INTRODUCTION 



Modification of forecasting techniques developed for deepwater 

 areas as part of the Antisubmarine Warfare Environmental Prediction 

 Services (ASWEPS) program will be required if prediction of near- 

 surface thermal structure is to be extended to the relatively shallow 

 water over the Continental Shelf. A program has been initiated whereby 

 thermal structure will be thoroughly Investigated in selected shallow- 

 water areas inshore of the 300-fathom isobath. An area seaward of the 

 Virginia Capes has been selected as an initial test area because of 

 interesting oceanographic features observed there and because of the 

 proximity of Fleet operating areas. Results of the initial survey, 

 conducted in two phases between 24 February and 11 March 1967, have been 

 reported previously (Fisher, 1968). This paper presents the results of 

 the second survey conducted in two phases between 19 September and 

 13 October 1967. 



Phases I and II of this survey were conducted from 19 to 22 September 

 and from 6 to 8 October 1967, respectively. Supplementary data in the 

 area were taken on 8, 12, and 13 October. Station locations during the 

 survey are shown in figures 1 through 3. Bathythermograph and Nansen 

 stations are sequentially designated by numerals and letters, respectively. 



DATA COLLECTION 



Sea surface temperature (SST) was measured with an airborne radiation 

 thermometer (ART) aboard the ASWEPS aircraft. Two flights were conducted 

 during Phase I and one flight was made during Phase II. The ART data 

 have been corrected for environmental effects in accordance with Pickett 

 (1966). Three overflights of the USNS BENJAMIN F. SANDS (T-AGOR-6) at 

 an altitude of 1,000 feet (318 meters) on 20 September showed a difference 

 of O.l'C between the ART and the near surface reference temperature (NSRT) 

 system located in the injection Intake of the SANDS about 3 meters below 

 the water surface. Navigational accuracy is believed to be within 5 

 kilometers. 



Vertical distribution of temperature and salinity was measured by 

 SANDS using Nansen casts and shipboard expendable bathythermographs 

 (SXBT). Seventy-eight SXBT and 8 Nansen stations were taken during 

 Phase I; 44 SXBT's and 8 Nansen stations were taken during Phase II. 

 During Phase I, SXBT's were dropped at 14.8 kilometer intervals while 

 SANDS steamed a set pattern on each of three consecutive days. The 

 pattern was arranged so that the center station was sampled several times 

 daily. In no case was the western (inshore) sector of the pattern completed, 

 because early morning fog restricted ship's speed. Nansen casts were 

 taken along a track normal to the Continental Shelf between the first 

 and second occupations of the SXBT pattern and were repeated between the 

 second and third occupations. Each section was composed of four casts 



