论文标题
从强度调节的连续波差异吸收激光雷达测量中，cO2柱二氧化碳柱检索期间的现场评估
Field Evaluation of Column CO2 Retrievals from Intensity-Modulated Continuous-Wave Differential Absorption Lidar Measurements during ACT-America
论文作者
论文摘要
我们提出了对Act-America项目期间大气色谱柱二氧化碳分数的空气强度调节连续波（IM-CW）liDAR测量的评估。该激光雷达系统在1.57111-UM CO2吸收线上同时在线传输和离线波长，每个调制波长都使用正交扫描频率波形。在通过短路径测量值校准该系统的光谱特性之后，我们使用Hitran SpectRoscic数据库从LIDAR测量的光学深度中得出平均柱二氧化碳混合比（XCO2）。基于对气象参数的原位测量和校准数据的二氧化碳浓度，我们证明了与XCO2值相比，我们的LiDAR CO2测量值从季节到季节都保持一致，并且具有0.80 ppm的绝对校准误差（标准偏差）为0.80 ppm。通过使用10秒或更长的移动平均线，可以获得1 ppm或更高的长期稳定性。确定0.1-S，1-S，10-S和60-S平均的估计CO2测量精度分别为3.4 ppm（0.84％），1.2 ppm（0.30％），0.43 ppm（0.10％）和0.26 ppm（0.26 ppm（0.063％））。这些分别对应于120、330、950和1600的测量信噪比。在一小时的飞行时间内，XCO2的漂移低于我们的检测极限约0.1 ppm。这些分析表明，测量稳定性，精度和准确性都远低于研究大气XCO2中天气尺度变化所需的阈值。
We present an evaluation of airborne Intensity-Modulated Continuous-Wave (IM-CW) lidar measurements of atmospheric column CO2 mole fractions during the ACT-America project. This lidar system transmits online and offline wavelengths simultaneously on the 1.57111-um CO2 absorption line, with each modulated wavelength using orthogonal swept frequency waveforms. After the spectral characteristics of this system were calibrated through short-path measurements, we used the HITRAN spectroscopic database to derive the average-column CO2 mixing ratio (XCO2) from the lidar measured optical depths. Based on in situ measurements of meteorological parameters and CO2 concentrations for calibration data, we demonstrate that our lidar CO2 measurements were consistent from season to season and had an absolute calibration error (standard deviation) of 0.80 ppm when compared to XCO2 values derived from in situ measurements. By using a 10-second or longer moving average, a long-term stability of 1 ppm or better was obtained. The estimated CO2 measurement precision for 0.1-s, 1-s, 10-s, and 60-s averages were determined to be 3.4 ppm (0.84%), 1.2 ppm (0.30%), 0.43 ppm (0.10%), and 0.26 ppm (0.063%), respectively. These correspond to measurement signal-to-noise ratios of 120, 330, 950, and 1600, respectively. The drift in XCO2 over one-hour of flight time was found to be below our detection limit of about 0.1 ppm. These analyses demonstrate that the measurement stability, precision and accuracy are all well below the thresholds needed to study synoptic-scale variations in atmospheric XCO2.
