Mechanisms of Convection-Wave Interactions

对流-波相互作用的机制

• 批准号: 0806553
• 负责人: Stefan Tulich
• 金额: $ 35.27万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0806553&HistoricalAwards=false
• 关键词: Mechanisms; Convection; Wave; Interactions

This project seeks to improve understanding of convection-wave interactions in the Tropics, with an emphasis on zonally-propagating, inertia-gravity wave disturbances with periods less than 2.5 days. Such disturbances are of interest owing to their strong ties to the diurnal cycle and potential role in the genesis of severe tropical storms, such as Hurricane Andrew 1992. Furthermore, space-time spectra of high-resolution satellite data show a dramatic westward bias in the propagation direction of these high-frequency wave modes, begging explanation and perhaps holding critical clues about wave-convection modulation mechanisms. A suite of carefully designed nested cloud-resolving model experiments on a uniform equatorial beta-plane will be performed using the Weather-Research Forecast (WRF) model system, to test hypotheses about what causes this asymmetry. Further insights will be gleaned from detailed diagnostic analyses, using techniques developed in previous work. These analyses will be applied to data from the idealized WRF model runs, as well as from other, much larger, realistic-boundary-condition model runs; and from observations. To assess the realism of the simulated wave structures, detailed comparisons will be made against composite radiosonde observations of temperature, moisture, and winds. Such observational composites already exist for low-frequency waves, but will be extended to diurnal and higher frequencies. The previously identified self-similarity of tropical convective wave life cycles across scales is expected to extend to these relatively short/fast waves, but with systematic differences across frequencies suggesting clues about the relative roles of temperature and moisture in wave dynamics. An important novelty of the observational component will be to bring in vertically-resolved cloud structure observations from CloudSat, which was launched in 2006.Scientific results of this work are expected to have broad impact in the atmospheric sciences by usefully informing efforts at improving convective parameterizations used in general-purpose regional and global models. Some of the modeling and diagnostic techniques will be packaged and offered as enhancements to the WRF model's "out-of-the-box" capabilities, as a service to the broader regional modeling community. This project will also contribute to the training and mentorship of a graduate student.

该项目旨在增进对热带地区对流-波相互作用的了解，重点是周期少于2.5天的纬向传播的惯性重力波扰动。这种扰动之所以令人感兴趣，是因为它们与昼夜循环有很强的联系，并可能在诸如1992年安德鲁飓风等严重热带风暴的形成中发挥作用。此外，高分辨率卫星数据的时空谱显示，这些高频波模的传播方向有戏剧性的西移，这需要解释，或许还掌握着关于波-对流调制机制的关键线索。将使用天气研究预报(WRF)模式系统在均匀的赤道Beta平面上进行一系列精心设计的嵌套云解析模式实验，以测试关于造成这种不对称的假设。将使用以前工作中开发的技术，从详细的诊断分析中收集进一步的见解。这些分析将应用于理想化的WRF模式运行的数据，以及来自其他更大的、现实的边界条件模式运行的数据；以及来自观测的数据。为了评估模拟的波浪结构的真实性，将与温度、湿度和风的复合无线电探空观测进行详细的比较。这样的观测合成已经存在于低频波，但将扩展到白天和更高的频率。先前发现的热带对流波生命周期在不同尺度上的自相似性预计将延伸到这些相对较短/较快的波，但不同频率的系统差异表明了温度和湿度在波动动力学中的相对作用。观测部分的一个重要创新之处将是引入2006年发射的CloudSat的垂直分辨云结构观测。这项工作的科学成果预计将对大气科学产生广泛影响，为改进通用区域和全球模式中使用的对流参数化提供有益的信息。一些建模和诊断技术将打包提供，作为WRF模型的“开箱即用”功能的增强，作为更广泛的区域建模社区的服务。该项目还将有助于研究生的培训和指导。