Abstract:In recent years, it has been recognized that changes of long-range weather are related with the fluctuations of the earth rotational rate. The achievements in domestic and overseas research of relationships between changes of the earth rotational rate and variations of longrange weather since 1980s are reviewed. The effect of changes of the earth's ratation rate for long-term weather chang and it's possible mechanism are summarized and analysed from different aspects.

Abstract:A brief introduction to a new advance in the NWP field: unified global NWP models with variable resolution is given. The principal purpose is to decrease the calculation cost of the NWP by unifying the limited area NWP model and the global spectral NWP model as an only operational one. A horizontal resolution, and a semi-implicit and semi-Lagrangian integration scheme were used in this unified NWP model. The French unified model went into operation in 1992. The results were very encouraging !

Abstract:The analysis is made for the relationship between the water resource in Beijing Tianjin Tangshan area and the summer precipition over the forty stations in the Haihe river basin and the Luanhe river Basin. It shows that interannual changes of water resource and precipitation are often in coincidence. The precipitation over the middle and lower reaches of the Luanhe river, the basin of the Yongdinghe river, the upper reaches of the Daqinghe river and the basin of the Fuyangxinhe river have important effects on the water resource in this area.Therelation equation of water resource and the precipitation over the important area has been made,the multiple correlation coefficient is 0. 96. The water resource in this area obviousely decreased decade by decade, especially the inflow water decreased extremely under the influence of climatic change. This suggests that we should pay more attention to this problem.The forecast methods for water resource in this ares are studied. It is shown, the south branch of winter jetstream in Asia and the sea surface temperature(SST) in the eastern equatorial Pacific may be used as reliable forecast parameters for the water resource, and theforecast equations are made by these parameters.

Abstract:The progress in studing fogs is summarized and the relationship between fog and air pollution is discussed from the acidification of fog water in polluted air, the deposition of air pollutants within fog layer, the scavenging of fog to air pollutants and the effects of air pollutants on formation or evolution of fogs. The author shows that fog events should be noticed in assessing or predicting air quality.

Abstract:Statistical analysis of the conditions of severe convective weather events,suggests that variable domains of its physical parametres,such as temperature,humidity and stability, are large. And its explanation is given.

Abstract:In June,one-fifth of the heavy-rains appeared at 700hPa under the situation of norther air flow over Wuhan and Changsha. The main quantitative factors and rainfall-class prediction method under stable shear situation are given.

Abstract:The improvement of Eurasian 500hPa ten days average prognostic eqaution has been improved with NWP product, besides the spatial-temporal scale, predictions among grid by grid correlation from Eurasian to the northern hemisphere,the climate geographical distribution of the long-wave weather system and the methods of teleconnection analysis etc. were chosen for the critical region, to construct new prognostic equation. A comparison betweenthese two prognosis, the forecast accuracy of the new prognosis was improved respectively,0. 15-0. 20 and 0. 10 on forecast height and position of the long-wave weather system.

Abstract:Physical quantities are calculated with ECMWF data of the wind fields at 850hPa and at 200hPa, and then, the forecast equation is established for the forecast experiment of Jianghuai regional torrential rain. The valuable results were obtained from the day-by-day test in Jun and July, 1993.

Abstract:The principle of Kalman filter (KF) and the recursive algorithm of KF are introduced from the view point of meteorological applications. In order to describe the application of the recursive algorithm of KF, a daily minimum temperature up to 36h ahead has been made for Beijing city for the period from 1 to 30 Jan. 1993. The results are satisfactory and approve that the method of KF is mostly practical. The advantages of KF compared to that of MOS method are that one do not have to collect large historical data. So KF will adapt easily to numerical weather prediction model changes.

Abstract:In order to master the law of drought or flood in the middle and lower reaches of the Yarlung Zangbo river, the relationship of the major factorsof the field water balance,precipitation and evaporation, is discussed, the potential maximum evaporation, the surplus and deficiency of moisture are calculated. The distributional maps are given.

Abstract:Hail suppresion experiment have been conducted in Shangqiu area, Henan provice for three years (1990- 1992). Data of the historical thundstorm and hail damage areas in the experimentcal period were applied to the analysis of the results. It is shown that the hail damaged farrnland was decreased by 0. 48 million Mu per year. The ratio of investment to benefits is 1:25. All experiments have obtained financial support from the insurance companys.