Abstract:A brief introduction of World Meteorological Organization (WMO),its purposes,function as well as its service were given.As one of the Specialized Agency of UN,WMO guides and coodinates its member countries′meteorological work by formulating a series of technical rules and regulations,standards,guidances;by seting up some important programs such as "World Weather Watch" and "World Climate Program".China as one of important member of WMO,has made its due contribution to WMO and international meteorological community.WMO′s role is highly recognized which has been guiding and assisting the development and modernization of China′s meteorological work.

Abstract:A probability forecast model of heavy rainfall was constructed by developing probability of precipitation amount (PoPA) and based on probability of moderate precipitation.Step function based on estimating POP in suitable intervals more accurately describs nonlinear probability distribution and closely relates to probability of heavy rainfall.By using predictors transformed into step function and estimating correlation ratio between predictors and heavy rainfall event,the regression estimation of event probabilities (REEP) of PoPA was completed.By using multi time data and NWP products,multi time predictive equations were constructed,and an ensemble prediction that synthesized multi time predictions improved forecast effect.Forecasting tests indicate that the probability forecast model of heavy rainfall is efficacious.

Abstract:Based on the data of daily precipitation for the period from 1951 to 1998 in Dalian,the beginning and ending date of rainy season every year were objectively determined by applying the scanning t-test,and compared with results from the current empirical method.It is shown that the scanning t-test is more objective and exact for determining the beginning and the ending date of rainy seasons.

Abstract:The regression analysis method of non-stochastic process and movable control over the target area was used to assess seeding effect.The target area was determinated by diffusion equation.For assessment effect of cloud seeding for agriculture,contribution coefficient of precipitation to crop production was obtained using integral regression of precipitation.An economic-benefit model of main crop was established.It can be used to assess quantitative effect of cloud seeding.

Abstract:The similar coefficient of meteorological factors between respective samples was calculated,and the correlated characteristic variables representing the relationship between the meteorological factors field and weather phenomena were given through a mathematical model.Using these results as the coefficient parameters,the optimal equation for similar forecast by introducting factors one by one according to fitting rate of forecast was established.An accurate and objective forecast of various elements for all counties was made.

Abstract:A prediction system of severe convection in Shanghai with perfect prediction was recommended.The initial conditions of prediction were based on surface synoptic system of numerical prediction fields recognized with computer,therefore the prediction accuracy was improved.In 1999,the operational experiments were carried out.The results show that the method is capable of forecasting severe convection in Shanghai.

Abstract:The design technology,basic function and application effect of quality control and visual processing system for sounding data were described.This system is not affected by different observatories,and is of good utility.

Abstract:The nonlinear predictors which reflect the features of local weather dynamics could be developed by the system of T106 products,and it can manipulate time internal with superposing method.The correlation could also be built with the mean values and extremes of grid date within the forecast area togather with the amount of precipitation. The predictors and predicatands were all manipnlated with 0,1 nonlinearization.The prognostic equation of precipitation with optimal subset regression was built,and the precipitation probability with multipal factorial probability weighing regression was forecasted. The system was all automated in 586 computer from data collection to output of probobility results.Its forecast conclusion was objective and quantitative,and it became a major tool of objective precipitation probability forecast.

Abstract:Fog is one of the severe weather events in autumn and winter in Beijing,and restrains the diffusion of the pollutant in the air.The air pollution concentration change during heavy fog days in Beijing area and the weather conditions producing heavy fog were analysed.

Abstract:Based on the analysis of climatic superority and weather condition limiting the anti seasonal vegetable cultivation in the eastern Dabieshan Mountain,the safe planting height,seed time and cultivation management of anti-seasonal vegetalbes were discussed.

Abstract:The trend of long-term change in temperature was studied with the maximum,minimum and mean temperature data in Jan.,June and annual temperature data of Lasa since 1960.The results indicate that the temperature warming occurs mainly in daytime in summer and at night in winter.