Ocean pCO2 calculated from dissolved inorganic carbon, alkalinity, and equations for K1 and K2:: validation based on laboratory measurements of CO2 in gas and seawater at equilibrium
Ocean pCO2 calculated from dissolved inorganic carbon, alkalinity, and equations for K1 and K2:: validation based on laboratory measurements of CO2 in gas and seawater at equilibrium
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DOI：
10.1016/s0304-4203(00)00022-0
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发表时间：
2000-05-01
期刊：
影响因子：
3
通讯作者：
Keeling, CD
中科院分区：
文献类型：
--
作者：
Lueker, TJ;Dickson, AG;Keeling, CD
海洋表面水中二氧化碳的分压，精确地表示为逸度(FCO(2))，由溶解的无机碳(DIC)和总碱度(TA)以及碳酸的第一和第二离解常数K-1和K-2确定。Mehrbach等人报道的K-1和K-2的原始测量值。[Mehrbach，C.，Culberson，C.H.，Hawley，J.E.，Pytkowicz，R.M.，1973.大气压下碳酸在海水中的表观离解常数的测定。利姆诺。大洋洲。PK(1)=3633.86/T-61.2172+9.67770lnT-0.011555 S+0.0001152 S-2pK(2)=471.78/T+25.9290-3.169671nT-0.01781 S+0.0001122 S-2我们证明了上述K-1和K-2公式给出的FCO(2)值与平衡值符合0.07+/-0.50%(95%可信区间，FCO(2)最高可达500微米大气压)。基于其他研究的K-1和K-2配方导致计算的FCO(2)值比测量值低约10%。在500亩大气压以上进行FCO(2)平衡，测得的FCO(2)值比计算值平均高3.35+/-1.22%(95%可信区间)。PK(1)和PK(2)中的不确定度与当代DIC和TA测量中典型的分析不确定度相结合，揭示了根据这些参数计算的海水FCO(2)的预期可靠性。例如，DIC和TA的不确定度分别为1.0微克克(-1)和2微克克(-1)(1标准差(S.D.))将导致在350亩ATM(1S.D.)下计算的1%或+/-3.5亩ATM的FCO(2)不确定。(C)2000 Elsevier Science B.V.保留所有权利。
The partial pressure of carbon dioxide in the ocean's surface waters, precisely expressed as the fugacity (fCO(2)) is determined from dissolved inorganic carbon (DIC) and total alkalinity (TA), and the first and second dissociation constants of carbonic acid, K-1 and K-2. The original measurements of K-1 and K-2 reported by Mehrbach et al. [Mehrbach, C., Culberson, C.H., Hawley, J.E., Pytkowicz, R.M., 1973. Measurement of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure. Limnol. Oceanogr. 18, 897-907] are reformulated to give equations for pK(1) and pK(2) (pK = - log(10)K) as a function of seawater temperature and salinity, consistent with the ''total hydrogen ion'' concentration scale:pK(1) = 3633.86/T - 61.2172 + 9.67770lnT - 0.011555 S + 0.0001152 S-2pK(2) = 471.78/T + 25.9290 - 3.169671nT - 0.01781 S + 0.0001122 S-2By equilibrating solutions of seawater with gas mixtures of known composition, we demonstrate that the above formulations of K-1 and K-2 give calculated fCO(2) values that agree with equilibrated values to 0.07 +/- 0.50% (95% confidence interval, fCO(2) up to 500 mu atm). Formulations of K-1 and K-2 based on other studies resulted in calculated fCO(2) values approximately 10% lower than the measurements. Equilibrations at fCO(2) above 500 mu atm yielded measured fCO(2) values higher than calculated values by on average 3.35 +/- 1.22% (95% confidence interval). The cause for the fCO(2) dependence of the results is not known.The uncertainties in pK(1) and pK(2) were combined with the analytical uncertainties typical of contemporary measurements of DIC and TA to reveal the expected reliability of seawater fCO(2) calculated from these parameters. For example, an uncertainty of 1.0 mu mol kg(-1) in DIC and 2 mu mol kg(-1) in TA (1 standard deviation (s.d.)) will result in uncertainty of the calculated fCO(2) of 1% or +/-3.5 mu atm at 350 mu atm (1 s.d.). (C) 2000 Elsevier Science B.V. All rights reserved.