| This paper analyses some characteristics of the macro- andmicro-physical structures and mechanism of a case of mixed cloud aswell as precipitation in a low vortex synoptic process on June 25 to 26,in 2005, by using different observational data, NCEP/NCAR reanalysisdata, remote sensing data such as FY-2C satellite data, TRMM satellitedata as well as Doppler Radar data, and the middle scale numericalsimulation models MM5.Some conclusions were drawn. In the process of the low vortexmoving, because of there being different dynamical, thermal and vaporconditions in the different area of the mixed cloud, eight intensemiddle-scale convective clusters appeared in the Huanghuai River areaand the Black Body Temperature was below 90℃. Because of theseconvective clusters effect for about more than ten hours, large areas inHenan province had precipitation and some palaces had strong rainfallsfrom 14 on June 25 to 7 on June 26. The TRMM satellite data showed usthat the stratiform precipitation rate was far below the convectiveprecipitation rate, and the latter was four times than the former. Theconvective precipitation spectrum which mainly from 10mm to 20mmwas wider than the stratiform which was mainly below 10mm. Besides,there was obvious difference between the stratiform cloud profile and theconvective cloud profile, mainly existing in the range and the height ofthe particle rose. Obviously the seeding-feeding mechanism and thewater drop collection process were great important in the convectiveprecipitation. The MM5v3.7 version numerical simulation model, which wasdesigned three levels nestdown and properly physics parameterizationoptions, was used in this paper to supplement above analyses. Thesimulated characteristic of the synoptic background, the cloud figure andthe precipitation were close to the fact. So based on these conclusions,the instability index, the thermal dynamics conditions, and themicro-physical characteristic (such as ice, snow, graupel, cloud water,and rainwater content) were calculated. Some conclusions were drawnbelow. The instability index in the strong rainfall area was much largerthan that in the periphery area. There was an important condition forcloud water convert to precipitation that the low atmospheric level hadso many vapors and the convergence transferred the vapor to the upperair made the convective cloud development. In the precipitation process,the cloud micro-physical structure changed obviously, which had muchcloud water all the time, but had little ice content. The snow and thegraupel content were so small in the beginning, but increased swiftlyafter 14 on June 25. So at the beginning, the warm rain process was inthe main status and latter the cold rain process was stronger than that.Above all, the cloud and precipitation distribution, theinhomogeneous structure, the micro-physical characteristic and the formmechanism in the low vortex synoptic process were analyzed anddiscussed carefully. Different scale characteristics were obviously in themixed cloud and precipitation, and they had closely interactions witheach other. The form of the precipitation always was the results oftogether actions of the large scale synoptic backgrounds, the middle scale conditions and micro-physical process in the cloud. So on thispoint of view, it is of great importance to completely study the cloud andprecipitation macro- and micro-physical structure characteristics in orderto forecast rainfall precisely and to choose the proper area in weathermodification.
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