Abstract:The current development of weather forecast technigue in the United States was presented. It is suggested that it is the technological development of the atmospheric probing,the numerical weather forecast and the visualization that impels the conventional weather forecast in the United States toward quantization and timing. The realization of quantitative precipitation forecast is an important mark of qualitative toward the quantitative weather forecast. On the basis of making the best use of the numerical model products,composing satellite and radar data,the method of the objective forecast is established. It makes a good effect on the forecasts of heavy rain and severe convective weather. The advancing of mesoanalysis of operational forecast system improves obviously the forecasting skill of precipitation. The interpretation of numerical weather forecast product and the operational forecast system in the United States are presented. Finally,the inspirations drawn for China's weather forecasts have been put forward.

Abstract:The qualitative concentration period of precipitation was quantitated in time and rainfall by using daily data. General equations of concentration period and concentration degree were formed. A single station flood index was given relating to precipitation concentration period,concentration degree and flood level. On this basis,precipitation concentration period,concentration degree and the flood index in Xinjiang River basin were determined. Finally,the forecast experiments were made with the flood index in the basin.

Abstract:The influence of the climatic variation of rainfall on the evaluation of precipitation enhancement effect was analysed. The results show that the evaluation of precipitation enhancement effects is influenced by the climatic variation of rainfall. In the abundent rainfall years in Fujian Province,the positive false effects are obtained,and in the lacking rainfall years,the negative false effects are obtained. The false effects of sequentail experiment are higher than that of other ones. The multifactor gradational experiment decreases the influence of climatic variation of rainfall on the evaluation of the effects.

Abstract:The spatial distribution of tropical cyclone precipitation shows that the heavy torrential rain caused by the landing northward tropcial cyclone occurs concentrately over the northwest of North China flatlands and the southeast of the Shandong-Liaodong penninsula. The comparative analysis was made and the result shows that the formation of the two heavy torrential rain areas aparted so far away were mainly realated to the position of the subtropical high in the preceding stage,the track of the landing northward tropical cyclone and the distribution of the physics fields except for the orography effect. At last,the indices and methods for forecasting these two types of heavy torrential rain were given correspondingly.

Abstract:A convective storm moved from east to west over the Bobal Gulf on May 20 1998 was analysed. Its features were discribed and the reason was discussed.

Abstract:The reasons of continuous heavy rainfall over a large area in South China in June 1998 were analysed using black-body temperature (TBB) data from GMS. The results show that such heavy rainfall is caused by the stronger cold air coming from northern China and frequently dominateds its merger with weaker southwest monsoon: The TBB dekad mean and anomaly fields could directly and quantitatively present the features and causes of the intensity and distribution of the cloud system with heavy rainfall.

Abstract:Using the GMS-5 multichannel data by the CMAPPS,high resolution image processing system in Shandong area was established. The structure,functions and-features of the software system were described. The key technologies including the GMS image position,sampling of infrared data and overlying of regional geographical information were discussed. Using the software system,the GMS image pictures in Shaddong area were processed. The result shows that the pictures are clearcut,and they are of high quality.

Abstract:A method composing the background factor of haevy rain forecast by using of scuding data was described. Some forecast factors of heavy rain were suggested after statistical analysis. These factors are of not only higher correlation but also of clear physical meaning for heavy rain forecast.

Abstract:Based on the 634 times of sounding data at 9 o'clock in June,July and August from 1971to 1978 at the hail suppression site in Yongdeng,Gansu province,the classification of weather phenomena and the surface observation were analysed. The results show that the height of 0'C dew-point temperture is an indicaton of halfday and the dew-point depressions at upper levels are of the signification representing the hail intensity. These indicators provide a reference for hail forecast.

Abstract:A major motivation is to diagnose the objective analysis results of different resolution numerical models through some methods and to compare the qualitative difference of the model analysis in NMC. The results show that it is obviously different that the analysis results of the medium-range numerical model in NMC have been carefully compared with that of ECMWF. The regions of the more obvious difference are near the Poles,the QinghaiXizang-Plateau in China and the Pacific Ocean area. On the other hand,the comparison of the objective analysis results between T106 and T63 model indicates that T106 is better than T63 for higher resolution.

Abstract:The observation data of 850 Farms in Heilongjiang province were analysed. There is drought in May and June,the period is a crucial stage of wheat needing water,corresponding wheat seedling to booting stage. The experiential formula was suggested to forecast soil moisture with the application wheat field measurement. The optimum irrigating time and amount were determined.