New insights into precipitation development as affected by novel investigations on the limitation of large raindrops' sizes

对大雨滴尺寸限制的新研究影响降水发展的新见解

• 批准号: 25482868
• 负责人: Professor Dr. Klaus Dieter Beheng (†)
• 金额: --
• 依托单位: Department Troposphärenforschung (IMK-TRO)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/25482868?language=en
• 关键词: New; insights; into; precipitation; development

To the ultimate goal to improve precipitation forecasts a basic mechanism limiting the size of large raindrops (collision-induced breakup), which has been examined in the very past by very few laboratory experiments only, is re-investigated. Its effect is estimated by numerical studies using a cloud-resolving operational weather forecast model of the German Weather Service. The studies are partitioned into two parts: At first numerical experiments with an advanced fluid-dynamics code were performed where the collision and the breakup of colliding large (rain)drops are followed in greatest detail. They will be checked by according laboratory experiments. The results provide characteristics whose values may depend on specific breakup modes if results of the few past experiments are confirmed. The new data will be used in a ID-rainshaft model. Besides equilibrium raindrop size spectra important in many fields related to precipitation physics as, e.g., in radar meteorology, the rainshaft model delivers basic values for deriving a (coarser) parameterization of breakup. Prom the latter values then a new parameterization of breakup is developed for operational applications. It will replace the traditional formulation which actually is part of a bulk cloudmicrophysical scheme running already in a cloud-resolving version of a weather forecast model of the German Weather Service. First sensitivity studies will be undertaken to assess the effect of the new data on the breakup process on precipitation.

为了提高降水预报的最终目标，一个基本的机制限制大雨滴的大小（碰撞引起的分裂），这在过去已经检查了很少的实验室实验，重新调查。它的影响是通过使用德国气象局的云解析业务天气预报模型进行数值研究来估计的。研究分为两个部分：首先进行了数值实验与先进的流体动力学代码的碰撞和破碎的碰撞大（雨）滴遵循最详细的。并通过相应的实验室实验进行验证。结果提供的特性，其值可能取决于特定的破碎模式，如果过去的几个实验的结果得到证实。新的数据将用于ID雨井模型。除了平衡雨滴谱在许多与降水物理学有关的领域中很重要外，在雷达气象学中，雨轴模式提供了用于导出（较粗略的）解体参数化的基本值。从后者的值，然后一个新的参数化的破碎业务应用开发。它将取代传统的公式，这实际上是一个批量云微物理计划的一部分，已经在德国气象局的天气预报模型的云解析版本中运行。将首先进行敏感性研究，以评估新数据对分裂过程对降水的影响。