Natural Seeder‐Feeder Process Originating From Mixed‐Phase Clouds Observed With Polarization Lidar and Radiosonde at a Mid‐Latitude Plain Site

Abstract

Natural seeder‐feeder processes play an essential role in the formation and enhancement of precipitation. However, the cloud‐seeding process from mixed‐phase clouds is still not well understood due to the lack of sufficient observations. Natural seeder‐feeder processes from mixed‐phase clouds (seeder clouds) to lower‐lying liquid clouds (feeder clouds) were observed on 19 occasions using ground‐based polarization lidar and radiosonde measurements from June 2018 to June 2020 at a mid‐latitude plain observatory in Wuhan (30.5°N, 114.4°E), China. Ice crystals originating from seeder clouds fell into feeder clouds located 0.2–2.2 km below. During the sedimentation between seeder and feeder clouds, ice crystals partly underwent sublimation when passing through the in‐between dry air layers. The feeder clouds inhibited those ice crystals from complete sublimation and grew them larger by riming or vapor deposition from a favorable liquid water supply. Subsequently, ice crystals were observed afresh falling from feeder clouds, forming ice virgae descending toward the surface. Owing to cloud seeding, feeder clouds with cloud‐top temperatures (CTTs) as warm as −0.2°C to −14.5°C could produce ice virgae, although these CTTs are generally considered somewhat insufficient to initiate primary ice nucleation. The observed optically thin feeder clouds prolonged the survival time/distance of falling ice crystals, indicating that denser feeder clouds may induce enhanced precipitation.

Atmospheric Refraction Delay Toward Millimeter‐Level Lunar Laser Ranging: Correcting the Temperature‐Induced Error With Real‐Time and Co‐Located Lidar Measurements

“…Our atmospheric observatory (30.5°N, 114.4°E) is on the campus of Wuhan University, Wuhan, China, which is ∼23.4 km away from the Wuhan Weather Station where the radiosondes are launched (He et al., 2022). We propose to install a PRR lidar beside the LLR system (see Figure 1) so that it can realize the simultaneous and co‐located temperature observations.…”

Quality assessment of aerosol lidars at 1064 nm in the framework of the MEMO campaign

“…Hauchecorne and et.al., 1992;Weng et al, 2018), cloud layers and cloud phase (e.g. Haarig et al, 2016;Lolli et al, 2018;He et al, 2022), and in particular aerosol distributions and characteristics (such as smoke plumes, properties and transport of mineral dust aerosols, marine aerosols and other pollutants (e.g. Papayannis et al, 2009;Engelmann et al, 2021;Groß et al, 2011;Qin et al, 2016;Mamouri and Ansmann, 2017;Wang et al, 2019a;Yin et al, 2019;Wang et al, 2019b;Yin et al, 2021;Wang et al, 2022) in the atmosphere.…”

Quality assessment of aerosol lidars at 1064 nm in the framework of the MEMO campaign

“…MPLNET was calibrated by normalizing their signal to the molecular profile but requires knowledge of the aerosol optical depth of the atmosphere to correct the transmission loss of laser power (Welton et al, 2001;Lolli et al, 2019). Since the MPLNET lidar sites are co-located with AERosol RObotic NETwork (AERONET;Holben et al, 1998) sites, the aerosol optical depth can be derived directly from the AERONET column optical depths measured by a sun photometer. A comprehensive method for self-checking lidar hardware was proposed by EARLINET (Freudenthaler et al, 2018).…”