简介：

简介：Throughoneandhalfyearcontinuousin-situmeasurements,thedistributionsandvariationsofsurfaceozoneanditsprecursorsatatypicalmixedagriculturalandmetropolitanarea-Changshu,YangtzeDeltaregion,werestudied.Thepreliminaryanalysisontheconcentrationlevelsandvariationsofsurfaceozoneindicatedtheobviousseasonalanddiurnalcyclesduringtheexperiment.Thehourlyaveragedconcentrationsofsurfaceozonewerehigh,inabout17%oftotalvalidhoursthesurfaceozoneconcentrationexceeded50ppb,andin22daysthehourlyaveragedozoneconcentrationwasgreaterthan100ppb.Therewereabout40%ofthedaysinthatthedailymaximum8-hourozoneconcentrationwasgreaterthan50ppb.Thedayswithdailymaximum8-hourozoneconcentrationgreaterthan80ppbwereabout33daysthataccountedforabout8%oftheobservationaldays.Thevariationsof5-daymovingaveragedozoneconcentrationsdependedbothontheweatherconditionsandonthechangesofozoneinbackgroundatmosphere.Photochemicalprocesshadthesignificantimpactsonozoneproductions.

简介：Duetoincreasedaerosolemissionsandunfavorableweatherconditions,severehazeeventshaveoccurredfrequentlyinChinainthelast10years.Inaddition,theinteractionbetweentheboundarylayerandtheaerosolradiativeeffectmaybeanotherimportantfactorinhazeformation.Tobetterunderstandtheeffectofthisinteraction,theaerosolradiativeeffectonaseverehazeepisodethattookplaceinDecember2013wasinvestigatedbyusingtwoWRFChemmodelsimulationswithdifferentaerosolconfigurations.Theresultsshowedthatthemaximalreductionofregionalaveragesurfaceshortwaveradiation,latentheat,andsensibleheatduringthiseventwere88,12,and37Wm~(–2),respectively.Theplanetaryboundarylayerheight,daytimetemperature,andwindspeeddroppedby276m,1°C,and0.33ms~(–1),respectively.Theventilationcoefficientdroppedby8%–24%forinthecentralandnorthwesternYangtzeRiverDelta(YRD).Theupperleveloftheatmospherewaswarmedandthelowerlevelwascooled,whichstabilizedthestratification.Inaword,thedispersionabilityoftheatmospherewasweakenedduetotheaerosolradiativefeedback.AdditionalresultsshowedthatthePM_(2.5)concentrationinthecentralandnorthwesternYRDincreasedby6–18μgm~(–3),whichislessthan15%oftheaveragePM_(2.5)concentrationduringtheseverelypollutedperiodinthisarea.TheverticalprofileshowedthatthePM_(2.5)andPM_(10)concentrationsincreasedbelow950hPa,withamaximumincreaseof7and8μgm~(–3),respectively.Concentrationsreducedbetween950and800hPa,however,withamaximumreductionof3.5and4.5μgm~(–3),respectively.Generally,theaerosolradiativeeffectaggravatedthelevelofpollution,buttheeffectwaslimited,andthishazeeventwasmainlycausedbythestagnantmeteorologicalconditions.Theinteractionbetweentheboundarylayerandtheaerosolradiativeeffectmayhavebeenlessimportantthanthelarge-scalestaticweatherconditionsfortheformation

简介：TheKotoda-Bortan(KB)model(LiuandKotoda1998)usedforestimatingevapotranspirationwasmodified.ThemonthlyevapotranspirationforvarioussurfacesintheYangtzeDelta(118-123■,28-33■)wascalculatedusingthemodifiedmodel,andtheannualregionalaverageofevapotranspirationfrom1961to1998wasobtainedusingaweightingmethod.Thespatialandtemporaldistributioncharacteristicsofevapotranspirationwereanalyzed.Itisfoundthattheregionalaveragedannualevapotranspirationhasadecreasingtrendoverthepast40years;thevaluedroppedbyabout24mmfrom1961to1998.Themainreasonforthistendencyisduetothechangeoflandsurfacecondition.Comparedwiththecaseof1980,thecurrentproportionsofpaddyfield,farmlandandwatersurfacehavedecreasedby1.353%,4.42%and2.597%respectively,whiletheproportionsofurbanareaandnon-agriculturelandhaveincreasedby3.345%.Thesechangesclearlyresultinadecreaseoftheregionalaveragedevapotranspiration.

简介：与潜在的涡度(PV)在这篇论文，潜在的涡度结构和在在212003年6月23日期间的长江和Huaihe河山谷上的风暴之发展形成的倒置被调查框架。风暴之发展形成被一个lower-troposphericPV异例主要由于潜伏的热版本在早阶段在长江和Huaihe河山谷上表明，它极大地影响由片表明了明智的PV倒置的联系lower-tropospheric重力势高度和风领域的进化。在以后的阶段，一个upper-troposphericPV异例发展，导致在在两个的气旋上的垅的生长在上游、下游，它为低级气旋发展提供一块有利背景地。但是表面热反常的效果总是在这风暴之发展形成期间阻碍气旋的发展到不同程度。位置和PV异例的力量是，这进一步被表明仔细，与低级气旋有关，开发，和lower-troposphericPV异例似乎例如，组成最重要的特征贡献大约60%到低级喷气(LLJ)。

简介：ＡｎａｌｙｓｉｓｏｆＣａｕｓｅｓａｎｄＳｅａｓｏｎａｌＰｒｅｄｉｃｔｉｏｎｏｆｔｈｅＳｅｖｅｒｅＦｌｏｏｄｓｉｎＹａｎｇｔｚｅ／ＨｕａｉｈｅＢａｓｉｎｓｄｕｒｉｎｇＳｕｍｍｅｒ１９９１ＸｕＱｕｎ（徐群）（ＪｉａｎｇｓｕＭｅｔｅｏｒｏｌｏｇｉｃａｌｉｎ...

简介：

简介：TobetterunderstandclimatevariationsofMeiyu,somenewindicatorsfortheonsetandretreatdates,duration,andMeiyuprecipitationintheYangtze-HuaiheRivervalleyareobjectivelydevelopedbyusingobserveddailyprecipitationdatafrom230stationsineasternChinaduring1954-2003.Therainyseasononsetandretreatdatesineachstationcanbedefinedintermsofthresholdsforrainfallintensityandpersistence.Then,theonsetandretreatdatesoftheMeiyufortheYangtze-HuaiheRiverbasinhavebeendeterminedwhenmorethan40%ofstationsreachthefirstrainyseasonthresholdsinthestudyregion.BasedontheindicatorsofMeiyuintheYangtze-HuaiheRiverbasin,variationsofMeiyurainfallduring1954-2003areanalyzed.TheresultssuggestthatMeiyurainfallintheYangtze-HuaiheRiverbasinhasincreasedinrecent50years.Inaddition,interannualandinterdecadalvariabilityofMeiyuisalsoobvious.Alltheindicatorsdisplayapredominantperiodofabout3years.

简介：ThisstudyexaminedtherainfallaroundthemiddleandlowerreachesoftheYangtzeRiverandrelatedatmosphericcirculationbyusingNCEPreanalysisdata.Thepurposeofthisstudyistoanalyzetheirdecadalvariationandtherelationshipamongrainfall,atmosphericcirculationaroundEastAsiaandtheENSOepisodes.Currentresultsarepresentedasfollows:(1)VeryclearincreasingtrendoftherainfallaroundthemiddleandlowreachesoftheYangtzeRiverduringtheMeiyuperiodandJunetoJulyisfoundintherecent15years.Meanwhile,thegeopotentialheightat500hPaaroundtheOkhotskSeaalsoholdssimilarincreasingtrend.ItisnoticeablethatENSOepisodestendtooccurmorefrequentlyintherecent15years.(2)AnindexdescribingEastAsiansummermonsooniswellcorrelatedwiththeSSTintheNino-3regioninprecedingautumnintherecent20yearsbutisnotpriortotheperiod.ThismeansthattheElNinophenomenonexertsmoreimpactsonEastAsiansummermonsoonrecently.(3)ThewarmphaseofPDOintherecent20yearsbasicallycoincideswiththeincreasingtrendoftheatmosphericcirculationinEastAsia.

简介：P—地区性的气候用一个parameterization计划建模说明亚格子的热效果的σ可伸缩山志学被用来模仿在1991的mei-yu时期期间发生在长江山谷以内的三个重降雨事件。模拟结果由考虑亚格子规模地形学计划显示出那，一个人能显著地为在这三个重降雨事件期间模仿雨量分布和紧张改进模型的表演，最特别第二和第三。降雨主要由于对流降水，这也被发现。在实验之间的比较，有或没有亚格子规模地形学的任何一个策划，证明用计划的模型在850hPa水平和上升运动和在长江山谷上在500hPa定位的潮湿集中中心复制了集中紧张和分发。然而，一些偏差仍然在大气的水分含量，集中分发和潮湿交通线路的模拟存在，它主要导致更低的模仿的降水层次。模拟结果的进一步的分析证明亚格子地形学计划修改了表面精力预算部件的分发，特别在南方和西藏的高原的西南边，导致发展和在700hPa的否定重力势高度差别和积极温度差错率差别的东方繁殖，它可能在东方中国上导致了改进降水模拟。

简介：(1)SAM断然在Yangtze的中间、更低的活动范围与Mei-yu相关很好以便强壮的春季SAM被更多的降雨在河并且反过来也如此的ther各个在Mei-yu跟随。(2)SAM否定地与SST相关很好近海中国以便当时，强壮的春季SAM以后被近海的低SST和弱夏季风在东亚伴随高SST近海被强壮的夏季风在东亚跟随。(3)强壮的异常春天SAM的Inthe年，重要风切变在Yangtze的中间、更低的活动范围上统治空气的中间和底层；在弱异常春天SAM的年里，shear是到在诺思中国上的北方的更多。(4)怎么在Yangtze的中间、更低的活动范围上做SAM锁子甲Mei-yu降雨？为他们的关联的内部机制是什么？他们仍然保持不清楚并且需要推进学习。

简介：以前的学习来到结论：基于南方亚洲人高度(SAH)的异例，在热带、副热带的区域上的100-hPageopotential高度，和100-hPa循环，我们能在长江山谷和诺思中国预言降水异例。测试它的有效性，一系列实验被设计了并且操作，它包括控制实验，敏感实验(它增加了异例进100-hPageopotential高度和风地)，并且四合成的实验。基于象EPR-CF，EPRCD，EPR-HF，和EPR-HD那样的镇静的起始的领域试验，能在长江山谷和诺思中国复制洪水或干旱。它建议在热带、副热带的区域上的SAH，100-hPageopotential高度，和发行量的异例可以可能在二个区域暗示夏天降水异例。SAH，100-hPageopotential高度，和西南的异例流动在以前的时期的敏感实验结果表演是干旱或洪水的一个信号在长江山谷和诺思中国的下列夏天。并且它也是在二个区域在夏天降水异例上有影响的因素之一。100-hPageopotential高度并且SAH和西南流动的异常加强的积极异例将在诺思中国在长江山谷和干旱导致洪水；当100-hPageopotential高度并且SAH和西南流动的异常变弱的否定异例将在诺思中国在长江山谷和洪水导致干旱时。[出版摘要]

简介：ByusingNCEP/NCARdailyreanalysisdataanddailyprecipitationdataof740stationsinChina,relationshipsbetweenthepositionvariationoftheWestPacificsubtropicalhigh(WPSH)andthediabaticheatingduringpersistentandintenserainsintheYangtze-HuaiheRiversbasinarestudied.TheresultsshowthatthepositionvariationofWPSHiscloselyassociatedwiththediabaticheating.Therearestrongapparentheatingsourcesandmoisturesinksinboththebasin(tothenorthofWPSH)andthenorthofBayofBengal(tothewestofWPSH)duringpersistentandintenserainevents.Inthebasin,Q1zbeginstoincrease3daysaheadofintenserainfall,maximizes2dayslaterandthenreducesgradually,butitchangeslittleafterprecipitationends,thuspreventingtheWPSHfrommovingnorthward.InthenorthofBayofBengal,2daysaheadofstrongrainfalloverthebasin,Q1zstartstoincreaseandpeaks1dayaftertherainoccurs,leadingtothewestwardextensionofWPSH.Afterwards,Q1zbeginsdecliningandtheWPSHmakesitseastwardretreataccordingly.Basedonthecompleteverticalvorticityequation,inmid-troposphere,theverticalvariationofheatinginthebasinisfavorabletotheincreaseofcyclonicvorticitynorthofWPSH,whichcounteractsthenorthwardmovementofWPSHandfavorsthepersistenceofrainbandsoverthebasin.TheverticalvariationofheatinginthenorthofBayofBengalisinfavoroftheincreaseofanti-cyclonicvorticitytothewestofWPSH,whichinducesthewestwardextensionofWPSH.

简介：NCEP/NCAR每日的分析数据和中国每日的gridded降水数据被用来学习在aprupt干旱洪水之间的关系转移中间低的活动范围在2011的长江和intraseasonal摆动(ISO；3060天)在中间高度的纬度在东亚上的上面的对流层的南方的循环。到洪水的从干旱的突然的转变发生在早6月。复杂实验直角的功能的开始的二个恢复领域证明从低纬度的向北方繁殖的westerlies在中间迟了的5月在长江(MLRYR)的中间低的活动范围上从高纬度与向南方繁殖的westerlies收敛。预定这集中在早中间的6月对应于洪水时期。ISO索引显著地并且断然在MLRYR上与降雨被相关。在干燥阶段期间(在转变前)，在MLRYR上的上面的对流层被气旋的流动描绘，在东方风，和集中。地区性的发行量被一列波浪火车在MLRYR上在湖贝加尔湖，在北中国上的反气旋，和气旋的东方上与气旋统治。在湿阶段期间，状况被颠倒。波浪火车的配置在干燥阶段期间赞成西的风骚乱的向南方的繁殖，当波浪火车的配置在MLRYR上在湿阶段期间赞成抽的效果和持续上升运动的发展和维护时。