Two impressive field programs were recently completed in the South and East China Seas as part of the Asian Seas International Acoustics Experiment (ASIAEX). Under the direction of the U.S. Office of Naval Research (ONR), scientists from several countries joined together to collect unique and high-quality acoustical, oceanographic, and geophysical data at the same place and time, enabling underwater acoustic fluctuations to be understood and modeled at the space and time scales of interest. A comprehensive field effort such as this one is required to decipher the cause and effect between environmental and acoustic variability which exist on a wide range of time and space scales.
Groundwork for the two largest experiments of ASIAEX was laid with preliminary survey and studies of spring in 2000. In 2000 in the East China Sea (ECS), a 21-day cruise on the R/V Revelle allowed extensive geophysical surveys of the upper sea floor using chirp sonars and a low-frequency air gun, as well as allowing some sampling of the physical oceanography. In the same year in the South China Sea (SCS), a SeaSoar survey aboard the R/V Ocean Researcher 1 delineated the major meso-scale features of the northeastern SCS, while a limited moored array obtained a first look at the dramatic non-linear internal waves. These pilot field studies proved indispensable when designing the two main field programs that were executed in spring 2001.