667 



Figure 28. Example of CEAS Database Access Options 



CEAS offers the user relatively 

 easy access to an entire variety 

 ofNAVOCEANO ocean data. 



Included are the seafloor sedi- 

 ments data, bulk properties such 

 as temperature and salinity, 

 satellite data, and some 

 acoustic data. 



4. ACOUSTIC DATA AND ACOUSTIC SENSING 

 OF THE OCEAN 



Except as menrioned, the MEDEA study did not review or 

 consider the large acoustic data holdings of the Navy. The 

 majority of acoustic data held by NAVOCEANO are the 

 multibeam bathymetric survey data, although there are exten- 

 sive holdings of ambient noise measurements and transmission 



Within the acoustic data collected for system development and 

 the systems designed for submarine detection, there are possible 

 opportunities for scientific use of ancillary products. For 

 instance, for many years there has been a interest in data that 

 would reveal long-term trends in ocean noise levels due to 

 shipping. The oceanographic community has long debated the 

 trends in the ocean noise environment and the natural and man- 

 made components of the ocean noise condition and variability. 



In a broad sense, acoustics is the major measurement tool for 

 ocean environments (bathymetry, distance, bottom roughness, 

 bottom characteristics, seismic noise, etc.). Acoustic 

 measurement systems work well because of the physical 

 transmissivitypropertiesofthe water medium. Electromagnetic 

 measurements are not possible in water except over short 

 distances or at very low frequencies. (Not coincidentally, this 

 is why the Navy was interested in sensing for submarines with 

 acoustics.) Therefore, the acoustic measurement data and 

 acoustic measurement expertise resident within the 

 NAVOCEANO oceanographic departments represent a valu- 

 able part of the Navy's classified holdings. 



It is also known that acoustic sensing of seismic events is a 

 sensitive method of measuring undersea seismic activity and 

 variations. Studies by the NOAA-Pacific Marine Environ- 

 mental Laboratory (PMEL) and others have demonstrated the 

 utility of undersea acoustic data for long range seismic 

 monitoring of ocean seismic activity. 



The Navy's acoustic data holdings and acoustic surveillance 

 systems could be given wider use similar to the efforts being 

 carried out within the Strategic Environmental R&D Program" s 

 toemploy the Integrated Undersea Surveillance System (lUSS) 

 to study endangered whale populations and ocean seismic 

 events. 



39 



