LiDAR measurements during rainfall: useful or not? Mutual synergy between LiDAR and a disdrometer for precipitation microphysics studies

In 2025 the main DECIPHER field campaign took place on the eastern slope of Monte Baldo, in the Italian Alps. Data from a Metek XR Streamline Doppler Wind Lidar and a Parsivel2 disdrometer, covering a combined period from 25 July to 23 September, were analysed under rain condition. A method was developed for the comparison between the point measurements of the disdrometer and the range-resolved attenuated backscattering values from the lidar. A total of 25 rainfall events were identified and studied. Some events show a good correlation between the vertical-mean attenuated backscatter and the lower-order moments (m0, m1 and m2) of the DSD. However, it was impossible to define a clear relationship, mainly due to the interference of clouds close to the ground. It was nevertheless possible to find that the sole presence of raindrops could not increase the vertical-mean beta beyond a certain value (around log10(beta/1) = -4.7). A second analysis on the below-cloud scavenging was conducted on 11 events by defining a "scavenging index" S. The S index showed a clear dependence on the time duration of the precipitation event but also on the rainrate, which is consistent with other studies in literature.