WIDE-BAND MEASUREMENTS AND ANALYSIS OF SOUNDSCAPE OF NORTHERN AREA

北方地区声景宽带测量与分析

• 批准号: 06680496
• 负责人: KOTAKI Minoru
• 金额: $ 1.02万
• 依托单位: HOKKAIDO TOKAI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680496/
• 关键词: Soundscape; Ray-tracing; Wide range Measurement; Map of local famous soundscape

(1) Measurements of SoundscapeWe have measured sound of the city (Sapporo) and in the mountains (Haruka-yama) in wide frequency range of 0-20kHz, and analyzed their power spectrums and characteristics of level changes. As a results of the analysis, the spectrum of natural sound has a peak level at the frequency about 1kHz, and decreasing gradually with frequency up to 7-8kHz, and remained almost unchanged above that frequency rage. The spectrum of the city, on the other hand, is decreasing with frequency monotonously, and its level of the frequency above 15kHz or so is very small.(2) Development of 3-D Ray-tracing Program of SoundWe developed three dimensional ray-tracing program for acoustic wave. For calculation of the propagation path of acoustic energy, we have to specify an atmospheric model such as temperature profiles, wind velocity models, sound speed models, terrain models, and so on. The program traces the acoustic ray path by numerically integrating Hamilton's equations, which are a differential expression of Fermat's principle.(3) Map of Well-known Sound in HokkaidoWe didn't start on making the map of famous sound scape in Hokkaido. However, Nippon Hoso Kyoukai (NHK) begun to invite a local famous sound and a spiritual sound over national levels.

(1)声景观的测量我们在0- 20 kHz的宽频率范围内测量了城市（札幌）和山区（Haruka-yama）的声音，并分析了它们的功率谱和电平变化特征。分析结果表明，自然声的频谱在1 kHz附近有一个峰值，随着频率的增加，峰值逐渐减小，直到7- 8 kHz，在此频率范围以上基本保持不变。另一方面，城市的频谱随频率单调下降，其频率在15 kHz以上的水平非常小。(2)三维声波射线追踪程序的开发我们开发了三维声波射线追踪程序。为了计算声波能量的传播路径，我们必须指定一个大气模型，如温度剖面、风速模型、声速模型、地形模型等。程序通过数值积分汉密尔顿方程来追踪声波射线路径，该方程是费马原理的微分表达式。(3)北海道著名的声音地图我们并没有开始制作北海道著名的声音景观地图。然而，日本广播协会（NHK）开始邀请当地著名的声音和国家层面的精神声音。