| In this paper, regular weather observation data, satellite pictures, Taiyuan droppler radar data on 8th-10th May 2009 and DMT data collected during flights on 8th and 10th May 2009 are studied, and the macrophysical and microphysical structure of a convective-stratiform mixed cloud and a stratiform cloud in Shanxi province are analysed.A heavy precipitation on 9th May 2009 which is caused by mesoscale convective systems is also simulated by WRF.The results are as follows.(1) The convective-stratiform mixed cloud detected by flight on 8th May 2009 formed after the zonal convective weaken which merged by small convective clouds. The formation of the zonal convective cloud experiences multi scale merging process,cloud cluster scale merging,and high core merging.The merging processes promote the development of cloud area,intensity,and height of cloud top.The average particle concentration measured by CDP,CIP,and PIP probes on 8th May 2009 are 132.4-220.2cm-3,1.54×10-1-6.28×100cm-3 and 9.09×10-4-7.34×10-3 cm-3 respectively.Two dimensional images show that graupel is the main ice particles in the cold layer, which implies that supercooled water is adequate.Collision and riming are the important mechanisms for graupel formation.The microphysical structure of the convective-stratiform mixed cloud in horizontal direction is inhomogenous.The average CDP spectra(diameter:2-50μm) are different with the heights,and the particles number concentration between 2 and 18μm increases with heights,but it decrease between 24 and 35μm.The average CIP spectra (diameter:25-1550μm) follow unimodal distributions except for that at 4100m. In the average PIP spectra (diameter:100-6200μm),the largest concentration and the spectral width occur at 4450m,which implies that convective cells and the surrounding area provide a good environment for the growth of larger solid precipitation particles.(2)The analyse of the stratiform cloud system influenced by the westly trough on 10th May 2009 shows that the largest cloud particles concentration measured by CDP in stratocumulus and altostratus are 375 cm-3 and 217 cm-3 respectively.The average larger cloud particles concentration measured by CIP in stratocumulus and altostratus are 2.45×10-2 cm-3 and 1.21×100 cm-3.The magnitude of precipitation particles concentration measured by PIP is 10-4-10-2 cm-3. Two dimensional images show that columnar and dendritic crystals are the main ice particles in the cold layer.In the laryer where temperature near 0℃,adhesion between columnar crystals play an important role in the aggregate formation process,which implys that riming and collision are the main mechanism for aggregate formation.The CDP spectrum mainly follow unimodal distribution,and CIP spectrum follow negative exponential distribution.In the PIP spectrum,the number concentration and the spectrum width of every bin decrease with the height.The PIP spectrum above 0℃follow negative exponential distribution,and the PIP spectrum below 0℃is obviously uncontinuous and either follow unimodal or bimodal distribution.(3) The heavy precipitation on 9 May 2009 can be simulated well by WRF.From the simulated radar combination reflectivity pictures, we can find out that the orientation of cloud system is southeast-northwest and there are some strong echoes in bars and blocks.The vertical structure of the areas with strong convection agrees with the threee layers concept model which is proposed by Gu Zhenchao.The ice particles are in upper layer, and the snow crystals, graupel and supercooled water mix in the middle layer, and liquid water is in lower layer. All kinds of water link together and cold and warm cloud precipitation mechanisms coexist in it.In the surrounding areas of the strong convection, rain is mainly caused by cold cloud precipitation mechanism.In the midwest of Shanxi province, the good power, heat and moisture conditions make the cloud develop fast and convective activities frequently happen.So the precipitation efficiency is high and the rain last long, which cause the heavy rainfall happen.
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