AI 中文总结
该研究针对80公里以上流星次声波，发现源高度增加会使接收器主导频率下降，近源分子吸收的大气低通滤波器会导致周期相关的能量估算偏倚，结果适用于空间碎片等高海拔次声源。
AI 中文摘要
在火流星研究中，次声波周期被广泛用作源能量的替代指标，但针对小型、高海拔区域流星的周期-产额关系的可靠性尚未得到系统评估。我们分析了90次来自约束良好的区域流星体事件的次声波探测结果（源高度20-111公里，距离47-268公里），证实接收器主导频率随源高度增加呈强单调下降趋势（斯皮尔曼相关系数r_s=-0.629，p=3.3×10^11）。80公里以上的探测结果中，无一次保留超过3赫兹的主导频率，100公里以上的探测结果中有75%以低于1赫兹的内容为主。偏相关分析表明，这主要是高度效应，而非传播距离的假象。采用广义伯格斯方程的近源耗散建模支持一种物理机制：运动粘度随高度呈指数增长，导致声学雷诺数下降，产生与频率相关的分子吸收，在源下方最初5公里内选择性衰减高频成分。我们的结果表明，这种大气低通滤波器会系统性地调制观测到的周期，若使用未校正的周期-产额关系，会使80-90公里以上源的基于周期的能量估算向上偏倚1至2个数量级。这些发现适用于任何高海拔次声源，包括空间碎片和受控再入。
英文摘要
Infrasound signal period is widely used as a proxy for source energy in bolide studies, but the reliability of period-yield relations for small, high-altitude regional meteors has not been systematically evaluated. We analyze 90 infrasound detections from well-constrained regional meteoroid events (source altitudes 20-111 km, ranges 47-268 km) and demonstrate a strong, monotonic decrease in receiver dominant frequency with increasing source altitude (Spearman r_{s} = -0.629, p = 3.3 x 10^11). No detections above 80 km retain dominant frequencies exceeding 3 Hz, and 75% of detections above 100 km are dominated by sub-1 Hz content. Partial correlation analysis indicates this is primarily an altitude effect, not a propagation distance artifact. Near-source dissipation modeling using the generalized Burgers equation supports a physical mechanism: the exponential increase in kinematic viscosity with altitude drives the acoustic Reynolds number downward, imposing frequency-dependent molecular absorption that selectively attenuates high-frequency content within the first 5 km below the source. Our results suggest that this atmospheric low-pass filter systematically modulates the observed period and can bias period-based energy estimates upward by one to two orders of magnitude for sources above 80-90 km when uncorrected period-yield relations are applied. These findings are relevant to any high-altitude infrasound source, including space debris and controlled reentries.
Comments39 pages, 10 figures
DOI：10.1007/s00024-026-04080-2
