Abstract. A new concept for a cluster of compact lidar systems named VAHCOLI (Vertical And Horizontal COverage by LIdars) is presented which allows to measure temperatures, winds, and aerosols in the middle atmosphere (∼10–110 km) with high temporal and vertical resolution of minutes and some tens of meters, respectively, simultaneously covering horizontal scales from few hundred meters to several hundred kilometers (four-dimensional coverage). The individual lidars (units) being used in VAHCOLI are based on a diode-pumped alexandrite laser currently designed to detect potassium (λ = 770 nm), as well as on sophisticated laser spectroscopy measuring all relevant frequencies (seeder laser, power laser, backscattered light) with high temporal resolution (2 ms) and high spectral resolution applying Doppler-free spectroscopy. The frequency of the lasers and the narrow-band filter in the receiving system are stabilized to typically 10–100 kHz which is a factor of roughly 10⁻⁵ smaller than the Doppler-broadened Rayleigh signal. Narrow-band filtering allows to measure Rayleigh and/or resonance scattering separately from the aerosol (Mie) signal, all during night and day. Lidars used for VAHCOLI are compact (volume: ∼1 m³) and are multi-purpose systems employing contemporary electronical, optical, and mechanical components. The units are designed to autonomously operate under harsh field conditions at remote locations. An error analysis with parameters of the anticipated system demonstrates that temperatures and line-of-sight winds can be measured from the lower stratosphere to the upper mesosphere with an accuracy of ±(0.1–5) K and ±(0.1–10) m/s, respectively, increasing with altitude. We demonstrate that some crucial dynamical processes in the middle atmosphere, such as gravity waves and stratified turbulence, can be covered by VAHCOLI with sufficient temporal/vertical/horizontal sampling and resolution. The four-dimensional capabilities of VAHCOLI allow to perform time-dependent analysis of the flow field, for example employing Helmholtz decomposition, and to carry out statistical tests regarding intermittency, helicity etc. First test measurements under field conditions with a prototype lidar being built for VAHCOLI were performed in January 2020. The lidar operated successfully during a six week period (night and day) without any adjustment. These observations covered a height range of ∼5–100 km and demonstrate the capability and applicability of this unit for the VAHCOLI concept.

中文翻译：

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VAHCOLI，激光雷达的新概念：技术设置，科学应用和首次测量

摘要。提出了一个紧凑的激光雷达系统集群的新概念，称为VAHCOLI（LIdars的垂直和水平覆盖），它可以以较高的时间和垂直分辨率测量中层大气（约10-110 km）中的温度，风和气溶胶。分钟和数十米分别覆盖数百米到几百公里的水平刻度（四维覆盖）。单个激光雷达（单位）在VAHCOLI中使用的是基于目前设计用于检测钾（λ= 770 nm）的二极管泵浦变石激光器，以及基于在高时间范围内测量所有相关频率（播种激光器，功率激光器，反向散射光）的复杂激光光谱学高分辨率（2毫秒）和采用无多普勒光谱仪的高光谱分辨率。接收系统中的激光器和窄带滤波器的频率通常稳定在10–100 kHz，这比多普勒增宽的瑞利信号小大约10 ^-5。窄带过滤可以在白天和黑夜与气溶胶（Mie）信号分开测量瑞利和/或共振散射。用于VAHCOLI的激光雷达紧凑（体积：约1 m ³），是采用现代电子，光学和机械组件的多功能系统。这些设备旨在在恶劣的现场条件下在偏远地区自主运行。对预期系统的参数进行的误差分析表明，可以测量从平流层下部到中高层的温度和视线风，精度为±（0.1-5）K和±（0.1-10）m / s分别随高度增加。我们证明，VAHCOLI可以覆盖中层大气中的一些关键动力学过程，例如重力波和分层湍流，并具有足够的时间/垂直/水平采样和分辨率。VAHCOLI的四维功能可以对流场进行时变分析，例如采用亥姆霍兹分解，并在2020年1月对现场条件进行了首次测试，并为VAHCOLI建造了原型激光雷达。该激光雷达在六周的时间内（昼夜）成功运行，无需进行任何调整。这些观测结果涵盖了大约5-100 km的高度范围，并证明了该装置对VAHCOLI概念的能力和适用性。