• DEPTH TO CENTER 



_J I l_ 



i« August 1974 



3 OCTOBER 1974 



JUN JUL AUG SEP OCT 



Figure 2.- 



Variations in cold cell temperature and depth along the MORMAC transect — May, 

 August, and October of 1974. 





TEMPERATURE RANGE 











IN THE COLD CELL 







a <8-9°i; 







C -c9-0°C 











- 



1 <EM»C 









- 









. 



i 



i 



i 



A 



\ 



i 



1 



• DEPTH TO CENTER 

 l 1 1 1 



Figure 3. — Variations in cold cell temperature and depth along the Santa Cruz transect — 

 May, June, September, and October of 1974. 



20). Temperatures in the cell ranged from less than 8° to 

 9°C. The horizontal extent was 68 nautical miles (126 

 km) and the cell ranged from 28 to 41 m in bottom depth 

 with a thickness of about 18 m at the center. By 11-12 

 June (Appendix Fig. 23) the outer fringes of the cell had 

 warmed to 13°C and water with temperatures from 10° 

 to 13°C had begun to move seaward over the shelf break. 

 The bottom depth range at this time was 32-49 m. 

 Within the cell, two separate parcels of water (.< 9°C) 

 were present between stations 26 and 30. On 3-4 Sep- 

 tember (Appendix Fig. 27) temperatures in the cell were 

 in the 9°-14°C range and part of the cell had moved over 

 the shelf break and extended to a depth of 70 m. The ton- 

 guelike shape of the 13° and 14°C isotherms showed the 

 initial stages of a process called "calving" by Cresswell 

 (1967) whereby a parcel of water separates from the 

 parent mass and moves seaward. During 9-10 October 

 'Appendix Fig. 31) the calving process was detected in an 

 advanced stage. A mass of water with temperatures rang- 

 ing from 12° to 14° C had separated from the cell on the 



shelf and was moving seaward over the shelf break. At 

 this time, the cell extended to a maximum bottom depth 

 of 70 m. These changes in temperature and depth are 

 summarized in Figure 3. 



Only two observations of the cold cell were made along 

 the HOTEL transect, and these were closely spaced in 

 time — 29-30 September (Appendix Fig. 28) and 1 Oc- 

 tober (Appendix Fig. 29). Appendix Figure 28 shows tem- 

 peratures ranging from less than 12° to 15° C in the cell 

 over a bottom depth range of 40-55 m. The horizontal ex- 

 tent was only 15 nautical miles (28 km). Slightly further 

 south, the temperatures ranged from less than 12° to 16° 

 over a bottom depth range of 40-63 m (Appendix Fig. 29). 

 Here the horizontal extent was 29 nautical miles (54 km). 

 The changes in temperature and depth are summarized 

 in Figure 4. 



Several generalizations can be made from a composite 

 plot of the changes in cold cell temperature and depth 

 with Figure 5. Minimum temperatures within the cell 

 remained low (8°-9°C) throughout the summer and 



