三套冰晶核化参数化方案在大气模式CAM5中的对比分析
投稿时间: 2016-09-14  最后修改时间: 2016-11-11  点此下载全文
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作者单位E-mail
史湘军 南京信息工程大学 shixj@nuist.edu.cn 
朱寿鹏 南京信息工程大学  
智协飞 南京信息工程大学  
杜康云 河北省气象局  
刘庆爱 河北省气象局  
王琳玮 上海市气象局 公共气象服务中心  
基金项目:中国科学院大气物理研究所LASG实验室2016年开放课题;中国气象局2015年度留学人员科技活动择优资助项目;江苏高校优势学科建设工程资助项目(PAPD)。
中文摘要:本文在同一模式平台上对比分析三套基于物理过程发展而来的冰晶核化参数化方案。除了大气模式CAM5自带的冰晶核化参数化方案 (Liu and Penner 2005, 简称LP方案), 另外两套参数化方案 (Barahona and Nenes 2009, 简称BN方案; K鋜cher et al. 2006,简称KL方案) 也被放入CAM5模式。模拟结果显示,这三套方案得出云辐射强迫、冰晶数浓度及其概率分布非常相似,都基本上接近观测。但是,使用KL方案时得出的全球平均云长波辐射强迫从工业革命前到当代增加 0.05 W m?2,明显低于LP方案的0.36 W m?2和BN方案的0.33 W m?2。由此可见,选择哪个冰晶核化参数化方案不会明显影响模式对冰云的模拟性能,但是对评估人为产生气溶胶的间接效应可能有显著影响。
中文关键词:冰晶核化  参数化方案  对比分析
 
Sensitivity study on three ice nucleation parameterizations with the Community Atmosphere Model (CAM5)
Abstract:The final purpose of this study is to investigate the contribution of ice nucleation parameterizations to the difference in estimating anthropogenic aerosol indirect forcing. Three physically-based ice nucleation parameterizations, developed by Liu and Penner (2005, hereafter LP), Barahona and Nenes (2009, hereafter BN) and Ka?rcher et al. (2006, hereafter KL), are analyzed in this paper. Offline experiments show that ice crystal number concentration calculated from KL parameterization is not sensitive to sulfate aerosols number concentration in most cases, whereas ice crystal number concentration calculated from LP and BN parameterizations are increased with increasing sulfate aerosols number concentration. Compared to BN and Kl parameterization, it is relatively easy for heterogeneous ice nucleation to inhibit homogeneous ice nucleation with LP parameterization. However, ice crystal number concentration calculated from LP parameterization is usually higher than BN and KL parameterizations. Besides the default LP parameterization in CAM5 model, BN and KL parameterizations are implemented in CAM5 for the comparison. The occurrence frequency of homogeneous freezing from simulation with LP parameterization is less than BN and KL parameterizations. But, all simulations show that the occurrence frequency of homogeneous freezing is less 0.1, which are in consistent with observation. Furthermore, there is no remarkable difference among these three parameterizations in ice crystal number concentration or cloud radiative forcing, and all simulation results show generally good agreements with cirrus cloud observations. This suggests that the model’s capability to simulate cirrus clouds is not sensitive to physically-based ice nucleation parameterizations. CAM5 experiment using the KL parameterization predicts a much smaller anthropogenic aerosol longwave indirect forcing (LWCF, 0.05 W m?2) than that using the LP (0.36 W m?2) and BN (0.33 W m?2) parameterizations. This indicates that ice nucleation parameterization plays an important role in estimating anthropogenic aerosol indirect forcing. Previous studies show that the annual global mean change in LWCF from pre-industrial times to present-day estimated from ECHAM5 model with KL parameterization is 0.05-0.20 W m?2, much less than the estimate (0.40-0.52 W m?2) by CAM5 model with LP parameterization. It seems that this difference can be mostly explained by ice nucleation parameterizations.
keywords:Ice Nucleation  Parameterization  Sensitivity
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