Mountain-Wave Evolution and Orographic Precipitation II

山地地形对当地和区域天气状况有重大影响。众所周知，山间气流会增强上坡两侧的降水，上升到大气不同层次的空气的影响对更大尺度的天气模式有下游影响。然而，关于细节的许多问题仍然存在。该奖项为一名研究人员和两名研究生提供资金，研究与大气与山地地形相互作用有关的主题。除了培养下一代科学家外，该奖项还将通过改善天气预报的潜力产生广泛的社会影响。工作的两个重点是提高对以下方面的认识：1)多尺度地形降水的动力学和可预测性；2)山波及其对天气尺度流的反馈。地形降水工作将采用理想模式进行。研究小组将利用气象研究与预报（WRF）的数值模式，通过在有和没有山脉和气旋的情况下诊断这些过程，研究动力学和微物理学对降水增加的相对贡献。将使用具有不同背景静态稳定性、湿度通量和山脊位置的案例进行额外的工作。地形降水成分还将包括中尺度可预测性的研究，因为研究人员假设，对大尺度气流的小扰动将对与中尺度地形特征相关的降水模式产生大扰动。山波工作将使用建模、理论和先前野外活动的观测来解决重力波阻力如何影响非平凡的大尺度流动，以及在什么条件下非线性过程强烈调节山波的振幅。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Mountainous terrain has a significant impact on local and regional weather conditions. The flow over mountains is known to enhance precipitation on the upslope sides, and the impact of the air rising to different levels of the atmosphere has a downstream impact on larger-scale weather patterns. However, many questions about the details remain. This award provides funding for a researcher and two graduate students to study topics related to atmospheric interactions with mountain topography. In addition to the training of the next generation of scientists, this award will have a broad societal impact through the potential to improve weather forecasts.The two main thrusts of the work are on improving understanding of: 1) the dynamics and predictability of multi-scale orographic precipitation and 2) mountain waves and their feedback on the synoptic-scale flow. The orographic precipitation work would be conducted using idealized modeling. The research team will investigate the relative contributions of dynamics and microphysics toward increasing precipitation by diagnosing those processes in scenarios with and without mountains and cyclones using the Weather Research and Forecasting (WRF) numerical model. Additional work will be conducted using cases with different background static stabilities, moisture fluxes, and ridge positions. The orographic precipitation component will also include work on mesoscale predictability as the researchers hypothesize that small perturbations to the large-scale flow will generate large perturbations to the precipitation patterns associated with mesoscale terrain features. The mountain wave work would use modeling, theory, and observations from prior field campaigns to address how gravity-wave-drag influences nontrivial large-scale flows and under what conditions nonlinear processes strongly regulate the amplitude of mountain waves.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.