Abstract:Superposed-epoch analyses of drought/flood index in China for the past 500 years show substantial differences in spatial pattern and temporal evolution of the drought/flood with respect to low and mid-high volcanic eruptions. Drought events might appear more frequently in the key years (that is, eruption years)in North China,while significant rainfall anomalies might ocuur with great probability only in the following years. Finally,it is inferred that there would not be direct . ralationships between both eruptions of Pinatuebo in the Philippines and Unzendake in Japan and the extraoridinarily catastrophic flood in Changjiang-Huai river valley in summer of 1991.

Abstract:We had established an acidic deposition network including 70 sites in Guangdong and Guangxi provinces and had done routine monitoring work on dry deposition and wet deposition simultaneously from January, 1988 to December, 1989. The results showed that frequency of acid rain was rising and was distributed along main wind direction from north to south in Guangdong and Guangxi provinces. The acidity of rain water was the most acidic and acid rain occured most frequently during spring season. The chemical composition of rain water were mainly Ca2+ , NH4+,SO42-. The average ratio of SO42-/NO3 -was 2. 7 times larger than that of the United States. The chemical components in rain water were mainly sulphate and it indicated that the acid rain in Guangdong and Guangxi provinces was caused by air pollution from coal burning.

Abstract:A number of vertical line sources was generally caused by catalytic agents, dispersed from falling pyrotechnical flares of an airplane or a rocket. With the gradient-transfer theory of turbulent diffusion, we present a ther'otical model of agents diffusion of vertical line sources in supercooled stratiform clouds and, we give a calculative formula of superposing effect of agents' concentration of numerous vertical line sources, which were perpendiculor to the direction of horizontal wind or were parallel to the direction of horizontal wind.

Abstract:With FTIR spectroscopy and absorption cell infrared transmittance of CH₄ has been measured. Using FASCODE 2 program the transmittance of CH₄ has been calculated and compared with measurement.

Abstract:Using the Combined Confidence Weighting Forecast method introduced by Tsui, T. L. , six kinds of objective forecast of different performances are tested in 3 forecast arears individually. The results indicate that the final combined forecast is more advanced than the each one of the six kinds of forecasts.

Abstract:The distributions of the water resource in the air under conditions of various synoptic patterns in the drier duration in Summer are analysed. An Approach to the physical conditions for artificial precipitation in each arid area is made.

Abstract:Seven cases of storm rainfall, seven cases of ordinary precipitation and seven cases of fine weather events are chosen. The thermodynamic, the dynamical characteristics and their differences of the three kinds of weather events are comprehensively analysed,as a result,the short range forecasting models are obtained.

Abstract:A free-oriented vertical cross-section with spherical trigonometric function is suitable to nu merical analysis in meteorological applications. It was shown that employing the scheme developed, the vertical structure of synoptic system can be exactly represented on the vertical cross section.

Abstract:Based on the group-after-group sowing experimental data of 1990 and 1991 ,the photosensi tivity and thermosensitivity of the direct seeding rice in dry land and the relations between the percentage of the inperfect grain and the factors of illumination and temperature are analysed. And also some agrometerological problems such as the best time for safe sowing,the best time for safe head sprouting, arid ect. are resolved according to the local climate. All these results could provide scientific basis for further popularity of the direct seeding rice in dry land.