Abstract:Based on dynamical analysis of data both from conventional and special observations in the Scientific Experiment over the Plateau made in 1979,with turbulent viscous stress and atmospheric stratification considered and by using a two-dimensional model designed to describe the passage of the westerlies over the Plateau on a zonal cross-section, a simulation ismade of the formation of zonal vortices in the Plateau boundary layerand their eastward movement out of the prominence as well as the variations of the zonal circulation caused thereby, etc.

Abstract:Based upon cause analysis of the low-level jet along the east side ofthe Rocky Mountains the concept of 《Interface Effect》 is established. Ithas been found that the basic reason for the formation of the low-leveljet in North America is the interface effect, whose mechanism is pushingby geostrophic wind, and thereby air columns in the lower troposphereare compressed between two surfaces-the ground and the bottom ofthe inversion-which slope with different patterns in a vertical cross-section normal to the jet stream. As a result, the air parcel is acceler-ated along the streamline and the anticyclonic shear of the current in-creased. Also, the diurnal variation of the jet is determined by the in-terface effect.

Abstract:Based on the data obtained scattered radiation (SR) over the QXPin summer is dealt with and a study is made of the effect on SR of the sun’s altitude angle, atmosphere transparency, elevation above sea levelas well as cloud forms and cloudiness. Berlage’s coefficient α is obtain-ed through computation and the variations of the daily total of SR areexamined.

Abstract:Based on the raindrop size distribution in a rainstorm due to the Plum-rain front of June 27-28, 1981, a preliminary study is made of the features of the distribution and the evolution with more effort devoted to the size distribution within and beyond the rain mass. Somesignificant results have been acquired.

Abstract:A limited-area numerical model is used to simulate the "73.7"rainstorm over the belt along the Yellow River from the Sanmen Gorgeto Huayuankou and the adjacent regions. Following Lavoie’s work(1972), a 3-layer atmospheric structure is presented which consists of:i) a constant-flux layer (in contact with the surface); ii) a well-mixedlayer (capped by an inversion) and iii) a deep stratum of stable air.For the well-mixed layer the average is obtained from the governing primitive equations and the other two layers are properly parameterized. The governing equations are solved numerically for mixed layer with consideration of the effect of its initial conditions on the follow-ing factors such as terrain influence, surface roughness, temperature variations, moisture fluxes and the release of latent heat. Results obtained by this model are close to those observed.

Abstract:An analysis is made of a sample of 732 12-hr rainfall fields forJune to July, 1975-80, to yield a quantitative description and objectiveclassification. Three aspects are examined: (i) how to reduce the in-stability and inhomogeneity in magnitude and distribution of the short-term precipitation fields to facilitate quantitative description; (ii)how to select the characteristic parameters in order to condense thefield quantities and (iii) the objective scattering analysis of different categories of rainfall amount and distribution, using these characteristic parameters. The results are found to be satisfactory.

Abstract:On the basis of data from the first TIPMEX (1979) an attempt ismade of a direct-calculation methds of Daily Effective Radiation Totals(DERT) over the Plateau. With analyses of data from 6 observing stations to show interrelations of the components of DERT to cloudi-ness, a universal formula is presented for computing DERT in thisarea. The relative errors given by the expression in different casesare as follows: 6.5% for a clear sky, 8.1% for a partly cloudy sky.8.8-11.5% for a cloudy sky and 19.0% for a overcast sky, the averageerror being 10. 8%.

Abstract:Based on the photographs of hailstone slices from the supercell occurring on May 1, 1981 over the Anhui-Jiangsu area north of the Yangtze river, an analysis is made of the types of embryos, characteristic features of stratification, distribution of air bubbles and icecrystal structures. The results suggest that both the clear and opaque layers are of the wet-growth category and thus these hailstones outfrom supercells are formed in the cloud under wet-growth process.Finally, a preliminary survey of the physical process in the formation of clear and opaque layers under wet-growth conditions is presented.

Abstract:In recent years a new technique has been developed which uses aground-based radio meter as a supplement for a radar in quantitative lymeasuring rainfall. Two kinds of joint systems of radar-radiometers of 8 mm and 3.2 cm wavelengths were set up in 1980 by the Institute of Atmospheric Physics, Academia Sinica. A solution scheme for the measurements given by one of the systems is proposed. By means of numerical experiments. the above scheme for 3.2 cm wave lengths and two others for the systems by use of radar only are examined andcompared. And errors caused by various factors of these methods are discussed. Some significant results are obtained concerning the feasi-bility of the methods used.