中文摘要：

选取青海大通地区一次地闪过程的雷声信号,利用信号处理理论,得到了观测点雷声的频谱;依据声波在大气中传播的理论,计算了大气对雷声传播的吸声系数,分析了吸声系数随环境因素的变化,结果表明：闪电发生距离、大气湿度和温度是影响雷声传播的主要因素.在一定闪电距离和大气环境下,吸声系数随频率的增加而增大;频率小于100Hz的雷声衰减很慢,空气相对湿度和温度对其吸声系数的影响也比较小,在一定距离内的衰减可以忽略;频率大于500Hz的高频信号吸声系数较大,并且随相对湿度的增加而快速递增;吸声系数随温度呈非单调变化,频率越大吸声系数峰值对应的温度越高.传播过程中,高频段信号优先衰减.由此推断：考虑了传播过程中的衰减因素后,雷声源的频谱中应该有比较强的频率高于500Hz的成分.

英文摘要：

Using the thunder signals of a C-G lightning process recorded in the Qinghai region and the theory of signal processing,the frequency spectrum of thunder at observation point is obtained;Based on the propagation theory of acoustic waves,the absorption coefficients in air are calculated and their variations with environmental factors are analyzed.The results show that under a certain profpagation distance and environmental condition,the absorption coefficient increases with frequency increasing.The attenuation of signal below 100Hz is negligible under a certain propagation distance and environmental factors.The attenuations for high-frequency signals of more than 500 Hz are large,their absorption coefficients increase rapidly with the relative humidity inereasing and vary nor-monotonical with temperature.It is deduced that high frequency components of more than 500Hz should be contained in the thunder source.