Effect of diurnal variation of aerosols on surface reaching solar radiation

• Inclusion of diurnal variation of aerosols in the estimation of radiative forcing.
• Observed day time AODs are higher (by factor 1.5) when compare to night time AOD.
• Diurnal variation of aerosols causes additional warming in the atmosphere.

In this report, we attempt to quantify direct aerosol radiative forcing by considering the diurnal variation of aerosols over central Himalayan region. The measured day time aerosol optical depth (AOD) values are higher by a small magnitude ≤15% during forenoon and reached as high as 90% by late afternoon when compare to night time AOD. The above observation gives clue about transport of regional polluted aerosols to the observational site. Our results show, 10 (16) % increment in atmospheric radiative forcing due to diurnal variation of aerosols instead of average aerosols during winter (post-monsoon) season.