热带太平洋海温指数的重新构建及与海洋性大陆区域气候的联系

发布时间：2018-05-25 17:09

本文选题：不同季节 + 中部型和东部型　；参考：《南京信息工程大学》2015年硕士论文

【摘要】：利用1963-2013年Hadley中心月平均海表温度资料,NCEP/NCAR再分析资料,以及1979-2013年CMAP月平均降水资料,根据两类厄尔尼诺事件发生时赤道太平洋地区海温异常的不同空间分布特征,即赤道中太平洋中部(CP)型和东太平洋东部(EP)型海温异常空间分布,从寻找与之相似的空间型角度出发,针对不同季节设计了表征热带太平洋地区两种海温异常类型的指数ICP/IEP,并探讨了热带太平洋各季节CP/EP型海温异常的不同海气耦合特征,以及两类ENSO与海洋性大陆区域气候的联系,结果表明：1、北半球冬季,赤道太平洋地区海温异常指数ICP和IEP,不仅表示了空间上相互独立的海温异常分布,时间域上也相互独立,因而能更好地表征和区分两类El Nino/La Nina事件。CP型和EP型海温异常事件相关的热带太平洋主要海气耦合特征存在显著差异,与传统的东部型El Nino事件发生时最大暖海温中心位于赤道东太平洋地区不同,中部型ElNino事件,异常增暖中心位于赤道中太平洋。中部型El Nino事件发生时,Walker环流的异常上升支向西偏移,异常降水集中于热带中太平洋,不似东部型事件发生时降水异常限定于赤道东太平洋地区。不论哪类事件,海洋性大陆均可受到影响,即CP或EP型El Nino发生时,海洋性大陆区域降水偏少。但比较而言,中部型ENSO对海洋性大陆区域的影响更大。2、北半球春季,ICP和IEP与其他学者定义的两类ENSO指数具有较高的相关性,具备描述和区分两类El Nino事件的能力。新指数在时、空上对春季厄尔尼诺事件区分效果明显。利用新指数表征北半球春季CP/EP型ENSO相关的环流异常和降水异常的空间分布特征时可发现：中部型ENSO发生时,沃克环流的异常上升支偏西,异常降水集中于日界线附近的热带中太平洋,与热带太平洋海温异常的空间分布相对应,整体呈现纬向三极型。而东部型ENSO相关的异常则主要表现为偶极型的分布特征。此外,两个关键区域CB：[178°W-152°W,5°S-5°N]和EB:[105°W-79°W,5°S-5°N]的SSTA的绝对大小可分别用作描述CP/EP型ENSO事件的强度,这对以后ENSO的监测工作具有重要的现实意义。3、北半球夏季,通过对比发现,较以往厄尔尼诺指数,新指数组不仅在空间划分上相互独立,而且在相同的研究时段内能更好地表征和区分两类厄尔尼诺事件。采用该新指数组探讨中部型和东部型海温异常事件相关的热带太平洋主要的海气耦合特征可发现,新指数组能清晰地反映出两类厄尔尼诺事件发生时不同的海气耦合特征：即与传统东部型厄尔尼诺最大暖海温中心位于赤道东太平洋地区不同,中部型厄尔尼诺事件,异常增暖中心位于赤道中太平洋。中部型异常上升支向西移至150。W附近,异常降水集中于日界线以西,不似东部型横跨整个赤道太平洋地区。两类厄尔尼诺事件相关的2m气温分布也存在着显著差异,表现出与海表温度异常分布相一致的特征。
[Abstract]:Based on the monthly mean sea surface temperature data of Hadley center during 1963-2013 and the monthly mean precipitation data of CMAP from 1979 to 2013, according to the spatial distribution characteristics of SST anomalies in the equatorial Pacific Ocean during the occurrence of the two kinds of El Nino events, the NCEP / NCAR reanalysis data are used. The spatial distribution of SST anomalies in the central equatorial Pacific Ocean and the eastern Pacific Ocean is as follows: from the point of view of searching for similar spatial patterns, For different seasons, the index ICP / IEP representing two types of SST anomalies in the tropical Pacific region is designed, and the characteristics of the CP/EP SST anomalies in each season of the tropical Pacific Ocean are discussed, and the relationship between the two types of SST anomalies and the oceanic continental climate is also discussed. The results show that in the Northern Hemisphere winter, the SST anomaly indices ICP and IEP in the equatorial Pacific Ocean not only represent the spatial independent SST anomaly distribution, but also are independent in the time domain. Therefore, there are significant differences between the two types of El Nino/La Nina events, CP type and EP type SST events, which can better characterize and distinguish the main ocean-atmosphere coupling characteristics in the tropical Pacific Ocean. Different from the traditional East-type El Nino event, the maximum warm SST center is located in the eastern equatorial Pacific Ocean, and the anomalous warming center is located in the Central equatorial Pacific Ocean during the central ElNino event. The anomalous ascending branch of the central El Nino event shifts westward, and the anomalous precipitation is concentrated in the central tropical Pacific, unlike that in the equatorial eastern Pacific region when the event occurred in the eastern part of the region. No matter what kind of events, the oceanic continent can be affected, that is, when CP or EP type El Nino occurs, the precipitation in the oceanic continental region is less. However, the influence of central type ENSO on oceanic continental area is greater than that of middle type ENSO. The Northern Hemisphere ENSO and IEP have a high correlation with the two kinds of ENSO indices defined by other scholars, and they have the ability to describe and distinguish the two kinds of El Nino events. The new index can distinguish the spring El Nino event obviously in space. When the new index is used to characterize the spatial distribution characteristics of the CP/EP type ENSO and precipitation anomalies in the Northern Hemisphere in spring, it is found that when the central type ENSO occurs, the anomalous ascending branches of the ENSO circulation tend to the west. The anomalous precipitation is concentrated in the tropical central Pacific near the daily boundary, corresponding to the spatial distribution of the tropical Pacific SST anomaly. However, the ENSO related anomalies of the eastern type mainly show dipole distribution characteristics. In addition, the absolute size of SSTA in two key regions: [178 掳W-152 掳Wn5 掳S-5 掳N] and EB: [105 掳W-79 掳Wn5 掳S-5 掳N] can be used to describe the intensity of CP/EP type ENSO events, respectively, which has important practical significance for the subsequent monitoring of ENSO. Compared with the former El Nino index, the new index group is not only independent of each other in space division, but also can better characterize and distinguish two kinds of El Nino events in the same research period. By using the new index set, it is found that the main ocean-atmosphere coupling characteristics of the tropical Pacific associated with the mid-type and eastern SST anomalies can be found. The new index group can clearly reflect the different characteristics of sea and air coupling when two kinds of El Nino events occur: the central El Ni 帽 o event is different from the traditional eastern El Ni 帽 o maximum warm SST center located in the equatorial eastern Pacific Ocean. The center of abnormal warming lies in the central equatorial Pacific Ocean. The central type of anomalous ascending branch moves westward to the vicinity of 150.W, and the anomalous precipitation is concentrated to the west of the diurnal boundary and does not resemble the eastern type crossing the entire equatorial Pacific Ocean. There are also significant differences between the two kinds of El Nino events related to 2m temperature distribution, showing the characteristics consistent with the sea surface temperature anomaly distribution.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P461.2;P731.11

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