火箭观测到的中层垂直速度扰动细微结构

FINE STRUCTURE IN MESOSPHERIC VERTICAL VELOCITY FLUCTUATIONS OBSERVED BY A CHAFF ROCKET

使用一枚携带ｃｈａｆｆ的火箭观测到的垂直速度数据，研究中层大气垂直速度扰动细微结构。结果表明，垂直速度扰动有明显的层状结构，各层厚度约１５０－５００ｍ，层间垂直分离距离在几百米到１－３ｋｍ间。在垂直速度方差和低Ｒｉ数峰值间以及动力不稳定和ＭＳＴ雷达回波区域间有好的对应关系。水平速度垂直波数谱与饱和谱在谱斜率和谱振幅上存在好的一致．这些观测结果表明，火箭测量到的细微结构可以用波场饱和解释。

Vertical velocity data observed from a chaff rocket measurement are used to study the small scale structure of the vertical velocity fluctuations. Our results indicate that the vertical velocity fluctuations have distinct layered structure. The fluctuating layers have thickness between about 150m and 500m, and the vertical separation between peaks ranges from a fes hundred meters to one to three kilometers. A good correspondence between the peaks of variance in the vertical velocity and low Ri and between the regions of dynamical instability and MST radar echo is found. Vertical wavenumber spectrum of the horizontal velocity indicates good agreement of the observed spectrum and saturated spectral model in both slope and amplitude. These results show that the fine structure observed by the rocket can be explained by means of wave field saturation.