water, reserving the word "front" for those small parts actually investigated. Since this 

 study focuses on a particular kind of oceanic front, the term "coastal front" will be used 

 for those oceanic fronts formed in the vicinity of coasts or continental shelves as a direct 

 result of local circulation or ocean basin boundary zone effects. G>astal fronts are 

 narrow linear zones with steep horizontal gradients of physical properties (temperature, 

 salinity, density, transparency, or color) at the sea surface separating different water masses. 



The availability of near real-time remotely sensed sea surface data on oceanic fronts 

 and water masses to shipborne scientists is a major breakthrough in oceanographic operations. 

 The areal extent, differences in sea state, sea surface temperature, and the frequent presence 

 of slicks over oceanic fronts make them particularly excellent subjects for remote sensing 

 methods in oceanography. Temperature differences are readily detectable by aircraft and 

 satellite scanners. Coastal fronts with their turbidity/color as well as temperature gradients 

 are detectable on visual-range as well as infrared band sensors of aircraft and spacecraft, 

 making them prime targets for remote sensing methods. The near real-time synoptic data 

 permit optimum use of ship time and a most complete grasp of the areal structure and time 

 changes of the upper water column as expressed at the sea surface . 



The need for synoptic temperature, salinity, and velocity data on the sea has been 

 expressed previously perhaps most vividly by the following authors; Sverdrup, Johnson, 

 and Fleming (1942) stated: 



"In nature, laminar flow is rarely or never encountered, but Instead turbulent flow 

 or turbulence prevails. By turbulent flow is understood a state in which random motion 

 of smaller or larger masses or the fluid is superimposed upon some simple pattern of flow. . 

 as a consequence a snap-shot of the instantaneous distribution of velocity, temperature, 

 salinity, and other variables would show a most complicated pattern, but so far no means 

 has been developed for establishing this picture. " 



In a study of the exchange of Gulf Stream Water with North Carolina Shelf Water in 

 Onslow Bay, Blanton (1971) using hydrographic stations and single current meter mooring 

 came to the following conclusion: 



"I feel that very little can be gained by additional hydrographic data of the kind 

 discussed here. We have a cursory understanding of the exchange process, but we are 

 completely in the dark on the time and space scales involved. Do the intrusions begin 

 as intense narrow currents at the shelf break that spread out once the water is forced 

 onto the shelf? Do they occur, instead as a broad "upwelling" over long lengths of 

 the edge of the shelf? How long does an intrusion last? What factors really govern it 

 such as winds, state or shelf water, position of the Gulf Stream? How do intrusions 

 of Virginian Coastal Water complicate the model presented here? It seems that all 

 these questions are beyond the scope of traditional shipboard oceanography. Synoptic 

 temperature and current data from key locations on the shelf are a logical next step in 

 a study of continental shelf processes. " 



In Blanton 's case, time lapse remote sensing of the fronts between Gulf Stream, Continental 

 Slope, Virginia Coastal, and Carolina Shelf waters would be a major contribution to his 



