不同类型El Nino事件对中国东部次年夏季降水季节内演变影响及成因研究

发布时间：2018-01-10 13:32

本文关键词：不同类型El Nino事件对中国东部次年夏季降水季节内演变影响及成因研究　出处：《南京信息工程大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文利用1950年1月～2011年12月全球海表温度(SST)资料、ONI (Oceanic Nino Index)序列、SODA的海洋多要素逐月资料、NCEP/NCAR风场、高度场、湿度场等再分析资料以及中国160站逐月降水资料,研究了不同类型El Nino事件的主要特征及其对中国东部次年夏季逐月及季节降水的影响及成因。得到如下主要结论： (1)对不同类型El Nino事件的定义及特征研究表明：1)根据El Nino事件期间SST最大正异常所在区域,将El Nino事件分为nino3、nino4和nino3.4型三种类型。2)海表温度变暖的线性趋势对El Nino事件分型没有明显影响。3)各型El Nino事件期间次表层海温异常分布不同,次表层海温异常大值区都位于类型定义所在的经度范围内。4)nino3型El Nino事件期间,在赤道东太平洋存在一个异常上升气流,而在太平洋西部菲律宾群岛附近存在一个异常的下沉气流,nino3.4型的分布形式与nino3型类似,但上升支的位置要比nino3型偏西,强度稍弱；nino4型的分布形式与其他两种形式差异较大,表现为它在太平洋区域存在两支异常的上升气流,一支位于太平洋东部ninol.nino2区,大约位于80°W,另一支位于日界线以西170°E附近,同时在印度洋东部大约90°E上空也存在一支上升气流。 (2)对不同类型El Nino事件的发展、成熟和衰减三个阶段划分及其特征的研究表明：1)在发展期,nino3型海表温度以及次表层海温的正异常(统称海温异常)都首先出现在赤道东南太平洋区域；nino4型的正海温异常首先出现在赤道太平洋中西部的nino4区;而nino3.4型的正异常则首先出现在赤道太平洋东南部和nino3.4区东部。到成熟期,海温异常强度加强。到衰减期,nino3型事件中赤道东太平洋正海温异常显著减弱,其它两类型事件在赤道东太平洋都已出现海温负距平。2)三种类型El Nino事件发展期、成熟期、衰减期三个阶段的walker环流异常分布也有一定差异。nino3型事件从发展期到衰减期,在热带印度洋—太平洋维持一个异常的反沃克环流圈；nino4型在发展期太平洋区域有两只异常的上升气流,到了成熟期则在印度洋—太平洋上空形成两个异常的饭沃克环流圈,衰减期时已不存在明显的下沉气流；nino3.4型中,各个阶段分布形式基本一致,只是强度由弱变强再变弱。 (3)对不同类型El Nino事件次年夏季逐月及季节降水的研究表明：1)不同类型El Nino事件对应次年中国东部6、7、8月降水异常场分布明显不同。三类型事件6月雨带主要位于华南地区。nino3型主雨带从6至7月明显北移到长江流域,8月则呈西多东少反相分布；从6至8月,nino4型雨带逐渐北移,nino3.4型雨带则从南到北再向东北移动。nino4型降水异常最强、nino3.4型最弱。2)就整个夏季而言,nino3、 nino4到nino3.4型事件对应次年夏季雨带呈现由南向北逐渐移动特征。nino3型主雨带主要位于西南东部到江南—带,nino4型主雨带主要位于长江和黄河流域之间,nino3.4型主雨带主要位于四川西南、河套及华北。 (4)对不同类型El Nino事件次年夏季和各月环流特征的研究表明：1)对于南亚高压,nino3型、nino4型事件后呈偏强、东伸和北抬的特点,且后者较前者时更强；nino3.4型事件后主要呈减弱、西退特征。对于西太副高,nino3型、nino4型事件后主要呈偏强、西伸、北抬特征,后者较前者更强,西伸北抬也更明显。nino3.4型后,副高以东撤、北抬特征为主。2)次年夏季,nino3型暖湿水汽的主要来源是西太平洋上空和中南半岛上空的反气旋式水汽环流；nino4暖湿气流主要来自于西北太平洋上空的反气旋式水汽环流,其位置要比nino3型北抬；nino3.4型的暖湿气流主要由两支,一支来自于低纬上空的东风气流经菲律宾群岛和海南岛,另一支位于孟加拉湾上空的反气旋式水汽环流。对于季中各月而言,nino3和nino4两种类型的暖湿气流的来源较相似,而nino3.4型则更多的出现一些水汽环流对,他们共同作用将暖湿气流向我国境内输送。3)从纬圈环流和经圈环流上看,nino3型事件的次年夏季,在25°N-30°N上其垂直运动和水汽含量配置最有利于降水的形成;而nino3.4型最有利于降水生成的配置则出现在35°N～400N之间,而对于nino4型,在25°N-30°N和35°N～40°N都有降水异常。从季中各月来看,6月,三种类型El Nino事件的异常上升支和水汽含量大值区都位于30。N以南,其中nino4型强度最强；7月,异常上升支和水汽含量大值区的位置都发生了北移,其中,nino3型移动幅度最小,nino3.4型移动幅度最大；到了8月,nino3型El Nino事件没有明显的上升下沉运动,nino4型上升气流进一步北抬,nino3.4型上升气流相比7月,强度更强,范围更大。
[Abstract]:In this paper, from January 1950 to December 2011, the global sea surface temperature (SST), ONI (Oceanic Nino Index) sequence, SODA marine elements monthly data, NCEP/NCAR height field, wind field, humidity field reanalysis data and monthly precipitation data of 160 stations China, main features of the different types of El Nino events and its influence on the next summer precipitation in eastern Chinese monthly and seasonal reasons and main conclusions are as follows:
(1) study on the definition and characteristics of different types of El Nino events show that: 1) according to the El Nino event during SST maximum positive anomaly area, the El Nino event is divided into NINO3, nino4 and nino3.4 of three types of.2) linear trend of sea surface temperature warming type on the El Nino event has no obvious effect.3) of various types of El Nino events during the period of the subsurface temperature anomaly distribution, subsurface ocean temperature anomalies are located in the high value region type definition longitude range.4) during NINO3 El Nino event in the equatorial eastern Pacific has an anomalous updraft, and in the Western Pacific Ocean near Philippines islands there is an anomaly the downdraft, distribution form and NINO3 type nino3.4 type is similar, but the rising branch location than NINO3 West, the strength was weak; the distribution form of nino4 type and the other two forms are quite different, as it exists in the Pacific region two A abnormal updraft, a ninol.nino2 is located in the eastern Pacific region, at about 80 DEG W, the other one is located near the west of the dateline 170 ~ E, while in the eastern part of India ocean about 90 degrees above the E also has an updraft.
(2) the development of different types of El Nino events, and three of mature decay stage division and its characteristics as follows: 1) in the development phase, NINO3 sea surface temperature and surface temperature is abnormal (collectively referred to as the sea surface temperature anomalies) occurred first in the Southeast Pacific equatorial region; positive SST anomalies first type nino4 in the western equatorial Pacific region nino4; and nino3.4 positive anomalies were first in the eastern equatorial Pacific and southeast area of nino3.4. To maturity, strengthen the SST anomaly intensity. To the decay period, type NINO3 in the eastern equatorial Pacific event positive SST anomalies decreased and the other two types of events in the equatorial eastern Pacific there has been negative SST anomalies.2) three types of El Nino development period, mature period, Walker circulation attenuation of the three stages of abnormal distribution also have certain differences in.Nino3 event attenuation from the development phase to the stage, in the heat With India and Pacific oceans, maintain an abnormal anti Walker circulation; nino4 type two abnormal updraft in the development of the Pacific region, two abnormal rice Walker circulation circle formation to maturity in India ocean, the Pacific Ocean, decaying stage is not obvious downdraft; type nino3.4 in each stage, the distribution form is basically the same, but the intensity from weak to strong and weak.
(3) of different types of El Nino events in the following summer monthly and seasonal precipitation in the study show that: 1) of different types of El Nino the following year China events corresponding to Eastern 6,7,8 monthly precipitation anomaly distribution is significantly different. Three types of events of the June rain mainly located in.Nino3 area in Southern China from 6 to July, the main rain belt northward to the Yangtze River in August a little more phase distribution; from 6 to August, the nino4 pattern nino3.4 pattern is gradually northward from the south to the north to northeast mobile.Nino4 precipitation anomalies in the strongest, nino3.4.2) is the weakest of the summer, NINO3, nino4 to nino3.4 corresponding to the event the next summer rain has gradually from the south to the north of mobile.Nino3 the main rain belt mainly located in the southwest to the South Eastern Zone, between the nino4 type main rain belt is mainly located in the Yangtze River and the the Yellow River River Basin, nino3.4 main belt mainly located in the southwest of Sichuan, and in North China.
(4) study of different types of El Nino events in the following summer and monthly circulation characteristics show that: 1) for South Asia high, NINO3 type, nino4 type after the incident was stronger, and the eastward and northward, and the latter is stronger; nino3.4 after the incident was weakened, West Back features for the Western Pacific subtropical high, NINO3 type, nino4 type after the incident was mainly westward, northward stronger features, the latter is stronger, West and North lift is more obvious after.Nino3.4, east of the subtropical high northward retreat, characteristic of.2) in the following summer, the main source of type NINO3 warm water vapor is reverse the cyclone vapor circulation over the Western Pacific and Indo China Peninsula over nino4; warm air anti cyclonic circulation water vapor mainly comes from the Northwest Pacific Ocean, its location than NINO3 type northward; warm air type nino3.4 consists of two branches, a branch of easterly flow from low latitude over Philippines Islands and Hainan Island, another is located over the bay of Bengal anticyclonic circulation water. For each month season, warm air source NINO3 and two types of nino4 are similar, while type nino3.4 some more water vapor circulation on the interaction, they will warm air flow within the territory of China transportation.3) from zonal circulation and the meridional circulation at NINO3 events in the following summer, at 25 DEG N-30 DEG N on the vertical motion and the water vapor content is most conducive to the formation of precipitation; and nino3.4 is most conducive to generating configuration is between 35 ~ N ~ 400N, and for nino4, in 25 DEG N-30 DEG N and 35 DEG N to 40 DEG N have abnormal precipitation. From June, the month of season, three types of El Nino events of the abnormal ascending and the water vapor content large value areas are located in the south of 30.N, in which nino4 was the strongest; in July, the abnormal ascending branch and the water vapor content big The value of location was the north, NINO3 mobile is the smallest nino3.4 mobile biggest; by August, the NINO3 El Nino event no significant increase of nino4 type updraft downdraft, further northward, nino3.4 type air rise compared to July, the stronger, larger scope.

【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】：2014
【分类号】：P426.6;P732

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