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，对开尔文-亥姆霍兹不稳定性（KHI）动力学及其对地球大气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热层（MLT），并对动力学做出重大贡献。 此外，KHI的演变影响VHF多普勒雷达风测量误差，产生强大的，持久的分层和系统倾斜的折射率表面的规模可与VHF雷达布拉格尺度。 本项目涉及这两个方面。 观测将在秘鲁的希卡马卡射电观测台进行，该观测台在整个低层大气和MLT中提供了灵敏度和分辨率的出色组合。SOUSY雷达（在JRO）提供的对流层中部高度的高距离分辨率和灵敏度，加上使用新开发的无人驾驶航空系统（称为微型自主飞行器）进行的并行、定量、高分辨率、现场测量，将对高分辨率KHI动态和雷达测量误差进行无与伦比的评估。强大的JRO发射机和大型天线阵列提供的相对高分辨率和更高功率的能力将把SOUSY结果扩展到MLT中。最后，这些观测结果将用于初始化一系列对KHI雷达后向散射和相关动力学参数的数值评估，使用一种新的能力进行直接数值模拟（DNS），以表征和指导KHI雷达后向散射和相关动力学参数的修正，测量误差伴随着这些动力学的一般流动条件。在雷达风测量的不准确性，从KHI是一个限制因素，在理解大气动力学的基本上所有这些观测和研究涉及运动尺度，包括：平均运动、风切变、大尺度潮汐和行星波活动、小尺度重力波动力学以及小尺度不稳定性和湍流生成过程。因此，该项目的结果将改善VHF雷达观测的所有应用，使科学界以及天气和气候建模应用受益匪浅。 该项目还将提高对波与不稳定动力学之间相互作用的定量理解，这些动力学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态的参数化更好。