Abstract:Four field programmes conducted in recent 5 years were reviewed.These field experiments were selected since they were designed to address the prediction problems of severe weather systems,such as torrential rain/flooding and strong winds. The concept of targeted or adaptive observation was established and tested operationally during the field experiments. The important improvement could be expected in the disaster weather prediction as the results of these field experiment, during which advanced sensors from different platforms with high spatial and temporal resolution recorded a lot of details of the truths in atmospheric movements that may not be properly understood yet. And even more, almost all these details collected in these field programmes could be shared through Internet.

Abstract:A substantial review on the results and application of the carbon isotope in tree ring to meteorology was presented,along with a prospective study in this filed.

Abstract:The disaster characteristics for East China caused by tropical cyclones in 1949—1999 were analyzed.By using numerical statistical analysis and quantitative calculation,the disaster index was built along separate routes.And on this base,objective damage assessment for TC was also given.A contrast testing with Suffir-Simpson index of TC was made using an independent data set.Finally,an assessment method for tropical cyclone disasters was given.

Abstract:The dust storm is a disastrous weather phenomenon which often occurs in spring in the Northwest of China and is difficult to forecast. Firstly, a synoptic concept model about its happening was developed.According to this model, a numerical forecasting method was designed by means of the calculation of the PBL regimes(stable, mechanically driven turbulence, forced convection and the free-convection regime) and friction velocity.The rationality is shown by a verification on the model with the PSU/NCAR numerical model MM5. Finally, a flowing chart of short-range forecasting method ,which combining the synoptic principle and numerical forecasting technology,was given.

Abstract:By using MM5 nonhydrostatic mode,a numerical simulation was made successfully to a northeastern vortex and shear caused rainstorm occurring from August 8th to 9th in 1998.The numerical simulation revealed follow results:the strong divergence formed in upper air lead to the strong precipitation center in the northwestern part of the low vortex,the shear formed by convergence of the southerly jets with the easterly ones also contributed a lot to the precipitation,ascending motion with the shear was apparently lower than one with the low vortex.Meanwhile,the contrast test shows that the southerly jets play the most important role in transporting water vapor to the precipitation area.The weakening or strengthening of water vapor within the southerly jet zone had a direct impact on the precipitation,especially to the shear caused precipitation.The strenthening of westerly cold air made the baroclinic function become stronger,further lead to the enhancement of both the low vortex and the precipitation.While the southerly air current was detained by the easterly cold air,which resulted in the ascending motion and influenced on the shear intensity and its resultant precipitation.The blocking high made an obstruction to its upsteam low-pressure systems and influenced both their position and intensity,thus had further influence on the precipitation.

Abstract:The method and operational flow of monitoring large-scale drought in Yunnan by using NOAA/AVHRR data are presented.Meanwhile key problems,such as index of distinguishing drought,method of area estimation,identification of crop drought and derivative of image product,were discussed.According to detailed analysis on monitoring product in the spring of 1999 in Qujing region,it was proved that using satellite Remote Sensing technique to monitor area, degree and allocation of large-scale drought is available in Yunnan.

Abstract:By using of the climatic rule and the condition of agricultural production in Longnan,the index figure of floods or drought used to judge the guantitative character of floods or drought in hot summer was ascertained.Based on the index figure from 1967 to 1996,with EOF analysis,the regions of floods or drought in hot summer in Longnan were divided into different parts.By analysing the character in these parts,the prediction model of the mean generating function method was established.

Abstract:The feature of satellite image and radar echo of the severe convective weather process occurring in the mid-west part of Inner Mongolia under the cold vortex system influence was analysed.The scientific base was provided for the read-time monitor of the mesoscale convective weather and cloud seeding activities for hail suppression.

Abstract:Based on the GMS-5 imagery and weather data,a severe convective storm on 9 August 1999 was analysed.The results show that (1)the brighter area in the moisture image is in the upper troposphere with higher moisture.It is one of the criteria in prediction of storm occurring area;(2)the coincidence of brighter area in moisture image with higher potential pseudo-equivalent temperature (θ_se) is an important physical factor in the occurence of a severe convective storm.

Abstract:With application of Singular Value Decomposition (SVD) and statistics method,the study was conducted on the time and space structures and the co-relationship between the Guangxi precipitation from autumn to next Mar.and the 500hPa height field and tropical,north Pacific sea surface temperature field.The results show that the first coupling field clearly reflects the ENSO signal with high correlation,and the second ocean-atmosphere coupling field reflects the good negative correlation between the sea temperature in the east of Japan Sea to be the key area and 500hPa height over the east of 100°E.The sea temperature-height field variation from 1998 was analysed,the 500hPa height field in the mid-high latitude of north Pacific is clearly below normal,and above normal in Asian continent and in the mid low latitude of north Pacific,which attributes to the significant weakening of the eastward cold air.The variation of ENSO in the sea temperature field and the La Nina developing process conform to the sea temperature variation modality of the first coupling field.The later period ocean-atmosphere variation conforms to the second coupling field of the sea temperature and atmosphere.It is concluded that the variation of ENSO and temperature ascent in the east of Japan sea favor the formation of abnormal circulation pattern which is the origin of the south China extraordinary drought at the end of this century.The quantitative monthly precipitation forecast in Guangxi from Aug.1998 to Mar.1999 with SVD method was presented.

Abstract:Based on the analysis of the relationship between vegetable and meteorological condition,the regression equation to guide the Beijing vegetable carriage by temperature (T) and relative humidity (RH) was derived.The results show that the T and RH exist the daily change and it′s suitable to carry vegetable in winter afternoon and summer morning over Beijing,while it′s best in spring and autumn.So Index of Vegetable Carriage is useful to city vegetable carriage.