基于武汉MST雷达的对流层异常强反射回波观测

为研究中层-平流层-对流层(MST)雷达在对流层高度上的回波机制，利用特殊天气条件(切断低压)下的雷达回波功率、风场，采用Lomb-Scargle谱分析、谐波拟合、Richardson数等方法分析对流层上部出现回波功率异常的现象。结果表明，在切断低压的天气条件下，急流和深对流造成持续存在的重力波源，重力波由下至上传播至对流层顶下方并发生饱和破碎，能量耗散在大气中，破坏了大气的静力稳定，形成K-H不稳定层，进而发展为湍流，使对流层区域出现雷达回波功率增强。

Observation of abnormal strong tropospheric echoes based on Wuhan MST radar

In order to study the echo mechanism of Mesosphere-Stratosphere-Troposphere(MST) radar at tropospheric height, the phenomenon of abnormal echo power in the upper troposphere is studied by using the radar echo power and wind field under special weather conditions(cut off low pressure), Lomb-Scargle spectrum analysis, harmonic fitting, Richardson number and other methods. Experimental and simulation results show that under the cutting off of low-pressure weather conditions, persistent gravitational waves are generated by the jet stream and deep convection, and the gravity waves are disseminated from the bottom up beneath tropopause and saturated broken, which dissipates energy in the atmosphere, destroys atmospheric static stability, and forms the Kelvin-Helmholtz(K-H) instability layer, and then develops into turbulence, thus making the region of radar echo power increased.