資源描述：
《trend forecast趨勢(shì)預(yù)測(cè)》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在應(yīng)用文檔-天天文庫(kù)。
1、-3-AMOFSG/7-SNNo.24AMOFSG/7-SNNo.2415/8/08AERODROMEMETEOROLOGICALOBSERVATIONANDFORECASTSTUDYGROUP(AMOFSG)SEVENTHMEETINGMontréal,9to12September2008AgendaItem6:AerodromeforecastsTRENDFORECAST(PresentedbyKeesBlom)SUMMARYThispaperdescribesaproposalforanewwayofissuingaTRENDtypelandingfore
2、castbyusingtheexpectedprevailingweatherparametervaluesincombinationwiththetemporaryvariationsoftheparametervalues.1.INTRODUCTION1.1InmanyStatesuseismadeoftheTRENDtypelandingforecastaccordingtoAnnex3—MeteorologicalServiceforInternationalAirNavigation,para6.3.3:“trendforecastshallconsi
3、stofaconcisestatementoftheexpectedsignificantchangesinthemeteorologicalconditionsatthataerodrometobeappendedtoalocalroutineorlocalspecialreport,oraMETARorSPECI.Theperiodofvalidityofatrendforecastshallbe2hoursfromthetimeofthereportwhichformspartofthelandingforecast”.1.2WithAmendment74
4、toAnnex3itbecamepossibletoissueAUTOMETARduringopeninghoursofaerodromes.FurthermorethishasleadtoissuingAUTOlocalreportsandAUTOlocalspecialreportsatsomeaerodromesaswell.-3-AMOFSG/7-SNNo.241.DISCUSSION1.1Automatedweatherreportinginitselfprovestogeneratemorelocalspecialreports(and?SPECI,
5、whenissued),sinceanautomatedsystemwillstrictlyadheretoregulations,wherehumanobserverstendtoanticipatechangesandareabletocombinechangeswhichoccurshortlyaftereachotherintoonereport.1.2PreparingTRENDforecastswitheverynewreporthasalwaystakenalotofeffortfromaviationforecasters,evenmorewhe
6、retheyareprovidingTRENDforecastsforseveralaerodromesfromacentralizedforecastoffice.1.3TRENDforecastsaccordingtothepresentrecommendationhavetoprovide………theexpectedsignificantchangesinthemeteorologicalconditions…...Especiallyinweathersituationswithrapidlychangingconditionsthisresultsin
7、manydifferentTRENDforecasts,whiletheprevailingweatherconditionsdohardlychange.Examples:METAREHAM041425Z14011KT4000SHRAFEW034CBBKN04005/01Q1007BECMG9999NSW=SPECIEHAM041435Z14011KT9999FEW034BKN04005/01Q1007TEMPO14017G28KT4000SHRASCT030CB=SPECIEHAM041435Z15015G25KT4000SHRAFEW032CBBKN040
8、05/01Q1007BE
