摘要
本文计算了北京、武汉、上海和海口等四个地区月平均气候条件下声雷达回波的分子吸收衰减。结果表明,分子吸收衰减与大气环境之间的关系是非线性的,分析回波时不能忽略其衰减,但可用地面气象资料来订正。本文还计算了考虑声波衰减后,由声雷达探测得出的对流条件下的C_r^2廓线,与Kaimal等实验结果更为接近,从而给出了一个求湍流衰减的近似方法。
The attenuations of sound by molecular absorption (ASMA) in the mean monthly climaticfields of Beijing, Wuhan, Shanghai and Hankou cities are calculated. The results show that ASMAhave complicated nonlinear relation with atmospheric temperature and moisture, and they shouldnot be ignored in the detection of turbulent structure coofficient of mixing layer by acousticradar, but it can be estimated with the surface meteorological data. An approximative method of calculating the attenuations of sound by turbulence is given.When both the attenuations of sound by molecular absorption and turbulence are considered, themagnitude of C_T^2 in unstable conditions obtained from echosonde is more close to the observationsfrom Kaimal et al..
