Mixing characteristics in non-precipitation stratocumulus clouds: a model intercomparison study
Authors
Fan Yang — Brookhaven National Laboratory *
Kyoung Ock Choi — Seoul National University
Kamal Kant Chandrakar — National Center for Atmospheric Research (NCAR)
Fabian Hoffmann — Ludwig-Maximilians-Universität München
Pei Hou — Michigan Technological University
Steven K. Krueger — University of Utah
Chunsong Lu — Nanjing University of Information Science and Technology
Mikhail Ovchinnikov — Pacific Northwest National Laboratory
Yangze Ren — Michigan Technological University
Shin-ichiro Shima — University of Hyogo
Peng Wu — Pacific Northwest National Laboratory
Chongzhi Yin — Nanjing University of Information Science and Technology
Seong Soo Yum — Yonsei University
Zeen Zhu — Brookhaven National Laboratory
Category
Warm low clouds, including aerosol interactions
Description
Recent aircraft measurements of marine stratocumulus clouds from three field campaigns (MASE, VOCALS, and ACE-ENA) consistently showed that cloud microphysical relationships varied with cloud altitudes, indicating inhomogeneous mixing near cloud top but homogeneous mixing in mid-levels of clouds. One hypothesis is that inhomogeneous mixing near the cloud top was real, but homogeneous mixing traits in mid-levels of clouds were not actually due to homogeneous mixing but due to vertical circulation of entrainment-affected and diluted parcels near the cloud top (Yum et al., 2015). Here, we conduct a total of eleven large-eddy simulations with different microphysics schemes (bulk, bin, and Lagrangian) as well as a low-dimensional model to simulate an idealized non-precipitation marine stratocumulus cloud. The model setup is based on the data collected during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign. Our results show that (1) the intermodal spread of simulated marine stratocumulus clouds using up-to-date cloud-resolving large-eddy simulations is much smaller than previous studies (e.g., DYCOMS) and (2) models are capable of reproducing the observed mixing characteristics in stratocumulus clouds (i.e., inhomogeneous mixing feature near the top and homogeneous mixing feature inside of the cloud), supporting the vertical circulation mixing mechanism.
Reference:
Yum, Seong Soo, Jian Wang, Yangang Liu, Gunnar Senum, Stephen Springston, Robert McGraw, and Jae Min Yeom. "Cloud microphysical relationships and their implication on entrainment and mixing mechanism for the stratocumulus clouds measured during the VOCALS project." Journal of Geophysical Research: Atmospheres 120, no. 10 (2015): 5047-5069.