM3))
- Temperature test ('passed' if TM6 > TM6T (summer), TM6 < TM6T (winter))
-
With the textfields in this subpanel, the user can specify distinct thresholds for the tests above:
- NDVI threshold NDVIT_LAND: The default is 0.2, the valid interval is [0.0, 1.0]
- Temperature threshold TM6T_LAND: The default is 300.0, the valid interval is [200.0, 320.0]
- 'Season': With this radio button group (toggle button), the user can specify if he wants to apply the 'winter' or the 'summer' criterion in the temperature test above.