兰州大学机构库 >大气科学学院
CMIP5模式对欧亚阻塞高压模拟能力检验及阻高变化趋势预估
Alternative TitleEvaluation of CMIP5 Models’ Capacity in Simulating the Eurasian Blocking Highs and Projection of Its Change Trend
叶培龙
Thesis Advisor王式功
2015-06-03
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword欧亚阻高 CMIP5模式 模拟能力检验 未来排放情景 阻高变化趋势预估
Abstract灾害性天气气候事件的发生往往与持续的阻塞高压事件有紧密的联系,如何准确地预估未来阻高的可能变化趋势是一个值得研究的科学问题。本文利用NCEP/NCAR再分析资料分析了近50年(1956-2005年)欧亚阻高的3个关键区不同阻高事件的发生频次及长生命期阻高的高度场、环流场特征,检验了CMIP5的13个气候模式对欧亚阻高的模拟能力,并根据未来的不同排放情景,预估了欧亚阻高的可能变化趋势。欧亚阻高区分为3个关键区,其发生次数,乌拉尔山关键区最多,且冬半年 略多于夏半年;鄂霍次克海关键区次之,且冬半年明显多于夏半年。与NCEP/NCAR再分析资料相比,本文使用CMIP5的13个模式中大部分低估了阻高发生天数。大部分模式均能模拟出欧亚阻高天数的纬向分布特征,其中,冬半年呈“双峰一谷”型,而夏半年呈“三峰二谷”型。大部分模式对乌拉尔山、贝加尔湖关键区夏半年和冬半年阻高事件发生频次模拟均偏少,但冬半年偏少程度小于夏半年;鄂霍次克海关键区冬半年的模拟是偏多的。与NCEP/NCAR再分析资料相比,中排放情景下,阻高天数1~5月较明显增加,6-8月显著减少,9-12月略有增加。长生命期阻高,两种情景下,乌拉尔山区减少显著(约40%),鄂霍次克海区略增加(RCP4.5:5%;RCP8.5:2%)。
Other AbstractRelated research shown that the occurrence of disastrous climate events are often closely associated with sustainable blocking events, therefore, how to accurately estimate the change of blocking is worthy of studying. Firstly, based on the NCEP/NCAR reanalysis data, the variation characteristics of different intensity and duration blocking over Northern Hemisphere are analyzed in detail. The frequency of blocking events from 1956 to 2005 over three key blocking regions over Eurasia have been analyzed, the characteristics of height and circulation field during the occurrence of long duration blocking events have been also analyzed. Based on this, the capability of CMIP5 (phase 5 of the Coupled Model Inter-comparison Project) models in simulating the spatial and temporal distribution characteristics of blocking, the frequency of different blocking events and the variation trend of blocking events over Eurasia have been assessed. Furthermore, based on the different emission scenarios, the possible change of Eurasian blocking has been estimated from 2016 to 2065. The main results are as follows: In the three key blocking region over Eurasia, the blocking events in the Ural region is highest, and wintertime is slightly more than summertime; the blocking events frequency of the Okhotsk region is less than that in the Ural region, and the frequency is more distinct in wintertime compared with that in summertime. Comparison with NCEP/NCAR reanalysis data reveal that blocking days are on average underestimated by the majority of CMIP5 models, Most of models generally underestimate blocking days from June to August in the summertime. Most of CMIP5 models could largely reproduce the zonal distribution of blocking days in summertime, wintertime and the whole year. It is found that the zonal distribution show “two peak one valley pattern” in wintertime and the whole year, but it show “three peak two valley pattern” in summertime. Most of CMIP5 models can simulate the distribution characteristics that the number of blocking events generally exhibits an exponential decrease with duration. Comparison CMIP5 models to NCEP/NCAR reanalysis data, reveals that, the frequency of blocking events are partially underestimated, especially for short duration blocking, and the bias is much more robust in summertime than in wintertime. Model projections of blocking days for the 21st century (2016-2065) are examined under the RCP 4.5 and RCP 8.5 pathways over Asia. The multi-...
URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/199870
Collection大气科学学院
Recommended Citation
GB/T 7714
叶培龙. CMIP5模式对欧亚阻塞高压模拟能力检验及阻高变化趋势预估[D]. 兰州. 兰州大学,2015.
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