| 与不同El Nino相伴的IOD事件的季节演变特征对比 |
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| 引用本文： | 祁莉,何珊珊,张文君,何金海.与不同El Nino相伴的IOD事件的季节演变特征对比[J].大气科学学报,2014,37(6):673-683. |
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| 作者姓名： | 祁莉 何珊珊 张文君 何金海 |
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| 作者单位： | 南京信息工程大学气象灾害预报预警与评估协同创新中心,江苏南京210044;气象灾害教育部重点实验室(南京信息工程大学),江苏南京210044 |
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| 基金项目： | 国家重点基础研究发展计划(973计划)项目，国家自然科学基金资助项目，长江学者和创新团队发展计划资助，江苏高校优势学科建设工程资助项目，广西科学研究与技术开发计划项目 |
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| 摘 要： | 基于1951—2012年逐月海洋和大气多种要素的再分析资料,分析了与两类El Nino相伴的IOD(Indian Ocean Dipole,印度洋偶极子)事件盛期的海洋和大气异常特征,并进一步对比了与不同类型El Nino相伴的IOD事件的季节演变及对应的海气耦合过程。结果表明:两类IOD事件盛期时,暖海温强度和位置有显著差异。发生在东部型El Nino期间的IOD事件(简称EP-IOD)盛期,正(负)SSTA中心出现在热带西北(赤道东南)印度洋,强度相当,对应的热带印度洋—海洋大陆异常Walker环流强度较强、范围较大;与中部型CP El Nino相伴的IOD事件(简称CP-IOD)的正SSTA相对较弱,且偏于南印度洋,异常Walker环流较弱、较窄。在季节演变中,两类IOD事件期间的局地海气过程差异显著,伴随着西印度洋西南季风减弱和东印度洋异常东风加强,EP-IOD事件的发展以西正东负的偶极型异常海温的出现及加强为主要特征;而CP-IOD事件的发生发展则与西北印度洋异常冷海温的生消及南印度洋暖水的堆积相伴,表现为"-+-"三极型SSTA的出现并转为西正东负偶极型的过程,夏季时出现在东印度洋的异常东风以及赤道中印度洋低层负涡度异常水平环流对其发展具有重要作用。
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| 关 键 词： | 印度洋偶极子 两类El Nio 季节演变 海气耦合 |
| 收稿时间： | 2014/3/28 0:00:00 |
| 修稿时间： | 2014/6/9 0:00:00 |
Contrasting seasonal evolution features of Indian Ocean Dipole accompanied with two-type El Nino |
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| QI Li,HE Shan-shan,ZHANG Wen-jun and HE Jin-hai.Contrasting seasonal evolution features of Indian Ocean Dipole accompanied with two-type El Nino[J].大气科学学报,2014,37(6):673-683. |
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| Authors: | QI Li HE Shan-shan ZHANG Wen-jun and HE Jin-hai |
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| Institution: | Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, NUIST, Nanjing 210044, China;Key Laboratory of Meteorological Disaster(NUIST), Ministry of Education, Nanjing 210044, China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, NUIST, Nanjing 210044, China;Key Laboratory of Meteorological Disaster(NUIST), Ministry of Education, Nanjing 210044, China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, NUIST, Nanjing 210044, China;Key Laboratory of Meteorological Disaster(NUIST), Ministry of Education, Nanjing 210044, China;Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, NUIST, Nanjing 210044, China;Key Laboratory of Meteorological Disaster(NUIST), Ministry of Education, Nanjing 210044, China |
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| Abstract: | The differences in the seasonal evolution features of Indian Ocean Dipole(IOD) accompanied with two-type El Nino have been investigated based on the observed dataset from 1951 to 2012.Here, this paper focuses on the ocean-atmosphere coupled processes over the tropical Indian Ocean during the evolution of IOD.Results show that, when IOD peaks, the intensity and location of the warming SST anomalies(SSTAs) are different between the IOD co-occurred with EP and CP El Nino.When IOD peaks during EP El Nino, tropical northwestern Indian Ocean warms up and the equatorial southeastern Indian Ocean cools off with a similar intensity, associated with a strong anomalous Walker circulation rising over the western Indian Ocean and sinking over the Maritime Continent.But the warm SSTA locates southward over the central Indian Ocean at the peak of the IOD during CP El Nino, associated with weaker anomalous rising over central Indian Ocean.As to the seasonal evolution of the IOD co-occurred with EP El Nino, the warm and cool SSTAs develop intensely in summer then peak in autumn, which is resulted from the weak southwest summer monsoon over western Indian Ocean and the strong anomalous easterly over eastern Indian Ocean.By comparison, the evolution of IOD during CP El Nino is associated with the strong anomalous easterly over eastern Indian Ocean and anomalous negative vorticity winds in the low troposphere over the central Indian Ocean.The dipole SSTA develops when the west pole of the triple pattern SSTA decays, which is different from the IOD co-occurred with EP El Nino. |
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| Keywords: | Indian Ocean Dipole (IOD) two-type E1 Nino seasonal evolution ocean-atmosphere coupling |
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