Laboratory studies of the form and oscillations towards breakup of falling raindrops in the Mainz Vertical Wind Tunnel and holographic field measurements of microphysical precipitation properties

实测的面雨量与雷达观测计算的雨量之间存在严重的不一致。一种改进估计的建议方法是利用雷达反射率给出降雨率的关系，其中包括雨滴的形状。由于这些毫米大小的雨滴是连续振荡的，因此必须知道轴比的准确动态平均值，才能在反射率降雨率关系中使用它们。在这项研究中，我们建议使用在垂直风洞中漂浮的毫米大小的水滴形状的高速时间序列分析来实现这一目标。具有特殊意义的是当量直径（Do）在1.1和3mm之间的液滴的轴比，理论上预测其动态平均轴比与平衡形状的轴比显着不同。此外，我们建议在AQUARadar现场实验（特殊观测阶段，SOP）中部署美因茨大学HODAR（全息液滴和气溶胶记录）仪器，用于现场地面测量雨滴和霰/冰雹粒度分布、空间水流星分布和单个水流星速度。结合AQUARadar-D的微雨雷达（MRR），可以在SOP期间同时进行微物理降水特性和雷达回波的空间相关测量。

Serious inconsistencies exist between measured areal rainfall and the rainfall as computed from radar observations. One suggested method to improve on the estimation is to use relationships giving rainfall rates from radar reflectivities which include the shape of the raindrops. As those millimeter size raindrops are continuously oscillating, one has to know the accurate dynamic average values of the axis ratios to be able to use them in the reflectivity rainfall rate relationship. In this study we propose to use high speed time series analysis of shapes of millimetre size drops floating in the vertical wind tunnel to achieve this goal. Of special significance are the axis ratios of the drops with equivalent diameters (Do) between 1.1 and 3 mm whose dynamic mean axis ratios are theoretically predicted to be significantly different from those for the equilibrium shape. Further we suggest for the AQUARadar field experiment (Special Observation Phase, SOP) the deployment of the University of Mainz HODAR (Holographic Droplet and Aerosol Recording) instrument for in-situ ground based measurements of rain droplet and graupel/hail grain size distributions, spatial hydrometeor distributions, and individual hydrometeor velocities. In connection with one micro rain radar (MRR) from AQUARadar-D simultaneous and spatially correlated measurements of microphysical precipitation properties and the radar return can be performed this way during SOP.