GEOCHEMISTRY AND PHYSICS OF OCEAN' CIRCULATION' 317 



Table IX. Results of Model Calculations 



Model Empirical Estimate 



aCi^ Antarctic -107%o -121%o 



aCI" Arctic -32%o -34%^ 



aCi^SASW -60%o -49%c 



CO2 Transfer rate 20 moles/m- yr 



R Atlantic 930 X 1012 j^^igg c/^,j. 430 moigs C/vr 



i? psw- -Antarctic 1850 X 10'' moles C/yr 



^ PDw--Antarctic 1525 X lO'" moles C/yr 



Mean residence times of water molecules in each oceanic 

 reservoir with respect to transfer to another reservoir are given in 

 Table X. Regardless of the simplicity of the model and lack of 

 coverage in the Pacific and Indian Oceans it is clear the deep 

 oceans are being renewed with a time scale of the order of magni- 

 tude of 1000 years. 



Table X. Mean Residence Times Based on Model 



Location Time, years 



Arctic 45 



NASW 10 



SASW 10 



NADW 600 



Antarctic 100 



P + ISW 25 



P + IDW 1300 



Three independent checks on this model suggest themselves. 

 The first, as summarized in Table XI, is a comparison with tritium 



Table XI. Tritium Crosscheck 



Assumptions 



1. Tritium addition rate approximately uniform over surface of ocean 



2. Pre-bomb tritium concentration in XASW 1 tritium unit. 

 Required production rate 



2 tritium atoms/cm-sec 

 Independent estimates 

 ~ 1 tritium atom/cm'sec 



