袁媛,李崇银,杨崧. 2014. 与厄尔尼诺和拉尼娜相联系的中国南方冬季降水的年代际异常特征[J]. 气象学报, 72(2):237-255, doi:10.11676/qxxb2014.014
与厄尔尼诺和拉尼娜相联系的中国南方冬季降水的年代际异常特征
Decadal anomalies of winter precipitation over southern China in association with El Niño and La Niña
投稿时间:2013-08-06  修订日期:2013-11-08
DOI:10.11676/qxxb2014.014
中文关键词:  东亚冬季风  冬季降水  厄尔尼诺和拉尼娜  非对称性  年代际变化
英文关键词:East Asian winter monsoon  Winter precipitation  El Niñ  o and La Niñ  a  Asymmetry  Decadal variability
基金项目:国家重点基础研究发展计划973项目(2013CB430203)、国家自然科学基金项目(41005038、41105053)、公益性行业(气象)专项(GYHY201306023、GYHY200906016)、江苏省气候变化协同创新中心项目。
作者单位
袁媛 国家气候中心, 中国气象局气候研究开放实验室, 北京, 100081 
李崇银 中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室, 北京, 100029
解放军理工大学气象海洋学院, 南京, 211101 
杨崧 中山大学环境科学与工程学院, 广州, 510275 
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中文摘要:
      利用NCEP/NCAR再分析大气环流资料、哈得来中心海温资料、中国700多站降水资料以及全球格点降水资料,详细分析了中国南方冬季降水异常的特征,并揭示了其所对应的欧亚大气环流和东亚冬季风异常与ENSO事件的联系,以及ENSO暖/冷位相对其影响的非对称性。研究进一步证明了厄尔尼诺是导致中国南方冬季降水偏多的重要外强迫因子,并指出拉尼娜对中国南方冬季降水的影响表现出明显的年代际变化特征。1980年之前的拉尼娜年冬季,东亚冬季风显著偏强,东亚大槽偏深,西北太平洋副热带高压偏弱偏东,中国南方受一致偏北风影响,气温偏低,降水偏少,多表现为冷干的气候特征。但1980年之后的拉尼娜年冬季,东亚大槽偏弱,印缅槽偏强,同时在菲律宾以西激发出异常气旋性环流,使得异常偏东风控制中国南方,有利于热带水汽输送增强,因此降水偏多。同时,1980年之后的拉尼娜事件还使得东亚副热带西风急流偏强偏北,中国南方处于急流入口区的右侧,通过二级环流使得中国南方上空的上升运动偏强,有利于降水偏多。因此,1980年之后的拉尼娜年冬季,中国南方易表现出冷湿的气候特征,有时也容易发生低温雨雪冰冻灾害。进一步分析表明,1980年以后拉尼娜成熟期海温异常空间分布型的变化,以及北半球大气环流的年代际变化可能是导致拉尼娜对东亚大气环流的影响在1980年之后发生变化的重要原因。
英文摘要:
      Using multiple datasets, this paper analyzes the characteristics of winter precipitation over southern China and its association with warm and cold phases of El Nio-Southern Oscillation during 1948-2011. The study proves that El Niño is an important external forcing factor resulting in above-normal winter precipitation in southern China. The study also reveals that the impact of La Niña on the winter precipitation in southern China has a decadal variability.
During the winter of La Niña before 1980, the East Asian winter monsoon is stronger than normal with a deeper trough over East Asia, and the western Pacific subtropical high weakens with its high ridge retreating more eastward. Therefore, anomalous northerly winds dominate over southern China, leading to a cold and dry winter. During La Niña winter after 1980, however, the East Asian trough is weaker than normal, unfavorable for the southward invasion of the winter monsoon, with the India-Burma the East trough intensified, and the anomalous low-level cyclone excited by La Niña located to the west of the Philippines. Therefore, anomalous easterly winds prevail over southern China, which increases moisture flux from the tropical oceans to southern China. Meanwhile, La Niña after 1980 may lead to an enhanced and more northward subtropical westerly jet over East Asia in winter. Since southern China is rightly located on the right side of the jet entrance region, anomalous ascending motion dominates there through the secondary vertical circulation, favoring more winter precipitation in southern China. Consequently, a cold and wet winter, sometimes with snowy and icy weathers, would occur in southern China during La Niña winter after 1980. Further analyses indicate that the change in the spatial distribution of sea surface temperature anomaly during the La Niña mature phase, as well as the decadal variation of the Northern Hemisphere atmospheric circulation, would be the important reasons for the decadal variability of the La Niña impact on the atmospheric circulation in East Asia and winter precipitation over southern China after 1980.
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