Collaborative Research: Improved Understanding/Prediction of Severe Convective Storms and Attendant Phenomena through Advanced Numerical Simulation

合作研究：通过先进的数值模拟提高对强对流风暴及其伴随现象的理解/预测

• 批准号: 0449753
• 负责人: Robert Wilhelmson
• 金额: $ 76.5万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0449753&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; Understanding; Prediction

The objective of this research is to improve understanding of severe convective storms and attendant phenomena through the use of advanced numerical simulation. Areas of focus include1) environmental and model parameters influencing tornado genesis, intensity, and longevity;2) tornado representation using improved model physics;3) multiple storm interactions influencing the intensity and longevity of low-level rotation;4) analysis and simulation of the 30 May 2003 back-building supercell line;5) tornadogenesis owing to rapid environmental changes;6) advances in storm scale assimilation: ENKF using polarimetric radar data.There are several themes that connect these areas. One theme centers on low-level storm rotation and its relationship to tornado genesis, evolution, and decay, particularly within supercells. Not only are the above foci aimed at improved understanding through high resolution numerical simulations but also at explaining the structure and behavior of storms that produce long track tornadoes. Coupled with these investigations will be a focus on improving the microphysical representation within severe storms. Advanced microphysics is needed for more accurate depiction of storm and tornado evolution, associated surface weather, and proper assimilation of polarimetric radar data. The simple single moment microphysics parameterizations commonly used today do not properly represent squall lines and supercells simultaneously, cannot forecast supercell precipitation reliably, and incompletely represent the microphysics within simulated supercells as observed by polarimetric radar.Another theme centers on the interaction of existing storms with themselves or with the presence of a boundary. Motivated by severe storm behavior on 19 April 1996, one focus extends initial work aimed at understanding mergers of storms in multicell and supercell environments that result in increased storm strength, storm rotation, and increased tornadic potential. This investigation will benefit from new technologies being developed at the National Center for Supercomputing Applications and with the NSF funded LEAD ITR project for managing, mining, and visualizing large sets of simulations. Another focus is aimed at understanding the back-building nature of some lines such as the one that occurred on 30 May 2003. Observational analysis of this event will be followed by numerical simulations to study the hypothesis that this occurs through enhanced convergence located where the prevailing cold front interacts with a southward moving outflow boundary of the southernmost supercell.The implementation and testing of expanded microphysics will provide input to others storm modelers on the important microphysical processes. It will also provide an indication to short-term forecasters of the impact that sophisticated physics can have on storm-scale model forecasts. Furthermore, given that the National Weather Service may soon upgrade the WSR-88D radar network to include polarimetric measurements, preliminary work is needed to understand how to best assimilate such measurements into storm-scale forecast models and which microphysics schemes can best incorporate these new measurements.

这项研究的目的是通过使用先进的数值模拟来提高对强对流风暴和随之而来的现象的了解。 重点领域包括 1) 影响龙卷风发生、强度和寿命的环境和模型参数；2) 使用改进的模型物理进行龙卷风表示；3) 影响低层旋转强度和寿命的多重风暴相互作用；4) 龙卷风的分析和模拟2003 年 5 月 30 日重建超级细胞系；5) 由于环境快速变化而产生龙卷风；6) 风暴规模同化的进展：使用极化雷达数据的 ENKF。有几个主题将这些领域联系起来。 其中一个主题集中于低层风暴旋转及其与龙卷风发生、演化和衰变的关系，特别是在超级单体内。 上述重点不仅旨在通过高分辨率数值模拟增进理解，而且旨在解释产生长轨迹龙卷风的风暴的结构和行为。 与这些调查相结合的重点是改善严重风暴中的微物理表征。 需要先进的微物理学来更准确地描述风暴和龙卷风的演变、相关的表面天气以及偏振雷达数据的正确同化。 目前常用的简单单矩微物理参数化不能同时正确地表示飑线和超级单体，不能可靠地预测超级单体降水，并且不能完全表示极化雷达观测到的模拟超级单体内的微物理。另一个主题集中于现有风暴与其自身的相互作用或存在边界。 受 1996 年 4 月 19 日严重风暴行为的推动，一项重点扩展了旨在了解多单元和超级单元环境中风暴合并的初步工作，这些合并导致风暴强度增加、风暴旋转和龙卷潜力增加。 这项调查将受益于国家超级计算应用中心正在开发的新技术以及 NSF 资助的 LEAD ITR 项目，用于管理、挖掘和可视化大型模拟。 另一个重点是了解某些线路的后台建设性质，例如 2003 年 5 月 30 日发生的那条线路。对该事件的观测分析之后将进行数值模拟，以研究这样的假设：这种情况是通过位于主导位置的增强收敛而发生的。冷锋与最南端超级单体向南移动的流出边界相互作用。扩展微物理的实施和测试将为其他风暴建模者提供重要微物理过程的输入。 它还将为短期预报员提供复杂物理学对风暴规模模型预报的影响的指示。 此外，鉴于国家气象局可能很快升级 WSR-88D 雷达网络以包括极化测量，需要开展初步工作来了解如何最好地将此类测量纳入风暴规模预报模型​​，以及哪些微物理方案可以最好地纳入这些新测量。