Ocean and Polar Research

Korea Institute of Ocean Science & Technology (한국해양과학기술원)
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A Comparison of Two Vertical-Mixing Schemes on the Simulation of the Mixed Layer Depth and Upper Ocean Temperature in an Ocean General Circulation Model

두 가지 연직혼합방안에 따른 해양대순환모형 혼합층깊이 및 상층수온 모사 민감도 비교

  • Yi, Dong-Won (Department of Marine Sciences and Convergence Technology, College of Science and Technology, Hanyang University) ;
  • Jang, Chan Joo (Ocean Circulation and Climate Research Division, KIOST) ;
  • Yeh, Sang-Wook (Department of Marine Sciences and Convergence Technology, College of Science and Technology, Hanyang University) ;
  • Park, Taewook (Ocean Circulation and Climate Research Division, KIOST) ;
  • Shin, Ho-Jeong (Ocean Circulation and Climate Research Division, KIOST) ;
  • Kim, Donghoon (Department of Atmospheric Science, College of Science, Yonsei University) ;
  • Kug, Jong-Seong (Ocean Circulation and Climate Research Division, KIOST)
  • 이동원 (한양대학교 과학기술대학 해양융합과학과) ;
  • 장찬주 (한국해양과학기술원 해양순환.기후연구부) ;
  • 예상욱 (한양대학교 과학기술대학 해양융합과학과) ;
  • 박태욱 (한국해양과학기술원 해양순환.기후연구부) ;
  • 신호정 (한국해양과학기술원 해양순환.기후연구부) ;
  • 김동훈 (연세대학교 이과대학 대기과학과) ;
  • 국종성 (한국해양과학기술원 해양순환.기후연구부)
  • Received : 2013.06.28
  • Accepted : 2013.09.16
  • Published : 2013.09.30
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Abstract

Vertical and horizontal mixing processes in the ocean mixed layer determine sea surface temperature and temperature variability. Accordingly, simulating these processes properly is crucial in order to obtain more accurate climate simulations and more reliable future projections using an ocean general circulation model (OGCM). In this study, by using Modular Ocean Model version 4 (MOM4) developed by Geophysical Fluid Dynamics Laboratory, the upper ocean temperature and mixed layer depth were simulated with two different vertical mixing schemes that are most widely used and then compared. The resultant differences were analyzed to understand the underlying mechanism, especially in the Tropical Pacific Ocean where the differences appeared to be the greatest. One of the schemes was the so-called KPP scheme that uses K-Profile parameterization with nonlocal vertical mixing and the other was the N scheme that was rather recently developed based on a second-order turbulence closure. In the equatorial Pacific, the N scheme simulates the mixed layer at a deeper level than the KPP scheme. One of the reasons is that the total vertical diffusivity coefficient simulated with the N scheme is ten times larger, at maximum, in the surface layer compared to the KPP scheme. Another reason is that the zonal current simulated with the N scheme peaks at a deeper ocean level than the KPP scheme, which indicates that the vertical shear was simulated on a larger scale by the N scheme and it enhanced the mixed layer depth. It is notable that while the N scheme simulates a deeper mixed layer in the equatorial Pacific compared to the KPP scheme, the sea surface temperature (SST) simulated with the N scheme was cooler in the central Pacific and warmer in the eastern Pacific. We postulated that the reason for this is that in the central Pacific atmospheric forcing plays an important role in determining SST and so does a strong upwelling in the eastern Pacific. In conclusion, what determines SST is crucial in interpreting the relationship between SST and mixed layer depth.

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References

  1. 이지혜, 노의근 (2012) GAIA과제: Comparison of the Vertical Mixing Schemes in the OGCM with the Sensitivity to the Latitudinal Dependence. 2012년도 한국해양과학기술 공동학술대회 초록집, EXCO, 대구, 2012년 5월 31일-6월 1일, pp 16
  2. Agrawal YC, Terray EA, Donelan MA, Hwang PA, Williams AJ, Drennan WM, Kahma KK, Kitaigorodskii SA (1992) Enhanced dissipation of kinetic-energy beneath surfacewaves. Nature 359(6392):219-220 https://doi.org/10.1038/359219a0
  3. Alexander MA, Timlin MS, Scott JD (2001) Winter-towinter recurrence of sea surface temperature, salinity and mixed layer depth anomalies. Prog Oceanogr 49(1-4):41-61 https://doi.org/10.1016/S0079-6611(01)00015-5
  4. Anis A, Moum JN (1992) The Superadiabatic Surface-Layer of the Ocean during Convection. J Phys Oceanogr 22(10):1221-1227 https://doi.org/10.1175/1520-0485(1992)022<1221:TSSLOT>2.0.CO;2
  5. Ayotte KW, Sullivan PP, Andren A, Doney SC, Holtslag AAM, Large WG, Mcwilliams JC, Moeng CH, Otte MJ, Tribbia JJ, Wyngaard JC (1996) An evaluation of neutral and convective planetary boundary-layer parameterizations relative to large eddy simulations. Bound-Lay Meteorol 79(1-2):131-175 https://doi.org/10.1007/BF00120078
  6. Bleck R (2002) An Oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates (Vol.4, p.55, 2002). Ocean Model 4(2):219-219 https://doi.org/10.1016/S1463-5003(01)00017-8
  7. Carton JA, Giese BS (2008) A reanalysis of ocean climate using Simple Ocean Data Assimilation (SODA). Mon Weather Rev 136(8):2999-3017 https://doi.org/10.1175/2007MWR1978.1
  8. Carton JA, Grodsky SA, Liu H (2008) Variability of the oceanic mixed layer, 1960-2004. J Climate 21(5):1029-1047 https://doi.org/10.1175/2007JCLI1798.1
  9. Chen D, Rothstein LM, Busalacchi AJ (1994) A hybrid vertical mixing scheme and its application to tropical ocean models. J Phys Oceanogr 24(10):2156-2179 https://doi.org/10.1175/1520-0485(1994)024<2156:AHVMSA>2.0.CO;2
  10. DiNezio PN, Kirtman BP, Clement AC, Lee SK, Vecchi GA, Wittenberg A (2013) Mean climate controls on the simulated response of ENSO to increasing greenhouse gases. J Climate 25(21):7399-7420
  11. Ekman VW (1905) On the influence of the earth's rotation on ocean currents. Ark Mat Astr Fys 2(11):1-53
  12. Griffies SM (2009) Elements of MOM4p1. NOAA Geophysical Fluid Dynamics Laboratory, GFDL Ocean Group Technical Report, 444 p
  13. Griffies SM, Winton M, Samuels BL (2004) The Large and Yeager (2004) dataset and CORE. NOAA Geophysical Fluid Dynamis Laboratory, 5 p
  14. Halliwell GR (2004) Evaluation of vertical coordinate and vertical mixing algorithms in the HYbrid-Coordinate Ocean Model (HYCOM). Ocean Model 7(3-4):285-322 https://doi.org/10.1016/j.ocemod.2003.10.002
  15. Large WG (1998) Modeling and parameterizing the ocean planetary boundary layer. Nato Adv Sci I C-Mat 516:81-120
  16. Large WG, Mcwilliams JC, Doney SC (1994) Oceanic vertical mixing - a review and a model with a nonlocal boundarylayer parameterization. Rev Geophys 32(4):363-403 https://doi.org/10.1029/94RG01872
  17. Li XJ, Chao Y, McWilliams JC, Fu LL (2001) A comparison of two vertical-mixing schemes in a Pacific Ocean general circulation model. J Climate 14(7):1377-1398 https://doi.org/10.1175/1520-0442(2001)014<1377:ACOTVM>2.0.CO;2
  18. Mailhot J, Benoit R (1982) A finite-element model of the atmospheric boundary-layer suitable for use with numerical weather prediction models. J Atmos Sci 39(10):2249-2266 https://doi.org/10.1175/1520-0469(1982)039<2249:AFEMOT>2.0.CO;2
  19. Mellor GL, Yamada T (1982) Development of a turbulence closure-model for geophysical fluid problems. Rev Geophys 20(4):851-875 https://doi.org/10.1029/RG020i004p00851
  20. Montegut CD, Madec G, Fischer AS, Lazar A, Iudicone D (2004) Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology. J Geophys Res-Oceans 109(C12003). doi:10.1029/2004JC002378
  21. NCAR (1989) NCAR ASCII Version of ETOPO5 earth surface elevation. Data Support Section (National Center for Atmospheric Research
  22. NCAR (1996) The NCAR CSM Ocean Model. National Center For Atmospheric Research Boulder, NCAR/TN-423+STR, 75 p
  23. Noh Y (1996) Dynamics of diurnal thermocline formation in the oceanic mixed layer. J Phys Oceanogr 26(10):2183-2195 https://doi.org/10.1175/1520-0485(1996)026<2183:DODTFI>2.0.CO;2
  24. Noh Y, Jnag C, Yamagata T, Chu PC, Kim C-H (2002) Simulation of more realistic upper-ocean processes from an OGCM with a new ocean mixed layer model. J Phys Oceanogr 32:1284-1307 https://doi.org/10.1175/1520-0485(2002)032<1284:SOMRUO>2.0.CO;2
  25. Noh Y, Kim HJ (1999) Simulations of temperature and turbulence structure of the oceanic boundary layer with the improved near-surface process. J Geophys Res-Oceans 104(C7):15621-15634 https://doi.org/10.1029/1999JC900068
  26. O'Brien JJ (1970) A note on the vertical structure of the eddy exchange coefficient in the planetary boundary layer. J Atmos Sci 27:1213-1215 https://doi.org/10.1175/1520-0469(1970)027<1213:ANOTVS>2.0.CO;2
  27. Osborn T, Farmer DM, Vagle S, Thorpe SA, Cure M (1992) Measurements of bubble plumes and turbulence from a submarine. Atmos Ocean 30(3):419-440 https://doi.org/10.1080/07055900.1992.9649447
  28. Pacanowski RC, Philander SGH (1981) Parameterization of vertical mixing in numerical-models of tropical oceans. J Phys Oceanogr 11(11):1443-1451 https://doi.org/10.1175/1520-0485(1981)011<1443:POVMIN>2.0.CO;2
  29. Price JF, Weller RA, Pinkel R (1986) Diurnal cycling - observations and models of the upper ocean response to diurnal heating, cooling, and wind mixing. J Geophys Res-Oceans 91(C7):8411-8427 https://doi.org/10.1029/JC091iC07p08411
  30. Thomson RE, Fine IV (2003) Estimating mixed layer depth from oceanic profile data. J Atmos Ocean Tech 20(2):319-329 https://doi.org/10.1175/1520-0426(2003)020<0319:EMLDFO>2.0.CO;2