Analysis On The Three Types Of Convective Cloud Precipitation Structure And Operating Conditions Based On Data Of Radar And Satellite

Using the Doppler radar data and the cloud parameter products retrieved from the satellites, the structures of different types of convective precipitation and their operating conditions were analyzed combined with the radio sounding and surface observation in this thesis, with an expectation of better understanding the operating conditions and improving the delicate analysis of the precipitation. The primary conclusions are as follows.The supercell storm is a right-shifting storm occurring under the circumstances with the conditional instability and significant vertical wind shear. There were a strong tilted updraft and a deep meso-cyclone in the hail storm and such structures as weak echo region, over-hang echo and echo wall were maintained. In the development of the hail cloud, the zero-line drew towards and then crossed the overhang echo zone. The trend of the zero-line is upturned, and the collection power of the cave-channel near the zero-line was so strong that it contributed to the formation of the hail. The favorably hail-forming area could be located by discerning the zero-line location. According to the strong echo dislocation of high and low levels, the characteristics of its vertical cross-session could be identified quickly and accurately by connecting the strong echo centers at the two heights,45dBZ region at6km height above0℃layer could be identified as hail formed region where potential of hail could be calculated to100%and there was a good effect of identifying the hail forming region. The strength of the convection could be indicated by the strong temperature decrease rate at the upper cloud, the height and intensity of the initial echo, Re and-dRe/dT, which provides a new way to hail suppression and early warning. The cave-channel which is below the zero-line is scientific area.Then the structure and transformation of cloud and precipitation of an extreme torrential rain in Beijing on21July2012was different at different stages. In the stage of warm area convective precipitation, the precipitation was activated by the warm rain mechanism, rain drops grew quickly with significant coagulation in the warm cloud, the warm rain process played a key role in the precipitation. The coagulation among the rain drops below the-10℃layer was particularly strong. In the area above the-10℃layer there was a deep region of ice evolution, the big ice particle dominated on the upper cloud and the transformation from the cloud to the rain was very fast.2) In the stage of the front convective precipitation, the cloud system developed into highly organized MCC system with a low centroid. The echo developed quickly at the layer with mixed water and ice, the frozen layer was the key area where microphysical of rain process occurred. Rain drops grew by the coagulation effect in the warm cloud.3) In the final stage of the backward front precipitation, the coagulation effect between the ice particles and cloud water was strong and the raindrop evaporation effect in the warm cloud was obvious that raindrops could not efficiently grew by the coagulation effect.The cumulus embedded stratus system is the main cloud system for activating the precipitation in the south of China, it would be more favorable for the areas with TBB below-30℃at the cloud top, the optical thickness over20and deeper cold layer, because this area could satisfied the seeding-supply mechanism. In the cumulus embedded stratus, the echo in the melting-layer was strong, the echo gradient in the mixed-phase cloud area was strong, so that the raindrops grew fast and the precipitation was feathered by the ice-phase process. The dense echo structure dominated by the cold cloud physical process should be chosen for activating the precipitation.