Abstract:The features of the large scale circulation which creates East Asia low-level jet in winter and the relationships of the low-level jet and heavy snow or snowstorms in Inner Mongolia are analyzed.The results show that when there is westerly upper jet in middle latitudes and if the cold low pressure trough in central Asia moves eastward and split in two ones,the East Asia low-level jet which causes heavy snow or snowstorms in Inner Mongolia will be created easily.It is pointed out that the process of adjustment of the westerly belt-large scale circulation could be a sign of the middle range prediction of heavy snow or snow storms in Inner Mongolia.

Abstract:Climatic characteristic and changes of snow cover over the Northern Hemisphere,Eurasian,North America and the Tibet Plateau are studied based on data of the Northern Hemisphere snow cover from 1966 to 2000.Correlation analysis shows that:(1) a inverse relationship between winter snow cover over Eurasia and monsoon rainfall over India,and Indian monsoon rainfall is not only influenced by snow cover over Eurasia,but also by ENSO.(2) there is an obvious relation between snow cover over the Tibet plateau during October to November and the following onset and rainfall of Indian monsoon,and the possible effective mechanism is proposed.

Abstract:The concept of bistatic Doppler weather radar and its application to wind observation in precipitation systems are introduced.The bistatic radar can measure the radial velocities in different directions simultaneously with less expense and maintenance.The data from bistatic radar can be used in analyzing the three dimension wind in precipitation system.But the bistatic radar has a short range coverage and is sensitive to contamination from transmitter sidelobes and secondary scattering from weather echoes due to the passive and low gain antenna.In addition,the radar needs rigid frequency and time coherences.The bistatic radar technology is a potential tool in meteorology.

Abstract:Based on the data by a single Doppler weather radar 3824-C,the characteristics of the echo of measoscale systems, including low-jet, warm advection,warm shear,cold shear and contrary wind area during a rainstorm are analyzed.It shows that these mesoscale systems are obvious signals for rainstorm feature.

Abstract:The performance tests for the hailpad made by polystyrene material were done in laboratory. From 1988 to 1998 hailpad were used in the field obsevation for sampling hailstones. It was showed that the hailpad almost could not absorbe water and but could stand wind , rain and sunshine in out-door conditions.The polystyrene material was uniform and its elasticity was small .The hail trace size on it was used to estimate the real size of hailstone and the average errors were from 4.3% to 12.2%. Therefore ,the diameter and number density of hailstone could be measured accurately.

Abstract:Based on the basic conditions of surface influence system and of the southwest jet at 700hPa,40 rainstorms in June-Augest from 1983 to 1999 in Qingdao City are classified into three patterns with the method of the synoptic dynamics and statistics:cyclone,typhoon and cold-front.According to the prediction experience,a 0,1 weight equation is obtained to forecast the rainstorm at Qingdao City in summer.For an example,the accuracy of cyclonic rainstorm is 46/59(78.9%).

Abstract:By using the forecast score(P),skill score(S) and anomaly correlation coefficient(A_CC),it was evaluated for the short-term climate forecast results of monthly/seasonal/annualy precipitation and temperature in Chengdu Regional Meteorological Center.And the results are also analyzed.

Abstract:Affected by the outside of the typhoon 0012 (Prapiroon),an unprecedented heavy rain process,with the character of locality,intensity and abruptness,occurred in the northeast of Jiangsu from 0800GTM 30 to 0800GTM 31 August.The analysis indicates that the stable easterly stream provided by the second quadrant of the outside of the typhoon and its disturbance constitute the mesoscale easterly stream convergence line synoptic system which results in heavy rain.The high frequency quasi east-west and quasi south-north distribution of the mesoscale easterly stream convergence line and their substitution is in agreement with the high-frequency area where rain mass with rainfall≥10mm occurs.The analysis on the surface velocity advection divergence (F) shows that intense rain mass nearly accord with the severe center with F≥0,in other words,intense rain mass explodes in Xiangshui and its vicinities where convergence strengthens or intensively maintained.The results by further analysis and statistics suggest that the changes of the surface velocity advection divergence is closely associated with the maintenance of intense local rain mass and the reinforcement of rain intensity.

Abstract:Based on the meteorological data in recent 40 years, the long term changes of sandstorms in Xinjiang are analysed.The frequency and influence scope of sandstorms occurred in Xinjiang both have the reducing trend in 1990′s. Meanwhile with the climate calefying the wet trend was obvious.By comparing the long-tem changes of climate and sandstorm,It is found that there maybe some synchronous connections between them.

Abstract:Precipitation data were obtained with GBPP-100 produced by PMS Co.in Harbin from May to July, 1999.Nine times stratiform clouds precipitation data are analyzed with the obtained several constructive results about distribution of raindrop size, microphysics parameters and its fluctuation features.

Abstract:Meteorological indicators of high and low bean yield are investigated by regression mode based on the data from 1971 to 1995 in Heilongjiang Province. The indicators show better forecasting ability of bean yield in the region.

Abstract:The meteorological conditions of mildewing,the climate characteristics of temperature,relative humidity and vapor pressure are analysed.Then,the calculating formula and mildewing index seek-table was designed.The forecast model of mildewing index was described and was used in decision-making service system.The forecast accuracy of the operational experiments in five months is 97.4%.