Dynamics of the Great Plains Low-Level Jet and Its Effect on Mesoscale Precipitation Systems

[9616728]阿瑞特夏季大平原低空急流是一种已知与恶劣天气事件有关的现象。更好地了解低空急流可以更好地预测大平原地区的恶劣天气。首席研究员将使用数值模拟和观测分析相结合的方法来量化在大平原低空急流形成过程中边界层过程和天气动力强迫的相对贡献。低空急流引起的辐散对中尺度降雨系统的影响也将被研究。该项目将使用来自最近实施的观测系统的数据，并将采用新的策略来分离导致低空急流的各种过程的贡献。重点将放在对物理过程的研究上，这些物理过程在以前的模拟研究中已经指出，对于低空急流及其随后对中尺度降水系统的影响是重要的，但尚未得到观测证实。这项研究的完成将提高我们对低空急流动力学基本问题的理解，并将支持改进大平原地区夜间降雨的预测。＊＊＊

9616728 Arritt The summertime Great Plains low-level jet is phenomenon known to be associated with severe weather events. Better understanding of the low-level jet could lead to better forecasts of severe weather within the Great Plains. The Principal Investigator will use a combination of numerical modeling and observational analysis to quantify the relative contributions of boundary-layer processes and synoptic dynamical forcing in the formation of the Great Plains low- level jet. The effect of divergence induced by the low-level jet on mesoscale rainfall systems also will be investigated. The project will use data from recently implemented observing systems and will adopt new strategies for isolating the contributions of the various processes that lead to the low-level jet. Emphasis will be given to the examination of physical processes that have been indicated in previous modeling studies as important for the low-level jet and its subsequent effects on mesoscale precipitation systems, but have not yet been confirmed by observations. Accomplishment of the research will provide improvements in our understanding of the fundamental issues in the dynamics of the low-level jet, and will support improvements in the prediction of nocturnal rainfall in the Great Plains region. ***