Abstract:The temporal and spatial characteristics of the persistence of monthly mean atmospheric circulation in the troposphere over the northern Hemisphere are investigated.It is indicated that the persistence is higher in upper-troposphere than in low-troposphere,in low-latitude than in highlatitude,in the eastern Hemisphere than in the western Hemisphere,in winter and summer than in spring and autumn.The factors influencing on the persistence are also analysed.It is found that the persistence links with solar activities,QBO,EL-Nino events and volcanic activities. Quasi-oscillations of 2 year,4 year and 6.5 year of the persistence are closely connected with the above metioned factors.

Abstract:The occurrence of rapid deepening of tropical cyclones in the Western North Pacific have been studied in the past few decades.Several standards of rapid deepening are introduced and a new standard is given according to typhoon data(1949-1990).The results of comparison between them show that new standard is marked in definition.It may be useful to climatological analysis and forecasting of rapid intensified tropical cyclones.

Abstract:The application of the group post-appraising method in weather forecasting is presented.It happens that the result is of difference to the forecasting of a certain day from different technological sources when possible weather situation prediction is made,or that each predictor will draw a different conclusion based on forecasters'own technological devices or approaches.Only then is it necessary by the approach to piece together various results as a whole so that group decision can be reached.The application is to make an overall evaluation of each result about rainfall and rain region plus the result based on experience.It has proved that the application is unique in this field and more effective and has actually become one of the effective approaches.

Abstract:The medium-range weather prediction spectral model T63 used at National Meteorological Center is described briefly.The primary 7 days operational forecast results are given,and they show that the useful forecast can reach 5-6 days.

Abstract:The system was established by principles of dynamics and themodynamics for textile mills and storage rooms.That service is accorded to run the air-adjust machines.Within the system the wet-bulb temperature forecast is based on synoptic model and statistical method.The forecasting accuracy is more than 70 percent.

Abstract:The TV meteorological service is an important window of meteorological service.The creation of TV weather forecast system combined computer technology.TV technology.with meteorological technology is improving meteorological service greatly.The system design,its structuce system analysis,computer cartoon technology and video technology in NMC are therefore introduced.

Abstract:The rainfall principal climate features and the long range rainfall changes of May in China are analyzed,according to the monthly rainfall data of 160 stations in China.Thus rainfall forecasting operational focal prints of May are defined further some useful climate phenomena are revealled for rainfall forecasting operation in May.The rainfall stage features of South China-North China region and their opposite phase(SN phenomena) are of realistic significance for long range rainfall forecasting operation in May.

Abstract:The climatic characteristics of tornadoes in China are presented according to the statistical modeling and analysis of the observed data.Based on the weather data in recent years, weather systems causing tornadoes were investigated,and the stratification structure and the wind field were analyzed.The characteristics of the parent cloud of tornadoes are also presented.

Abstract:The essential features of mesoscale convective complex in Northeast China(NMCC) and it's developing process were induced by analysing the satellite cloud pictures of ten years.Because of the effect of geographical conditions,NMCC is different from MCC in the Great Plain of the United States,northwest of China and North China.As a special convective weather system,there is marked difference between the feature of NMCC and that of the general mesoscale convective cloud clusters.

Abstract:The climatic characteristics of fog in most parts of North China plain are presented and the features of wind field and pressure at low levels during.the fog weather are briefly introduced.Meanwhile,some indexes by eliminating fog in Tianjin are also described.

Abstract:The characteristics of a severe weather of glaze icing are of the long maintenance of time and of the supercooling rainfall.By using 56 sounding and upper-wind data,the macro thermal and dynamical characteristics of cloud layer over the central part of Guizhou plateau were analysed.It was found that the cloud depth,the existence of warm(T>0℃) layer and the turbulence intensity in mid-upper cloud layer have great influence on supercooling rainfall.The synoptic system and the large scale circulation conditions for long maintenance were also discussed.