Abstract:It is pointed out that two principal motivations exist for formulating and expressing weather forecasts in probabilistic terms,that is,the human's deepening cognition of the stochastic nature inherent in weather and climate change,and the increasing need for quantitative and precise decision-making in socioeconomic activities. The relation between probabilistic forecasting and meteorological economic decision-making is briefly discussed. Finally,a decision-making model is given to demonstrate that the economic value of probabilistic forecasts generally exceeds that of categorical forecasts.

Abstract:It is worthy of regarding for us to understand that the active front accompanies with thunderstorm and strong wind,even hair,which endangers the agricultural products,while the active front passes Taiwan. The structure of vertical and horizontal active front was analysed preliminarily by using radar information and weather data on 19 April 1992.

Abstract:A computer retrieval system for the in formation of meteorological science and technology was first established and put into the operational use in the Information Institute of the Chinese Academy of Meteorological Science in 1995. The main content includes the composition and charicterastics of the retrieval system,two CD-ROM data base operated in the system and the method of their use,and the resources of on-line retrieval. Finally the way to obtain the meteorological information by Internet is briefly described.

Abstract:The three model fields of Atlantic-Europe circulation pattern W,C or E at 500hPa are obtained from historical data,and W,C or E circulation pattern for any day can be determined according to the minimum of Euc-distance between the given field and the model fields. Additionally,the points that minimum height value is located at are found for all parallels in the given region and smooth mean longitude and mean height for those points can be regarded as the position and intensity of the East Asia trough. This work will make the evaluation of physical parameter of the general circulation more objective and automatic.

Abstract:Based on the facts that the earth is getting warmer and the meteorological observing station's air temperature is increasing rapidly,the climate warming and urban heat island effect of Shenzhen city are studied,under the conditions of the rapid changing of observation environment and the absence of a compared observation after Shenzhen became a big city. The results indicate that the climate warming and the urban heat island effect are of seasonality obviously at Shenzhen. There is a difference between day and night,and far more obvious at night than day.

Abstract:Using the drought data about 500 years,drought disaster in agriculture,industry and environment are analysed. The periodicity and phase of drought and flood are studied by the use of power spectrum and fuzzy discriminate analysis. The evolution of drought and flood is given.

Abstract:Tropical cyclone belongs to tropical synoptic system. It has plenty of vapor sources because its generating location and life cycle are mostly over oceans or sea. But in the moving process,as the ambient field was changing,there is unlikely heavy precipitation in the areas affected by tropical cyclone. By way of introduction of the conception of dry and moisture tropical cyclone and selection of the three typical examples,the contrast analysis of their synopic situation and physical field is conducted.

Abstract:The method of using the underlying surface temperature from the forth channel data of AVHRR to monitor the drought in centeral Sichuan Province is described,and some interesting results are obtained. The underlying surface temperature is much linearly interrelated to the drought index,and it's spacial distribution is almost consistent with the condition of drought.Through comprehensive analysis of the underlying surface temperature from remote sensing,realtime surface observations,observations from agriculture meteorology,and information from the drought,it is possible to monitor the trend of a drought for large area in real-time.

Abstract:Based on the parameterization rules for closure,an algebraic stress model was prepared for canopy flow. The simulation results of the model are compared satisfactorily with that from the wheat and corn field.

Abstract:The main studying objects were the severe rainstorms which had happened since 1980's and aroused grave mountain torrents and mud-rock flows in the mountainous area in Liaodong peninsula. The formation reasons of severe rainstorms were inquired in suitable disposition and interaction,environmental conditions and physical mechanism for weather systems of large,middle and small scales,at high,middle and low latitudes and altitudes. It was shown that there is no obvious difference in thermal condition between the severe and normal rainstorms,and both need quasisaturated atmospheric layer resulted from the transportation and convergence of low altitude warm and moist air. The most remarkable feature is the dynamic condition of the violent vertical upward motion caused by the superposition of the violent convergence in the low level and the divergence in the upper air.

Abstract:The micro-physical structure of precipitable stratiform clouds are analysed in the westerly trough system over the central and south parts of Hebei Province on April 16,1991. The results indicate that the development of precipitation was carried out mainly in the stratiform clouds in the middle and upper levels. Although there are favorable conditions for ice crystal growth i.e. the catalyzables of supercooled area and water. The development of precipitation is disadvantageous due to the thin water supply clouds and the high cloud base. After the aircraft seeding operation,the micro-structure of the clouds has been varied (the water content of cloud droplets and rain droplets increased obviously. There is an evident expanding in the droplets spectrum. etc. ),the precipitation capacity increased in the area of seeding operation and influenced area within the effective period of artificial catalysis. These results are in agreement with the clouds modification.

Abstract:The 96-,120-,144-,and 168-hour forecast capabilities of T63L16 NWP model for East Asian troughs and surface cold highs which occured from January to April in 1995 are verified.The results show that the model is of strong capabilities for cold air medium range forcast.

Abstract:The model of forcasting the production of wheat and barley by the weighting method of Limit production is developed based on the production of barley and wheat,agricultural technology and weather data. The model is:>y=y_M-y_农-y_灾-y_气 or y=y_M[1-(∑a_i+∑b_j+∑c_n)] It is adopted to forecast the production of barley and wheat in the Yancheng area. Experimental forecasts in the past suggest that the error of the model is less than 5%.