Seasonal Change in Productivity

First I set the variable prod = fuel. This amounts to a seasonally varying biological productivity, which varies between 1 and — 1 moles of carbon per cubic meter per year. I start the calculation at 1 year, with the initial values equal to the seawater values, and run it out to a time of 10 years. 

The evaporative concentration increases the water s ionic strength, which affects the activity coefficients and thus the carbonate solubility and dissociation constants (Butler, 1982). I ignore this effect here, but it should be included in a more realistic simulation. 

The radiocarbon ratio also evolves very rapidly from its initial value of -50 to an average value of about -8 per mil. This evolution is not a consequence of evaporative concentration but, instead, of an approach to equilibrium with atmospheric carbon dioxide. Average surface seawater contains significantly less radiocarbon than does the atmosphere because its isotopic composition is affected by exchange with the deep ocean as 

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The petroleum products prices change with crude oil prices and seasonal product demands. Fuel oil dmand is higher in winter to provide heat to those places where the weather is cold, while the demand for gasoline is higher in summer because of the increased travel of vacationers. To deal with these seasonal changes in product demands, the EBR unit is designed to produce products that are in demand (Nongbri and Clausen, 1992). 

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