DC* Calculations
		Gruber, N., J. L. Sarmiento and T. F. Stocker, An improved method for detecting anthropogenic CO2 in the oceans, Global Biogeochem. Cycles, 10, 809-837, 1996.
				Canth = Cm - DCbio - Ceq280 – D C diseq
	Where: Canth    = Anthropogenic carbon concentration Cm    = Measured total carbon concentration DCbio    = Change in TCO2 as a result of biological activity Ceq280   = TCO2 of waters in equilibrium with an atmospheric CO2 of 280 µatm D C diseq    = Air-sea difference in CO2 concentration expressed in µmol kg-1 of TCO2
			DC* = Cm - DCbio - Ceq280 = Canth + D C diseq