1975-76 



LT2S 



LT2B 



P3! 



LT4S 



LT4B 



Shelf-break stations 



1975 P12 



Long Island 

 1975 



1975-76 



1976 



LT3D 



-1.2 -8.1 -2.2 -5.1 -0.5 -4.4 



3.(1 3.1 1.4 3.2 4.1 3.9 



424 426 436 413 407 383 



' Numbers for each subset are: top. upshelf component in cm/s; middle, offshelf component in cm/s; bottom, total variance (dj-). 

 ' Julian day calendar: 1975, days 1-365; 1976. days 1-166 (one added to each day beginning March 1 to account for leap year). 



currents were generally similar to those observed in spring 

 1975, but at somewhat lower net speeds, except for De- 

 cember, typically 50 to 70 km per month. During May 

 and June the flow maintained, or slightly increased, speed, 

 but became more variable in direction, reversing the 

 "normal" southwestward pattern. In July the flow contin- 

 ued to be variable in direction and also diminished in 

 speed. The net displacement during July was less than 40 

 km to the west northwest. During the first 2 weeks of 

 August (not shown) net water movement virtually ceased. 

 The net displacement observed during the 3 months be- 

 tween May 4 and August 2, 1976, was about 120 km to- 

 wards 340° T. 



Statistics of each 30-day segment are arranged for easy 

 comparison in figure 7-4 and table 7-2. These consist of 

 the vector mean (represented in table 7-2 as upshelf and 



offshelf components) and the total variance (u,'). The 

 uncertainty in determination of the monthly mean values 

 due to the relatively large variance is less than 1 cm/s. The 

 substantial difference between the average flows of cor- 

 responding months during spring 1975 and 1976, followed 

 by a prolonged period (90 days) of onshore flow below 

 the thermocline off New Jersey, is especially evident in 

 figure 7-4. 



Flushing of the New Jersey coastal region is undoubt- 

 edly important for the ecological health of the marine 

 environment. The principal difference that might have 

 affectea the flushing of the area and the development of 

 anoxic conditions in 1976 was the reduction of speed and 

 reversal (alongshore component directed upshelf) of di- 

 rection of the water movement in the bottom layer off 

 New Jersey, compared to spring 1975. 



155 



