INTRODUCTION 



During 1967 the U.S. Naval Oceanographic Office conducted two 

 surveys specifically designed to determine thermal structure character- 

 istics in and near the Gulf Stream. The main interest was movement of 

 the northern edge of the Gulf Stream and study of the interaction of 

 the Gulf Stream and Slope Water to the north of the stream. Meanders 

 have been discovered along the northern boundary of the Gulf Stream 

 (The Gulf Stream, Vol. 1, No. 7), and many small-scale features exist 

 north of the Gulf Stream (Fuglister, 1963). At times, the two appear 

 to be independent of each other. Ordinary data do not permit demonstra- 

 tion of feature characteristics, such as origin, width, depth, and propa- 

 gation speed. Without these basic facts, adequate predictions are not 

 possible. 



The two 1967 surveys were designed to answer some of these questions 

 by providing a good data base. The surveys, one by aircraft and one by 

 ship, provided good examples showing the Gulf Stream wall, its fluctua- 

 tions, and movement of warm and cold features north and south of the 

 Gulf Stream, as well as some interesting atmospheric effects. 



The first survey was conducted in April by a Naval Oceanographic 

 Office aircraft using an airborne radiation thermometer (ART) to obtain 

 sea surface temperatures. The track, covering the area indicated in 

 figure 1, was planned so that it would penetrate the Gulf Stream, out- 

 line the northern edge of the stream, and show some detail north of 

 the edge. The track was flown on 4 consecutive days (10, 11, 12, and 

 13 April). Flying weather was good throughout the period, but the 

 weather pattern changed considerably. 



The ART survey pointed out that data at depth were needed to ade- 

 quately determine oceanographic processes, thus a second survey was 

 planned for October and November to provide such data using mechanical 

 and expendable BT's. This survey was conducted by the USNS GILLISS 

 over a 4 -week period from 17 October through 9 November 1967 in the 

 region shown in the right of figure 1. The GILLISS survey was repeated, 

 each point being observed after an interval of approximately two weeks. 



The survey area was designed to enable investigation of the Gulf 

 Stream, water mass movement to the north, and relative inactivity to 

 the south. Good weather prevailed; the data sample was quite complete 

 and not adversely affected by bad observing conditions. The time interval 

 for the two surveys should be kept in mind; the ART changes are daily, 

 but the ship changes occurred over a 2-week period. 



AIRBORNE RADIATION THERMOMETER SURVEY 



Aircraft sensors are a luxury that has only recently become avail- 

 able to oceanographers. This luxury provides the ability to observe 



