DOI: 10.1002/jgrd.50604
论文题名: Dominant roles of subgrid-scale cloud structures in model diversity of cloud radiative effects
作者: Zhang F. ; Liang X.-Z. ; Li J. ; Zeng Q.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 14 起始页码: 7733
结束页码: 7749
语种: 英语
英文关键词: CAR system
; cloud radiative effect
; intermodel discrepancy
; nonlinear
; radiation
; subgrid-scale cloud structure
Scopus关键词: CAR system
; Cloud radiative effects
; Cloud structure
; intermodel discrepancy
; nonlinear
; Heat radiation
; climate modeling
; cloud
; cloud radiative forcing
; ensemble forecasting
; homogeneity
; nonlinearity
; numerical model
; one-dimensional modeling
; shortwave radiation
英文摘要: Today, large model discrepancies exist in estimated cloud radiative effects (CREs) and irradiances across 1-D radiative transfer schemes aimed for climate models. The primary purpose of this study is to understand physical causes of such model discrepancies, especially in CREs under partly cloudy sky. To achieve this goal, the unique Cloud-Aerosol-Radiation (CAR) ensemble modeling system was employed, offline driven by the ERA-Interim global data for July 2004 with no feedback considered. For evaluating each individual contribution from the existing scheme diversity of cloud horizontal inhomogeneity, cloud optical properties, cloud vertical overlap, and gas absorptions, several sets of numerical experiments were conducted. It is the first time to explicitly demonstrate that after removing most of the disagreement in cloud fields, model spreads of CREs among the CAR's seven major radiation schemes, as well as those of radiative fluxes, dramatically diminish. Taking global mean CREs for example, their current model ranges can decrease to <4 W m-2 from about 10 W m-2 for shortwave and also to <4 W m-2 from 5-8 W m-2 for longwave. Dominant roles of subgrid-scale cloud structures (including vertical overlap and horizontal variability) were proven in general, explaining about 40-75% of the total model spreads. We have also found that model spreads of CREs are very sensitive to cloud cover fractions. Such nonlinear sensitivity can be largely reduced after removing the model difference in the treatments of cloud vertical overlap. Key Points Current model spreads of CREs and radiative fluxes can be dramatically reduced We demonstrated dominant roles of cloud subgrid structure in model diversities We reduced current nonlinear sensitivity of model spreads to cloud fractions ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63530
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Earth System Science Interdisciplinary Center, University of Maryland, 5825 University Research Court, College Park, MD 20740-3823, United States; Earth System Science Interdisciplinary Center, Department of Atmospheric and Oceanic Science, University of Maryland, College Park MD, United States; Canadian Centre for Climate Modelling and Analysis, Environment Canada, Victoria BC, Canada; International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
Recommended Citation:
Zhang F.,Liang X.-Z.,Li J.,et al. Dominant roles of subgrid-scale cloud structures in model diversity of cloud radiative effects[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(14)