It is generally accepted that seawater transmits sound over longer distances than freshwater. However, whether this general explanation applies equally to aircraft noise generated in the air has not been sufficiently examined. In this study, the acoustic transmission characteristics of freshwater and seawater were compared under identical conditions, and the influence of SOFAR (Sound Fixing and Ranging) channels and shallow-water acoustic waveguides in marine environments was investigated. The analysis conditions were set to identical water temperature, pressure, frequency, and sound source; freshwater was set to a salinity of 0.1 PSU, while seawater was set to approximately 34 PSU, which is the average surface salinity of the South Sea of Korea. Additionally, low-frequency and general transmission characteristics were compared by applying 250 Hz and 1,000 Hz, which are representative frequencies of aircraft noise. The analysis results showed that the differences in sound speed and acoustic impedance between freshwater and seawater under identical conditions were not significant. Furthermore, it was found that the long-distance sound transmission characteristics of the ocean are primarily governed by oceanic environmental conditions, including water depth, temperature, pressure, and seabed topography, rather than by the physical properties of seawater itself. Meanwhile, since aircraft noise originates in the air and most of its acoustic energy is reflected at the air-water interface, the amount of acoustic energy entering the water was found to be very limited. Consequently, the influence of SOFAR channels and shallow-water acoustic waveguides on the underwater transmission of aircraft noise was found to be very limited. Consequently, the likelihood that aircraft noise generated in the waters around Gadeokdo will be transmitted over long distances across the Korea Strait and cause widespread impacts on marine life is low. In conclusion, even when considering SOFAR channels and shallow-water acoustic waveguides, the conclusion of previous studies that the underwater impact of aircraft noise is limited remains valid.

Abstract
1. 서 론
    1.1 연구의 배경 및 목적
    1.2 기존 문헌검토 및 시사점
    1.3 연구의 범위 및 분석 조건
2. 본 론
    2.1 민물과 바닷물의 음향 전달 특성 비교
    2.2 해양 장거리 전달 메커니즘과 항공기 소음의 적용 가능성
3. 결론 및 연구의 한계점
    3.1 결 론
    3.2 연구의 한계점 및 추후 연구 계획
References

• 윤동국(Sehan University of Flight Operation, Professor) | Dongkook Yun
• 이명식(Korea Airports Corporation) | Myeongsik Lee
• 이준호(Korea Airports Corporation) | Jun Ho Lee Corresponding author