Studies of Midlatitude Mesoscale Convective Systems

中纬度中尺度对流系统研究

• 批准号: 0500061
• 负责人: Richard Johnson
• 金额: $ 96.02万
• 依托单位: Colorado State University
• 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: 2005-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0500061&HistoricalAwards=false
• 关键词: Studies; Midlatitude; Mesoscale; Convective; Systems

The objective of this research is to enhance understanding of processes associated with midlatitude mesoscale convective systems (MCSs) and their accompanying severe weather, and ultimately to improve the prediction of such systems. Of particular interest are MCSs having varying patterns of organization of their attendant stratiform precipitation regions and those producing high winds and extreme rainfall. At present, the surface meteorological features associated such systems are not well documented.To address this problem, the Principal Investigator will utilize surface observations from the Oklahoma Mesonet (administered by the Oklahoma Climatological Survey), a dataset now with a record length of ten years, radar data from the WSR-88D network, and Rapid Update Cycle (RUC) analyses to investigate the surface and environmental conditions (wind, pressure, thermodynamic, and precipitation features) accompanying MCSs with trailing, leading, and parallel stratiform precipitation; bow echoes; mesoscale convective vortices (MCVs); and MCSs that produce extreme rainfall. The Oklahoma Mesonet data, consisting of 5-min surface observations at about 30-km resolution, will enable detailed analyses of the mesoscale surface pressure fields. Particular attention will be focused on mesohigh/wake low couplets within MCSs.The intellectual merit of the research derives from the new understanding it will provide of the structure and physical processes associated with a broad range of mesoscale convective systems. The surface signatures of MCSs having different orientations of their stratiform precipitation regions (trailing, leading, and parallel), bow echoes, MCVs, and extreme-rain-producing MCSs have heretofore only been documented from a limited number of case studies. The ten-year record of Oklahoma Mesonet observations now affords the opportunity to more comprehensively determine the surface signatures of a large sample of such precipitation systems, from which inferences can be made about their dynamics. The broader impacts of the research relate to how it will improve understanding and ultimately prediction of MCSs and accompanying severe weather. The surface features associated with a large class of MCSs are measures, sometimes direct and sometimes indirect, of their severity and processes within the storms. For example, bow echoes are characterized by extreme surface winds, MCSs with trailing stratiform precipitation by mesohigh/wake low couplets, and certain extreme rain-producing storms by regeneration of new cells in the same location along storm-generated outflow boundaries. The recognition of such features in relation to the storms they produce is important to weather services for reliable nowcasting and short-term forecasting. These storms are responsible annually for significant life and property damage, and currently the forecast skill for them is low. This research is ultimately directed toward improving the skill in such forecasts.

这项研究的目的是加强对中纬度中尺度对流系统（MCS）及其伴随的恶劣天气过程的理解，并最终提高此类系统的预测。 特别令人感兴趣的是MCS具有不同的组织模式，其伴随的层状降水区和那些产生大风和极端降雨。 目前，与这些系统相关的地面气象特征还没有很好的记录。为了解决这个问题，首席研究员将利用俄克拉荷马州Mesonet的地面观测数据（由俄克拉荷马州气候调查局管理），一个数据集，现在有十年的记录长度，来自WSR-88 D网络的雷达数据，以及快速更新周期（RUC）分析，以调查地表和环境条件（风，压力，热力学和降水特征）伴随MCS与尾随，领先和平行层状降水;弓回波;中尺度对流涡旋（MCV）;和MCS，产生极端降雨。 俄克拉荷马州的中尺度数据，包括5分钟的地面观测约30公里的分辨率，将使详细分析中尺度表面压力场。 特别注意将集中在MCSs. The研究的知识价值来自新的理解，它将提供与广泛的中尺度对流系统的结构和物理过程中的中高/尾流低couplets。 MCS的层状降水区域（尾随，领先，和平行），弓形回波，MCV，和极端降雨生产MCS具有不同的方向的表面签名迄今为止只记录了有限数量的案例研究。 俄克拉荷马州中尺度网观测的十年记录现在提供了一个机会，可以更全面地确定这种降水系统的大样本的表面特征，从中可以推断出它们的动态。该研究的更广泛影响涉及如何提高对MCS和伴随的恶劣天气的理解和最终预测。 与一大类MCS相关的表面特征是对它们在风暴中的严重性和过程的测量，有时是直接的，有时是间接的。 例如，弓形回波的特征是极端的地面风，MCS与尾随层状降水的中高/尾流低对，和某些极端的暴雨产生的风暴再生的新单元在同一位置沿着风暴产生的流出边界。 认识到这些特征与它们产生的风暴之间的关系，对于气象服务提供可靠的临近预报和短期预报十分重要。 这些风暴每年都会造成重大的生命和财产损失，目前对它们的预测能力很低。 这项研究最终是为了提高这种预测的技能。