INTRODUCTION 



Notes on Data 



Bathythermograms (BT's), weather charts, and simultaneous weather and 

 wave observations were used to determine the functional relationship 

 between parameters of mixing, stability, convergence or divergence, and 

 wind waves. For this purpose, a large amount of continuous data was 

 required from the same observation point over several years. Only an 

 extreme minimum of this requirement was satisfied. BT's taken by various 

 Atlantic Ocean weather ships and processed (corrected, printed on cards, 

 and catalogued) by the BT Branch, National Oceanographic Data Center, 

 were available for the years 19^9 through 19 5^- • Data of Ocean Weather 

 Station (OWS) CHARLIE (52°^8» N, 35°30' W) were selected for the basic 

 computations, because this station offered a fair amount of data and 

 appeared to be affected less than other weather stations by permanent 

 and semi-permanent currents. However, not all of the approximately 5>000 

 BT's of station CHARLIE were applicable; sporadic BT's could not be used. 

 Many BT casts did not reach the thermocline; glass BT slides often are 

 either scratched and rendered illegible or may show unexplainable incon- 

 sistencies of temperature and depth when compared with observations taken 

 a few hours earlier or later. After all deficient BT's were discarded, 

 the remainder was about 30 percent of the total. 



BT's from weather stations and other ships were mainly taken under 

 fair weather conditions; rough weather BT's are scarce. The latter 

 circumstance makes extraction of consistent information on upper layer 

 properties and their variations more difficult. 



Data from weather stations BRAVO (56°30' N, 51° W), ECHO (35° N, 

 k8° W), and DELTA (kh° N, hl° W) were used for testing the prediction 

 method. Two tests were made at each of these stations using BT's from 

 19^9 through 19 5^ • Each test consisted of about 30 observations selected 

 at random from the 6-year period. Each observation was a group with more 

 than three BT's taken over a period of at least 2k hours. 



BT's of station CHARLIE were processed for 1956 and 1957; however, 

 they were not included in the computations of the mixing factor. There- 

 fore, two tests were also conducted using the data from this station. 



The Bathythermogram 



Although general concepts and names exist for various layers and 

 boundaries indicated by a BT, various observers often interpret the mixed- 

 layer depth, vertical extent of the thermocline, and other characteristics 

 of the upper layers differently. Some BT's do not show definite or dis- 

 tinct boundaries; furthermore, no generally accepted criteria exist for 

 their interpretation. Figure 1 shows some typical BT traces with their 

 parts and various elements defined as used in this study. 



