Abstract:Heavy fog occured for five successive days from Dec. 27 to 31,1996. Using a drop size meter and ADAS,soundings of microphysical structures of radiation fog and soundings of vertical distributions of some related meteorological elements,such as temperature,pressure,moisture,wind and so on were conducted. By analysing these data thoroughly,the microphysical structure characteristics and evolution processes of radiation fog in Huning region were discovered. Results suggest that there is a close connection between the microphysical structures of fog and the degree of air pollution,and a long lived inversion has an effect on the former. Furthermore,quasi periodic oscillations with periods of 20～30 minutes are observed in liquid water content,spectrum width,and peak diameter etc..

Abstract:The torrential rain over the southern Haihe river basin during August 1996 (‘96.8’ event) was analysed by using real time observation,T63 model and satellite cloud picture data. The results are as follows: the ‘96.8’ event occurred in the circumstance of the sub tropical high of continual two times northward jumpping and a strong meridional circulation in the sub tropical area,the sub tropical high,typhoon 9608,mid and low level jet and low level weaker cold air from the Northeast to the North China Plain co operated to generate a stable cloud cluster of the rainfall,the developing MCC over the southern Haihe river basin brought about the continuous torrential rain.

Abstract:Based on the centenary rainfall data in Beijing and El Nino event data and Un El Nino event data (include La Nina event),the relation of the torrential rain and El Nino event was analysed. It is shown that (a) the flood period emerge drought and the number of the equivalent torrential rain day is less than four at the maximum effective year of El Nino event,the flood period emerge flooding and the number of the equivalent torrential rain day is more than four at the maximum efective year of Un Elnino event. (b) the number of the equivalent torrential rain day increases relatively in the next year of the Maximum effective year of El Nino event or next maximum effective year of Un El Nino event. The number of the equivalent torrential rain day reduces relatively in the next year of Un El Nino event or Next maximum effective year of El Nino event.

Abstract:The synthetic method and system structure of grain yield forecasting were introduced. The system includes some forecasting models,such as meteorological,socioeconomic and the synthetic of both. Historical fitting and forecasting effect of three different models were analyzed by studying some cases. The result shows that the synthetic model is better than unitary model,but improvement is still needed for operation.

Abstract:The method of drawing Emagram pattern with microcomputer was introduced. Two parameters of energy connecting to atmospheric convection were given,which including CIN,CAPE . Two real cases were analysed,and the scheme of calculation for convective energy was discussed.

Abstract:By dividing Summer rainfall in Sandong province,the teleconnections between precipitation in each divisions and the circulation characteristicts in and before summrs and the sea surface temperature are studied by means of correlative analysis. The results show that the correlations between summer rainfall and circulation characteristics and SST are significant. Based on the above analysis,the factors are selected,and the prediction models of multidimension mean generation function are developed. Finally,the summer rainfall tendencies before the year of 2000 in each division and the whole province are given.

Abstract:The hydrostatic model of MM5 is nested to the global spectral model of NMC. It is compared with three lateral boundary conditions on prediction quality of surface elements of 27 observational stations in east China in March 1997. It is shown that effects with different lateral boundary conditions on prediction quality are fairly difference.

Abstract:The severity of drought/flood is divided by Z index in flood season in Lhasa,Tibet. Then the correlation between 5mm and over precipitation equivalent days and the drought/flood severity was studied. Results show that the severity which determined by Z index tally with the facts. The 5mm and over precipitation equivalent days not only indicate the precipitatiion in flood season but also express high correlation with drought/flood severity.

Abstract:By checking the predictions of various types from the mean generating function time serial model,it is discovered that the mean generating function model is able to give satisfactory results,not only to the statistical values of observations (e.g. yearly or monthly means),but also to the instant values of observations (e.g. max temperatures),not only to the smoothly varied variables (e.g. temperature),but also to the violently changed variables (e.g.sunspot). Some methods to improve the mean generating function model are presented also.

Abstract:The analysis was conducted for two winter thunderstorms on December 21,1990 and December 31,1996 in Shenyang,Liaoning province. The results show that the two winter thunderstorms were due to cyclones explosive developing in short time. The explosive developing cyclones cause both large range of snow in northern area and strong convection weather. Cyclones moved along the path as the letter "U",got into Bohai sea and developed quickly. 850 and 700 hPa high explosive warming and explosive wetting caused potential instable stratification occurrence,they are the key to the winter thunderstorm forecast. In addition,urban heat island effect is very important to trigger off the winter thunderstorm.

Abstract:Through germination test,the germination percentage,germination potentiality,and germination index of 3 corn varieties of early,middle and late maturity in Northeastern China under dark conditions with 4℃,8℃,13℃,17℃,21℃ and 25℃ were studied,and the germination critical temperature for 3 varieties were given. The results show that low temperature inhibited seed germination and reduced germination ability. The germination critical temperature of 3 varieties are 3.2~5.2℃. The lower of germination critical temperature,the more powerful of seed germination resistant to low temperature. The rare earth treatment has the role of raising corn seeds germination percentage and promote germination.

Abstract:Using the data obtained by Midu County Popularization Center of Agricultaral Technique for many years,the relationship between the prevalence of leaf withering disease for a winter early species of garlic and meteorological condition was analysed. It was found that the disease damage is related to planting raea,growing year,seeding time,precipitation event and sunshine duration. The countermeasures preventing the disease were suggested.