Improving GOES Advanced Baseline Imager (ABI) aerosol optical depth (AOD) retrievals using an empirical bias correction algorithm
Abstract. The Advanced Baseline Imager (ABI) on board the
Geostationary Operational Environmental Satellite-R (GOES-R) series enables
retrieval of aerosol optical depth (AOD) from geostationary satellites using
a multiband algorithm similar to those of polar-orbiting satellites'
sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS)
and Visible Infrared Imaging Radiometer Suite (VIIRS). However, this work
demonstrates that the current version of GOES-16 (GOES-East) ABI AOD has
diurnally varying biases due to limitations in the land surface reflectance
relationships between the 0.47  µ m band and the 2.2  µ m band and between the 0.64  µ m band and 2.2  µ m band used in the ABI AOD
retrieval algorithm, which vary with the Sun–satellite geometry and NDVI
(normalized difference vegetation index). To reduce these biases, an
empirical bias correction algorithm has been developed based on the lowest
observed ABI AOD of an adjacent 30 d period and the background AOD at each
time step and at each pixel. The bias correction algorithm improves the
performance of ABI AOD compared to AErosol RObotic NETwork (AERONET) AOD,
especially for the high and medium (top 2) quality ABI AOD. AOD data for the period 6 August to 31 December 2018 are used to evaluate the bias
correction algorithm. After bias correction, the correlation between the top 2 quality ABI AOD and AERONET AOD improves from 0.87 to 0.91, the mean bias
improves from 0.04 to 0.00, and root-mean-square error (RMSE) improves from
0.09 to 0.05. These results for the bias-corrected top 2 qualities ABI AOD
are comparable to those of the corrected high-quality ABI AOD. By using the
top 2 qualities of ABI AOD in conjunction with the bias correction
algorithm, the areal coverage of ABI AOD is increased by about 100 %
without loss of data accuracy.