Impact of a noon-time annular solar eclipse on the mixing layer height and vertical distribution of aerosols in the atmospheric boundary layer

Impact of the long duration noontime annular solar eclipse on 15 January 2010 on the vertical distribution of aerosols and mixing layer height (HM) in a well-developed convective atmospheric boundary layer (ABL) has been investigated using continuous Lidar observations over a tropical coastal station, Thumba (8.5°N, 76.9°E). This study shows that HM has decreased from its peak value of ∼1800 m at 12:00 h to ∼1000 m following the annular phase of the eclipse (13:17 h), while the corresponding decrease in the total aerosol abundance of ABL is ∼29%. The post-eclipse increase of HM is rapid compared to that during forenoon.

► Boundary layer aerosol abundance is significantly modified by solar eclipse.
► Mixing height has decreased from ∼1800 m at 12:00 h to ∼1000 m after peak eclipse.
► Mixing height increases more rapidly during post-eclipse period compared to forenoon.
► Aerosol amount in the boundary layer has decreased by ∼29% during eclipse.
► Post-eclipse convection has enhanced aerosol content in the boundary layer by ∼18%.