There was a study by Alfaro-Contreras et al. [2016], who used OMI AI and CALIOP aerosol profile, as well as MODIS cloud product, to examine the frequency of above-cloud absorbing aerosols. https://www.atmos-chem-phys.net/16/47/2016/. 

Thanks Xu. 

We are planning to capture the trans boundary movement of dust and biomass burning aerosols from upper gangetic plain to lower part. We have 4-5 aeronet stations over this gangetic plain, what we will try to exploit.

What would be your recommendation in selecting the region surrounding an aeronet station, I mean it should be an average area like 10*10km or pixels 3*3?

I am also concerned with the overpass of Calipso over the gangetic plain.

Anyway, I congratulate you on your publication on Top-down estimate of dust emissions ........through integration GEOS-Chem adjoint model. We also wish to address the similar issue over the gangetic plain, south Asia. 

How do you like this article ?? 

Article Evaluation of MODIS Collection 6 aerosol retrieval algorithm...

I would recommend 50x50 km2 for satellite sampling and +/- 30 min for AERONET sampling, which was suggested by Ichoku et al.. (2002) doi:10.1029/2001GL013206 and has been widely used for evaluating MODIS AODs. You may want check on this article: https://www.atmos-chem-phys.net/15/5903/2015/acp-15-5903-2015.pdf

Thank you for commenting on our Top-down article. Application to Indo-Gangetic Plain will be very interesting. Do you know if there has been any published studies on top-down aerosol emissions over this region, particularly for dust and smoke aerosols? Yes, I would like to read your article.