Collaborative Research: Quantifying KHI, Turbulence Processes and Radar Biases Using Radar Observations and In Situ Measurements at JRO and Very-High-Resolution DNS

这是一个为期3年的项目，旨在开展开尔文-亥姆霍兹不稳定(KHI)动力学及其对地球大气中湍流和混合的影响的实验和理论研究。众所周知，KHI发生在整个低层大气以及中间层和低热层(MLT)，并对动力学有重大贡献。此外，KHI的演变通过在与VHF雷达布拉格尺度相当的尺度上产生强烈的、持久的分层和系统的折射率面倾斜来影响VHF多普勒雷达测风误差。这个项目涉及这两个方面。观测将在秘鲁的Jicamara射电观测站(JRO)进行，该观测站在整个低层大气和MLT中提供了非凡的灵敏度和分辨率。Sousy雷达(在JRO)提供的高距离分辨率和中对流层高度的灵敏度，加上使用新开发的名为微型自主飞行器(MAV)的无人驾驶航空系统进行的同步、定量、高分辨率的现场测量，将对高分辨率KHI动力学和雷达测量误差提供无与伦比的评估。强大的JRO发射机和大型天线阵列所提供的相对高分辨率和更高功率的能力将把Sousy结果扩展到MLT中。最后，这些观测将被用来初始化对KHI雷达后向散射和相关动力学参数的一系列数值评估，使用一种新的能力来执行直接数值模拟(DN)，以表征和指导在一般气流条件下伴随这些动力学的测量误差。KHI雷达测风的不准确是在基本上所有运动尺度上理解大气动力学的限制因素，包括：平均运动、风切变、大尺度潮汐和行星波活动、较小尺度的重力波动力学、以及小尺度不稳定和湍流生成过程。因此，该项目的结果将改进甚高频雷达观测的几乎所有应用，为科学界以及天气和气候模拟应用带来巨大好处。该项目还将改进对波动和不稳定动力学之间相互作用的定量理解，这些不稳定动力学驱动着整个大气和所有尺度上的运动。这将导致天气和气候模式中小尺度动力学的更好的参数化。

This is a 3-year project to undertake experimental and theoretical studies of Kelvin-Helmholtz Instability (KHI) dynamics and their implications for turbulence and mixing in the Earth atmosphere. KHI is known to occur throughout the lower atmosphere as well as the mesosphere and lower thermosphere (MLT) and to contribute significantly to the dynamics. In addition, KHI evolution affects VHF Doppler radar wind measurement errors by producing strong, persistent layering and a systematic tilting of refractive index surfaces on scales comparable to VHF radar Bragg scales. This project addresses both of these aspects. Observations will be performed at the Jicamarca Radio Observatory (JRO) in Peru, which provides an exceptional combination of sensitivity and resolution throughout the lower atmosphere and the MLT. High range resolution and sensitivity at mid-tropospheric heights provided by the SOUSY Radar (at JRO), coupled with concurrent, quantitative, high-resolution, in situ measurements made using a newly developed unmanned aerial system, named the micro-autonomous vehicle (MAV), will provide an unsurpassed assessment of both high resolution KHI dynamics and radar measurement errors. The relatively high-resolution and higher-power capability provided by the powerful JRO transmitter and large antenna array will then extend the SOUSY results into the MLT. Finally, these observations will be used to initialize a series of numerical assessments of KHI radar backscatter and associated dynamical parameters using a new capability to perform direct numerical simulations (DNS) to characterize, and guide corrections of, measurement errors accompanying these dynamics for general flow conditions.The inaccuracies in radar wind measurements from KHI is a limiting factor in understanding atmospheric dynamics on essentially all scales of motion, including: mean motions, wind shears, large-scale tidal and planetary wave activity, smaller-scale gravity wave dynamics, and small-scale instabilities and turbulence-generating processes. The results from this project, therefore, will improve practically all applications of VHF radar observations to great benefit of the scientific community as well as weather and climate modeling applications. The project also will result in improved quantitative understanding of interactions between waves and instability dynamics that drive motions throughout the atmosphere and at all scales. This will lead to better parameterization of small-scale dynamics in weather and climate models.