DOI: 10.1002/2015MS000589
Scopus记录号: 2-s2.0-84966415563
论文题名: On the relationships among cloud cover, mixed-phase partitioning, and planetary albedo in GCMs
作者: McCoy D ; T ; , Tan I ; , Hartmann D ; L ; , Zelinka M ; D ; , Storelvmo T
刊名: Journal of Advances in Modeling Earth Systems
ISSN: 19422466
出版年: 2016
卷: 8, 期: 2 起始页码: 650
结束页码: 668
语种: 英语
英文关键词: Atmospheric humidity
; Atmospheric temperature
; Cryogenic liquids
; Feedback
; Ice
; Liquids
; Parameterization
; Radiometry
; Solar radiation
; Supercooling
; Albedo
; Climate sensitivity
; Cloud feedbacks
; Cloud fraction
; Mixed phase
; Climate models
; air temperature
; albedo
; atmospheric modeling
; climate feedback
; climate modeling
; cloud cover
; parameterization
; partitioning
; planetary atmosphere
; reflectivity
; sensitivity analysis
; shortwave radiation
; Southern Hemisphere
英文摘要: In this study, it is shown that CMIP5 global climate models (GCMs) that convert supercooled water to ice at relatively warm temperatures tend to have a greater mean-state cloud fraction and more negative cloud feedback in the middle and high latitude Southern Hemisphere. We investigate possible reasons for these relationships by analyzing the mixed-phase parameterizations in 26 GCMs. The atmospheric temperature where ice and liquid are equally prevalent (T5050) is used to characterize the mixed-phase parameterization in each GCM. Liquid clouds have a higher albedo than ice clouds, so, all else being equal, models with more supercooled liquid water would also have a higher planetary albedo. The lower cloud fraction in these models compensates the higher cloud reflectivity and results in clouds that reflect shortwave radiation (SW) in reasonable agreement with observations, but gives clouds that are too bright and too few. The temperature at which supercooled liquid can remain unfrozen is strongly anti-correlated with cloud fraction in the climate mean state across the model ensemble, but we know of no robust physical mechanism to explain this behavior, especially because this anti-correlation extends through the subtropics. A set of perturbed physics simulations with the Community Atmospheric Model Version 4 (CAM4) shows that, if its temperature-dependent phase partitioning is varied and the critical relative humidity for cloud formation in each model run is also tuned to bring reflected SW into agreement with observations, then cloud fraction increases and liquid water path (LWP) decreases with T5050, as in the CMIP5 ensemble. © 2016. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75909
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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作者单位: Atmospheric Sciences Department, University of Washington, Seattle, WA, United States; Geology and Geophysics Department, Yale University, New Haven, CT, United States; Program for Climate Model Diagnosis and Intercomparison, Lawrence Livermore National Laboratory, Livermore, CA, United States
Recommended Citation:
McCoy D,T,, Tan I,et al. On the relationships among cloud cover, mixed-phase partitioning, and planetary albedo in GCMs[J]. Journal of Advances in Modeling Earth Systems,2016-01-01,8(2)