Cirrus scenes in Barcelona, Spain: Geometrical and optical properties and radiative effects.

For the first time, geometrical, optical and radiative properties of cirrus clouds, measured with a Polarized Micro Pulse Lidar (P-MPL) in Barcelona, have been analysed. For this purpose, the identification of cirrus scenes and the application of the two-way transmittance method have been applied to P-MPL products, published in the website of Micro Pulse Lidar NETwork (MPLNET), along with radiosondes from 2019-2021. The radiative properties of cirrus scenes have been determined through the use of an ensemble scattering model for cirrus clouds and their radiative effects have been calculated with GAME (Global Atmospheric ModEl) model. The results show that the highest occurrence of cirrus is in spring, the cirrus being in 81% of the cases either visible or opaque. Most cirrus have a COD between 0.1-0.2 (49%), LR around 30 sr (53%), linear cloud depolarization ratio between 0.3-0.5 (50%) and IWC lower than 0.01g/m3 (80%). Also, the net radiative effects of 4 selected cirrus case studies were found to be positive at both daytime and nighttime. [ABSTRACT FROM AUTHOR]