Collaborative Research: Profiling of Winter Storms

合作研究：冬季风暴概况

• 批准号: 1247404
• 负责人: Robert Rauber
• 金额: $ 94.26万
• 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: 2013
• 资助国家: 美国
• 起止时间: 2013-01-15 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1247404&HistoricalAwards=false
• 关键词: Collaborative; Research; Profiling; Winter; Storms

Processes governing the spatial and temporal variability of precipitation within the "comma head" sector of extratropical cyclones remain poorly understood. This sector of baroclinic storm systems is often the focus of hazardous winter weather including heavy snowfall, blizzards and ice storms that markedly impact transportation and other human activities. This investigative team seeks to improve our understanding of precipitation substructures within this zone by addressing outstanding questions arising from the Profiling of Winter Storms (PLOWS) field campaign, which was carried out during the winters of 2008-09 and 2009-10. Observations collected during PLOWS included extensive in-situ microphysical data gathered by the NSF/NCAR C-130 aircraft, high-resolution remote sampling of precipitation structures by the University of Wyoming Cloud Radar and Lidar carried aboard the C-130, complementary views from ground-based radars and profiling systems, and special serial rawinsonde launches. Additional insights will be gained through high-resolution simulations suitable for comparison with a wide range of observed precipitation substructures. Planned investigations will center on: (1) The nature and source of instability creating cloud top generating cells, including determination of updraft magnitudes, origins and role supercooled water in the generation and growth of ice particles near cloud top, ice particle concentrations within generating cells and associated precipitation plumes, and processes leading to the rather ubiquitous generating-cell structures observed during PLOWS; (2) the means by which potential instability is generated within zones characterized by deep upright elevated convection on the warmer side of comma-head regions, the relationship between the "dry-slot" upper-tropospheric airstream moving over warm-frontal surfaces, and determination of the role of synoptic-scale vertical motions accompanying frontogenesis in triggering release of this instability; (3) the origins of linear precipitation bands and their potential creation by synoptic-scale deformation acting upon descending ice particle plumes issued by elevated generating cells, as well as differing ice particle characteristics within and outside these bands; (4) the relationship of polarization radar signatures to measured in situ microphysical properties, and in particular determination of whether supercooled water or its effects (e.g., rimed particles) can be dependably detected via remote sensing; and (5) the nature of stratiform- vs. convective-cloud region flows with attention to fine scale wave features, frontal interfaces, their effects on microphysical processes, and their relationship to isentropic surfaces, shearing instability, and low-level fronts in the production of locally-enhanced precipitation rates.The intellectual merit of this effort rests on full exploitation of the unique and extensive PLOWS project dataset to address longstanding questions concerning the nature and origins of precipitation within winter cyclones in more complete and definitive ways than has heretofore been possible. Broader impacts of this research will include a carefully designed mix of undergraduate and graduate education and testing of improved operational strategies for remote sensing of winter weather systems hinging on emerging observational assets including NOAA's newly-upgraded dual-polarization network of WSR-88D radars. Anticipated longer-term impacts include improved ability of numerical models to simulate precipitation substructures in winter storms with direct application to forecasts benefiting the public, as well as recruitment of new scientists qualified to undertake atmospheric field research.

控制温带气旋“逗号头”区内降水时空变化的过程仍然知之甚少。 斜压风暴系统的这一区域通常是冬季危险天气的焦点，包括大雪、暴风雪和冰暴，严重影响交通和其他人类活动。 该调查小组旨在通过解决 2008 年 9 月和 2009 年 10 月冬季进行的冬季风暴分析 (PLOWS) 实地活动中出现的突出问题，提高我们对该区域内降水基础结构的了解。 PLOWS 期间收集的观测数据包括 NSF/NCAR C-130 飞机收集的大量现场微物理数据、C-130 上携带的怀俄明大学云雷达和激光雷达对降水结构进行高分辨率远程采样、地面补充视图基于雷达和剖面分析系统，以及特殊的系列拉文探空仪发射。 通过适合与各种观测到的降水子结构进行比较的高分辨率模拟，将获得更多见解。计划的研究将集中在：（1）产生云顶生成单元的不稳定性的性质和来源，包括确定上升气流的大小、来源和过冷水在云顶附近冰颗粒的生成和生长中的作用、生成单元内的冰颗粒浓度以及相关的降水羽流，以及导致犁耕期间观察到的相当普遍的生成细胞结构的过程； (2) 在以逗点头区域温暖一侧的深层直立高对流为特征的区域内产生潜在不稳定的方式，在暖锋面上移动的“干槽”对流层上层气流之间的关系，以及确定伴随锋生的天气尺度垂直运动在触发这种不稳定性释放中的作用； (3) 线性降水带的起源及其通过天气尺度变形作用于由升高的生成单元发出的下降冰粒羽流而产生的潜在产生，以及这些带内外不同的冰粒特征； (4) 偏振雷达特征与现场测量的微物理特性的关系，特别是确定是否可以通过遥感可靠地检测到过冷水或其影响（例如，边缘颗粒）； (5) 层状云区域流与对流云区域流的性质，关注细尺度波特征、锋面界面、它们对微物理过程的影响，以及它们与等熵表面、剪切不稳定性和低层锋面的关系这项工作的智力价值在于充分利用独特且广泛的 PLOWS 项目数据集，以比以往更完整和明确的方式解决有关冬季气旋降水的性质和起源的长期问题。迄今为止都是可能的。 这项研究的更广泛影响将包括精心设计的本科生和研究生教育组合，以及对冬季天气系统遥感改进操作策略的测试，这取决于新兴的观测资产，包括 NOAA 新升级的 WSR-88D 雷达双极化网络。预期的长期影响包括提高数值模型模拟冬季风暴降水子结构的能力，直接应用于造福公众的预测，以及招募有资格进行大气现场研究的新科学家。