Improved Different Absorption LIDAR System for Measurement of Atmospheric Water Vapor and Temperature

这一小型企业创新研究第一阶段项目将探讨用于测量大气水汽和温度分布的交钥匙差分吸收激光雷达(DIAL)系统的可行性。先进的大气模型需要对现有测量技术不准确的高海拔地区的湿度和温度进行空间分辨率测量。为了满足这些需求，拟议的系统结合了市面上可获得的激光光源，以产生控制良好的窄线宽脉冲，从而实现对水蒸气浓度的远程测量，灵敏度为0.5毫克/公斤，温度在2K以内。该系统将由开发良好并已为高可靠性设计的激光光源建造。波长控制将由放大到适当脉冲能量的单模半导体激光器提供。确定放大的半导体激光脉冲的特征将是第一阶段的主要研究目标。使用脉冲放大的连续波激光将改进频率控制，这对于在对流层顶和平流层下部进行准确测量至关重要。此外，通过利用单模半导体激光器的可调谐和窄线宽，可以测量吸水线比率，从而可以确定远程温度。该系统将紧凑、坚固、具有高壁塞效率，并将在俯视几何结构中安全运行。

This Small Business Innovation Research Phase I project will address the feasibility of a turn-key Differential Absorption LIDAR (DIAL) system for the measurement of atmospheric water vapor and temperature profiles. Advanced atmospheric models require spatially resolved measurements of humidity and temperature at high altitude where existing measurement techniques are inaccurate. To address these needs, the proposed system combines commercially available laser sources to generate well controlled, narrow line width pulses that will allow remote measurement of water vapor concentration with a sensitivity of 0.5 mg/kg and temperatures to within 2 K. The system will be constructed from laser sources that are well developed and have already been engineered for high reliability. Wavelength control will be provided by a single-mode diode laser amplified to suitable pulse energies. Characterizing the amplified diode laser pulses will be the key research objective in Phase I. Use of a pulse-amplified cw laser will result in improved frequency control that is essential for accurate measurement at the tropopause and lower stratosphere. Furthermore, by taking advantage of both the tunability and narrow line width of a single-mode diode laser, water absorption line ratios can be measured from which remote temperatures can be determined. The system will be compact, robust, have high wall-plug efficiency, and will operate safely in a look-down geometry.