Physical Sciences and Mathematics Commons^™

A Single-Photon Lidar Observes Atmospheric Clouds At Decimeter Scales: Resolving Droplet Activation Within Cloud Base, Fan Yang, Alexander B. Kostinski, Zeen Zhu, Katia Lamer, Edward Luke, Pavlos Kollias, Yong Meng Sua, Pei Hou, Raymond Shaw, Andrew M. Vogelmann

Michigan Tech Research Data

Clouds, crucial for understanding climate, begin with droplet formation from aerosols, but observations of this fleeting activation step are lacking in the atmosphere. Here we use a time-gated time-correlated single-photon counting lidar to observe cloud base structures at decimeter scales. Results show that the air-cloud interface is not a perfect boundary but rather is a transition zone where transformation of aerosol particles into cloud droplets occurs. The observed distributions of first-arriving photons within the transition zone reflect vertical development of a cloud, including droplet activation and condensational growth. Further, the highly resolved vertical profile of backscattered photons above cloud base …