Structural Characteristics On Two Kinds Of Stratiform Cloud And The Observation Analysis Of Artificial Precipitation Conditions

The physical structure,the distribution regularity of supercooled water,and the precipitation mechanism of the stratiform cloud and the mixed stratiform-convective cloud in the north,which are the basises of the criterion and index to establish artificial precipitation conditions.Therefore, further study of the characteristics on macro-and micro-and which physical structure under different weather systems;and understanding the distributionc of cloud supercooled water and its precipitation mechanism;and establishing the related concept model, is of great significance for the scientific implementation of artificial precipitation operation.This article is based on two designed observation of flight on September25,2012in Shanxi and April5,2013in Henan and combined with the satellite, radar, sounding, rainfall and other supporting information, which analyzed the characteristics on macro-and micro-physical structure and the precipitation mechanism of the stratiform cloud and the mixed stratiform-convective cloud. Main results are as follows:1. On September25,2012in shanxi,the weather process is the low trough and the cold front which caused the precipitation of the stratiform cloud. The top-height of the cloud is10km-13km;the top-temperature of the cloud is-40℃--50℃.The height of0℃layer is4000meters.This cloud system did not have interlayer and the structure is deep; the characteristics about macro-and micro-and physical structures on horizontal and vertical direction of structure are apparent even stable.This cloud system had little supercooled water in the cold area.It mainly had solid ice phase particles,which growth through sublimation, and the particle shape is stable in the process of falling in cold areas.In the cold district,the spectrum distribution of small cloud particles (CDP) is exponential;the spectrum distribution of big cloud particles (CIP) is bimodal; the spectrum distribution of precipitation particles (PIP) is three peaks; and on the same height of different position, the particle spectrum type and concentration are basically identical. In the warm area, the spectrum distribution type of big cloud particles (CIP) and precipitation particles (PIP) turned from multimodal into unimodal.Based on the analysis of the whole flight process of detection, the physical characteristics are uniform on the layered structures during different times, and supercooled water lack,which not suitable for artificial seeding ice cores and artificial precipitation operation. 2.0n April5,2013in henan, the precipitation is caused by the low trough and the cold front in this weather process.The temperature of the cloud top is near-10℃--24℃.The cloud vertical structure overall coherence and without interlayer, and the vertical development is rapid.The radar echo didin’t have light band. In the cold zone,the diameter of small cloud particle decreases with height reduced;the diameter of big cloud particle increased with the decrease of height;and the spectrum distribution of particle was bimodal in cold area.The diameter of precipitation particle increased with height decrease and the particle spectrum type is irregular.On the4950meters altitude, the cloud particles are most of ice crystals,but with a small amount of acicular solid particles.Cloud particles are gradually condensation growth in the process of falling. On the altitude of4000m,3650m and3000m,the acicular particles increased obviously. On2400meters altitude, the solid particles are already turned into snow and other particles in the condition of condensation and climbing growth.In the process of falling,the precipitation particles growth with climbing and clings. Above4km altitude,the supercooled water is extremely rich, the concentration of cloud particle is comply with the conditions of cloud seeding and the sowing area is the major part of the cloud.