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首页> 美国政府科技报告 >PRELIMINARY ANALYSIS OF MEASURED SOUND PROPAGATION OVER VARIOUS SEASONAL SNOW COVERS
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PRELIMINARY ANALYSIS OF MEASURED SOUND PROPAGATION OVER VARIOUS SEASONAL SNOW COVERS

机译：不同季节性雪覆盖下测量声传播的初步分析

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MEASUREMENTS OF ACOUSTIC PULSE PROPAGATION IN THE 5 TO 500-HZ FREQUENCY BAND WERE CONDUCTED UNDER VARIOUS SNOW COVER CONDITIONS DURING THE 1989 TO 1990 WINTER IN NEW HAMPSHIRE. THE OBJECTIVE WAS TO DETERMINE THE EFFECT OF SNOW COVER THICKNESS AND OTHER SNOW PROPERTIES ON THE ABSORPTION OF ACOUSTIC PULSES. BLANK PISTOL SHOTS WERE USED AS THE SOURCE OF THE ACOUSTIC WAVES, AND GEOPHONES AND MICROPHONES IN AN 80 M-LONG LINEAR ARRAY SERVED AS RECEIVERS. SNOW THICKNESSES RANGED FROM 0.05 TO 0.35 M, AND DENSITIES VARIED FROM 100 TO 350 KG M(SUP -3) DURING THE 10 SEPARATE MEASUREMENT DAYS. PRELIMINARY ANALYSIS INDICATES THAT THE PEAK PULSE AMPLITUDE DECAYED IN PROPORTION TO APPROX. GAMMA (SUP -1.7) FOR MOST CONDITIONS AND THAT THE ACOUSTIC-TO-SEISMIC RATIOS VARIED FROM ABOUT 4 TO 15 X 10(EXP -6) M S(SUP -1) PA(SUP -1). THEORETICAL WAVEFORMS WERE CALCULATED FOR PROPAGATION IN A HOMOGENEOUS ATMOSPHERE USING ATTENBOROUGH'S MODEL OF GROUND IMPEDANCE. AN AUTOMATIC FITTING PROCEDURE FOR THE NORMALIZED EXPERIMENTAL AND THEORETICAL WAVEFORMS WAS USED TO DETERMINE THE EFFECTIVE FLOW RESISTIVITY OF THE SNOW COVERS, AND GAVE VALUES OF 10 TO 35 KN S M(SUP -4), IN AGREEMENT WITH EARLIER RESULTS.

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