For close range （almost 8-15km） propagation, bottom-bounce energy （BBE） usually suffers from a great trans- mission loss due to a large grazing angle interacting with the ocean bottom, and the surface duct energy ...For close range （almost 8-15km） propagation, bottom-bounce energy （BBE） usually suffers from a great trans- mission loss due to a large grazing angle interacting with the ocean bottom, and the surface duct energy leakage （SDEL） might be able to make a significant contribution to shadow zone insonification. This study aims at making a comparison between SDEL and BBE in a shadow zone with a source depth of 50 m for close range propagation. Analysis of experimental data shows that for lower frequencies the SDEL can be comparable with the BBE up to a range of 12km. Numerical simulations suggest that the transmission loss （TL） of 90dB is a proper value to quantify the role of the SDEL in shadow zone insonification. When TL of the SDEL is about 90 dB, it is believed to be comparable with the BBE. Studies on the effect of mix layer depth （MLD） on the SDEL indicate that larger MLD and lower frequencies can help to create favorable conditions for SDEL and that there exists an optimal MLD for SDEL at certain frequency. Statistics of MLD distribution in the South China Sea （SCS） show that winter is favorable for SDEL and the situation reverses in summer. Eddies are known to occur frequently in the SCS and the study on the effect of eddies on the SDEL suggests that the presence of an eddy will influence the SDEL significantly by modifying the MLD.展开更多
On October 13,the second China-CELAC High-Level Academic Forum cum the sixth China-Latin America and the Caribbean Think Tank Forum was held.Co-hosted by the Institute of Latin American Studies of Chinese Academy of S...On October 13,the second China-CELAC High-Level Academic Forum cum the sixth China-Latin America and the Caribbean Think Tank Forum was held.Co-hosted by the Institute of Latin American Studies of Chinese Academy of Social Sciences(CASS),the Bureau of International Cooperation of CASS,the United Nations Economic Commission for Latin America and the Caribbean(ECLAC),the Chinese People’s Institute of Foreign Affairs(CPIFA),China Institute of International Studies(CIIS)and China Foundation for International Studies(CFIS),the forum was attended by more than 30 experts and scholars from China and Latin American countries,including former Chilean President Eduardo Frei Ruiz-Tagle and ECLAC Executive Secretary Alicia Bárcena.In his remarks at the forum’s closing ceremony,CIIS President Xu Bu expressed the institute’s willingness to contribute to China-Latin America community with a shared future by intellectual exchanges and cooperation.展开更多
文摘For close range （almost 8-15km） propagation, bottom-bounce energy （BBE） usually suffers from a great trans- mission loss due to a large grazing angle interacting with the ocean bottom, and the surface duct energy leakage （SDEL） might be able to make a significant contribution to shadow zone insonification. This study aims at making a comparison between SDEL and BBE in a shadow zone with a source depth of 50 m for close range propagation. Analysis of experimental data shows that for lower frequencies the SDEL can be comparable with the BBE up to a range of 12km. Numerical simulations suggest that the transmission loss （TL） of 90dB is a proper value to quantify the role of the SDEL in shadow zone insonification. When TL of the SDEL is about 90 dB, it is believed to be comparable with the BBE. Studies on the effect of mix layer depth （MLD） on the SDEL indicate that larger MLD and lower frequencies can help to create favorable conditions for SDEL and that there exists an optimal MLD for SDEL at certain frequency. Statistics of MLD distribution in the South China Sea （SCS） show that winter is favorable for SDEL and the situation reverses in summer. Eddies are known to occur frequently in the SCS and the study on the effect of eddies on the SDEL suggests that the presence of an eddy will influence the SDEL significantly by modifying the MLD.
文摘On October 13,the second China-CELAC High-Level Academic Forum cum the sixth China-Latin America and the Caribbean Think Tank Forum was held.Co-hosted by the Institute of Latin American Studies of Chinese Academy of Social Sciences(CASS),the Bureau of International Cooperation of CASS,the United Nations Economic Commission for Latin America and the Caribbean(ECLAC),the Chinese People’s Institute of Foreign Affairs(CPIFA),China Institute of International Studies(CIIS)and China Foundation for International Studies(CFIS),the forum was attended by more than 30 experts and scholars from China and Latin American countries,including former Chilean President Eduardo Frei Ruiz-Tagle and ECLAC Executive Secretary Alicia Bárcena.In his remarks at the forum’s closing ceremony,CIIS President Xu Bu expressed the institute’s willingness to contribute to China-Latin America community with a shared future by intellectual exchanges and cooperation.
