Abstract:A synoptic analysis is made of the low-latitude pentad mean circulation at 100, 500, and 1000 mb from May through July of 1979, with the conclusion that the seasonal transformation of the low-latitude atmospheric circulation from winter to summer of that year occurred in the time between the second pentad and the fourth one of June. The second characteristic vector obtained from the solution of the arrays of the pentad mean flow field in the diffenent layers by the method of natural orthogonal expansion is an important component characterizing the seasonal transformation of the circulation and is called the monsoon component. The statistical analysis of the heating effect of the Qinghai-Xizang Plateau and the time coefficient of the second characteristic vector shows that there exists an obvious correlation between them. And it is found from the synoptic analysis of the diffusivity field and vertical motion field of the second vector that the correlation is due to the vertical circulation cells over the region between the Plateau and its neighbourhood, and the low latitudes.

Abstract:Nested grid experiments are made for the barotropic primitive equation by a one-way interaction method. The quasi-Lagranian difference scheme by space factorization is used for both fine and coarse grids and the interracial boundary conditions (Scheme 2)proposed by Liao Dongxian et al. Scheme 2 is in keeping with the said difference scheme. Experiments show that in the 24-hr fine grid forecasts by Scheme 2 the inflow and outflow in the system with the unstability at the outflow eliminated are better than those by the half-momentum scheme and the interracial boundary conditions directly provided for the fine grid by the course grid (Scheme 1). Scheme 2 and Scheme 1, when combined with the method of Davies’s "Relaxation Regions", become Scheme 4 and Scheme 3, respectively. The results are much the same as those by using Scheme 1 and Scheme 2. It is found that Scheme 4 is a little better than Scheme 2.

Abstract:An objective analytic method by which both grids and regions can be changed is set up by using spline interpolation. Many experiments have been done for the relevant parameters used in the analysis. Points for attention when the method is used are discussed in the paper. The method not only can be applied to various aspects of meteorological practice but also can improve the efficiency of the work done. The results in case study prove to be quite satisfactory.

Abstract:Based on the simplified circulation model of the tropical cyclone, a qualitative analysis is made of the approximate analytical solution to the partial differential equation describing the tropical cyclonic disturbance. The evolution Characteristics of the tropical cyclone and the effects of the heat field distribution, the water vapour at the boundary layer and the initial wind field on the developing disturbance are discussed in detail. The analysis provides a theoretical ground for studying the development of the tropical Cyclonic disturbance.

Abstract:The quasi-geostrophic potential vorticity equation used in this paper is linearized under the conditions that the basic atmospheric currents vary gradually with time and space. Some reasonable results are obtained from the discussion made of the variation of the spiral structure of spherical planetary waves in the baroelinic atmosphere and its contribution to the transport of sensible heat.

Abstract:A mixed polynomial method is adopted to expand the fields of the total amount of ozone at 40°—85°N from July 1957 through June 1967. Analyses of the coefficients in the expansions reveal the characteristic features of the distribution in space of the secular monthly means of the ozone field and the variation of these features with seasons. By the smae method the information processing has been accomplished for the height field at 10, 30, 50, 100, 300 and 500 mb at 20-65°N in the corresponding period of time. On this basis studies are made by syno-p tic-statistical method of the distribution of the total amount of ozone and its seasonal variation as well as its correlation with that of the stratospheric-tropospheric circulation.

Abstract:The method of quadratic discrimination through orthogonal transformation is introduced to optimize quadratic discrimination function and has proved more effective than the method of stepwise multiple discrimination. It is noteworthy that when there are a large number of predictors it is better to make a preliminary choice by using stepwise multiple discrimination or stepwise regression so that the calculation can be made more stable and the effectiveness of discrimination can be improved.

Abstract:The laws governing the secular variation of droughts and studies for their trend are closely related to our national economy, especially to the agricultural production. Analyses are made of the time and space distribution, stages and periodicity of droughts in both the southern and northern parts of Jiangsu Province during the past 200 years By use of the two main cycles calculated and referring to the 11-year quasiperiodic law for the relative number of sunspots, the authors present the trend of the occurrence of droughts in the coming 20 years.

Abstract:Discussions are made of the concept of agrometeorological year harvest and the significance of its prediction. Theagrometeorological year harvest of early rice in Kunshan County,Jiangsu Province in 1981 is taken as an example in making an agrometeorological year harvest prediction, for which two practicable schemes,stepwise discrimination and fuzzy identification, are presented.

Abstract:In order te fulfil the requirements for quantitative analysis of the infrared cloud pictures received from the satellite, the properties required for circuit design arid the facilities needed for fitting the cloud picture receiver and facsimile apparatus are presented in this paper. Besides,criteria are given for determining whether or not the discrimination of cloud picture reccived can fulfil the requirements for quantitative analysis.