Global Ocean Data Analysis Project: Difference between revisions

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The GLODAPv1.1 climatology contains analysed fields of "present day" (1990s) [[Total inorganic carbon|dissolved inorganic carbon]] (DIC), [[alkalinity]], [[carbon-14]] (¹⁴C), [[CFC-11]] and [[CFC-12]].<ref>Key, R.M., Kozyr, A., Sabine, C.L., Lee, K., Wanninkhof, R., Bullister, J., Feely, R.A., Millero, F., Mordy, C. and Peng, T.-H. (2004). A global ocean carbon climatology: Results from GLODAP. ''Global Biogeochemical Cycles'' '''18''', GB4031</ref> The fields consist of [[Three-dimensional space|three-dimensional]], objectively-analysed global grids at 1° [[Image resolution#Spatial resolution|horizontal resolution]], interpolated onto 33 standardised [[water column|vertical intervals]]<ref>Standardised intervals are at 0, 10, 20, 30, 50, 75, 100, 125, 150, 200, 250, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1750, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500 m</ref> from the surface (0 m) to the [[Abyssal zone|abyssal]] [[Seabed|seafloor]] (5500 m). In terms of temporal resolution, the relative scarcity of the source data mean that, unlike the [[World Ocean Atlas]], averaged fields are only produced for the annual time-scale. The GLODAP climatology is missing data in certain oceanic provinces including the [[Arctic Ocean]], the [[Caribbean Sea]], the [[Mediterranean Sea]] and [[Maritime Southeast Asia]].

Additionally, analysis has attempted to separate natural from anthropogenic DIC, to produce fields of pre-[[industrialIndustrial revolutionRevolution|industrial]] (18th century) DIC and "present day" anthropogenic {{CO2}}. This separation allows estimation of the magnitude of the ocean [[carbon dioxide sink|sink]] for anthropogenic {{CO2}}, 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/20080625100559/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.] {{Webarchive|url=https://web.archive.org/web/20070927215722/http://www.royalsoc.ac.uk/displaypagedoc.asp?id=13314 |date=2007-09-27 }} 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 {{CO2}} 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 {{CO2}} 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 {{CO2}} 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 | issue = 3 | doi = 10.1029/2004GB002397 |bibcode = 2005GBioC..19.3014M | s2cid = 3468049 | doi-access = free }}</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 |journal=Earth System Science Data |volume=8 |issue= 2|pages=297–323 |doi=10.5194/essd-8-297-2016 |bibcode=2016ESSD....8..297O |doi-access=free |hdl=10261/135582 |hdl-access=free }}</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 |journal=Earth System Science Data |volume=8 |issue= 2|pages=325–340 |doi=10.5194/essd-8-325-2016 |bibcode=2016ESSD....8..325L |doi-access=free |hdl=10261/135584 |hdl-access=free }}</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 |journal=Tellus |volume=58B |issue= 5|pages=376–390 |doi=10.1111/j.1600-0889.2006.00222.x |bibcode=2006TellB..58..376W |doi-access=free }}</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]] [[Saturated solution|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]]), and relates to an oceanographic property, the [[carbonate compensation depth]]. Values of this below 1 indicate [[undersaturation]], and potential dissolution, while values above 1 indicate [[supersaturation]], and relative stability.

==Gallery==

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| [[File:WOA05Estimated GLODAPannual pimean DICsea AYoolsurface dissolved inorganic carbon for the 1700s (GLODAP).png|thumb|Pre-industrial DIC]]

| [[File:WOA05Annual GLODAPmean pdsea DICsurface AYooldissolved inorganic carbon for the 1990s (GLODAP).png|thumb|"Present day" DIC]]

| [[File:WOA05Annual GLODAPmean pdsea aco2surface AYoolanthropogenic dissolved inorganic carbon concentration (GLODAP).png|thumb|"Present day" anthropogenic {{CO2}}]]

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| [[File:WOA05 GLODAP pd ALK AYool.png|thumb|"Present day" alkalinity]]