The Effects of Cloud Development and Structure on the Generation of Deep Vertically Propagating Mountain Waves

云的发育和结构对深层垂直传播山波产生的影响

• 批准号: 1418519
• 负责人: Brian Billings
• 金额: $ 5.21万
• 依托单位: St. Cloud State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1418519&HistoricalAwards=false
• 关键词: Effects; Cloud; Development; Structure; Generation

The objective of this research is to further clarify the effects of low-level upstream moisture on the amplitude of gravity waves generated by complex terrain when actual cloud formation processes are considered. A particular focus is the net result of two competing processes which will act to strengthen or weaken the wave activity. The method to be used begins with gathering a verification dataset of the upstream cloud structure by using a stereo photogrammetry system during the upcoming DEEPWAVE experiment. These cloud observations will be combined with upper tropospheric gravity wave data obtained by NCAR's High-performance Instrumented Airborne Platform for Environmental Research (HIAPER) and, ideally, upstream wind profiler and radiosonde profiles collected by the Integrated Sounding System (ISS), which have already been requested as part of DEEPWAVE. The observed events will then be studied using numerical simulations in an attempt to identify conditions leading to three scenarios: 1) amplification of wave activity relative to a dry event, 2) weakening of wave activity relative to a dry event, and 3) no change in amplitude due to offsetting of the two factors.Intellectual Merit :When the special problem of moisture effects on mountain wave activity has been examined by investigators, the focus has been on how the presence of water vapor and latent heat release modifies the air's static stability. However, separate idealized modeling studies of flow blocking show that the actual microphysical processes involved in cloud condensation can result in different behavior than that predicted from pure thermodynamics. The only way to truly know that these effects occur in the real atmosphere is to observe them, after which numerical simulations which closely match the observed behavior can be used to explain the underlying physics. Thus, the research proposed here will allow for a more complete explanation of the effects of moisture on mountain wave activity, which is part of a larger problem involving describing this activity when all possible factors (e.g. boundary layer effects) are considered.Broader Impacts :The numerous impacts of deep, vertically propagating mountain waves are well covered by the motivation for the DEEPWAVE experiment itself. These include aviation turbulence due to breaking waves, the effect of mountain wave drag on general climate modeling, and the destruction of ozone through formation of polar stratospheric clouds. As with any human impact, there will be a desire to predict these effects and the underlying wave activity which is done with a combination of numerical modeling and subjective forecaster judgment, both of which will be improved by this research. Between the cloud photogrammetry, upstream sounding profiles, and wave information collected by HIAPER, a complete verification dataset exists for testing numerical model output with observations. Obvious areas to look for improvement would be in the microphysics parameterization, which can be matched against the cloud observations. Additionally, documenting the resulting wave activity for different large scale synoptic patterns and moisture amounts will aid human forecasters in anticipating events based on routinely available observations, such as satellite. Since this research is being performed out of an undergraduate meteorology program, there will also be excellent educational opportunities for students at an early stage in their careers. While one student will participate in the actual field campaign itself, along with the planning and subsequent analysis, the datasets collected can be easily incorporated into classroom material (especially cloud physics and wave dynamics), emphasizing the real-world applications of the more theoretical topics.

本研究的目的是进一步阐明当考虑实际云形成过程时，低层上游湿度对复杂地形产生的重力波振幅的影响。一个特别的焦点是两个相互竞争的过程的净结果，这两个过程将加强或削弱波浪活动。在即将进行的DEEPWAVE实验中，使用立体摄影测量系统收集上游云结构的验证数据集。这些云观测将与NCAR的高性能环境研究机载仪器平台（HIAPER）获得的对流层上部重力波数据相结合，理想情况下，上游风廓线仪和综合探测系统（ISS）收集的无线电探空仪剖面图已经被要求作为DEEPWAVE的一部分。然后将使用数值模拟对观测到的事件进行研究，试图确定导致三种情况的条件：1）相对于干事件，波活动放大; 2）相对于干事件，波活动减弱; 3）由于两个因素的抵消，振幅没有变化。当研究人员研究了湿度对山波活动的影响这一特殊问题时，研究的重点是水蒸气和潜热释放的存在如何改变空气的静态稳定性。然而，单独的理想化的流动阻塞的模拟研究表明，云凝结所涉及的实际微物理过程可能会导致不同的行为比从纯热力学预测。真正知道这些效应发生在真实的大气中的唯一方法是观察它们，然后可以使用与观察到的行为密切匹配的数值模拟来解释潜在的物理学。因此，这里提出的研究将允许一个更完整的解释的影响，水分对山波活动，这是一个更大的问题，涉及描述这种活动时，所有可能的因素（如边界层效应）被认为是一部分。更广泛的影响：深，垂直传播的山波的众多影响很好地涵盖了深实验本身的动机。其中包括由于破碎波引起的航空湍流，山波阻力对一般气候建模的影响，以及通过形成极地平流层云对臭氧的破坏。与任何人类影响一样，人们希望预测这些影响和潜在的波浪活动，这是通过数值建模和主观预报员判断的结合来完成的，这两者都将通过这项研究得到改善。在HIAPER收集的云摄影测量，上游探空剖面和波浪信息之间，存在一个完整的验证数据集，用于测试数值模式输出与观测。需要改进的明显领域是微物理参数化，它可以与云观测相匹配。此外，记录不同大尺度天气模式和湿度的波活动将有助于人类预报员根据常规观测（如卫星观测）预测事件。由于这项研究是在本科气象学课程之外进行的，因此也将为学生在职业生涯的早期阶段提供良好的教育机会。虽然一名学生将参与实际的实地活动本身，沿着的规划和随后的分析，收集的数据集可以很容易地纳入课堂材料（特别是云物理学和波动动力学），强调更多的理论主题的实际应用。