Abstract:A linear, steady-state, baroclinic, primitive equation, threedimensional spectral model, in which Newtonian cooling, Rayleigh friction and biharmonic diffusion are included, is used to investigate the effects of idealized and actual topography on the planetary-scale forced stationary waves. Computational results confirm the qualitative analysis of β-plane barotropic theory. The orographically forced planetary waves have a equivalent barotropic vertical structure, and the rotational (nondivergent) component of perturbation flow field is dominant at middle and high latitudes, whereas the divergent(irrotational) component is mainly concentrated in the tropical region. The orographically forced stationary waves in the northern winter are dominated by zonal wave number two and the Tibetan Plateau plays a most important role in its maintenance, while the forcing by the orographic effect of either the Rocky mountaius or the Greenland Plateau seems to be of secondary importance.

Abstract:In this paper, an objective analysis scheme is designed for the multilevel nested grid and irregular grid of numerical weather prediction models. The method can either be used for the irregularly spaced latitude longitude grid system or meet the needs for the vocational work and scientific research in meteorological observatories and weather stations. The scheme presented in this paper is simple, practical, and easy to learn. Cases of July 2, 08 GMT and December 25, 08GMT, 1979 are selected to analyze the 500 hPa height field by using the 500 hPa height and wind data. The experimental results are proved to be quite satisfactory.

Abstract:Based on 53 major mesoscale rain events occurring in springtime over Oklahoma, the mesoscale convective systems can be divided into three basic types: rainstorm, severe storm and mixed type of rain and severe storms. Analysis shows that the weather differences between the systems are due to those of intensity and size of their convective and stratiform components and are also related to the environ mental conditions and synoptic background situations in which they exist.

Abstract:The power-spectral and maximum entropy-spectral analyses of the drought/flood data in the lower reaches of the Changjiang River have revealed the fluctuations of the cold/warmth south of the Huaihe River for the periods of 2—3, 5—6, 7—14, 17—20 and 27—32 years. It is evident by using the cross-spectral method that there is a significant correlation between the drought/flood and the cold/warmth. It is found that the evolution of the cold/warmth in winter is prior to the drought/flood in summer within the low-frequency range, but they are in phase within the middle-and high-frequency ranges.

Abstract:In this paper, the instability of shearline perturbations in the JiangHuai mei-yu period is studied and the principal results are obtained as. follows: 1) the growth rate of zonal perturbations is far smaller than that of symmetric perturbations; 2)the growth rate is strongly dependent on wavelengths and stratification stability; 3)the condition for the maximum growth rate of symmetric perturbations is R_i<-0.1, and that for the minimum growth rate is R_i<0.92 or 1/4; and 4) the wavelengths of the most unstable waves which initiate a severe convective storm or a thunderstorm are about 200—400 km.

Abstract:A 2-dimensional numerical model is established for the study of the effects of water surface on fog formation and development. In the model, heat-vapor exchange between the underlying surface and the atmosphere and turbuleat diffusion have been considered in detail. Some useful results are obtained by using the model.

Abstract:Four tillering characteristic parameters have been calculated by an improved logistic equation fitted with experimental data. Accordingly, hybrid indica rice cultivated in the south of China can be divided into four ecologic types. Parallel meteorological data further confirm that these types are concentrated in certain geographical areas. Quantitative analysis is made of the agrometeorological conditions for the ecologic types. This paper also discusses how to make use of traditional rice cultivation techniques to improve the tillering characteristics.

Abstract:Given in this paper is a new method of drawing the geographic referencing grid for APT and HRPT data transmitted by the orbital weather satellite. By using this method computing efficiency can be increased without having to analyze longitude and latitude contours and thus errors in geographic referencing due to contour analysis can be eliminated.

Abstract:Usually, conventional incoherent weather radar is used to provide only the information on the position of a weather target and its radar reflectivity by detecting echo intensity. In this paper the fluctuating spectrum and its spectral width are estimated by fast Fourier transformation of the discrete sample of precipitation echoes at a specified position with a microcomputer(Apple Ⅱ) connected with a home-made incoherent weather radar 713. Based on the relation between fluctuating spectrum and Doppler spectrum, calculation has been performed for the width and shape typical of the Doppler velocity spectrum, which are very useful in meteorology.

Abstract:Determination has been made of the ice nucleation of AgI with rainmaing and hail suppression rocket JFJ. A preliminary study suggests that 4 grams or 2 grams of AgI is desirable. The rate of ice nucleation is 1-2 orders higher than that with shell 37 and one order higher than that with rocket JBR-56 at temperature -16℃ or more. The number of AgI particles formed after the explosion of rocket JFJ from electronic microscope analysis is 1.7×10¹⁶g^-1, corresponding approximately to actual determination.

Abstract:Based on the typical data collected from the Village of Erlangmiao, Heze Prefecture, Shandong Province, an optimal model for the coupled ecological system of agricnlture, forestry and husbandary is developed by means of the simplex of linear programming. Calculation shows that plantation of economic trees in the tree-netted cultivated fields and extension of wheat-summer soybean on the cropland can greatly increase the economic benefit and improve the soil. In order to make full use of forage grass resources, it is better to raise cows, sheep, rabbits and swine in animal husbandary. Products can be used at a multiple level repeatedly by cultivating mushrooms or other shade-enduring plants among trees and planting mulberry trees for silkworm raising, an operation that contributes to the stability and balance of the coupled ecological system and brings more economic, ecological and social benefits.

Abstract:Using the calculated results of Sellers model, the dynamic process of the stochastic response system is linearized and, thereby, a stochastic dynamic model for the time-dependent variation in temperature of the earth-atmosphere system in different latitudinal zones is constructed. The principal characteristics of the temperature variation, derived from this model, are in good agreement with the actual situation. And finally. resttlts from the simulative test for the global ocean heat transport effect is given.