南印度洋偶极子的变化特征及其与ENSO事件的联系
投稿时间: 2017-02-21  最后修改时间: 2017-05-12  点此下载全文
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王黎娟 南京信息工程大学 气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044 wljfw@163.com 
陈爽 南京信息工程大学 气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044;襄阳市气象台, 湖北 襄阳 441000  
张海燕 南京信息工程大学 气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心, 江苏 南京 210044  
基金项目:江苏省高校自然科学研究重大项目(14KJA170004);国家自然科学基金资助项目(41575081);江苏省自然科学基金项目(BK20131432)
中文摘要:利用Hadley Center逐月海温资料以及NCEP/NCAR逐月风场、海平面气压场等资料探讨了南印度洋偶极子(Southern Indian Ocean Dipole,SIOD)的变化特征及其与ENSO事件的联系。结果表明:1)发生在南半球副热带印度洋地区的海温异常西南-东北反相的南印度洋偶极子现象,具有明显的季节锁相特征:10-12月发生发展,次年1-3月发展成熟达到盛期,4-6月减弱消亡;SIOD的形成主要受大尺度大气环流的影响,马斯克林高压以及澳大利亚低(高)压位置和强度的变化引起的副热带印度洋海表面风场的异常,影响了海温的变化,进而形成SIOD。2)南半球副热带印度洋地区的海温变化与赤道中东太平洋地区海温异常密切联系,前冬ENSO事件与SIOD有显著的负相关关系,大多数正SIOD发生在La Niña事件之后,大多数负SIOD发生在El Niño事件之后;也存在部分SIOD事件的发生既不伴随La Niña现象,也不伴随El Niño现象。3) ENSO事件产生的异常垂直运动和赤道异常纬向风对南半球副热带印度洋地区的海平面气压以及海表面风场的强度和位置的变化有重要作用,可以分别影响SIOD东西极子的演变,进而对SIOD产生影响。4) SIOD事件也可单独发生,一般负事件比正事件早一个月发生,同时由于没有ENSO事件的作用,海温异常反相的现象不能持续,单独发生的SIOD事件生命期较短。
中文关键词:南印度洋偶极子  拉尼娜  厄尔尼诺
 
Characteristics of Southern Indian Ocean Dipole variation and its relationship with ENSO events
Abstract:Based on the Hadley Center monthly sea surface temperature data,the NCEP/NCAR monthly sea level pressure data,sea surface wind data and the vertical velocity data at 500 hPa,the characteristics of Southern Indian Ocean Dipole(SIOD) variation and its relationship with ENSO are studied.The results showed that the SIOD is characterized by occurrence of a cold(warm) SST anomaly in the northeast Indian Ocean and a warm(cold) SST anomaly in the southwest,which are seasonal phase-locked.It develops from October to December,reaches a climax in the following January to March,and decays from April to June.The formation mechanism of SIOD is affected by the large-scale atmospheric circulation.The location and intensity variations of Mascarene high and Australian High(Low) contribute to the sea surface wind anomalies,which results in SST anomalies and then leads to the SIOD.There is a close relationship between the sea surface temperature in the austral subtropical Indian Ocean and that in the equatorial central eastern Pacific Ocean.The SIOD event is significantly negatively correlated with ENSO which occur in the previous winter.Most of the positive SIOD events occur after La Niña events,whereas most of the negative SIOD events occur after El Niño events.In some cases,SIOD appears after neither of the two events.The anomalous vertical motion and anomalous tropical zonal wind,which are induced by ENSO,can affect the intensity and location of sea surface pressure and sea surface wind fields in the austral subtropical Indian Ocean,and can further influence the evolution of the eastern and western poles of SIOD,respectively.Furthermore,SIOD can also occur in isolation,and the occurrence of the negative SIOD events is usually one month earlier than that of the positive SIOD events.The anomalous sea surface temperature cannot develop continuously without the effect of ENSO,which leads to a short life span of the SIOD.
keywords:Southern Indian Ocean Dipole (SIOD)  La Niña  El Niño
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