23个CMIP5模式对厄尔尼诺事件生命史演变模拟能力的评估
投稿时间: 2018-03-30  最后修改时间: 2018-05-17  点此下载全文
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作者单位E-mail
姜有山 南京市气象局 jysnjsqxt@163.com 
张高杰 中国民用航空西北地区空中交通管理局气象中心  
陈明诚 南京信息工程大学 13913027486 
葛旭阳 南京信息工程大学  
基金项目:华东区域气象科技协同创新基金合作项目(QYHZ201604)
中文摘要:利用23个CMIP5气候模式历史模拟试验数据,评估模式对于厄尔尼诺事件生命史演变的模拟能力。评估结果显示,有1/3的模式可以很好的再现厄尔尼诺生命史演变过程,而另有1/3的模式对厄尔尼诺生命史模拟能力较弱。观测分析结果表明,动力(海洋温度平流)和热力(海洋表面热量通量)强迫作用都对厄尔尼诺快速衰减过程起到贡献作用。前者主要与西北太平洋区域风场响应有关,而后者主要与 “云-辐射-海温”负反馈过程有关。模拟能力较强的CMIP5模式中海温距平中心相对偏东,因此海洋纬向平流负反馈和短波辐射负反馈作用较强,衰减阶段中海温衰减更快。而模拟能力较弱的气候模式中海温距平中心相对偏西,因此动力和热力过程较弱,海温衰减缓慢。由于衰减变率不同,前者海表温度距平在发展年次年夏季时符号发生改变,而后者依然维持相同的符号。由季节决定的大气-海洋相互作用所引发的不稳定增长过程在北半球秋季时期进一步参与其中,因此较好的模式中负海温距平继续增长并转变成拉尼娜,而模拟能力较弱的模式中始终维持暖海温距平,没有形成拉尼娜。分析结果同时表明,仍然有1/3的气候模式不能很好的模拟出厄尔尼诺事件位相锁定特征。
中文关键词:海气相互作用,模式评估,ENSO动力学,生命史演变
 
Evolution features of El Ni駉 events simulated by 23 CMIP5 models
Abstract:Based on the output data in 23 CMIP5 models, the evolution features of El Ni駉 events are investigated. The results show that one third of the CMIP5 models can capture the fast decaying process in El Ni駉 life cycle, and also one third of the models has a slow decay. Both dynamic and thermodynamic processes contribute to the fast decaying process. The former is related to wind responses in western Pacific, whereas the latter is associated with cloud-radiation-SST feedback. The good model has a sea surface temperature anomaly center located in the equatorial eastern Pacific region, while it tends to shift westward in the pool model. As a result, a strong negative SSTA tendency occurs during El Ni駉 decaying phase in the good model, compared to a much weaker SSTA tendency in the pool model. Such a differ-ence leads to SSTA sign change for El Ni駉 in the good model but no sign change in pool model by end of summer of the second year. A season-dependent coupled instability kicks in during northern fall, leading to the development of a La Ni馻 by end of the second year for the former, but the maintainence of an El Ni駉 episode for the latter. Results also show that the simulated El Ni駉 has a bad phase locking in one third of the CMIP5 models.
keywords:Sea-air interaction  Model assessment  ENSO dynamics  Life evolution
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