| 北大西洋涛动和南半球环状模不同位相配置对我国南方夏季降水的协同影响 |
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| 引用本文： | 李景鑫,任宏利,陆波,刘景鹏,康延臻.北大西洋涛动和南半球环状模不同位相配置对我国南方夏季降水的协同影响[J].地球物理学报,2017,60(10):3730-3744. |
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| 作者姓名： | 李景鑫 任宏利 陆波 刘景鹏 康延臻 |
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| 作者单位： | 1. 中国气象科学研究院气候系统研究所, 北京 100081;2. 国家气候中心气候研究开放实验室, 北京 100081;3. 中国气象局-南京大学气候预测研究联合实验室, 北京 100081;4. 兰州大学大气科学学院, 兰州 730000 |
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| 基金项目： | 国家重点基础研究发展计划973项目（2013CB430203），公益性行业（气象）科研专项（GYHY201406022），中国气象局气象预报业务关键技术发展项目（YBGJXM（2017）05），中国气象科学研究院基本科研业务费专项资金（2015Z001，2017Y005）联合资助. |
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| 摘 要： | 利用我国气象台站观测资料和再分析格点数据,诊断研究了前期春季(4-5月份)北大西洋涛动(North Atlantic Oscillation,NAO)和南半球环状模(Southern Annular Mode,SAM)在不同位相配置下对我国南方夏季降水异常变化的协同影响作用.分析结果表明,在剔除ENSO最强信号影响后,我国南方夏季降水异常分布显著地依赖于前期春季两个较为独立的年际变率主模态(NAO和SAM)位相的不同配置,即降水异常型主要表现为两个因子单独作用的叠加效果,当前春SAM正位相偏强而NAO负位相偏强时,二者的影响呈现协同正效应,我国南方夏季(6-7月份)降水表现为全区正异常,特别在长江中下游及其以南附近地区最为显著;反之,当前春SAM呈偏强的负位相而NAO偏强的正位相配置时,二者的影响呈现协同负效应,对应我国夏季长江中下游地区降水表现为显著负异常.对其可能的影响机理研究表明,在SAM与NAO位相相反情况下,二者均会通过海气相互作用过程影响到热带大西洋北部海温的异常变化,进而形成协同作用,增强北大西洋海温三极子模态异常信号,从而通过欧亚大陆的遥相关波列对东亚夏季风和我国南方降水产生显著影响.相比之下,当SAM与NAO同位相时,可能表现为抵消效应,不利于北大西洋海温三极子发展,从而削弱对我国南方夏季降水的影响,此方面还有待进一步研究.
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| 关 键 词： | NAO SAM 协同影响 中国南方 夏季降水 |
| 收稿时间： | 2016-08-23 |
Collaborative effects of phase configurations of North Atlantic Oscillation and Southern Annular Mode on summer precipitation anomalies over Southern China |
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| LI Jing-Xin,REN Hong-Li,LU Bo,LIU Jing-Peng,KANG Yan-Zhen.Collaborative effects of phase configurations of North Atlantic Oscillation and Southern Annular Mode on summer precipitation anomalies over Southern China[J].Chinese Journal of Geophysics,2017,60(10):3730-3744. |
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| Authors: | LI Jing-Xin REN Hong-Li LU Bo LIU Jing-Peng KANG Yan-Zhen |
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| Institution: | 1. Institute of Climate System, Chinese Academy of Meteorological Sciences, Beijing 100081, China;2. Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing 100081, China;3. CMA-NJU Joint Laboratory for Climate Prediction Studies, Beijing 100081, China;4. College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China |
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| Abstract: | We have studied the collaborative effects of phase configurations in the prophase spring (April and May) of the North Atlantic Oscillation (NAO) and Southern Annular Mode (SAM) on abnormal precipitation in the ensuing summer (June and July) in southern China by utilizing the dataset of meteorological stations and NCEP reanalysis. Results demonstrate that the summer precipitation anomalies over southern China significantly respond to the various phase configurations of NAO and SAM, the dominant modes of interannual variability, after excluding the strongest ENSO years. Namely, the patterns of precipitation anomalies are primarily affected by the combination effects of NAO and SAM. The strong positive phase of SAM associated with strong negative phase of NAO synergistically makes significant normal anomalies of summer precipitation in the most areas of southern China, especially in the middle and lower reaches of the Yangtze as well as the vicinity to the south. On the contrary, coupling strong negative phase of SAM with strong positive phase of NAO strengthens negative anomalies in the middle and lower reaches of the Yangtze, implying collaborative negative effects. It is pointed out that inverting phases between SAM and NAO make the abnormal alteration of sea surface temperature in the northern tropical Atlantic through the ocean-atmosphere interactions, which collaboratively enhance the abnormal tripole-pattern signal of the sea surface temperature in the North Atlantic. Furthermore, the teleconnection wave train propagating over Eurasia, associated with the generated tripole-pattern signal, has significantly influenced the East Asian summer monsoon and summer precipitation in southern China. However, identical phases of SAM and NAO inhibit the development of the abnormal tripole-pattern signal of sea surface temperature in the North Atlantic to further weaken the impact on the summer precipitation in southern China, which needs further in-depth study in the future. |
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| Keywords: | NAO SAM Collaborative effects Southern China Summer precipitation |
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