Acoustic Sounding on the Lower Atmospheric Inversion Layer

[摘要] he vertical structure of the atmospheric boundary layer is studied by a facsimile record of a monostatic acoustic sounder. The echo intensity and pattern on height-time chart changes according to the meteorological conditions. Layered echos come back from the stable stratification of the atmosphere; the inversion layer. The depths of the layered echo are compared with the heights of the surface inversion layer observed by a tethered balloon borne sonde or low-level radiosonde. The same comparison is examined for the top and bottom heights of the lifted inversion layer. The relationships between the vertical temperature gradient and the existence of echoes are examined even if the intensity of the facsimile record changes with the temperature gradient and the gain-offset of the recorder. The stable stratification corresponds to the layered echo return. The super-adiabatic lapse rate or unstable temperature gradient gives the weed type echo. The weak or no echo is due to the temperature gradient between dry adiabatic and equi-temperature gradient. A classification for the facsimile record of the acoustic sounder is proposed according to the atmospheric stability; unstable, neutral and stable. The facsimile record is grouped into three major groups; vertical (weed), no significant echo and horizontal (layered) type.

[学科分类] 大气科学