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”区域降水时空变化的过程仍然知之甚少。斜压风暴系统的这一部分通常是冬季危险天气的焦点，包括大雪、暴风雪和冰暴，这些天气明显影响交通和其他人类活动。该调查小组旨在通过解决2008-09年和2009-10年冬季进行的冬季风暴分析（PLOWS）野外活动中出现的悬而未决的问题，提高我们对该区域降水亚结构的理解。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，怀俄明大学云雷达和C-130上携带的激光雷达对降水结构进行的高分辨率远程采样，来自地面雷达和剖面系统的补充视图，以及特殊的系列雷达探空仪发射。通过高分辨率模拟，将获得更多的见解，适合与观测到的大范围降水亚结构进行比较。计划的调查将集中在：(1)形成云顶生成单体的不稳定性的性质和来源，包括确定上升气流的大小、过冷水在云顶附近冰粒的产生和生长中的起源和作用、生成单体内的冰粒浓度和相关的降水羽流，以及导致PLOWS期间观测到的相当普遍的生成单体结构的过程；(2)逗号区较暖侧的深直立高架对流区产生潜在不稳定的方式，在暖锋面上方移动的对流层上层“干槽”气流之间的关系，以及伴随锋生的天气尺度垂直运动在触发这种不稳定释放中的作用；(3)线状降水带的起源及其在天气尺度形变作用下由高空生单体发出的下降冰粒羽流的可能性，以及线状降水带内外不同的冰粒特征；(4)极化雷达特征与实测的原位微物理性质的关系，特别是确定是否可以通过遥感可靠地探测到过冷水或其影响（例如，雾状颗粒）；(5)层状云与对流云区域流动的性质，关注细尺度波特征、锋面界面、它们对微物理过程的影响，以及它们与等熵面、剪切不稳定和低层锋在局地增强降水率产生中的关系。这项工作的智力价值在于充分利用独特而广泛的PLOWS项目数据集，以比以往更完整和更明确的方式解决有关冬季气旋中降水的性质和起源的长期问题。这项研究的广泛影响将包括精心设计的本科和研究生教育组合，以及基于新兴观测资产（包括NOAA新升级的WSR-88D雷达双极化网络）的冬季天气系统遥感改进操作策略的测试。预期的长期影响包括提高数值模式模拟冬季风暴降水子结构的能力，并直接应用于造福公众的预报，以及招募新的有资格从事大气实地研究的科学家。