Numerical Simulation and Analysis of Mesoscale Convective Systems and Severe Storms

Due to its large economic impact as well as importance for public safety, the study of atmospheric convective systems is a high priority topic of research. Under this award the Principal Investigator will continue research on a variety of topics associated with convective storms. Specific topics to be addressed include:--Development of a radar-based climatology focusing on the spatial and temporal distribution of convection during the growth stages of mesoscale convective systems (MCS) over the U.S. to characterize the most common patterns of development that leads to MCS formation and to understand the variability of processes governing different classes of MCSs. -- Perform sensitivity studies with an advanced mesoscale numerical model to examine the relative dominance of environmental controls versus the details of early convective forcing on MCS structure and evolution.-- Using a numerical model, investigate the effects of soil moisture amounts and its inhomogeneity on the initiation and strength of MCSs.-- Using WSR-88D Doppler radar data, examine specific derecho (localized high wind) events to determine if they are characterized by a definable mesocyclone over a stable air mass and perform numerical simulations of selected cases to determine mechanisms responsible for severe wind formation.-- Obtain further insight into processes responsible for tornado formation by simulating well -documented tornadic and null cases, and by performing further idealized simu-lations.-- Investigate the processes of hail formation in two distinctive severe storm types using simplified and complex microphysical parameterizations.-- Reexamine existing data collected in the urban environment by performing numerical sensitivity experiments for both nocturnal organized convection and afternoon locally-forced convection.Successful completion of this research will lead to improved understanding and ability to forecast several types of high impact weather including flash flooding, tornadoes, high winds and severe hail.A-i

由于其经济影响很大，并且对公共安全的重要性，大气对流系统的研究是研究的优先考虑。 根据该奖项，首席调查员将继续研究与对流风暴相关的各种主题。 要解决的具体主题包括： - 基于雷达的气候发展，重点是美国对美国的增长阶段（MCS）在美国对对流的空间和时间分布，以表征导致MCS形成的最常见发展模式，并了解MCS不同类别的过程的变化。 - 通过先进的中尺度数值模型进行敏感性研究，以检查环境控制的相对优势与早期对流强迫对MCS结构和进化的细节。-使用数值模型，研究土壤湿度量及其不均匀性的影响及其对MCS的启动和强度的效果。通过在稳定的空气质量上进行可定义的介体细胞并对选定的病例进行数值模拟，以确定负责严重风的机制。-通过模拟有效的龙卷风和无效的案例，进一步了解负责龙卷风形成的过程，并通过进一步的理想形式进行了两种独特的参数，并通过模拟了进一步的型号，并使用了两种独特的参数。 Reexamine existing data collected in the urban environment by performing numerical sensitivity experiments for both nocturnal organized convection and afternoon locally-forced convection.Successful completion of this research will lead to improved understanding and ability to forecast several types of high impact weather including flash flooding, tornadoes, high winds and severe hail.A-i