Validation of OMI seasonal and spatio-temporal variations in aerosol-cloud interactions over Banizoumbou using AERONET data

Abstract

Aerosols and cloud interaction remains highly important in the climatic process and its validation with space-based Ozone Monitoring Instrument (OMI) and ground-based observation of Aeronet Robotic Network (AERONET) is therefore essential. OMI and AERONET AODs was logrithmically subset and variations observed in both instruments show spatio-temporal quality of being more noticeable, which could lead to changes in the microphysical scale of clouds and instrumental biases. In this study, we have examined the spatio-temporal OMI AODs variations over Banizoumbou and validated results using AERONET AOD, precipitable water and cloud fraction data from Moderate Resolution Imaging Spectroradiometer (MODIS) from the period between 2014 and 2018. Additionally, estimated the absolute mean bias values of both AODs, correlating the results and performing the mean and standard deviation analysis. To validate instrumental error in retrieving AOD values, we calculated the root mean square error (RMSE) and mean absolute error (MAE) with standard error of measurements and perform 7 day kinematic back trajectories at various initial pressures to estimate zonal and meridional jet winds. Additionally, the seasonal loading of aerosols from the Dust Surface Mass Concentration shows aerosols masking cloud. The results show that winter season has period of good AODs agreement and the absolute bias error and its standard deviation for OMI and AERONET AODs is 0.216 ± 0.08. The correlation results obtained with cloud and precipitable water are 0.51, 0.32 and 0.20, −0.18 which show high monsoon AOD dominance the desert. It could be concluded that instrumental performance has spatio-temporal bias.