Browse > Article
http://dx.doi.org/10.7850/jkso.2016.21.1.1

Sea Surface pCO2 and Its Variability in the Ulleung Basin, East Sea Constrained by a Neural Network Model  

PARK, SOYEONA (Division of Earth Environmental System, Oceanography Major, the Graduate School, Pusan National University)
LEE, TONGSUP (Department of Oceanography, Pusan National University)
JO, YOUNG-HEON (Department of Oceanography, Pusan National University)
Publication Information
The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY / v.21, no.1, 2016 , pp. 1-10 More about this Journal
Abstract
Currently available surface seawater partial pressure carbon dioxide ($pCO_2$) data sets in the East Sea are not enough to quantify statistically the carbon dioxide flux through the air-sea interface. To complement the scarcity of the $pCO_2$ measurements, we construct a neural network (NN) model based on satellite data to map $pCO_2$ for the areas, which were not observed. The NN model is constructed for the Ulleung Basin, where $pCO_2$ data are best available, to map and estimate the variability of $pCO_2$ based on in situ $pCO_2$ for the years from 2003 to 2012, and the sea surface temperature (SST) and chlorophyll data from the MODIS (Moderate-resolution Imaging Spectroradiometer) sensor of the Aqua satellite along with geographic information. The NN model was trained to achieve higher than 95% of a correlation between in situ and predicted $pCO_2$ values. The RMSE (root mean square error) of the NN model output was $19.2{\mu}atm$ and much less than the variability of in situ $pCO_2$. The variability of $pCO_2$ with respect to SST and chlorophyll shows a strong negative correlation with SST than chlorophyll. As SST decreases the variability of $pCO_2$ increases. When SST is lower than $15^{\circ}C$, $pCO_2$ variability is clearly affected by both SST and chlorophyll. In contrast when SST is higher than $15^{\circ}C$, the variability of $pCO_2$ is less sensitive to changes in SST and chlorophyll. The mean rate of the annual $pCO_2$ increase estimated by the NN model output in the Ulleung Basin is $0.8{\mu}atm\;yr^{-1}$ from 2003 to 2014. As NN model can successfully map $pCO_2$ data for the whole study area with a higher resolution and less RMSE compared to the previous studies, the NN model can be a potentially useful tool for the understanding of the carbon cycle in the East Sea, where accessibility is limited by the international affairs.
Keywords
$pCO_2$; neural network model; mapping; Ulleung Basin; East Sea;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 Beale, M., M.T. Hagan and H.B. Demuth, 2010. Neural Network Toolbox 7. MathWorks, Natick, Mass, 951 pp.
2 Borges, A.V., B. Delille and M. Frankignoulle, 2005. Budgeting sinks and sources of $CO_2$ in the coastal ocean: Diversity of ecosystems counts. Geophys. Res. Lett., 32: L14601, doi: 10.1029/2005GL023053.   DOI
3 Broecker, W.S., 1982. Ocean chemistry during glacial time. Geochim. Cosmochim. Acta, 46(10): 1689-1705 pp.   DOI
4 Cai, W.-J., M.H. Dai and Y.C. Wang, 2006. Air-sea exchange of carbon dioxide in ocean margins: A province-based synthesis. Geophys. Res. Lett., 33: L12603, doi: 10.1029/2006GL026219.   DOI
5 Chen, C.-T. A. and A. V. Borges, 2009. Reconciling opposing views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystem as sources of atmospheric $CO_2$. Deep-Sea Res. Pt. II, 56: 578-590, doi:10.1016/j.dsr2.2009.01.001.   DOI
6 Cho, Y.-K. and K. Kim, 1996. Seasonal variation of East Korea Warm Current and its relation with the cold water. Societe franco-japonaise d'oceanographie, La mer 34: 172-182.
7 Choi, S.H., 1995. Distributions of $pCO_2$ and $pCH_4$ in surface seawaters of the East Sea, M.S. thesis, Seoul National University, Seoul, 92 pp.
8 Choi, S.H., D. Kim, J. Shim and H.S. Min, 2011. The spatial distribution of surface $fCO_2$ in the Southwestern East Sea/Japan sea during summer 2005. Ocean Sci. J., 46(1): 13-21.   DOI
9 Choi, S.-H., D. Kim, J.H. Shim, K.H. Kim, H.S. Min and K.R. Kim, 2012. Seasonal variations of surface $fCO_2$ and sea-air $CO_2$ fluxes in the Ulleung Basin of the East/Japan Sea. Terr. Atmos. Ocean. Sci., 23(3): 343-353.   DOI
10 Choi, S.H., 2012. The Sea-Air $CO_2$ fluxes in the Korean Marginal Seas and the Western North Pacific. Ph.D Thesis, Seoul National University, Seoul, 123 pp.
11 Friedrich, T. and A. Oschlies, 2009a. Neural network-based estimates of North Atlantic surface $pCO_2$ from satellite data: A methodological study. J. Geophys. Res., 114, C03020, doi: 10.1029/2007JC004646.   DOI
12 Friedrich, T. and A. Oschlies, 2009b. Basin-scale $pCO_2$ maps estimated from ARGO float data: A model study, J. Geophys. Res., 114, C10012, doi:10.1029/2009JC005322.   DOI
13 Intergovernmental Panel on Climate Change (IPCC), 2013. Climate change 2013: the physical science basis, Cambridge University Press, 996 pp.
14 Jo, Y.H., M. Dai, W. Zhai, X.H. Yan and S. Shang, 2012. On the variations of sea surface $pCO_2$ in the northern South China Sea: A remote sensing based neural network approach. J. Geophys. Res.: Oceans (1978-2012), 117, C08022, doi:10.1029/2011JC007745.   DOI
15 Kang, D.J., 1999. A study on the carbon cycle in the East Sea. Ph.D Thesis, Seoul National University, Seoul, 159 pp.
16 Kim, J.Y., D.J. Kang, T. Lee, and K.-R. Kim, 2014. Long-term trend of $CO_2$ and ocean acidification in the surface water of the Ulleung Basin, the East/Japan Sea inferred from the underway observational data. Biogeosciences, 11(9): 2443-2454.   DOI
17 Mitchell, D.A., D.R. Watts, M. Wimbush, W.J. Teague, K.L. Tracey, J.W. Book, K.-I. Chang, M.-S. Suk and J.-H. Yoon, 2005. Upper circulation patterns in the Ulleung Basin. Deep-Sea Res. Pt. II, 52: 1617-1638.
18 Kim, K.-R. and K. Kim, 1996. What is happening in the East Sea (Japan Sea)?: Recent chemical observations during CREAMS93-96. J. Korean Soc. Oceanogr., 31: 164-172.
19 Landschutzer, P., N. Gruber, D.C.E. Bakker, U. Schuster, S. Nakaoka, M.R. Payne, T.P. Sasse and J. Zeng, 2013. A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink. Biogeosciences, 10(11): 7793-7815.   DOI
20 Lefevre, N., A. Watson and A.R. Watson, 2005. A comparison of multiple regression and neural network techniques for mapping in situ $pCO_2$ data. Tellus B, 57: 375-384.   DOI
21 Oh, D.-C., M.-K. Park, S.-H. Choi, D.-J. Kang, S.-Y. Park, J.-S. Hwang, A. Andrey, G.-H. Hong and K.-R. Kim, 1999. The Air-Sea Exchange of $CO_2$ in the East Sea(Japan Sea). J. Oceanogr., 55: 157-169.   DOI
22 Omar, A.M., T. Johannessen, A. Olsen, S. Kaltin and F. Rey, 2007. Seasonal and interannual variability of the air-sea $CO_2$ flux in the Atlantic sector of the Barents Sea. Mar. Chem., 104: 203-213.   DOI
23 Sabine, C.L., R.A. Feely, N. Gruber, R.M. Key, K. Lee, J.L. Bullister, R. Wanninkhof, C.S. Wong, D.W.R. Wallace, B. Tilbrook, F.J. Millero, T.-H. Peng, K. Alexander, O. Tsueno and A.F. Rios, 2004. The oceanic sink for anthropogenic $CO_2$. Science, 305(5682): 367-371.   DOI
24 Sarmiento, J.L. and N. Gruber, 2002. SINKS FOR ANTHROPOGENIC CARBQN.
25 Talley, L.D., J.L. Reid, and P.E. Robbins, 2003. Data-based meridional overturning stream functions for the global ocean. J. Climate, 16(19): 3213-3226.   DOI
26 Takahashi, T., J. Olafsson, J.G. Goddard, D.W. Chipman and S.C. Sutherland, 1993. Seasonal variation of $CO_2$ and nutrients in the high-latitude surface oceans: A comparative study. Global Biogeochem. Cycles, 7(4): 843-878.   DOI
27 Takahashi, T., S.C. Sutherland, C. Sweeney, A. Poisson, N. Metzl, B. Tilbrook, N. Bates, R. Wanninkhof, R.F. Feely, C. Sabine, J. Olafsson and Y. Nojiri, 2002. Global sea-air $CO_2$ flux based on climatological surface ocean $pCO_2$ and seasonal biological and temperature effects. Deep-Sea Res. Pt. II, 49: 1601-1622.   DOI
28 Takahashi, T., S.C. Sutherland, R. Wanninkhof, C. Sweeney, R.A. Feely, D.W. Chipman, B. Hales, G. Friederich, F. Chavez, C. Sabine, A. Watson, D.C.E. Bakker, U. Schuster, N. Metzl, Y.-I. Hisayuki, M. Ishii, T. Midorikawa, Y. Nojiri, A. Kortzinger, T. Steinhoff, M. Hoppema, J. Olafsson, T.S. Arnarson, B. Tilbrook, T. Johannessen, A. Olsen, R. Bellerby, C.S. Wong, B. Delille, N.R. Bates and H. J. and De Baar, 2009. Climatological mean and decadal change in surface ocean $pCO_2$ and net sea-air $CO_2$ flux over the global oceans. Deep-Sea Res. Pt. II, 56(8): 554-577.   DOI
29 Telszewski, M., X.A. Padin, and A.F. Rios, 2009. Estimating the monthly $pCO_2$ distribution in the North Atlantic using a self-organizing neural network. Biogeosciences, 6(8): 1405-1421.   DOI
30 Thomas H., Y. Bozec, K. Elkalay and H.J. De Baar, 2004. Enhanced open ocean storage of $CO_2$ from shelf sea pumping. Science, 304: 1005-1008.   DOI
31 Tsunogai, S., S. Watanabe and T. Sato, 1999. Is there a "continental shelf pump" for the absorption of atmospheric $CO_2$?. Tellus B, 51(3): 701-712.   DOI
32 Yamada, K., J. Ishizaka, S. Yoo, H.C. Kim and S. Chiba, 2004. Seasonal and interannual variability of sea surface chlorophyll_a concentration in the Japan/East Sea (JES). Prog. Oceanogr., 61(2): 193-211.   DOI
33 Tsunogai, S., K. Kawada, S. Watanabe and T. Aramaki, 2003. CFCs indicating renewal of the Japan Sea Deep Water in winter 2000-2001. J. Oceanogr., 59: 685-693.   DOI
34 Volk, T. and M. Hoffert, 1985. Ocean carbon pumps: analysis of relative strengths and efficiencies in ocean-driven atmospheric $CO_2$ changes, In: The Carbon Cycle and atmospheric $CO_2$: Natural Variations Archean to Present, edited by: Sundquist, E.T. and W.S. Broecker, Geophysical Monograph 32, American Geophysical Union, Wash. D.C. pp. 99-110.