学科分类
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500 个结果
  • 简介:ToinvestigategeneticdiversitiesamongtheAAgenomeOryzaspeciesintheSoutheastandSouthAsia,atotalof428accessionsoftheAAgenomeOryzaspeciesweregenotypedusing36simplesequencerepeats(SSR)markersdistributedthroughoutthericegenome.Allofthe36SSRmarkersgeneratedpolymorphicbands,revealing100%polymorphism.Thenumberofallelesperlocusrangedfrom3to17withthemeanof8.6.TheNei’sgeneticdiversityindex(He)rangedfrom0.337atRM455to0.865atRM169withanaveragevalueof0.650.ThegeneticdiversityoftheAAgenomeOryzaspeciesintheSoutheastAsiawasobviouslyhigherthanthatintheSouthAsia.AmongthedetectedOryzaspeciesintheSouthandSoutheastAsia,O.rufipogonshowedthehighestgeneticdiversity.Meanwhile,ahighergeneticdifferentiation(Fst)wasfoundamongthedetectedOryzaspeciesintheSoutheastAsiathanintheSouthAsia.TheFstvaluebetweenO.nivaraandO.sativawasthehighest.Theresultsfromthenumberofspecificalleles,specificloci,andallelefrequencyconfirmedthegreatergeneticvariationamongthedetectedspecies.Inaddition,thespecificalleleinRM161displayedhigherfrequency(0.193),suggestingitsimportantfunctioninidentifyingOryzaspeciesofAAgenome.

  • 标签: GENOME ORYZA SPECIES simple sequence REPEAT
  • 简介:ThepentadaverageminimumoutgoingIongwaveradiation(OLR)dataoverthenorthernSouthChinaSea(SCS)areselectedasindexestoanalyzetheintensityoftheconvectionconnectedwiththeSCSmonsoononset.StatisticanalysisdemonstratesthattheindexcanaccountfortheintensityoftheSCSmonsoonabout,atleast,75%.Asignificantnegativecorrelation(confidentlevelover90%)betweenShandong'ssummerrainfallandtheindexisfoundonlyintheperiodof24-26pentadsandlimitedtotheareaabovethedeeperwaterbasinoftheSCS(10°-20°N,110°-117.5°E).ThustheminimumOLRoverthedeeperwaterbasinduring24-26pentadscanbeusedasavaluablepredictorforthelong-leadforecastoftheprecipitation.The500hPageopotentialheightdataintheNorthernHemispherefortheperiodfrom1951to2000areusedinordertocharacterizethephysicalmechanismsinvolved.Thecompositeanomaliesofthe500hPalevelallowfortheidentificationanddetectionoftheteleconnectionoftheEastAsia-NorthAmerica(EAP)patternthatisresponsibletosomeextentfortheinterannualvariabilityoftheprecipitationofShandongProvince.Besides,theinterannualdifferencesoftheintraseasonalvariations(ISV)ofOLRandtheirnorthwardtransmissionprobablymakeacontributiontothepositionofthesubtropicalhighwhichisvitalforthesummerrainfallintheprovince.

  • 标签: 南海 夏季 山东 降水 对流强度 甚长长波辐射
  • 简介:是在由三个主要预报中心在西方的诺思太平洋上形成的热带气旋的数字出现在内部年度、内部十的可变性和期刊变化的特征的比较,i.e.China气象学的管理(CMA),东京(JMA)的地区性的专业化气象学的中心和关岛的联合台风警告中心(JTWC),有热带气旋(TC)或台风的下列重要的点(1)气候学(TS的紧张上的TC或更强壮)表演

  • 标签: 统计人物 差别比较 热带气旋频率 非同质
  • 简介:Almosthalfoftheoceanicwatercolumnsexhibitdouble-diffusion.Theimportanceofdouble-diffusioninglobaloceans'saltandheatfluxes,water-massformationandmixing,andcirculationisincreasinglyrecognized.However,suchanimportantphysicalprocessintheoceanhasnotbeenwellstudied.Oneofthereasonsisthedifficultyofparameterizingandquantifyingtheprocesses.Thepaperpresentedhereattemptstoquantifythedouble-diffusivefluxesofsaltandheatintheocean.Previousqualitativeanalysisbyapplyingthewater-massTurnerangle,mTu,totheNorthPacificIntermediateWater(NPIW)layershowedafavorableconditionforsalt-fingeringintheupperNPIWduetotheoverlyingwarm/saltywaterabovethecold/freshNPIWcore,andadoubly-stableconditioninthelowerNPIWwherepotentialtemperaturedecreaseswithdepthwhilesalinityincreases,inducingdoublestratificationwithrespecttobothpotentialtemperatureandsalinity.Thepresentstudygivesaquantitativeestimateofdouble-diffusivefluxesofsaltandheatcontributedbysalt-fingeringintheupperNPIWlayer.

  • 标签: 北太平洋 介质水流 双扩散 盐分 热量 NPIW
  • 简介:ThelocationandlateQuaternaryactivityoftheCentral-NorthSegmentoftheTaihangMountainsPiedmontfaultzonehavebeenstudiedbyshallowseismicsurveyandcombineddrillexploration.OurresultsshowthattheBaoding-ShijiazhuangfaultandtheXushuifaultwereactiveinthelatePleistocene,butthesouthXushuifaulthasbeeninactivesincethelatePleistocene.Themaximummagnitudeofpotentialearthquakeofthefaultsis6.0.

  • 标签: 晚第四纪活动 山前断裂带 太行山 浅层地震勘探 更新世晚期 晚更新世
  • 简介:我们评估了在北伊朗在里海附近在Tavalesh区域影响大米鱼耕作的采纳的因素。我们与无限制的问题进行了调查。数据随机从184个回答者(61个采用者和123非采用者)被收集从选择村庄取样了并且分析了使用逻辑回归和多反应分析。家庭尺寸,与一个扩展代理人的接触的数字,在扩展教育活动的参予,在社会机构的会员和农场工人的存在是为大米鱼耕作系统的采纳的最重要的社会经济的因素。另外,经济问题是采用者报导的最普通的问题。象存取的缺乏那样的另外的问题捞食物拨出,鱼的损失,高质量的鱼鱼种和脱水和差的水质量的存取的缺乏对很多个农民也重要。

  • 标签: LOGISTIC回归分析 稻田养鱼 影响因素 LOGISTIC回归分析 伊朗 社会经济因素
  • 简介:北方大西洋摆动(NAO)是在北半球的气候可变性的领先的模式之一。它清楚地在气象学的变量联系到变化,这被显示出,例如地面温度,在半球的规模。然而,最近的研究表明了NAO空间模式也取决于太阳的强迫。因此,它气象学的变量上的效果必须变化取决于这个因素。而且,它能是阳光通过可变性模式影响气候,是这研究的焦点的一个假设。我们发现在NAO/AO和半球的温度之间的关系变化取决于太阳活动。结果看积极重要关联太阳活动是否仅仅高。另外,结果支持那项太阳活动影响对流的想法在经由同温层的极的旋涡的变化的北半球的球的气候变化。

  • 标签: 太阳活动周期 北大西洋涛动 北半球 地面温度 相互关系
  • 简介:DISTRIBUTIONOFLOWFREQUENCYWAVESINNORTHPACIFICANDINTRASEASONALABNORMALITYOFTHEWESTERNPACIFICSUBTROPICALHIGHLiXingliang(李兴亮)(Me...

  • 标签: LOW FREQUENCY wave SUBTROPICAL high ABNORMALITY
  • 简介:Lomagundi-Jatuli事件(LJE)是保存13C在在世界范围的Paleoproterozoic碳酸盐的+5和+16之间的carb价值。然而,这些旅行的持续时间,振幅和模式仍然保持糟糕抑制了。在北方中国Craton的2.14-1.83GaHutuo组是一>10km厚火山--沉积顺序,包括>5km在在上被扔的厚保存得很好的碳酸盐--对亚tidal环境潮汐。碳酸盐的152件最不改变的样品的公司同位素、元素的分析揭示了三阶段的13C进化。它以只积极的13Ccarb(+1.3到+3.4)在Dashiling和Qingshicun形成在~上演2.1Ga碳酸盐,从积极价值由转变列在后面到震荡在~的积极、否定的价值3000mWenshan,Hebiancun,Jianancun,和Daguandong形成的厚碳酸盐,并且与只否定的13C保存在的carb价值>500mHuaiyincun和Beidaxing形成的厚dolostones。看来许多LJE,特别地那些极其积极的13Ccarb信号,没在Hutuo碳酸盐被记录。只积极的13Ccarb价值(+1.3到+3.4)多半在更低的形成保存了对应于LJE的目的,而随后二个阶段反映LJE和Shunga-Francevillian事件(SFE)的发作的余殃。现在的数据点到碳上的氧的增加的影响从Doucun骑车到Dongye亚群并且证明在北方中国Craton的LJE的结束与在Fennoscandia和南非的那些是将近同时的。

  • 标签: 碳同位素 华北地区 滹沱群 古元古代 碳酸盐岩 CARB
  • 简介:ThecropmodelWorldFoodStudies(WOFOST)wastunedandvalidatedwithmeteorologicalaswellaswinterwheatgrowthandyielddataat24stationsin5provincesofNorthChinafrom1997to2003.Theparameterizationobtainedbythetuningwasthenusedtomodeltheimpactsofclimatechangeonwinterwheatgrowthforallstationsusinglong-termweatherdatafrom1950to2000.Twosimulationsweremade,onewithallmeteorologicaldata(rainfed)andtheotherwithoutwaterstress(potential).Theresultsindicatethatthefloweringandmaturitydatesoccurred3.3and3daysearlierinthe1990sthanthatinthe1960sduetoa0.65℃temperatureincrease.Thesimulatedrainfedyieldsshowthattheaveragedroughtinducedyields(potentialminusrainfedyields)havedecreasedby9.7%overthelast50years.Thisistobecomparedwitha0.02%decreaseinyieldiftheprecipitationlimitislifted.Althoughtheprecipitationduringthegrowingseasonhasdecreasedoverthelast50years,thedroughteffectsontherainfedyieldsremainedtobepracticallyunchangedasthespringprecipitationdidnotdecreasemarkedly.

  • 标签: CROP growth model World Food Studies
  • 简介:Thisstudyfocusesonthedecadalvariabilityoftropicalcyclones(TC)overtheWesternNorthPacific(WNP)andhowthesechangesarerelatedtotheMadden-JulianOscillation(MJO).ItwasdonewiththehelpoftheReal-timeMultivariateMJOindexfromtheAustralianGovernmentBureauofMeteorologyoftheCentreforAustralianWeatherandClimateResearch,TCdatafromtheJointTyphoonWarmingCenterbesttrackdatasets,anddailyandmonthlydatasetsfromtheNCEP/NCARreanalysiscenter.TheresultsshowthattheTCfrequencyintheWNPexhibitedastatisticallysignificantdecreaseduring1998-2010comparedtoduring1979-1997.ThedecreaseinTCfrequencyintheWNPmainlyoccurredduringMJOactivephases(i.e.,phases4,5,6,and7).FurtherinvestigationoftheclimatebackgroundandthepropagationdifferencesoftheMJObetween1979-1997and1998-2010wasperformed.TheLaNina-liketropicalseasurfacetemperaturecoolingcausedstrongerWalkercirculationandthusinducedunfavorableatmosphereconditionsforWNPTCgenesisincludingalow-leveleasterlyanomaly,anegativerelativevorticityanomaly,anincreaseinsea-levelpressure,andstrongerverticalwindshear.Moreover,shorteningoftheMJOcycle,declineinthedurationoftheactivephasesintheWNP,andeasterlyanomalyandshrinkageoftheconvectionareaduringMJOactivephasesmayalsopartlyexplainthedecadalvariationofTC.

  • 标签: CLIMATE EOF tropical cyclone MJO Western North Pacific decadal change
  • 简介:PrecipitationobservationscollectedatweatherstationsineasternChina,theNCEP/NCARreanalysisdata,thetropicalcyclone(TC)BestTrackDataset,andasensitivitynumericalexperimentwereusedinthepresentstudytoinvestigatetheroleintheEastAsiansummermonsoon(EASM)systemplayedbyfrequentTCactivitiesoverthewesternNorthPacific(WNP).Resultsindicatedthat,inactiveTCyears,theEASMisstrongerandthesoutherlywindsinthelowertroposphereadvancefarthernorthandreachhigherlatitudes.Meanwhile,themonsoonrainbeltremainsinthelowerandmiddlereachesoftheYangtzeRivervalleyforarelativelyshortperiod,leadingtolessprecipitationthere.BoththewesternPacificsubtropicalhighandtheSouthAsianhighweakenwiththenorthwardshiftoftheridgelinesforbothhigh-pressuresystemsaswellastheEastAsiansubtropicalupper-leveljet.Therefore,theimpactsoffrequentTCactivitiesovertheWNPoneachindividualcomponentoftheEASMareinphasewiththoseofthestrongerEASMitself,amplifyingfeaturesofthealreadystrengthenedEASM.

  • 标签: East Asian summer MONSOON TROPICAL CYCLONE
  • 简介:ThepolicyoftheChinesegovernmentconcerningthehorizontalexpansionofthecultivatedlandthroughthereclamationofdesertsoilsresultinatotalincreaseof665.985km2duringtheperiod1987-1999inNorthShaanxi.Thisincreaseislessthanthelossinarablelandbyurbanization.Theacceleratedrateofchangeinagriculturalareascallsformorerapidsurveysofurbanizationandlossofarableland.Remotesensinghasanumberofadvantagesoverground-basedmethodsforsuchsurveys.Themulti-scaleconceptofremotesensingdatahelpusstudytheprobleminfourtowns.Severalmapswereproducedtoanalyzethesituationofurbancoverageindifferenttimes.Theevaluationofthestatus,rateandriskofurbanizationarebasedonanacceptedaverageofurbanincreaseas2%ofpopulationgrowthperyear.

  • 标签: GIS 地球信息系统 城市化 强制入口 可耕地 荒漠化
  • 简介:Usingthehigh-qualityobservedmeteorologicaldata,changesofthethermalconditionsandprecipitationovertheNorthChinaPlainfrom1961to2009wereexamined.Trendsofaccumulatedtemperatureandnegativetemperature,growingseasonduration,aswellasseasonalandannualrainfallsat48stationswereanalyzed.Theresultsshowthattheaccumulatedtemperatureincreasedsignificantlyby348.5℃dayduetoglobalwarmingduring1961-2009whiletheabsoluteaccumulatednegativetemperaturedecreasedapparentlyby175.3℃day.Thestartofgrowingseasondisplayedasignificantnegativetrendof-14.3daysduring1961-2009,buttheendofgrowingseasondelayedinsignificantlyby6.7days.Asaresult,thelengthofgrowingseasonincreasedby21.0days.Theannualandautumnrainfallsdecreasedslightlywhilesummerrainfallandsummerrainydaysdecreasedsignificantly.Incontrast,springrainfallincreasedslightlywithoutsignificanttrends.AlltheresultsindicatethatthethermalconditionswereimprovedtobenefitthecropgrowthovertheNorthChinaPlainduring1961-2009,andthedecreasingannualandsummerrainfallshadnodirectnegativeimpactonthecropgrowth.ButthedecreasingsummerrainfallwaslikelytoinfluencethewaterresourcesinNorthChina,especiallytheundergroundwater,reservoirwater,aswellasriverrunoff,whichwouldhaveinfluencedtheirrigationofagriculture.

  • 标签: 生长季节 华北平原 降水量 积温 夏季降水 年降雨量
  • 简介:TheGarouaZoneinNorthCameroon,thesubjectofthisstudy,isknowntohaveundergonetectonicmovementsduringtheCretaceous,butthezone’sstructuraldataremainpoorlyknown.ThisstudyexploitstheBougueranomalytoimproveknowledgeofGarouatectonicsstructures.Inordertocharacterizethesestructures,twomethodsareused:Euler’sdeconvolutionmethodandthemethodofthehorizontalgradientoftheverticalderivative.SuperpositionoftheEuler’ssolutionsmapforindexN=1withthemapfromthehorizontalgradientoftheverticalderivativemethodallowsdeterminationofgravimetriclineaments,interpretedasfaultsoraslinearcontacts,fromwhichwededuceastructuralmapofthestudyarea.Basedonthismap,weidentifysixteenlineaments,ofwhichwecounteightaslinearcontactsandeightasfaults.Amongthefaults,wedenoteoneofdepthbetween4and8km,fivefaultsofdepthrangingbetween8and13km,andtwofaultsofdepthsbetween13and36km.Analysisofthesefaultsshowsthatthesevendeepestfaultsmightpresentanaturalriskinourstudyarea.Forpurposesofcivilprotection,suchdeepfaultsshouldbemonitoredandtakenintoconsiderationintheimplementationoflargepublicworks.Thestructuralmap,establishedhereinfromdataonthein-depthextensionofeachfault,thusincreasesscientificknowledgeintheareathatcanbeusedtositepublicworksinwaysthatreducerisk.

  • 标签: Bouguer ANOMALY horizontal DERIVATIVE vertical DERIVATIVE
  • 简介:Nitrogen(N)lossesfromammoniumbicarbonateorureaappliedtowheatandthenfollowedimmediatelybyirrigationwereinvestigated.Ammoniavolatilizationwasdeterminedbyamicrometeorologicalmethod(ammoniasampler),totalNlosswasestimatedbythe^15Nmassbalancemethod,anddenitrificationlosswasmeasuredbythediferencemethod(calculatedfromthedifferencebetweenthetotalNlossandammonialoss)andadirectmethod(measuringtheemissionof(N2+N2O)-^15N).Totalammonialossesfromammoniumbicarbonateandureain33dayswere8.7%and0.9%oftheappliednitrogen,respectively.ThecorrespondingtotalNlosseswere21.6%and29.5%,Apparentdenitrificationlosses(bythedifferencemethod)wereratherhigh,being12.9%fromammoniumbicarbonateand28.6%fromurea.However,noemissionof(N2+N2O)-^15Nwasdetectedusingthedirectmethod.

  • 标签: 氨挥发 脱氮作用 氮肥 小麦 华北地区 气态