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Additionally, analysis has attempted to separate natural from anthropogenic DIC, to produce fields of pre-[[industrial revolution|industrial]] (18th century) DIC and "present day" anthropogenic CO<sub>2</sub>. This separation allows estimation of the magnitude of the ocean [[carbon dioxide sink|sink]] for anthropogenic CO<sub>2</sub>, and is important for studies of phenomena such as [[ocean acidification]].<ref name=orr05>Orr, J. C. ''et al.'' (2005). [http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms.] {{webarchive |url=https://web.archive.org/web/20080625000000/http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf |date=June 25, 2008 }} ''Nature'' '''437''', 681-686</ref><ref name=raven05>Raven, J. A. ''et al.'' (2005). [http://www.royalsoc.ac.uk/displaypagedoc.asp?id=13314 Ocean acidification due to increasing atmospheric carbon dioxide.] Royal Society, London, UK</ref> However, as anthropogenic DIC is chemically and physically identical to natural DIC, this separation is difficult. GLODAP used a mathematical technique known as C* (C-star)<ref>Gruber, N., Sarmiento, J.L. and Stocker, T.F. (1996). An improved method for detecting anthropogenic CO<sub>2</sub> in the oceans, ''Global Biogeochemical Cycles'' '''10''':809– 837</ref> to [[deconvolution|deconvolute]] anthropogenic from natural DIC (there are a number of alternative methods). This uses information about ocean [[biogeochemistry]] and CO<sub>2</sub> surface disequilibrium together with other ocean tracers including carbon-14, CFC-11 and CFC-12 (which indicate [[water mass]] age) to try to separate out natural CO<sub>2</sub> from that added during the ongoing anthropogenic transient. The technique is not straightforward and has associated errors, although it is gradually being refined to improve it. Its findings are generally supported by independent predictions made by dynamic models.<ref name=orr05/><ref>{{cite journal | last1 = Matsumoto | first1 = K. | last2 = Gruber | first2 = N. | title = How accurate is the estimation of anthropogenic carbon in the ocean? An evaluation of the DC* method | journal = Global Biogeochem. Cycles | volume = 19 | date = 2005 | doi = 10.1029/2004GB002397 |bibcode = 2005GBioC..19.3014M }}</ref>
The GLODAPv2 climatology largely repeats the earlier format, but makes use of the large number of observations of the ocean's carbon cycle made over the intervening period (2000—2013).<ref name="olsen2016">{{cite journal |last1=Olsen |first1=A. |last2=Key |first2=R.M. |last3=van Heuven |first3=S. |last4=Lauvset |first4=S.K. |last5=Velo |first5=A. |last6=Lin |first6=X. |last7=Schirnick |first7=C. |last8=Kozyr |first8=A. |last9=Tanhua |first9=T. |last10=Hoppema |first10=M. |last11=Jutterström |first11=S. |last12=Steinfeldt |first12=R. |last13=Jeansson |first13=E. |last14=Ishii |first14=M. |last15=Pérez |first15=F.F. |last16=Suzuki |first16=T. |date=2016 |title=The Global Ocean Data Analysis Project version 2 (GLODAPv2) – an internally consistent data product for the world ocean |url=https://www.earth-syst-sci-data.net/8/297/2016/ |journal=Earth System Science Data |volume=8 |issue= |pages=297-323 |doi=10.5194/essd-8-297-2016 |access-date=2018-07-02 |bibcode=2016ESSD....8..297O }}</ref><ref name="lauvset2016">{{cite journal |last1=Lauvset |first1=S.K. |last2=Key |first2=R.M. |last3=Olsen |first3=A. |last4=van Heuven |first4=S. |last5=Velo |first5=A. |last6=Lin |first6=X. |last7=Schirnick |first7=C. |last8=Kozyr |first8=A. |last9=Tanhua |first9=T. |last10=Hoppema |first10=M. |last11=Jutterström |first11=S. |last12=Steinfeldt |first12=R. |last13=Jeansson |first13=E. |last14=Ishii |first14=M. |last15=Pérez |first15=F.F. |last16=Suzuki |first16=T. |last17=Watelet |first17=S. |date=2016 |title=A new global interior ocean mapped climatology: the 1° × 1° GLODAP version 2 |url=https://www.earth-syst-sci-data.net/8/325/2016/ |journal=Earth System Science Data |volume=8 |issue= |pages=325-340 |doi=10.5194/essd-8-325-2016 |access-date=2018-07-02 |bibcode=2016ESSD....8..325L }}</ref> The analysed "present-day" fields in the resulting dataset are [[Normalization (statistics)|normalised]] to year 2002. Anthropogenic carbon was estimated in GLODAPv2 using a "transit-time distribution" (TTD) method (an approach using a [[Green's function]]).<ref name="waugh2006">{{cite journal |last1=Waugh |first1=D.W. |last2=Hall |first2=T.M. |last3=McNeil |first3=B.I. |last4=Key |first4=R. |last5=Matear |first5=R.J. |date=2006 |title=Anthropogenic {{CO2}} in the oceans estimated using transit-time distributions |url= |journal=Tellus |volume=58B |issue= |pages=376-390 |doi=10.1111/j.1600-0889.2006.00222.x |access-date=2018-07-02 |bibcode=2006TellB..58..376W |url=https://doi.org/10.1111/j.1600-0889.2006.00222.x }}</ref><ref name="lauvset2016"/> In addition to updated fields of DIC (total and anthropogenic) and alkalinity, GLODAPv2 includes fields of seawater [[pH]] and [[calcium carbonate]] [[Saturation_(chemistry)#Solutions|saturation state]] (Ω; omega). The latter is a non-dimensional number calculated by dividing the local [[carbonate]] ion concentration by the ambient saturation concentration for calcium carbonate (for the [[Biomineralization|biomineral]] [[Polymorphism (materials science)|polymorphs]] [[calcite]] and [[aragonite]]). Values of this below 1 indicate [[undersaturation]], and potential dissolution, while values above 1 indicate [[supersaturation]], and relative stability.
==Gallery==
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