widespread use. Another avenue for improving the data base is to continue to expand conventional measurement systems (e.g., radiosondes) by using Navy resources and remote control vehicles. Regardless of the sensing methods, more data and innovative data fusion techniques will be needed to gain a better understanding of coastal meteorology and verify models.

Overall, no aspect of naval warfare is immune to the effects of the coastal atmosphere. Better understanding and accurate prediction of coastal zone weather represent perhaps the greatest challenges in meteorology because all physical processes in the land-air, sea, and land play a significant role in the evolution of the air-ocean environment.

Electromagnetics

During the S&T session on electromagnetics, several key issues were discussed. They affect both the basic research and applied development sides of the Navy's R&D programs.

Electric field measurements

Ongoing Navy development projects in electromagnetic surveillance tend to concentrate on measurement of the magnetic field as opposed to the electric field. This is a natural consequence of the relatively widespread commercial availability of magnetic field sensors, whereas electric field detection in the ocean remains largely a custom technology developed by academic investigators. Nevertheless, electric field detection offers potential advantages, including greater simplicity and lower cost than magnetic field detection. Electric field sensors are passive voltmeters coupled to the ocean by low impedance electrodes, and they can achieve extremely low instrumental noise levels. They are also insensitive to motion of the detector, unlike vector magnetometers. Further, the electric field from a point source attenuates by the inverse of the distance squared, but the magnetic field decreases by the inverse of the distance cubed. Assuming comparable relative noise levels, the detection range might be greater using the electric field.

There are many scientific and engineering issues that must be investigated further, and it is not clear whether electric field approaches are superior in all instances. Nevertheless, more attention should be focused on electric field detection, and a more detailed assessment of its value for use by the Navy should be made.



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