亚澳季风系统年代际变化与不同类型ENSO事件爆发的关系研究

发布时间：2017-12-27 17:38

本文关键词：亚澳季风系统年代际变化与不同类型ENSO事件爆发的关系研究　出处：《安徽农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：亚澳季风系统是全球季风系统中的重要组成部分,其强度与模态异常对整个亚洲与澳洲地区乃至全球的气候变化都具有重要影响。本文选用1948-2011年的美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)逐月再分析资料、由英国哈得来中心提供的海表面温度资料(1948-2011)和日本气象厅(JMA)提供的全球海洋温盐场数据(1950-2010),采用经验正交函数分析法、合成分析、偏相关分析等方法对东亚冬季风与澳洲夏季风的年代际变化和相互作用以及两支季风与两类厄尔尼诺爆发的关系进行了研究。本文还利用地球系统模式(CESM)最新的大气气候模式模块(CAM5.3)对澳大利亚西部印度洋海域海温进行强迫模式实验,验证东亚冬季风与澳洲夏季风的相互作用。本文研究结果表明,东亚冬季风和澳洲夏季风存在明显的年代际变化,东亚冬季风和澳洲夏季风都在90年代前后发生了年代际的变化,东亚冬季风开始减弱而澳洲夏季风开始变得相对较强。较强的澳洲夏季风,使得海洋性大陆东部海域高层出现辐散扰动,赤道地区的辐散扰动在高层激发出罗斯贝波源出现在东亚大陆的南部与南海北部区域上空,这一响应在高层形成了拉伸项的正涡度异常和平流项的负涡度异常。正的涡度异常造成高层的辐合并在这一区域形成下沉运动。这样的异常下沉运动维系了东亚大陆南部的高压异常,最终这样的高压异常的存在引起南北气压差减弱进而导致东亚冬季风减弱。而且本文利用CESM模式中的大气模块CAM5.3进行的模式实验不仅证实了澳洲夏季风增强会减弱东亚冬季风,还证实了这种影响机理的存在。研究还发现,东亚冬季风异常强的年份之后一年更容易爆发传统型厄尔尼诺,澳洲夏季风异常较强的年份之后一年更容易爆发中部型厄尔尼诺。前者主要是通过赤道西风与海温的Bjerknes正反馈引起传统型厄尔尼诺爆发,后者主要是通过中东太平洋异常环流,在东太平洋地区通过云与海表面温度的负反馈作用引发该地区的高压形成。异常高压阻碍西风沿着赤道向东推进,反而向墨西哥西部海域吹去,逐步在这一区域形成暖海温异常,进而逐渐导致中部型厄尔尼诺爆发。亚澳季风系统这样的变化与两类厄尔尼诺之间的关系也为90年代后中部型厄尔尼诺的增多提供了可能的原理解释,也进一步说明了ENSO事件与季风在不同季节,不同年代际时间尺度上相互作用与影响的复杂性。
[Abstract]:The Asian Australian monsoon system is an important part of the global monsoon system, climate change, its strength and modal of the whole of Asia and Australia anomaly region and the world has a very important effect. The National Center for atmospheric research, the National Center for environmental prediction / the year 1948-2011 reanalysis (NCEP/NCAR), by the British Hadley Center to provide the data of sea surface temperature (1948-2011) and the Japan Meteorological Agency (JMA) Global Ocean thermohaline data provided by (1950-2010), using empirical orthogonal function analysis method, synthesis analysis partial correlation analysis method on the East Asian Winter Monsoon and the Australian summer monsoon interdecadal changes and interaction as well as the relationship between the two and two types of monsoon of outbreak of El nino. In this paper, we also use the latest atmospheric climate module (CAM5.3) of the earth system model (CESM) to conduct the forced mode experiment on the sea surface temperature in the western India sea, and verify the interaction between the East Asian Winter Monsoon and the Australian summer monsoon. The research results show that the East Asian Winter Monsoon and the Australian summer monsoon have obvious interdecadal variations. The East Asian Winter Monsoon and the Australian summer monsoon all have interdecadal changes before and after 90s. The East Asian winter monsoon is weakening, and the Australian summer monsoon is relatively strong. The strong Australian summer monsoon, the sea, East Sea high divergence disturbance, equatorial divergence disturbance stimulated Rossby source over the East Asian continent of South and north of the South China Sea area at the top, the negative response forms stretching vortex vorticity anomaly flow of anomalies in peace senior. The positive vorticity anomaly causes the convergence of the high rise and the subsidence in this region. Such abnormal subsidence maintains the high pressure anomaly in the southern part of the East Asian continent. Eventually, the existence of such high pressure causes the difference between the north and the South air pressure, which weakens the East Asian winter monsoon. Moreover, we use the model experiment of atmospheric module CAM5.3 in CESM mode, which not only confirms that the summer monsoon in Australia will weaken the East Asian winter monsoon, but also confirm the existence of this influence mechanism. The study also found that the East Asian winter monsoon is more likely to break out of the traditional El Nino year after the year with strong winter monsoon. The former is mainly caused by the positive feedback from the equatorial westerly and the sea surface temperature. The traditional El Nino outburst is caused by the Bjerknes positive feedback from the equatorial westerly and SST. The latter is mainly caused by the abnormal circulation of the Middle East Pacific and the negative feedback effect of the cloud and the sea surface temperature in the eastern Pacific area, causing the formation of high pressure in the area. Abnormal high pressure hinders the westerly wind advancing along the equator to the East. Instead, it moves to the west of Mexico sea and gradually forms a warm sea temperature anomaly in this area, which gradually leads to the central El Nino outbreak. The relationship between the Asian Australian monsoon system change and two kinds of El Nino also increased in 90s after the central El Nino provides possible explanation principle, to further explain the ENSO events and monsoon in different seasons, the complexity of different inter decadal scale interaction and influence.
【学位授予单位】：安徽农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P732;P425.42

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