简介:回顾了作为实用天文学和大地测量学中基本研究课题之一的大气折射映射函数研究的进展。介绍了近几年上海天文台发展的大气折射母函数方法,以及由此导出的大气折射解析解。对如今广泛地应用在空间测量技术中的几种映射函数做出评述;分析了NMF模型的优点和不足之处。介绍了由大气折射母函数方法引出的大气延迟新连分式映射函数和天文大气折射的映射函数方法。利用VLBI实验中高度截止角与基线长度重复率的关系、探空气球(radiosonde)观测资料、PRARE资料比较了各种映射函数的结果。特别指出了映射函数方法对天文大气折射和光学波段测距精度的改进。讨论了大气折射计算中的主要误差源。
简介:ThePRCMinistryofScienceandTechnologyofficiallyapprovedtheimplementationoftheprojectasoneofNationalKeyScienceandTechnologyProjectsinNovember2001andentrustedtheChinaMeteorologicalAdministration(CMA)withtheleadership.Thenewsbriefingoftheprojectstaring-upwasheldceremoniouslyatCMAon29December2001.ProjectGoal:undertheconditionsofhigh-performancesupercomputersandhightemporalandspatialresolutionmeteorologicaldata,makinggooduseofbothinternationalanddomesticnewscientificachievements,todevelopournewgenerationnumericalweatherforecastingoperationsystemindependentlysotomeettheneedsofthedevelopmentofthecountryanditsmeteorologicalservice.
简介:Inviewofthefactthattheatmosphereiscapableofmemory,thisresearchsuggestedanddevelopedtheviewpointofatmosphericmemorialdynamics.Byintroducingamemoryfunctionintothedynamic-thermodynamicequationsoftheatmosphere,theseequationscanbetransformedintodifference-integralequations.Inthisway,thenumericalsolutionoftheatmosphericmotioncanbeobtainedbyusingseveralinitialfieldsratherthanonlyoneinitialfield.Theretrospectivetimeintegrationschemeisanoriginalschemebasedthesystemself-memorizationprinciple,whichdiffersgreatlyfromother