Continuous water vapor and temperature profiles are critically needed for improved understanding of the lower atmosphere and potential advances in weather forecasting skill. Ground-based, national-scale profiling networks are part of a suite of instruments to provide such observations; however, the technological method must be cost-effective and quantitative. We have been developing an active remote sensing technology based on a diode-laser-based lidar technology to address this observational need. Narrowband, high-spectral-fidelity diode lasers enable accurate and calibration-free measurements requiring a minimal set of assumptions based on direct absorption (Beer–Lambert law) and a ratio of two signals. These well-proven quantitative methods are known as differential absorption lidar (DIAL) and high-spectral-resolution lidar (HSRL). This diode-laser-based architecture, characterized by less powerful laser transmitters than those historically used for atmospheric studies, can be made eye-safe and robust. Nevertheless, it also requires solar background suppression techniques such as narrow-field-of-view receivers with an ultra-narrow bandpass to observe individual photons backscattered from the atmosphere. We discuss this diode-laser-based lidar architecture's latest generation and analyze how it addresses a national-scale profiling network's need to provide continuous thermodynamic observations. The work presented focuses on general architecture changes that pertain to both the water vapor and the temperature profiling capabilities of the MicroPulse DIAL (MPD). However, the specific subcomponent testing and instrument validation presented are for the water vapor measurements only. A fiber-coupled seed laser transmitter optimization is performed and shown to meet all of the requirements for the DIAL technique. Further improvements – such as a fiber-coupled near-range receiver, the ability to perform quality control via automatic receiver scanning, advanced multi-channel scalar capabilities, and advanced processing techniques – are discussed. These new developments increase narrowband DIAL technology readiness and are shown to allow higher-quality water vapor measurements closer to the surface via preliminary intercomparisons within the MPD network itself and with radiosondes.

中文翻译：

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MicroPulse DIAL (MPD) – 一种基于二极管激光的激光雷达架构，用于定量大气廓线

迫切需要连续的水蒸气和温度分布图来提高对低层大气的了解和天气预报技能的潜在进步。地面、国家级剖面网络是提供此类观测的一套仪器的一部分；然而，技术方法必须具有成本效益和定量性。我们一直在开发一种基于基于二极管激光的激光雷达技术的主动遥感技术，以满足这种观测需求。窄带、高光谱保真二极管激光器可实现准确且免校准的测量，需要基于直接吸收（比尔-朗伯定律）和两个信号的比率的最少假设集。这些经过充分验证的定量方法被称为差分吸收激光雷达 (DIAL) 和高光谱分辨率激光雷达 (HSRL)。这种基于二极管激光器的架构的特点是其激光发射器的功率低于历史上用于大气研究的那些，可以使人眼安全且坚固耐用。尽管如此，它还需要太阳背景抑制技术，例如具有超窄带通的窄视场接收器，以观察从大气中反向散射的单个光子。我们讨论了这种基于二极管激光器的最新一代激光雷达架构，并分析了它如何满足国家级剖面网络提供连续热力学观测的需求。所介绍的工作侧重于与 MicroPulse DIAL (MPD) 的水蒸气和温度分析功能相关的一般架构变化。然而，提供的特定子组件测试和仪器验证仅适用于水蒸气测量。执行并显示光纤耦合种子激光发射器优化以满足 DIAL 技术的所有要求。进一步的改进——例如光纤耦合近程接收器、通过自动接收器扫描执行质量控制的能力、先进的多通道标量能力和先进的处理技术——都在讨论中。这些新的发展提高了窄带 DIAL 技术的成熟度，并被证明可以通过 MPD 网络本身和无线电探空仪的初步比对更接近地表进行更高质量的水汽测量。执行并显示光纤耦合种子激光发射器优化以满足 DIAL 技术的所有要求。进一步的改进——例如光纤耦合近程接收器、通过自动接收器扫描执行质量控制的能力、先进的多通道标量能力和先进的处理技术——都在讨论中。这些新的发展提高了窄带 DIAL 技术的成熟度，并被证明可以通过 MPD 网络本身和无线电探空仪的初步比对更接近地表进行更高质量的水汽测量。执行并显示光纤耦合种子激光发射器优化以满足 DIAL 技术的所有要求。进一步的改进——例如光纤耦合近程接收器、通过自动接收器扫描执行质量控制的能力、先进的多通道标量能力和先进的处理技术——都在讨论中。这些新的发展提高了窄带 DIAL 技术的成熟度，并被证明可以通过 MPD 网络本身和无线电探空仪的初步比对更接近地表进行更高质量的水汽测量。