The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY (한국해양학회지:바다)

The Korean Society of Oceanography (한국해양학회)
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Determining Spatial and Temporal Variations of Surface Particulate Organic Carbon (POC) using in situ Measurements and Remote Sensing Data in the Northeastern Gulf of Mexico during El $Ni\tilde{n}o$ and La $Ni\tilde{n}a$

현장관측 및 원격탐사 자료를 이용한 북동 멕시코 만에서 El $Ni\tilde{n}o$와 La $Ni\tilde{n}a$ 기간 동안 표층 입자성 유기탄소의 시/공간적 변화 연구

  • Son, Young-Baek (Korea Ocean Satellite Center, KORDI) ;
  • Gardner, Wilford D. (Department of Oceanography, Texas A&M University)
  • 손영백 (한국해양연구원 해양위성센터) ;
  • Received : 2009.12.28
  • Accepted : 2010.02.22
  • Published : 2010.05.30
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Abstract

Surface particulate organic carbon (POC) concentration was measured in the Northeastern Gulf of Mexico on 9 cruises from November 1997 to August 2000 to investigate the seasonal and spatial variability related to synchronous remote sensing data (Sea-viewing Wide Field-of-view Sensor (SeaWiFS), sea surface temperature (SST), sea surface height anomaly (SSHA), and sea surface wind (SSW)) and recorded river discharge data. Surface POC concentrations have higher values (>100 $mg/m^3$) on the inner shelf and near the Mississippi Delta, and decrease across the shelf and slope. The inter-annual variations of surface POC concentrations are relatively higher during 1997 and 1998 (El Nino) than during 1999 and 2000 (La Nina) in the study area. This phenomenon is directly related to the output of Mississippi River and other major rivers, which associated with global climate change such as ENSO events. Although highest river runoff into the northern Gulf of Mexico Coast occurs in early spring and lowest flow in late summer and fall, wide-range POC plumes are observed during the summer cruises and lower concentrations and narrow dispersion of POC during the spring and fall cruises. During the summer seasons, the river discharge remarkably decreases compared to the spring, but increasing temperature causes strong stratification of the water column and increasing buoyancy in near-surface waters. Low-density plumes containing higher POC concentrations extend out over the shelf and slope with spatial patterns and controlled by the Loop Current and eddies, which dominate offshore circulation. Although river discharge is normal or abnormal during the spring and fall seasons, increasing wind stress and decreasing temperature cause vertical mixing, with higher surface POC concentrations confined to the inner shelf.

북동 멕시코 만에서 particulate organic carbon(POC)의 시/공간적 변화를 조사하기 위하여, 1997년 11월부터 2000년 8월까지 총 9번의 관측이 이루어 졌으며, 같은 기간 동안 위성자료(해색, 표층수온, 해면고도이상, 표층바람)와 주요 강들 의 유출량이 조사되었다. POC 농도는 내 대륙붕과 미시시피 하구 역에서 높은 값을 (>100 $mg/m^3$) 나타내고 대륙붕과 대륙사면으로 가면서 감소된다. POC의 경년 변화는 상대적으로 1997과 1998년(El $Ni\tilde{n}o$)이 1999과 2000년(La $Ni\tilde{n}a$) 보다 상대적으로 증가되어 나타난다. 이런 현상은 미시시피강 및 다른 주요 강들에 영향을 주는 강우량 변화에 따른 담수 유 입의 변화와 직접적으로 연관되어 있으며, 강우량 변화는 ENSO 현상과 같은 세계 기후변화와 관련이 있는 것으로 사료 된다. 북동 멕시코 만 연안으로 유입되는 주요 강들의 방류량은 초봄에 증가되어 여름과 가을에 감소되지만, 공간적으로 확장된 높은 농도의 POC 분포는 여름 조사기간에서 관측되고, 낮은 농도 및 제한된 확산은 가을과 초 봄 관측에서 나타 난다. 여름철 동안 상대적인 강의 유출량은 봄에 비하여 현저하게 감소하지만, 증가된 표층수온은 수층을 강하게 성층화 시키고 표층에서 부력을 증가시킨다. 이런 조건에서 고농도의 POC를 함유하는 저염수는 상부 대륙사면까지 확장되고 이 는 Loop Current와 Loop Current Eddies의해서 조절된다. 봄과 가을 동안 유출량은 보통이거나 이상을 보이지만, 증가된 바람과 낮은 표층수온으로 인하여 수직적 혼합을 유발하고 이는 높은 농도의 POC를 내 대륙붕에 제한 시키는 것으로 사료된다.

Keywords

References

  1. Biggs, D.C., 1992. Nutrients, plankton, and productivity in a warmcore ring in the Western Gulf of Mexico. J. Geophys. Res., 97: 2143-2154. https://doi.org/10.1029/90JC02020
  2. Biggs, D.C. and F.E. Muller-Karger, 1994. Shìp and satellite observation of chlorophyll stocks in interesting cyclone-anticyclone eddy pairs in the western Gulf of Mexico. J. Geophys. Res., 99(4): 7371-7384. https://doi.org/10.1029/93JC02153
  3. Brooks, D.A. and R.V Legeckis, 1982. A ship and satellite view of hydrographic features in the western Gulf of Mexico. J. Geophys. Res., 87: 4195-4206. https://doi.org/10.1029/JC087iC06p04195
  4. Elliott, B.A., 1982. Anticyclonic rings in the Gulf of Mexico. J. Phys. Oceanogr., 12: 1292-1309. https://doi.org/10.1175/1520-0485(1982)012<1292:ARITGO>2.0.CO;2
  5. Enfield, D.B., A.M. Mestas-Nunez and P.J. Trimble, 2001. The Atlantic multidecadal oscillation and its relation to raìnfall and river flows in the continental US. Geophys. Res. Lett., 28: 2077-2080. https://doi.org/10.1029/2000GL012745
  6. Frolov, S.A., G.G. Sutyrin, G.D. Rowe and L.M. Rothstein, 2004. Loop Current eddy interaction with the western boundary in the Gulf of Mexico. J. Phys. Oceanogr., 34: 2223-2237. https://doi.org/10.1175/1520-0485(2004)034<2223:LCEIWT>2.0.CO;2
  7. Gilbes, F., C. Thomas, J.J. Walsh and F.E. Muller-Karger, 1996. An episodic chlorophyll plume on the West Florida Shelf. Cont. Shelf Res., 16: 1201-1224. https://doi.org/10.1016/0278-4343(95)00065-8
  8. Hu, C., F.E. Muller-Karger, D.C. Biggs, K.L. Carder, B. Nababan, D. Dadeau and J. Vanderbloemen, 2003. Comparison of ship and satellite bio-optical measurements on the continental margin of the NE Gulf of Mexico. Int. J. Rcmote Sens., 24(13): 2597-2612. https://doi.org/10.1080/0143116031000067007
  9. Hu, C., F.E. Muller-Karger, G.A. Vargo, M.B. Neely and E. Johns, 2004. Linkages between coastal runoff and the Florida Keys ecosystem: A study of a dark plume event. Geophys. Res. Lett., 31: doí: 10.1029/2004GL020382.
  10. JGOFS, 1966. Protocols for the Joint Global Ocean Flux Study (JGOFS) core measurements. Report #19, Intergovernmental Oceanographic Commission, Bergen, Norway, 170 pp.
  11. McClain, C.R., G.C. Feldman and S.B. Hooker, 2004. An overview of the SeaWiFS project and strategies for producing a climate research quality global ocean bio-optical time series. Deep-Sea Res. II, 51: 5-42. https://doi.org/10.1016/j.dsr2.2003.11.001
  12. Molinari, R.L. and D.A. Mayer, 1982. Current meter observations on the continental slope at two sites in the eastern Gulf of Mexico. J. Phys. Oceanogr. 12: 1480-1492. https://doi.org/10.1175/1520-0485(1982)012<1480:CMOOTC>2.0.CO;2
  13. Morey, S.L., P.J. Martin, J.J. O'Brien, A.A. Wallcraft and J. ZavalaHidalgo, 2003. Export pathways for river discharged fresh water in the northern Gulf of Mexico. J. Geophys. Res., 108(C10): 3303 doi:10.1029/20002JC001674
  14. Oey, L.-Y., 1995. Eddy and wind-forced shelf circulation. J. Geophys. Res., 100: 8621-8637. https://doi.org/10.1029/95JC00785
  15. Ohlmann, J.C. and P.P. Niiler, 2005. Circulation over the continental shelf in the northern Gulf of Mexico. Pro. Oceanogr., 64: 45-81. https://doi.org/10.1016/j.pocean.2005.02.001
  16. Rabalais, N.N., R.E. Turner, D. Justic, Q. Dortch, WJ. Wiseman and B.K. Sen Gupta, 1996. Nutrient Changes in the Mississippi River and system responses on the adjacent continental shelf. Estuaries, 19: 386-407. https://doi.org/10.2307/1352458
  17. Ropelewski, C.F. and M.S. Halpert, 1986. North American precipitation tation and temperature patterns associated with the El Nino/Southern Oscillation (ENSO). Mon. Weather Rev., 114: 2352-2362. https://doi.org/10.1175/1520-0493(1986)114<2352:NAPATP>2.0.CO;2
  18. Sahl, L.E., D.A. Wiesenburg and W.J. Merrell, 1997. Interactions of mesoscale features with Texas shelf and slope waters. Cont. Shelf Res., 17: 117-136. https://doi.org/10.1016/S0278-4343(96)00017-9
  19. Schmidt, N., E.K. Lipp, J.B. Rose and M.E. Luter, 2001. ENSO influences on seasonaI rainfall and river discharge in Florida. J. Clim., 14: 615-628. https://doi.org/10.1175/1520-0442(2001)014<0615:EIOSRA>2.0.CO;2
  20. Smìth, S.R., P.M. Green, A.P. Leonardi and J.J. O'Brien, 1998. Role of multiple-level tropospheric circulations in forcing ENSO winter precipitation anomalies. Mon. Weather Rev., 126: 3102-3116. https://doi.org/10.1175/1520-0493(1998)126<3102:ROMLTC>2.0.CO;2
  21. Son, Y.B., WD. Gardner, A.Y. Mìshonov and M.J. Richardson, 2009. Multispectral remote-sensing aIgorithms for particulate organic carbon (POC): The Gulf of Mexico. Remote Sens. Environ., 113: 50-61. https://doi.org/10.1016/j.rse.2008.08.011
  22. Son, Y.B., (2006). POC algorithms based on spectral remote sensing data and its temporal and spatial variability in the Gulf of Mexico, Ph.D. thesis, 200 pp., Texas A&M Univ., College Station.
  23. SWFDOG, 2002. SatelIite images track "black water" event off Florida coast. EOS, 83: 281-285.
  24. Vukovich, F.M. and GA. Maul, 1985. Cyclonic Eddies in the Eastern Gulf of Mexico. J. Phys. Oceanogr., 15: 105-117. https://doi.org/10.1175/1520-0485(1985)015<0105:CEITEG>2.0.CO;2
  25. Walker, N.D., L.J. Rouse, B. Rouge, GS. Fargion and D.C. Biggs, 1994. The great flood of summer 1993: Mississippi River discharge studied. EOS, 75: 409.
  26. WaIker, N.D., 1996. Satellite assessment of Mississippi River plume variability: causes and predictability. Remote Sens. Environ., 58: 21-35. https://doi.org/10.1016/0034-4257(95)00259-6
  27. Wentz, F.J., 1997. A well-calibrated ocean aIgorithms for SSM/I. J. Geophys. Res., 102(C4): 8703-8718. https://doi.org/10.1029/96JC01751