基于中高层大气激光雷达的汤加火山灰探测

    Detection of Tonga Volcanic Ash Using Middle and Upper Atmospheric Lidar

    • 采用中高层大气激光雷达在武汉 (30.5°N, 114.3°E)上空对汤加火山灰进行探测, 分析汤加火山灰2022年3月至7月在武汉上空传播时的强度变化, 并对火山灰的埃指数进行了分析. 研究发现, 在2022年3月8日至2022年4月7日期间, 探测到的火山灰信号相对较弱, 从2022年4月10日开始, 探测到的火山灰回波信号强度突然增强, 并且该信号在随后的几个月中持续稳定维持在海拔20~25 km之间. 这一现象表明, 火山灰的传播在这段时间内发生了明显变化, 可能与大气的流动特征密切相关. 通过对所探测的火山灰高度进行分析, 发现火山灰在平流层中的传播呈现不均匀的层状结构, 显示火山灰在不同高度和层次之间的分布差异, 为进一步研究火山灰在大气中的传播机制和对环境的影响提供了重要的依据. 此外, 根据所获得的激光雷达数据分析结果可知, 在2022年4-7月, 探测到的火山灰高度与火山灰颗粒尺寸的相关性较弱, 这表明火山灰颗粒的运动和沉降行为可能受到多种复杂因素的影响.

       

      Abstract: This study presents the first report of detecting Tonga volcanic ash over Wuhan (30.5°N, 114.3°E) using a middle and upper atmospheric lidar system. The research analyzes the intensity variations of Tonga volcanic ash as it spread over Wuhan from March to July 2022, and also examines the volcanic ash’s Ångström exponent. The findings reveal that from 8 March to 7 April 2022, the detected volcanic ash signals were relatively weak. However, starting on 10 April 2022, the lidar detected a sudden increase in the strength of the volcanic ash return signals, which remained consistently strong between altitudes of 20~25 km over the following months. This phenomenon suggests a significant change in the volcanic ash’s propagation during this period, which may be closely related to atmospheric flow patterns. Further analysis of the detected volcanic ash heights revealed an uneven, layered structure in the stratosphere, indicating a distinct distribution of volcanic ash at different altitudes. This provides important insights into the mechanisms of volcanic ash propagation in the atmosphere and its environmental impact. Additionally, the lidar data analysis from April to July 2022 shows a weak correlation between the detected volcanic ash altitude and the particle size. This suggests that the movement and settling behavior of volcanic ash particles are likely influenced by various complex factors, rather than being governed solely by their size.

       

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