Abstract:A severe rainfall process occurring in the east of Hubei province from 2000 BST of July 20 to 2000 BST of July 21,1998 was simulated by a η-coordinate mesoscale numerical model.According to the actural rainfall area, the humidity initial field at the level from 850hPa to 400hPa was adjusted.The test result shows that the forecast efficiency is strongly determined by the initial value of the mesoscale moisture at the mid-level and low-level.When the objective analysis on the radio-sounding data fails to correctly indicate the existence of the mesoscale high humidity area,the forecast extremely deviates from the actural situation.But when the humidity field is adjusted in accordance with the actual rainfall area,the forecast efficiency is greatly improved.The simulation effect reveals the importance of using intensive observation rainfall data to improve the initial field of the numerical model especially after the resolution of the model is increased.

Abstract:Using high resolution GMS TBB data and every 6h NCEP/NCAR reanalysis data,the synoptic course of a heavy rain over Beijing on 5 July,1998 was studied.Results show that the convective activity can be developed and maintained easily following the ahead of V pattern low TBB region,and there are two convective activities occurring in western Beijing on 5 July.It is also found that local variation and advective term of apparent heat sources(Q₁) or moisture sinks(Q₂) can not be neglected alone except considering both in the meantime,Q₁ and Q₂ are mostly contributed by vertical advective terms,the heat center of Q₁ is near by 500hPa,while the heat center of Q₂ is about at 700hPa.The spatial and temporal distributions of Q₁ and Q₂ which describe the strong vertical eddy heat and moisture transport during the heavy rain were presented in detail.

Abstract:Hardware and software required to run Vis5D,the main points of installing Vis5D and its major functions were introduced.The typical examples of Vis5D images were given.The method of converting numerical weather models output to v5d format files was emphatically pointed out.The process of using and animating meteorological images produced by Vis5D on MS Windows PC was simply described.

Abstract:Four kinds of approaches were introduced.They are of synoptic pattern,MAPS numerical model,artificial neural network and Japanese numerical model for forecasting area rainfall in the Sanxia region and analyses impact of the experiment during the summer in 1999.Results show that the forecasting effects are better for artificial neural network and MAPS numerical model.Finally improving measures are given for the first three kinds of approaches.

Abstract:All potential subset regression models were used to forecast experiment of the beginning of the rainy season in Yunnan province.The grid point data of 500 hPa and SST during the periods from Jan.to Dec.next before this year and from Jan.to Mar.this year were selected for the influent factors.The factors combined with rainfall at weather stations in Yunnan province were used to built the optimum subset regression model.The model was applied to forecast the rainfall of rainy season in 1998 and 1999.The model forecast accurate is better than the stepwise regression.

Abstract:By using the data of daily water supply,the correlation between daily water supply and the meteorological factors,such as air temperature,rainfall and sunshine,were analyzed.The highly correlative factor,air temperature,was chosen and the simple forecasting model of daily water supply was established by regression analysis.

Abstract:On the basis of the classification of rainy or dry summer,monthly OLR data,observed by NOAA satellite,were used to analyze the convective differences of rainy and dry summer.It is found that the negative anomaly is dominant in winter and spring before wet summer,while the positive anomaly is mainly appeared previous to dry summer in tropical ocean areas.Forecast models were established by using OLR in Jan.and Apr.in four tropical ocean areas,and the models based on Apr.OLR in the tropical west Pacific and the Indian Ocean show better ability of prediction.

Abstract:On the basis of analysis of the satellite cloud picture.combined with routine meteorological information and the products of T106 numerical forecast,the mechanism of a locally sudden torrential rain in Wenzhou area on 4 September,1999 and the characters of meso scale structure about IR cloud atlas and physics field were analyzed.The results about the cause of this locally sudden torrential rain will benefit the operational prediction.

Abstract:By an analysis of some characteristics of the environment physical field of a typical MCC,an important aspect of the environment conditions of the emergence and development of the MCC over the northwest of Shandong Province was revealed.The results show that MCC appears in the air layers of deep and thick high-energy-scale,quasi saturation and latent instability in the northwestern side of the subtropical high,and the middle-latitude short wave trough of 500hPa moving eastward is the initiation system of MCC.The conver-gence stream field of the upper-level jet stream and low-level jet stream play an important part in the emergence and development of the MCC.

Abstract:After the first observation on polarization of rainbow,the features of some atmospheric optical phenomena such as rainbow and halo,etc. were analysed.Fresnel formula can be used to calculated poporization angles.The results show as follows,all kinds of angles are far from the same each other.the main rainbow and minor one are respectively 0.93 and 0.81.The difference between repeated rainbows is also sharp by above 0.75.The 46°halo angle is 0.16,while 22°disc halo′s is only 0.04.There is a certain variation limit for angles of the false solar circle and solar column with incident angle.Rainbow,false solar circle and solar column are reflective polorization,mainly characterized by vibration verticle to incident plane.Halo 46°and disc halo 22°are refractive ones,mainly characterized by vibration parallel to incident plane.In the end,polorization of ″water rainbow″ and ″ice rainbow″ were discused emphatically.

Abstract:A correlation analysis was conducted by using of the historical samples of the routine synoptic maps in winter from 1990 to 1997.The canonical factor fields were selected.The historical samples were used to make model and classification,then the NWP of T106L19 and the average field block distance optimum analogue method were combined to forecast the winter gale in the Yellow River Delta.The objective and automatic system of gale forecast was presented.

Abstract:Since mesoscale numerical model MM5V2 is on the upgrade and more and more data provided for mesoscale numerical model,the system of mesoscale numerical model becomes a major means in forecasting disaster weather.The characteristics of MM5V2—model initiation and model forecast,were summarize,and some meaningful study results for the development of mesoscale numerical model were presented.

Abstract:An introduce to origination and development of the ultraviolet prediction abroad and the methods,service contents and trends of the ultraviolet prediction in U.S.,Japan,Canada and so on.