简介:ByusingtheobservationalO3dataofKunmingandHongKongduringtheperiodof1997-2001,thepaperstudiesthedistributionandvariationoftotalozoneinlowlatituderegionofChina.ThestudyshowsthatthecharacteristicsofvariationinKunmingandHongKongareverysimilar,andthetotalozoneinthewesternareasislargerthanintheeasternones.Itismaximuminsummerandminimuminwinter.
简介:在西南中国的云南的低纬度高地的降水政体服从于在东方亚洲夏天季风和印度夏天之间的相互作用表面山志学的季风,和影响。在它的空间、时间的模式的变化的理解着急地为气候变化设计,水文学影响建模,和地区性、下游的水资源管理被需要。用在最后几十年(1950s2007)的低纬度高地的每日的降水记录,降水的一个时间系列索引,包括年度降水,多雨的天的数字,吝啬的年度降水紧张,雨季的发作的日期,降水的度和时期季节的集中,最高1天、3天、7天的降水,和降水在不同紧张上面为降水多雨的天总计并且数(例如10公里,25公里一没有趋势的预先增白的Mann-Kendall趋势测试然后被用来检测时间系列数据的趋势。结果证明在年度降水和越过低纬度高地的降水趋势的强壮的季节的区别没有重要趋势。弹簧和冬季正在变得更湿,夏天正在变得更干燥。秋天在东方正在变得更干燥并且在西方更湿。作为后果,降水的seasonality稍微正在变弱。雨季和最高的降水的时期的开始趋于更早。同时,低纬度高地也见证不太多雨的天,更强烈的降水,稍微更长中等、重的降水事件,和更经常的极端降水事件。另外,降水趋势的地区性的区别是显著的。这些变化可以与东方亚洲夏天季风变弱并且南方亚洲人夏天季风,以及特殊多山的地面的走廊障碍效果加强被联系。然而,包含的物理机制仍然需要以后被揭开。
简介:Bymeansofsimulationexperimentswithatwo-dimensionalzonal-meanmodel,astudyismadeoftheinfluenceofthewesternNorth-Pacificmidlatitudesea-surfacetemperature(SST)anomaliesonthecirculationpatternandwet-seasonalprecipitationovertheEast-ChinaChangjiang-HuaihereachesandtheNorth-Chinaplain.TheSSTanomaliesaredividedintotwotypes,onebeing“colderinthesouthandwarmerinthenorth”andtheotherjustopposite,dependingonseason.Resultsshowthattheoccurrenceoftheanomaliesisfollowedbyconsiderablechangesinthepositionofthesubtropicalhighhappeningfor3-5monthstocome.Forinstance,thespring“colderinthesouthandwarmerinthenorth”anomaloustype(i.e.,colderfor20—35°N,andwarmernorthof35°N)leadstotheintensificationofthesummersubtropicalhigh,withtheridgelinemovedslightlynorthward,resultingindroughtoverChangjiangreachesforJuly-AugustandinexcessiverainfallintheNorth-Chinaplain,andviceversa.
简介:Magneticreconnectionisthemostfundamentalenergy-transfermechanismintheuniversethatconvertsmagneticenergyintoheatandkineticenergyofchargedparticles.Forreconnectiontooccur,thefrozen-inconditionmustbreakdowninalocalizedregion,commonlycalledthe‘diffusionregion’.InEarth’smagnetosphere,iondiffusionregionshavealreadybeenobserved,whileelectrondiffusionregionshavenotbeendetectedduetotheirsmallscales(oftheorderofafewkm)(Paschmann,2008).Inthispaperwereport,forthefirsttime,insituobservationsofanactiveelectrondiffusionregionbythefourClusterspacecraftattheEarth’shighlatitudemagnetopause.Theelectrondiffusionregionischaracterizedbynongyrotropicelectrondistribution,strongfield-alignedcurrentscarriedbyelectronsandbi-directionalsuper-Alfvénicelectronjets.Alsoobservedweremultiplemicro-scalefluxropes,withascalesizeofabout5c/ωpe(12km,withc/ωpetheelectroninertiallength),thatarecrucialforelectronaccelerationintheguide-fieldreconnectionprocess(Drakeetal.,2006a).Thedatademonstratetheexistenceoftheelectrondiffusionregionincollisionlessguide-fieldreconnectionatthemagnetopause.
简介:AparameterizedradiationandcloudmodeldevelopedattheUniversityofUtah,U.S.A.hasbeenusedtocomputetheatmosphericradiativepropertiesinZhangyeareaduringthepilotexperimentofHEIFEinSeptemberof1988.SomecharacteristicsofatmosphericradiativeheatingfieldsduringtheautumninZhangyeareahavebeenanalysed,andsomequestionsthatmeritattentioninthefutureobservationarealsodiscussedinthispaper.
简介:在一个更低的纬度高原和水汽交通的特征的重降雨的分析被使用常规数据和更稠密的表面数据进行了。结果出现:(1)当温暖的更潮湿的空气和冷空气与对方一起交往了时,重降雨被一系列中央规模系统在有利大规模条件下面引起。同时,在上层、降低水平的喷气之间联合被揭示。在那里存在,这也被发现在在云南的重降雨的主要影响系统之中的一些不同特征例如Indian-Myanmar马槽和冷空气的路径,与那些相比在东方和华南。(2)在中央之间的相互作用在地面附近放大集中线可以是为中央规模系统,和中央规模系统的动态、热的动态结构的出现的可能的被触发机制是很明显的。集中线可以仔细联系到云南的地面,中国。(3)水汽预算的计算表明为重降雨的水汽供应的主要来源在孟加拉的海湾。在这种情况中,尽管水汽的数量是,水汽能被搬运进云南不到那在在东方和华南的更低的对流层。另外,为三维的空气包裹轨道的分析更好揭示了并且描述来源地点和水汽的交通到云南。
简介:Theformingmechanismsoflow-latitudecirculationcellsandprecipitationduringanEastAsiancoldsurgehavebeenstudiedbyusingafive-layerprimitiveequationmodel.Numericalexperimentsshowthatinmid-highlatitudes,thepropagationoftheEastAsianwintermonsoonisnearlyadryprocess;inlow-latitudes,theeffectsofcumuluscon-vectionintensifythenortheastmonsoonandnortheasttradewind;however,theyalsopreventtheintertropicalconvergencezone(ITCZ)fromfurthersouthwardinvasion,andstrengthenthemeridionalandzonalcellsoverEastAsia.NumericalresultsalsoindicatethatthewintermonsoonprecipitationinIndonesiaandNorthernAustraliacanexistindependently.BoththeSouthChinaSea(SCS)coldsurgeandtheWestPacificnortheastcross-equatorialtradewindareofimportancefortheformationoftheNorthernAustraliasummermonsoonanditsprecipitation.Numericalresultsshowthatthedevelopmentofcumulusconvection,triggeredbytheSCScoldsurge,isacrucialfactorinformingtheheavymonsoonprecipitationandlow-levelstationarydisturbancesinIndonesiaandBorneo.Thetropicaltopographyandnortheasttradewinddisturbancesonlyaffecttheintensityofprecipitationthere.
简介:ThedramaticchangesintheArcticclimatesystemduringrecentdecadesareoneofthemostprominentfeaturesofglobalclimatechange.Twomoststrikingandfundamentalcharacteristicsaretheamplifiednear-surfacewarmingataratetwicetheglobalaveragesincethemid20thcentury(e.g.,BlundenandArndt,2012;Huangetal.,2017),andtherapiddeclineofsea-iceextentatapaceof12.9%(10yr)-landthinningoficethicknessby40%since1979(e.g.,KwokandRothrock,2009;Meieretal.,2012).Inconjunctionwiththesechanges,thefrequencyofoccurrenceofextremeclimateandweathereventshasostensiblyincreasedacrosstheNorthernHemispheremid-latitudes,includingadversecoldspells,severeheatwaves,destructivefloods,andpersistentdroughts(e.g.,CoumouandRahmstorf,2012).ThefactthatArcticclimatechangeshavecoincidedwithanincreaseinthefrequencyofoccurrenceofextremeeventshasinspiredbroadinterestinpossiblelinkages--notonlyintheclimatecommunity,butalsothegeneralpublic,mediaagencies,anddecisionmakers--inparticularconsideringtheprojectedfuturecontinuationandaccelerationofArcticwarmingandsea-icedecline(e.g.,ZhangandWalsh,2006;Zhang,2010;Stroeveetal.,2012;WangandOverland,2012).