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

这项研究的目的是进一步阐明当考虑实际的云形成过程时，低层上游湿度对复杂地形产生的重力波幅度的影响。一个特别的焦点是两个相互竞争的过程的净结果，这两个过程将采取行动加强或削弱浪潮活动。将使用的方法首先是在即将到来的DEEPWAVE实验期间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的高性能仪器机载环境研究平台(HIAPER)获得的对流层上层重力波数据结合在一起，理想情况下，还将与综合探空系统(ISS)收集的上游风廓线和无线电探空仪剖面相结合，这些数据已经作为DEEPWAVE的一部分提出了要求。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)相对于干事件的波动活动的放大，2)相对于干事件的波活动的减弱，以及3)由于两个因素的抵消而不改变幅度。智力上的优点：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，重点一直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，单独的流动阻塞理想化模拟研究表明，云凝结所涉及的实际微物理过程可能导致与纯热力学预测的行为不同的行为。真正知道这些效应发生在真实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现象。因此，这里提出的研究将允许更完整地解释水分对山波活动的影响，这是一个更大的问题的一部分，涉及在考虑所有可能的因素(例如边界层效应)时描述这种活动。更广泛的影响：深度、垂直传播的山波的众多影响被DEEPWAVE实验本身的动机很好地掩盖了。其中包括破碎波引起的航空湍流、山浪拖曳对一般气候模拟的影响，以及极地平流层云形成对臭氧的破坏。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组合完成的，这两个方面都将通过这项研究得到改善。在HIAPER收集的云摄影测量、上游探测剖面和波浪信息之间，存在一个完整的验证数据集，用于检验数值模式输出与观测。显然，需要改进的领域将是微物理参数化，这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结果波活动将有助于人类预报员根据常规观测(如卫星)预测事件。由于这项研究是在本科气象学课程之外进行的，因此也将为处于职业生涯早期阶段的学生提供极好的教育机会。虽然一名学生将参与实际的现场活动本身，以及规划和随后的分析，但收集的数据集可以很容易地纳入课堂材料(特别是云物理和波浪动力学)，强调更多理论主题的现实应用。

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.