Navigation was conducted by Loran-A throughout the survey. Radar 
tracking by NASA, Wallops Island, determined navigational accuracy to 
be within 3.5 km 95 percent of the time based on experiments conducted 
seaward of Wallops Island (Athey, 1969). 
Each flight was designed for optimum delineation of surface 
features in the surveyed area. Plans were modified during the series 
of flights as experience was gained. The flight plan yielding optimum 
results contained multiple legs normal to the Gulf Stream axis. 
Twelve flights were conducted during the 9-month survey with at least 
one flight conducted every month except March. 
DATA ANALYSIS 
Data analysis revealed four recurring oceanic processes affecting 
thermal structure in the Virginia Capes area: (1) lateral displacement 
of the northern edge of the Gulf Stream, (2) intrusion of cold water 
from the northwestern quadrant of the survey area to a position ad- 
jacent to the northern edge, (3) location of a frontal zone contiguous 
with the Continental Slope during winter, and (4) formation of two 
warm areas inshore of the northern edge, one a recurring eddy having a 
lifetime measured in days, the second a semipermanent eddy having a 
lifetime measured in months. Six flights have been chosen to illus- 
trate these processes under varying weather and seasonal conditions. 
Additional data showing similar but less-defined features are given 
in the appendix. 
The first flight chosen for discussion was made on 15 November 
1968 (figure 1), three days after a violent storm moved through the 
area. Winds to 90 knots (45 m/sec) were recorded at Wallops Island, 
Virginia, during the peak of the storm. On the day of the flight, 
however, the weather conditions had moderated with westerly winds of 
8 to 12 knots (4.1 to 6.2 m/sec) and 1-meter seas. 
Major features observed during the flight are (1) a meanderlike 
bend of the Gulf Stream in the northeastern quadrant of the survey 
area, (2) an area of warm water (SST>21°C) adjacent to the Continental 
Shelf in the southwestern quadrant, and (3) a cold intrusion (SST<13°C) 
separating the two warm areas. Judging from surface temperature (>23°C) 
and strength of the gradient, the warm area in the northeastern quadrant 
appears to be a mesoscale Gulf Stream meander, but the thickness of the 
feature as measured by BT A (figure 1) suggests that it is only a 
shallow displacement of the northern edge. The warm area to the 
southwest is somewhat thicker (40 meters shown by BT B), but does not 
have the strong surface gradient associated with meanders. SST (<22°C) 
in the warm area is also slightly less than the SST of the Gulf Stream. 
The cold intrusion separating the two warm areas appears to be entrained 
in the Gulf Stream. BT C, taken a few kilometers east of the cold 
water, is representative of Slope Water during late autumn by virtue 
