Recent advances in the knowledge of physical structures in the ocean and progress in the understanding of related physical processes present new opportunities for realistic ocean scientific studies and efficient marine operations. Over the past two decades, typical synoptic structures of energetic mesoscale meanders and eddies have been determined. Some regions of the world ocean, such as the Gulf Stream system are relatively well observed and studied, whereas others, such as the North Atlantic Current system, still require descriptive research. However, modern methods and strategies can yield rapid results when previously unexplored regions are investigated. New instruments, platforms, sampling schemes, and particularly the coverage afforded by satellite-borne sensors are all contributing to the new knowledge of the physical fields. Dynamical studies, modeling, and simulations provide understanding and feedback. Numerical ocean modeling, which is essential for the representation of realistic fields, is developing very rapidly. Critical support is provided by advances in computer software and hardware, including both supercomputers and workstations.