Climatological data for Wilmington (National Oceanic and Atmospheric 

 Administration, 1972a, 1973b) revealed zero precipitation for the day of 

 the ERTS-1 observation and the preceding 2 days. Weather observations 

 made at 3-hour intervals on 2 June 1973, starting at 0100 hours (e.s.t.)j 

 showed that air temperature rose from 59° Fahrenheit at 0400 hours 

 (e.s.t.)j the lowest recorded temperature for that month, to 82° Fahren- 

 heit at 1000 hours, the highest recorded temperature for the day. In a 

 6-hour interval, air temperature rose 23° Fahrenheit. Recorded wind- 

 speeds for 0100, 0400, and 0700 hours (e.s.t.) were zero, but the wind 

 picked up to 8 knots by 1000 hours. 



The color change is probably caused by a difference in density which 

 may result from changes in salinity, quantity, and type of suspended 

 matter (e.g., sediment plumes), concentrations of marine life and nutri- 

 ents, or a combination of these. These changes are often observed 

 between water masses of different temperatures. A map of the coast of 

 the Carol inas showing sea surface isotherms recorded by an airborne 

 radiation thermometer on 24 and 25 June 1973, the closest days to the 

 ERTS-1 observation is presented in Figure 5 (U.S. Coast Guard, 1973). 

 Dotted lines along some of the isotherms represent extrapolations made by 

 the investigators. A trough of cooler water originates off the coast 

 north of Cape Lookout and extends south as far as Cape Fear, as evidenced 

 by the linearity of the 25° Celsius isotherm and a small entrapped 24° 

 Celsius isotherm. A small 27° Celsius isotherm is just off Cape Fear. 

 A body of warmer water may also be trapped by the 25° Celsius isotherm 

 between Capes Lookout and Fear. As previously noted, the change in water 

 temperature may be a factor in causing a tonal change in the photos. 

 The darker tone representing warmer water was borne out by examination of 

 the next ERTS-1 frame to the south (ERTS 1314-15213, not shown). The 

 same tonal variation is apparent toward the southeast roughly coinciding 

 with the Gulf Stream. Figure 4 shows that the outline of a probable 

 density mass roughly coincides with the isothermal pattern. Although the 

 temperature recordings were made on different days than the ERTS-1 

 recording, it is assumed that isothermal variations on the sea surface 

 tend to follow predictable patterns during a given season along a par- 

 ticular coastal segment. 



3. Inlet Bars . 



Bars are generally found at the landward and seaward ends of inlet 

 channels. These bars usually appear as lobate or delta-shaped sand bodies 

 originating at the channel ends. The bars are formed by deposition of 

 sediment transported alongshore to the inlet and carried through the 

 inlet by tidal flow. During floodtide the materials are carried through 

 the inlet and deposited on the inner bar. During ebbtide, some of the 

 materials deposited in the inner complex are transported back through the 

 inlet to the ocean bar. Ebbtide and floodtide channels form in both the 

 ocean and inner bar formations; both the bars and channels generally 

 migrate. Geometry and migration of these features are related to the 

 rate of littoral material movement to and within the inlet, and the 

 prevailing tidal currents. 



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