简介:Inrecentyears,radiooccultation(RO)technologymakinguseofglobalpositioningsystem(GPS)signalshasbeenexploitedtoobtainprofilesofatmosphericparametersintheneutralatmosphere.Inthispaper,theROrefractivityprofilesobtainedfromtheConstellationObservingSystemforMeteorology,IonosphereandClimate(COSMIC)missionarestatisticallycomparedwiththeobservationsof38radiosondestationsprovidedbytheAustralianBureauofMeteorologyduringtheperiodfrom15July2006through15July2007.Di?erentcollocationcriteriaarecomparedatfirst,andCOSMICROsoundingsthatoccurwithin3hoursand300kmofradiosondemeasurementsareusedforthefinalstatisticalcomparison.TheoverallresultsshowthattheagreementsbetweentheCOSMICrefractivityprofilesandtheradiosondesoundingsfromthe38stationsareverygoodat0–30kmaltitude,withmeanabsoluterelativerefractivitydeviationsoflessthan0.5%.Latitudinalcomparisonsindicatethattherearenegativerefractivitydeviationsinthelowertroposphereoverthelowlatitudeandmiddlelatituderegionsandlargestandarddeviationsexistinthelowertroposphereoflowlatituderegions,whichcanreachupto~6%.ThecomparisonsofCOSMICROrefractivityprofilesandradiosondeobservationsfor3polarstationsinfourdifferentseasonsindicatethattheaccuracyofGPSROprofilesisbetterintheAustralsummerandautumnthanintheAustralspringandwinterduringtheyearfromSeptember2006toAugust2007.
简介:Inrecentyears,aconsiderableamountofmicroscopicspheruleshavebeenfoundinconcentratesrecoveredfromsomestrataboundgolddepositsoccurringinMiddle-UpperTriassicturbiditeseriesinnorthwesternSichuan.Studyindicatesthatthesespherulesarecosmicdust.ItisthefirsttimethatcosmicdustofextraterrestrialoriginhasbeenfoundinhydrothermalgolddepositsinChina.Thespherulesaresteel-greyincolourandshowmetallicluster.Theirgrainsizeiscommonlylessthan100μm.Accordingtotheircomposition,theybelongtochromium-richironcosmicdust.Thespheruleshavecomplexanddiversemicroscopicstructuresandtextures,i.e.theyshowaverydistinctWidmanstatenstructure.Thevariationofcosmicdustcontentingolddepositsexhibitsapositivecorrelationwiththemineralizationintensitiesandhydrothermalalteration.Sucharelationindicatesthattheoresub-stancesmaytransportnotonlymechanicallybutalsomaychemicallyinhydrothermalsolutions.
简介:ThecharacteristicsoftheatmosphericboundarylayerheightovertheglobaloceanwerestudiedbasedontheConstellationObservationSystemofMeteorology,IonosphereandClimate(COSMIC)refractivitydatafrom2007to2012.Resultsshowthattheheightismuchcharacteristicofseasonal,inter-annualandregionalvariation.Globally,thespatialdistributionoftheannualmeantopheightshowsasymmetricalzonalstructure,whichismorezonalintheSouthernHemispherethanintheNorthernHemisphere.Theboundarylayertopishighestinthetropicsandgraduallydecreasestowardshigherlatitudes.Theheightisinarangeof3to3.5kminthetropics,2to2.5kminthesubtropicalregions,and1to1.5kmorevenlowerinmiddleandhighlatitudes.Thediurnalvariationofthetopheightisnotobvious,withtheheightvaryingfromtenstohundredsofmeters.Furthermore,itisdifferentfromregiontoregion,someregionshavethemaximumheightduring9:00to12:00,othersat15:00to18:00.
简介:摘 要:对流层作为人类生产生活不可或缺的一部分,是人们进行气象科学生产研究的重要对象,其中对流层顶(Tropopause Height,TPH)作为对流层和平流层物质交换的过渡区域,对人类研究对流层变化的重要参考指标。COSMIC作为一种新兴的低轨掩星星座,利用遥测GNSS信号来获取相应的空间大气参数,成为大气探测以及空间探测的重要手段。本文利用COSMIC的WetPrf产品数据,对全球对流层顶参数进行反演,并根据不同的月份及年际变化分析了其参数振荡特点。结果表明,南北半球的对流层顶高度及温度呈现较为显著的月份变化,南北高纬度区域更为显著。