Intercomparison of model simulations of mixed-phase clouds observed during the ARM Mixed-Phase Arctic Cloud Experiment. Part I: Single layer cloud

• Main Authors: Klein, S A, McCoy, R B, Morrison, H, Ackerman, A, Avramov, A, deBoer, G, Chen, M, Cole, J, DelGenio, A, Golaz, J, Hashino, T, Harrington, J, Hoose, C, Khairoutdinov, M, Larson, V, Liu, X, Luo, Y, McFarquhar, G, Menon, S, Neggers, R, Park, S, Poellot, M, von Salzen, K, Schmidt, J, Sednev, I, Shipway, B, Shupe, M, Spangenberg, D, Sud, Y, Turner, D, Veron, D, Falk, M, Foster, M, Fridlind, A, Walker, G, Wang, Z, Wolf, A, Xie, S, Xu, K, Yang, F, Zhang, G
• Language: unknown
• Published: 2021
• Subjects: 58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; AIRCRAFT; BENCHMARKS; BOUNDARY LAYERS; CLOUDS; PRECIPITATION; RADIATIONS; SENSITIVITY; SIMULATION; WATER; Arctic
• Online Access: http://www.osti.gov/servlets/purl/962801; https://www.osti.gov/biblio/962801

Results are presented from an intercomparison of single-column and cloud-resolving model simulations of a cold-air outbreak mixed-phase stratocumulus cloud observed during the Atmospheric Radiation Measurement (ARM) program's Mixed-Phase Arctic Cloud Experiment. The observed cloud occurred in a well-mixed boundary layer with a cloud top temperature of -15 C. The observed liquid water path of around 160 g m{sup -2} was about two-thirds of the adiabatic value and much greater than the mass of ice crystal precipitation which when integrated from the surface to cloud top was around 15 g m{sup -2}. The simulations were performed by seventeen single-column models (SCMs) and nine cloud-resolving models (CRMs). While the simulated ice water path is generally consistent with the observed values, the median SCM and CRM liquid water path is a factor of three smaller than observed. Results from a sensitivity study in which models removed ice microphysics indicate that in many models the interaction between liquid and ice-phase microphysics is responsible for the large model underestimate of liquid water path. Despite this general underestimate, the simulated liquid and ice water paths of several models are consistent with the observed values. Furthermore, there is some evidence that models with more sophisticated microphysics simulate liquid and ice water paths that are in better agreement with the observed values, although considerable scatter is also present. Although no single factor guarantees a good simulation, these results emphasize the need for improvement in the model representation of mixed-phase microphysics. This case study, which has been well observed from both aircraft and ground-based remote sensors, could be a benchmark for model simulations of mixed-phase clouds.