Sensitivity of CAM5-Simulated Arctic Clouds and Radiation to Ice Nucleation Parameterization

• DOI: 10.1175/jcli-d-12-00517.1
• Publication Date: 2013-02-27T15:50:10Z
• Authors: Shaocheng Xie; Xiaohong Liu; Chuanfeng Zhao; Yuying Zhang
• Keywords: Liquid water path; Ice nucleus; Cloud forcing; Cloud height; Ice cloud

Abstract Sensitivity of Arctic clouds and radiation in the Community Atmospheric Model, version 5, to ice nucleation process is examined by testing a new physically based scheme that links variation nuclei (IN) number concentration aerosol properties. The default parameterizes IN simply as function supersaturation. leads significant reduction simulated at all latitudes while changes cloud amounts properties are mainly seen high- midlatitude storm tracks. In Arctic, there considerable increase midlevel decrease low-level clouds, which result from complex interaction among macrophysics, microphysics, large-scale environment. smaller concentrations an liquid water path caused slowdown Bergeron–Findeisen mixed-phase clouds. Overall, optical depth stronger radiative forcing (net cooling) top atmosphere. comparison with satellite data shows slightly improves simulations over most but produces too many Considerable improvements their when compared ground-based measurements. Issues observations model–observation region discussed.