基于MST雷达的对流层顶观测研究

The researches on the tropopause based on the radiosonde and obscuration have revealed variation characteristics of the height and temperature of the tropopause. However, the radar detection has the advantage of high temporal resolution and continuous observation, which can not only enrich the observation data of the tropopause, but also can study the variation of the tropopause structure. Nevertheless, the research on the tropopause based on radar detection is still in its infancy in the nation so far. This project builds the universal automatic interpretation model of radar tropopause based on the echo energy difference among the radar spatial beams by using the continuous observation data for many years from Wuhan and Beijing MST radar built by the Chinese Meridian Project. This project use the observations from two MST radars, radiosondes and occultation to study the temporal and spatial evolution rule of radar tropopause structure, identify the radar tropopause processes of formation, dense, sparse, and layer disappearance, and discuss the difference between the radar tropopause and meteorological tropopause. Meanwhile, combining detection models of the atmospheric waves (gravity waves, tidal waves, planetary waves, et al.) based on the 3D wind field data from MST radar and radar echo characteristics under the special weather, studies the effects of the atmospheric waves and strong convective on the radar tropopause structure. This project can deeply understand the generation and change mechanism of the tropopause, and expand the application field of MST radar.

基于无线电探空仪和掩星数据的对流层顶观测揭示了对流层顶高度和温度的变化特性，而雷达探测具有高时间分辨率、持续观测的优势，不仅可以丰富对流层顶观测资料，还可开展对流层顶结构形态变化研究。目前，国内关于雷达探测对流层顶研究相对薄弱，尚没有系统开展。本项目基于国家子午工程武汉和北京两部MST雷达多年连续观测资料，构建基于雷达空间波束回波差异的普适性雷达对流层顶自动判读模型，并结合无线电探空仪和掩星数据，从雷达探测的角度研究对流层顶结构形态的时空演变特性，辨明对流层顶的生成、疏密和层间消亡等过程，分析雷达对流层顶与气象对流层顶的差异，进而建立更加完善的对流层顶探测分析模式。同时，基于MST雷达低空大气波动（重力波、潮汐波和行星波等）检测模型，以及特殊天气下雷达回波特征，研究低层大气波动和强对流天气对对流层顶结构形态的影响。本项目研究有助于深入理解对流层顶生成变化物理机制，拓展MST雷达应用领域。

基于无线电探空仪和掩星数据的对流层顶观测揭示了对流层顶高度和温度的变化特性，而雷达探测具有高时间分辨率、持续观测的优势，不仅可以丰富对流层顶观测资料，还可开展对流层顶结构形态变化研究。目前，国内关于雷达探测对流层顶研究相对薄弱，尚没有系统开展。本项目基于国家子午工程武汉和北京两部国产MST雷达多年连续观测资料，建立普适性雷达对流层顶判读模型，不仅可以获取雷达对流层顶高度，而且可以表征对流层顶结构疏密情况。项目组利用掩星弯曲角数据统计分析了2012年全年全球对流层顶的平均高度和温度分布，结合武汉和北京两地纬度差异分析了同纬度区间雷达对流层顶和气象对流层顶的差异性，同时结合全年数据分析了雷达对流层顶高度和对流层顶结构形态的时空演变规律。此外，基于周期谱分析方法，项目组分析了武汉和北京两地对流层顶结构形态的变化规律，发现在不同时期大气重力、波潮汐波和行星波都对雷达对流层结构形态有很强的调制作用。最后利用MST雷达多波束观测优势，项目组分析了强对流天气对于雷达对流层顶结构形态的影响，揭示了局部恶劣天气环境下大气能量的传输特征。