广西秋季干旱成因分析.docx

广西秋季干旱成因分析.docx

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广西秋季干旱成因分析

中山大学硕士学位论文

广西秋季干旱成因分析

学位申请人：

导师姓名及职称：

专业名称：

气象学

答辩委员会成员（签名）：

主席：

成员：

中山大学大气科学系

二〇〇八年十二月三日

学位论文原创性声明

本人郑重声明：

所呈交的学位论文，是本人在导师的指导下，独立进行研究工作所取得的成果。

除文中已经注明引用的内容外，本论文不包含任何其他个人或集体已经发表或撰写过的作品成果。

对本文的研究作出重要贡献的个人和集体，均已在文中以明确方式标明。

本人完全意识到本声明的法律结果由本人承担。

学位论文作者签名：

日期：

2008年10月9日

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学位论文作者签名：

导师签名：

日期：

年月日日期：

年月日

论文题目：

广西秋季干旱成因分析

摘要

本工作利用均匀分布在广西境内的89个气象观测台站1961～2006年逐日降水资料、NCEP/NCAR全球月平均要素场再分析资料、NOAA/NCEP/CPCONI指数资料、月平均ERSST.v2海温资料、WHOI全球海气通量分析资料（OAFlux）、以及比利时SIDC月度太阳黑子活动数据，运用客观定量化的小波分析、趋势（突变）分析、合成偏差分析、相关分析、水汽通量分析计算等多种方法，对广西区域秋季异常干旱（降水）事件的时空异常分布和变化特征、年际年代际变化的相关因子、天气气候背景以及可能的影响因子、成因机制等方面内容进行了综合分析，揭示出一些新的观测事实，得到以下结果：

广西秋季的降水具有南多北少的特征，境内秋旱出现频繁：

全区各地的秋旱频率多在30%～40％，其中桂东南是广西秋旱发生最为频繁、也是近年来旱情趋于严重的地区。

广西秋季降水变化以全区一致旱涝的分布型占主要地位；此外，广西秋季降水还具有东西差异型、南北差异型以及自桂西北到桂东南呈“＋－＋”（或“－＋－”）的波状分布型式等其它三种典型的分布型式。

广西秋季降水存在着年代际变化和年际变化两个显著的振荡特征；二者对广西秋季降水具有同等重要的影响；近二十年来广西秋季降水有逐渐减少的趋势，且从2003年开始可能出现了趋于明显减少的气候突变。

以ENSO事件为典型特征的赤道太平洋地区热力振荡与广西秋季降水的年际变化密切关联；而太阳活动的周期性变化则是年代际变化的重要影响因子，由此造成的广西秋季严重干旱持续现象值得关注。

中纬度东太平洋海温变化与广西秋季降水呈显著负相关、而中低纬中西部太平洋则为显著的正相关区；另外，在印尼西部沿岸的东印度洋区域，海洋热力变化与广西秋季降水也有较为显著的负相关关系，显示出印度洋海洋热力状况对广西秋季降水也有相当程度的复杂影响。

秋季热带气旋是广西秋季降水最重要的天气系统，直接影响广西的秋季热带气旋数目在很大程度上决定了广西秋季降水的多寡以及旱情的严重程度。

降水偏少年影响广西的热带气旋的平均强度和生存周期明显偏小、登陆地点也明显偏南。

海气相互作用的分析表明，广西秋季降水的多寡与南海、孟加拉湾以及赤道以南印尼澳洲沿岸的大片东印度洋海区的海气通量输送均呈显著的负相关关系；而与赤道中东太平洋以及南太平洋大片海区的海气通量输送呈显著的正相关关系。

其中，我国南海等西太平洋区域的海气通量异常变化可能是受东亚大陆高压异常变化影响、导致相关区域全风速异常变化而引起的。

另外，从孟加拉湾到印尼西部沿海到澳洲西部沿岸的东印度洋的大片海区，其海气通量异常所激发的大气异常型与广西秋季干旱状况有着密切的关联。

广西秋季旱涝的大致环流背景是：

当中纬度亚欧大陆——东亚西太平洋沿岸——日本海以东太平洋地区大气环流的两脊一槽“高－低－高”波状分布形势不易被破坏、且两脊区均偏高偏强时，广西秋季降水偏少、旱象加重；而当这种“两脊一槽”形势破坏、出现只有大陆高压脊偏高、东亚大槽和太平洋高压脊均偏低的“西高东低”形势的环流调整时，广西秋季降水增多、严重旱情不容易出现。

就广西秋季干旱成因分析而言，常用的海温和环流分析方法对辨别中高纬度的影响系统是有帮助的，但对低纬度影响系统的分析能力有限；而进行海气相互作用分析，则可以弥补上述不足，发现更多的有价值的低纬度影响因子信息。

2004年是广西秋旱极端严重的一年，分析显示：

该年秋季影响广西降水的海洋热力异常主要以太平洋海域的热力异常为主，其中中纬度东太平洋和赤道中、东太平洋海域是异常变化最明显的两个区域；而日本列岛周边海域的海－气交换通量变化幅度也异常明显；该年秋季自南海北部北部湾区域到台湾海峡一带的广阔海域上空还出现了历年同期罕见的大片水汽输送负偏差区；这些结果表明，太平洋区域海洋热力和环流异常变化可能是造成2004年秋季广西异常严重旱情发生的主要原因。

关键词：

秋旱，副高，海气交换通量，太阳黑子，突变，成因

Title：

CauseAnalysisoftheAutumnDroughtinGuangxi

Major:

Meteorology

Name:

LiYuzhong

Supervisor:

Prof.LiWeibiao

Abstract

Basedontheprecipitationsfrom89stationsinGuangxiofferedbyGuangximeteorologicalobservatory,NCEP/NCARglobalmonthlymeanreanalyses,NOAA/NCEP/CPCONIindexdata,ERSST.v2SSTdata,WHOIOAFluxdata,andBelgiumSIDCsunspotactivitiesdata,usingobjectiveandquantitativeanalysissuchaswaveletanalysis,trendanalysis,compositionanalysis,correlationanalysis,moisturechannelanalysis,thetextanalyzesthespace-timeabnormaldistributingcharacteristicandtransformationcharacteristic,synopticandclimatebackground,conceivableinfectiongenesandcauseofformationfortheexceptionaldroughteventatautumninGuangxiarea,thenopenoutsamenewobservationandreality,theresultsshowthat:

TheautumnprecipitationinGuangxihasthecharacterthattherainfallatthesouthernpartismorethanthatatthenorthernpart,andthedroughteventhasahighfrequency.Usingtheprecipitationanomalypercentindextoanalyzethefrequencyofthedroughtevent,wefindthattheautumndroughtfrequencyineachareaofGuangxiisbetween30%and40%,andthesoutheasternofGuangxiistheareathattheautumndroughthappenmostandtheravagesofadroughtisgoingtoseriousattherecentyear.

TheautumnprecipitationinGuangxihastwonotableoscillationcharacteristicswhicharedecadalchange（whichcycleis10~12years）andinterannualchange（whichcycleis4~6years）,andbothofthemhaveimportanteffecttotheautumnprecipitationinGuangxi.Atthenear20years,TheautumnprecipitationinGuangxiisgoingtobereduceandmaybehasaclimatebreakthattherainfallisreducingobviouslysince2003.

AttheyearsthattheautumnprecipitationinGuangxiisless,bothofthePacificsubtropicalhighandAsiaandEuropecontinenthigharestronger,whilethedeparturefieldatAsiaandpacificareainmiddlelatitudedistributeas“+–+–”,andthemeridionalityoftheseasonaveragecirculationisbeingsmaller.ThecoldairactivityismorenorthernsoitaffectsthesouthChinaless.OntheeffectofthestrongContinentHigh,themoisturefromthePacificandtheSouthSeacannotgototheinlandofSouthChinawhichleadstothemoisturetransportationoftheareabeinglow,andtheautumndroughtismoreserious.

Theanalysisofair-seainteractionshows:

thereisanegativecorrelationbetweentheautumnprecipitationofGuangxiprovinceandtheair-seatransportationinSouthChinaSea,BayofBengalAndeastofIndianocean;positivecorrelationwiththeair-seatransportationinmiddle-eastpacificocean.ItisfoundthatsubtropicalhighmayaffectthechangingofwindspeedinSouthChinaandwestPacificocean,whichwillleadtotheabnormalofair-seafluxtransportation.What'smore,theair-seainteractioninBayofBengalAndeastofIndianoceancanalsoaffecttheabnormalcirculationinautumnthenleadtoautumndraughtinGuangxiprovince.

AttheyearthattheautumnprecipitationinGuangxiismore,thedeparturefieldatAsiaandPacificareainmiddlelatitudedistributeas‘easthighandwestlow’.Ontheonehand,itleadstotheEasttroughdeepeningandthemeridionalityofgeneralcirculationbecomebiggerwhichsteeringthecoldaireffecttheSouthChinamorecontinually.Ontheotherhand,thePacificsubtropicalhighmovesouthernlyandwesternlyleadstotheContinentHighandtheWestPacificsubtropicalhighconnectandtheSouthChinaisaffectedbytheeastaircurrentonthesouthsideofthesubtropicalhigh,whichmakethemoistureeasiertransporttotheinlandofSouthChina.ThecoldairactivityandthefavorablewaterconditionmaketheautumnprecipitationinGuangximoreandtheseriousdroughteventhardtohappen.

ThethermalconditionofthePacificiscorrelatednearlywithcirculationpatternchangeoftheautumnprecipitationinGuangxi.TheENSOinterannualoscillationhasgoodrelationwiththeautumnprecipitationinGuangxi,whichindicatethatthethermaloscillationofthePacificsuchasENSOmaybethemostimportantfactoroftheautumnprecipitationinterannualchangeofGuangxi;andtheinterannualchangeofsunspothasobviouslyrelationshipwiththeautumnprecipitationinterannualoscillationofGuangxiwhichexplainthattheseasonalchangeofsunmaybethepivotaleffectfactorfortheautumnprecipitationdecadalchangeofGuangxi.

It'sdeadlyseriousdroughtin2004inGuangxi.TheanalysisshowsthattheabnormalthermalconditionofthePacificisthemostimportanteffectfactortothisyear.

KeyWords:

AutumnDrought;SubtropicalHigh;Air-SeaHeatFluxes；Sunspot;AbruptChange；Cause

原创性声明·············································································································（I）

使用授权声明········································································································（Ⅱ）

中文摘要················································································································（III）

ABSTRACT············································································································（Ⅴ）

目录····················································································································（Ⅶ）

第1章前言·······································································································

（1）

1.1有关干旱的描述和对干旱特征的研究···················································

（2）

1.2有关干旱成因的研究···············································································（3）

1.3有关广西干旱的研究···············································································（4）

1.4存在的问题以及本论文的研究内容·······················································（5）

第2章资料和分析方法···················································································（7）

2.1资料来源·································································································（7）

2.2主要概念定义和研究方法简介·····························································（7）

第3章广西秋季干旱的气候特征及近期极端干旱个例介绍·························（13）

3.1广西秋季气候概况··················································································（13）

3.2广西秋季降水的时空变化特征······························································（14）

3.3广西秋季干旱的分布和变化特征··························································（20）

3.4广西近期秋季极端干旱个例介绍··························································（22）

3.5小结········································································································（24）

第4章广西秋季干旱（降水）年际、年代际变化的相关因子特征分析··········（25）

4.1广西秋季干旱（降水）与同期海洋热力变化的相互关系··················（25）

4.2广西秋季干旱（降水）与热带气旋系统的相互关系··························（25）

4.3广西秋季干旱（降水）与海-气交换通量变化的相互关系················（29）

4.4广西秋季干旱（降水）与ENSO的联系············································（36）

4.5广西秋季干旱（降水）与太阳黑子活动的联系································（37）

4.6小结··········································································································（38）

第5章广西秋季干旱的环流特征分析·····························································（40）

5.1广西秋季中低层位势高度场的变化特征分析······································（40）

5.2广西秋季近地面层流场的变化特征分析··············································（45）

5.3广西秋季海平面气压场和温度场的变化特征分析······························（46）

5.4广西秋季水汽输送通量特征分析··························································（46）

5.5广西秋季干旱的成因分析······································································（50）

5.6小结··········································································································（51）

第6章2004年广西秋季异常干旱个例分析··········