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

合作研究：利用 JRO 和超高分辨率 DNS 的雷达观测和原位测量来量化 KHI、湍流过程和雷达偏差

• 批准号: 1041977
• 负责人: David Fritts
• 金额: $ 28.5万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2012-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1041977&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; KHI; Turbulence

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.

这是一个为期 3 年的项目，旨在对开尔文-亥姆霍兹不稳定性 (KHI) 动力学及其对地球大气中的湍流和混合的影响进行实验和理论研究。众所周知，KHI 发生在整个低层大气以及中间层和低层热层 (MLT)，并对动力学做出了重大贡献。 此外，KHI 演化通过产生强烈、持续的分层和折射率表面的系统倾斜（其尺度可与 VHF 雷达布拉格尺度相当）来影响 VHF 多普勒雷达风测量误差。 该项目解决了这两方面的问题。 观测将在秘鲁的吉卡马卡射电天文台 (JRO) 进行，该天文台在整个低层大气和 MLT 中提供了卓越的灵敏度和分辨率组合。由 SUSY 雷达（JRO）提供的对流层中高度的高距离分辨率和灵敏度，加上使用新开发的无人机系统（称为微型自主飞行器（MAV））进行的并发、定量、高分辨率、原位测量），将为高分辨率 KHI 动态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提供的相对高分辨率和较高功率能力将把 SUSY 结果扩展到 MLT。最后，这些观测结果将用于初始化 KHI 雷达后向散射和相关动态参数的一系列数值评估，使用执行直接数值模拟 (DNS) 的新功能来表征并指导修正伴随这些动态的一般流动测量误差KHI 雷达风测量的不准确性是理解基本上所有运动尺度上的大气动力学的限制因素，包括：平均运动、风切变、大规模潮汐和行星波活动、较小尺度重力波动力学以及小规模的不稳定和湍流产生过程。因此，该项目的结果将改善 VHF 雷达观测的几乎所有应用，为科学界以及天气和气候建模应用带来巨大利益。 该项目还将提高对波浪与不稳定性动力学之间相互作用的定量理解，这些相互作用驱动整个大气层和所有尺度的运动。这将导致天气和气候模型中小尺度动力学的更好参数化。