Abstract:In the evening of July 27th, 1984, a whole process of a cumulonimbers precipitation was observed in Peking University, which had two developing processes and two declining processes. The first process of precipitation lasted a short time(33min) and had a high average rainfall density (12.9mm/hr). The pH value of the first precipitation was about 7.0.The second process of precipitation kept a long time(126min) had a low average rainfall density 1.6mm/hr, With the strong washout of precipitation, the atmosphere under the cloud became cleaner. The pH value of the second precipitation dropped 6.6 continually and the conductance became down markebly.

Abstract:In this paper, it is proved that there are some differences between the magnitudes of the structure functions or correlation functions measured from observed data and that derived from true values because of the rule of observational random errors, and the mean square of the observational random errors or the standardized observational random errors of any meteorological element can be estimated by extrapolating the curves of the two functions to the zero distances respectively.

Abstract:In this paper, some kinds of sodar echoes associated with, certain atmospheric stability classification taken from north, China are discussed. Moreover, the vertical variations of atmospheric stability classification in boundary laryer are also shown.

Abstract:Based on the classification of, rainsform image affecting Shanxi Province, its ge-nesis regions, life cycles and tracks are discussed, and the relation between the temperature of cloud top and 3-hours precipitation intencity is. analysed. Using this statistical result, some physical parameters and radar echoes, a method of 6-hour rainstorm forecast is obtained, The forecast accuracy is satifactory.

Abstract:In this paper, based on the principle of virtual displacement, the changes in form of the particle system composing the fluid are calculated that leads to the "crowding" under the action of the Coriolis force. For a gas, the "crowding" will result in an imhomogeneous distribution of density, thus causing a pressure difference on both sides in the direction of its motion. Such "crowding" can serve as.a reference in finding the accurate solusion of the pressure distribution of air masses.