Abstract:On the basis of the theory of multi-equilibrium of the atmosphere proposed by Charney and Devote(1979), anumerical model for predicting the departures from the monthly or seasonal normals of geopotential heights at the 500-hPa level is constructed. The results show that this model has certain predictability for weather systems of longer life-spans. Several predicted cases are analysed. Problems about the model are discussed and approaches for further improvement suggested.

Abstract:On the basis of the parameterized form of the Fraedrich’s zero-dimension energy balance model, a stochastic model of global temperature variation is constructed, the solution of which is found to be a red noise process. The correspondence between the computed spectra by the model and the observed ones of annual mean temperature anomalies in the Northern Hemisphere from 1881 to 1980 is statistically examined.The result shows that the proposed stochastic model can be used to calculate the characteristic statistical features of temperature variation, such as mean values and variances, of the Northern Hemisphere.

Abstract:A numberical model is developed, based on a large amount of observations of diffuse radiation taken at various sites in field experiments over rugger terrain. Three main problems are discussed: Computation of diffuse sky radiation toward a tilted plane; effect of protruding topography; and the amount of radiation reflected by the surrounding high ground to the slope in question. Finally, an analysis is made of the distributive characteristics of diffuse radiation over the southern section of the Dabie mountain range, showing good correspondence between the field of diffuse radiation in this rugged area and its topographic field. It is found that a more important role is played by the facing of the slope in winter but by the shading effect in summer.

Abstract:A non-hydrostatic numerical model is constructed for mesoscale studies,buoyancy equation being introduced into the model to reduce computational error of buoyancy. Control tests to verify the capability of the model to simulate the development and maintenance of the mesoscale circulation processes have been conducted. Characteristic features for generating and maintaining mesoscale systems are shown by the model qualitatively. It is found that. for more complex mesoscale systems, the development of the initial purturbation is related to its dynamical and thermodynamical structures but the maintenance of the systems relies more on the instability of the atmosphere. It is also found that computing stability is sensible to initial conditions.

Abstract:The effects of the basic current are considered. By means of the WKBJ method, the dispersion relation and the energy equation of the nonhomogeneous internal inertia-gravity wave are obtained.Case study of June 26, 1981 shows that the area of heavy rainfall corresponds to the possitive maximum of the wave energy and that the southern boundary of the rainbelt coincides with the zero line of mean vorticity for the layer between 1000hPa and 500hPa.

Abstract:With the aid of the relationship found between the features of fields of precipitation anomalies in adjacent geographic regions, an interpolation model for precipitation of 42 stations in china is established in terms of the empirical orthogonal function. Evenly distributed, continuous sequences of precipitation in the period 1881—1981 are thus obtained. By solving the empirical orthogonal function for annual and seasonal precipitation departures, it is found that the alternative appearance of belts of positive and negative departures is the basic pattern for precipitation distribution in China.The principal components of annual and seasonal precipitation amounts for all 42 stations show no apparent long-term trend. Statistically significant periods foundby the analysis of variance spectrum are concentrated in the cycles of 35, 4.7 and 2 years.The cycle of approximately 4.7 years may be related to the Southern Oscillation. In addition,the amplitudes of mean precipitation departures are seemingly linked with the 11-year sunspot cycle.Near the year of maximum soiar activity, the frequency of drought or excessive rain increases notably.

Abstract:Along with adiscussion on the application and the statistical processing of albedo data, factors influencing the value of surface albedo and its areal and temporal distribution over China are analyzed, data being available from 60 actinological stations. Two empirical formulas for estimating mean monthly albedo, taking into account snow cover and temperatures respectively. Mean albedo charts of China for significant months representing the four seasons are constructed, with the characteristic distribution of types of soil and vegetation being considered.

Abstract:The growth of rice and its yield formation are closely relatied to the environmental factors. An attempt is made to link the growth of rice organically with its environmental factors through the physiological processes of photosynthesis and respiration so that the growth process may be described quantitatively. The model incorporates the accumulation of dry matter, the dynamic variations, of photosynthesis, respiration and leaf area. Satisfactory results are obtained in the simulation though room for improvement remains.

Abstract:The assemblage, design and functions of the system are introduced. Information of more meteorological elements may be derived from the cloud image data when this system is put into operational application and hence value of the cloud data is greatly increased.

Abstract:An automatic system to control the radar antenna for the Constant Altitude Plane Position Indicator is constructed. It consists of a step motor, a microcomputer and a radar servo system. This automatic system operates at high speed with precision and can nimbly alter the rising mode of the elevation. After making a slight modification, the system is applicable to automatically control the azimuth angle to suit the need of other types of indicator display.

Abstract:It is shown from the analysis that the interaction of the systems of various scales may lead to the growth of vortex disturbance and the intensification of the low-level convergence as well as the jet stream. Diagnostic investigation is conducted on the development of baroclinity, large-scale ascending motion and changes in the thermodynamic structure.

Abstract:Based on the records from 1951 to 1980 for 130 weather stations over China the characteristic features of areal and temporal distribution of standard deviation of monthly mean air tempeeatures are investigated. In addition, the relation between the variation of this standard deviation and the position of the climatic frontal zone is also analysed. It is found that the area of high values of the standard deviation coincides with the position of the climatic frontal zone and they both move southward in the winter months and northward in summer.

Abstract:Efficiency of artificial rain-making experiment 1975—1984 over the drainage area for Gutian Reservoir and reservoir operations at 1985 are statistically analysed and the physical processes examined. Result indicate that clouding seeding during the rainy season (April-June)enhances natural precipitation and is found to be beneficial to powergencrating and drought relief.