Happy new year everybody. I'd like to point your attention to the Polly-XT measurements of clouds and aerosol taken in the morning of 10 January 2019.

Below you see a nice quicklook created from PollyXT data. Besides cloud layers at all heights above 2 km, a pronounced planetary boundary layer (PBL) is visible at heights below 2 km. This is nicely shown in the upper panel in the Figure below that shows the attenuated backscatter coefficient observed at 1064 nm. A look at the lower panel, showing the 532-nm volume depolarization ratio, indicates the presence of a depolarizing layer at the top of the PBL. This is according to recent studies of TROPOS dried sea salt aerosol, containing crystallized salt particles. Their non-sphericity causes a certain degree of depolarization to the backscattered light.


It is also worth looking at the observed cloud layers: between 0500 and 0800 UTC the cloud layer at 3-4 km height does not produce any ice particles, even though temperatures at cloud top (detected by the cloud radar, not seen by the lidar) where below -8 to -10 °C.