风场对重力波的滤波现象

THE OBSERVATION OF WIND FILTERED IONOSPHERIC GRAVITY WAVES

对MillstoneHill台站数字测高仪DGS－256漂移探测数据进行的分析表明，背景风场对重力波扰动具有明显的滤波作用．这种滤波效应主要表现为：扰动传播方向具有顺时针旋转的日变化特征，扰动相对出现率峰值出现在扰动传播方向与背景风场方向之间的夹角为180°－225°之间．扰动时空尺度越小，其传播越趋向于逆风场方向．

This paper analyses the drift data of the digisonde (DGS-256) at Millstone Hill (288.5°E, 42.6°N ) The result shows that the propagation direction of ionospheric gravity wave disturbances rotates clockwise throughout the day, the maximum of the disturbances occurrence is at the angles between 180°and 225° reative to the caiculated direction of background wind. Evidentiy, the result implies that disturbanas are wind filtered. Further analysis shows that the smaller the disturbance's scale, the more obvious it propagathe on the opposite direction of wind.