Figure 2. — Continued. 



TEMPERATURE OBSERVATIONS 

 Northern Middle Atlantic Bight 



Spring 1968-76.— The Northern Bight spring temper- 

 atures are represented in Figure 4 and Table 6 which 

 show both the year-to-year variations and the 9-yr 

 means. The lowest and highest adjusted temperatures 

 were 5.1°C in 1970 and 8.3°C in 1976 and the series clear- 

 ly illustrates a warming trend since 1970. The observed 

 temperatures coincide closely with the adjusted values in 

 all years except 1970 and 1974 (when the cruises were 20- 

 30 days later than usual) but generally show the same 



trends. The adjusted time-series mean of 6.7°C was only 

 0.2°C less than the mean of the observed conditions. 

 Both adjusted and observed temperatures were below 

 average prior to 1972 and above average for 1972. The 

 spring anomalies are summarized in Figure 5 and 

 Table 7 . 



The frequency distribution of TCI's in years with sim- 

 ilar observed indices shows an inconsistency in their rela- 

 tive percentages (Table 1). The TCI percentages were 

 quite similar in the cold years of 1969 (6.0°C) and 1971 

 (5.9°C) but quite different, especially the 6°-8°C TCI, in 

 the warm years of 1974 (8.1°C) and 1976 (8.2°C). On the 

 average, slope water, identified here as >10°C, accounts 

 for 20^ of the total bottom thermal environment. On the 



