retrieve_cloudmask

ASTERimage.retrieve_cloudmask(output_binary=True, include_thermal_test=True, include_channel_r5=True)[source]

ASTER cloud mask.

Four thresholding test based on visual bands distringuish between the dark ocean surface and bright clouds. An additional test corrects uncertain labeled pixels during broken cloud conditions and pixels with sun glint. A detailed description can be found in Werner et al., 2016.

See also

get_reflectance(): Get reflectance values from ASTER’s

near-infrared and short-wave channels.

get_brightnesstemperature(): Get brightness temperature

values from ASTER’s thermal channels.

func:multiple_logical`:

Apply logical function to multiple arguments.

Parameters:

  • output_binary (bool) –

    Switch between binary and full cloud mask flags. binary: 0 - clear (flag 2 & flag 3)

    1 - cloudy (flag 4 & flag 5)

    full: 2 - confidently clear

    3 - probably clear 4 - probably cloudy 5 - confidently cloudy

  • include_thermal_test (bool) – Switch for including test 5, which uses the thermal channel 14 at 11mu with 90m pixel resolution. The reduced resolution can introduce artificial straight cloud boundaries.

  • include_channel_r5 (bool) – Switch for including channel 5 in the thresholding tests. The SWIR sensor, including channel 5, suffered from temperature problems after May 2007. Per default, later recorded images are set to a value that has no influence on the thresholding tests.

Returns:

Cloud mask.

Return type:

ndarray[float]

References

Werner, F., Wind, G., Zhang, Z., Platnick, S., Di Girolamo, L., Zhao, G., Amarasinghe, N., and Meyer, K.: Marine boundary layer cloud property retrievals from high-resolution ASTER observations: case studies and comparison with Terra MODIS, Atmos. Meas. Techannel., 9, 5869-5894, https://doi.org/10.5194/amt-9-5869-2016, 2016.