شبیه‌سازی با روش پیچک بزرگ لایة آمیخته شمال دریای عربی متأثر از شکست موج و گردش لانگمویر ناشی از مونسون تابستانی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری، دانشکده علوم وفنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران

2 دانشکده علوم وفنون دریایی، دانشگاه هرمزگان، بندرعباس، ایران

3 استاد، گروه فیزیک، دانشکده علوم پایه، دانشگاه اصفهان، اصفهان، ایران

4 دانشکده علوم و فنون دریایی، دانشگاه هرمزگان

چکیده

در این پژوهش، شبیه‌سازی با روش پیچک بزرگ لایۀ آمیختة شمال دریای عربی با استفاده از مدل عددی پالم در شرایط سهیم بودن یا نبودن پدیده‌های شکست موج و گردش لانگمویر ناشی از باد مونسون تابستانی انجام شده است. ابعاد افقی این مقاله در افق 300 متر در 300 متر، عمق شبیه‌سازی شده 80 متر و فاصلة شبکه در هر سه جهت برابر با 25/1 متر است. به‌منظور اعمال اثر باد جنوب غربی، شار اندازه حرکت ناشی از باد در هر دو راستای   و  تعریف شده است. با توجه به هدف اصلی مقاله، به‌جای تلاش برای شبیه‌سازی شکست موج، با اعمال نوسانات تصادفی در سطح دریا، تأثیرات شکست موج بر لایة سطحی دریا در نظر گرفته شد. نتایج تحقیق نشان می‌دهد که شکست موج فقط بر اعماق نزدیک به سطح دریا (کم‌تر از 5 متر) تأثیرگذار است؛ حال آن‌که باریکه‌های به وجود آمده از گردش لانگمویر تا اعماق زیادی که مرتبه‌ای از طول‌موج در نظر گرفته شده است، نقش ایفا می‌کنند. همچنین این نتیجه حاصل شد که تلفیق هر دو پدیدة شکست موج و گردش لانگمویر موجب کاهش اندک انرژی جنبشی تلاطمی می‌شود که این امر می‌تواند از تأثیراختلالی شکست موج بر میدان سرعت به وجود آمده از نیروی تاو در سطح ناشی شده باشد. بااین‌وجود، برخلاف مطالعات پیشین، در هیچ عمقی اثر برش سرعت به‌عنوان عاملی تعیین‌کننده در بزرگی TKE به‌حساب نیامد.

کلیدواژه‌ها


عنوان مقاله [English]

Large Eddy Simulation of Ocean Mixed Layer of the Northern Arabian Sea Influenced by Wave Breaking and Langmuir Circulation

نویسندگان [English]

  • Iman Mehraby Dastenay 1
  • Hossein Malakooti 2
  • Smaeyl Hassanzadeh 3
  • Maryam Rahbani 4
1 Ph.D.c., Department of Marine science and technology, University of Hormozgan, Bandar Abbas, Iran
2 Department of Marine science and technology, University of Hormozgan, Bandar Abbas, Iran
3 Professor, Department of Physics, Faculty of Sciences, University of Isfahan, Isfahan, Iran
4 Department of Marine Science and Technology, University of Hormozgan
چکیده [English]

In this research, LES of ocean mixed layer of the north of Arabian Sea is conducted using PALM (Paralyzed Large Eddy Simulation) model experiments with or without the contribution of wave breaking and Langmuir circulation formed by summer monsoon. Unlike previous studies, wind induced momentum flux is defined in both x and y direction to apply SW wind. According to the main purpose of this work, the effects of wave breaking on the mixed layer is produced by defining random fluctuations on the sea surface, instead of trying to simulate wave breaking. Results showed wave breaking only affects the sea surface, less than 5 m; meanwhile, strips of Langmuir circulation are effective until a depth which is an order of the wavelength. Although, it was found that combining both effects of wave breaking and Langmuir circulation cause a slight decrease of Turbulent Kinetic Energy which can be caused by the distortion effect of wave breaking on the velocity field. Hence, unlike previous studies, the effect of velocity shear don’t play an important role in the magnitude of TKE.

کلیدواژه‌ها [English]

  • Turbulence
  • Large Eddy Simulation
  • PALM numerical model
  • ocean mixed layer
  • Arabian sea
  • Indian Monsoon

[1] Beal LM, Hormann V, Lumpkin R, Foltz G R, The Response of the Surface Circulation of the Arabian Sea to Monsoonal Forcing. Journal of Physical Oceanography. 2013; 43: 2008-22.

[2] Riser SC, Nystuen J, Rogers A. Monsoon effects in the Bay of Bengal inferred from profiling float-based measurements of wind speed and rainfall. Limnol. Oceanogr. 2008; 53: 2080–93.

[3] Kumar SP, Narvekar J. Seasonal variability of the mixed layer in the central Arabian Sea and its implication on nutrients and primary productivity. Deep-Sea Research II. 2005; 52: 1848–61.

[4] Craik AD, Leibovich S. A rational model for Langmuir circulations. Journal of Fluid Mechanics. 1976 Feb; 73(3):401-26.

[5] Pearson BC, Grant AL, Polton JA, Belcher SE. Langmuir turbulence and surface heating in the ocean surface boundary layer. Journal of Physical Oceanography. 2015 Dec; 45(12):2897-911.

[6] Large WG, McWilliams JC, Doney SC. Oceanic vertical mixing: A review and a model with a nonlocal boundary layer parameterization. Reviews of Geophysics. 1994 Nov;32(4):363-403.

[7] Price JF, Weller RA, Pinkel R. Diurnal cycling: Observations and models of the upper ocean response to diurnal heating, cooling, and wind mixing. Journal of Geophysical Research: Oceans. 1986 Jul 15; 91(C7):8411-27.

[8] Siegel DA, Domaradzki JA. Large-eddy simulation of decaying stably stratified turbulence. Journal of physical oceanography. 1994 Nov;24(11):2353-86.

[9] Wang D, Large WG, McWilliams JC. Large‐eddy simulation of the equatorial ocean boundary layer: Diurnal cycling, eddy viscosity, and horizontal rotation. Journal of Geophysical Research: Oceans. 1996 Feb 15; 101(C2):3649-62.

[10] Wang D, McWilliams JC, Large WG. Large-eddy simulation of the diurnal cycle of deep equatorial turbulence. Journal of Physical Oceanography. 1998 Jan; 28(1):129-48.

[11] Wang D, Müller P. Effects of equatorial undercurrent shear on upper-ocean mixing and internal waves. Journal of physical oceanography. 2002 Mar; 32(3):1041-57.

[12] Skyllingstad ED, Denbo DW. An ocean large‐eddy simulation of Langmuir circulations and convection in the surface mixed layer. Journal of Geophysical Research: Oceans. 1995 May 15;100(C5):8501-22.

[13] McWILLIAMS JC, Sullivan PP, Moeng CH. Langmuir turbulence in the ocean. Journal of Fluid Mechanics. 1997 Mar; 334:1-30.

[14] Scully ME, Fisher AW, Suttles SE, Sanford LP, Boicourt WC. Characterization and modulation of Langmuir circulation in Chesapeake Bay. Journal of Physical Oceanography. 2015 Oct;45(10):2621-39.

[15]Gargett AE, Grosch CE. Turbulence process domination under the combined forcings of wind stress, the Langmuir vortex force, and surface cooling. Journal of Physical Oceanography. 2014 Jan;44(1):44-67.

 [16] Gargett A, Wells J, Tejada-Martínez A, Grosch C. Langmuir supercells: A dominant mechanism for sediment resuspension and transport in shallow shelf seas. Science. 2004; 306: 1925–1928

[17] Gargett AE, Wells JR. Langmuir turbulence in shallow water. Part 1. Observations. Journal of Fluid Mechanics. 2007 Apr; 576:27-61.

 [18] Kukulka T, Plueddemann AJ, Trowbridge JH, Sullivan PP. The influence of crosswind tidal currents on Langmuir circulation in a shallow ocean. Journal of Geophysical Research: Oceans. 2011 Aug;116(C8).

[19] Kukulka T, Plueddemann AJ, Sullivan PP. Nonlocal transport due to Langmuir circulation in a coastal ocean. Journal of Geophysical Research: Oceans. 2012 Dec;117(C12).

[20] Li S, Li M, Gerbi GP, Song JB. Roles of breaking waves and Langmuir circulation in the surface boundary layer of a coastal ocean. Journal of Geophysical Research: Oceans. 2013 Oct;118(10):5173-87.

[21] Tejada-Martinez AE, Grosch CE. Langmuir turbulence in shallow water. Part 2. Large-eddy simulation. Journal of Fluid Mechanics. 2007 Apr;576:63-108.

[22] Noh Y, Min HS, Raasch S. Large eddy simulation of the ocean mixed layer: The effects of wave breaking and Langmuir circulation. Journal of physical oceanography. 2004 Apr;34(4):720-35.

[23]Noh Y, Goh G, Raasch S, Gryschka M. Formation of a diurnal thermocline in the ocean mixed layer simulated by LES. Journal of Physical Oceanography. 2009 May;39(5):1244-57.

[24] Rao RR, Molinari RL, Festa JF. Evolution of the climatological near‐surface thermal structure of the tropical Indian Ocean: 1. Description of mean monthly mixed layer depth, and sea surface temperature, surface current, and surface meteorological fields. Journal of Geophysical Research: Oceans. 1989 Aug 15; 94(C8):10801-15.

[25] Rao RR, Sivakumar R. Seasonal variability of sea surface salinity and salt budget of the mixed layer of the north Indian Ocean. Journal of Geophysical Research: Oceans. 2003 Jan; 108(C1):9-1.

 [26] Carton JA, Grodsky SA, Liu H. Variability of the oceanic mixed layer, 1960–2004. Journal of Climate. 2008 Mar;21(5):1029-47.

[27] Sreenivas P, Patnaik KV, Prasad KV. Monthly variability of mixed layer over Arabian Sea using ARGO data. Marine Geodesy. 2008 Feb 29;31(1):17-38.

[28] Lee C M, Jones B.H, Brink K H, Fischer A S. The upper-ocean response to monsoonal forcing in the Arabian Sea: seasonal and spatial variability. Deep-Sea Research II. 2000; 47: 1177–1226

[29] Weller RA, Baumgartner MF, Josey SA, Fischer AS, Kindle JC. Atmospheric forcing in the Arabian Sea during 1994–1995: observations and comparisons with climatology and models. Deep-Sea Research II. 1998; 45: 1961–1999

[30] Weller RA, Fischer AS, Rudnick DL, Eriksen CC, Dickey TD, Marra J et al. Moored observations of upper-ocean response to the monsoons in the Arabian Sea during 1994–1995. Deep Sea Research Part II: Topical Studies in Oceanography. 2002 Jan 1;49(12):2195-230.

[31] Prasad TG. A comparison of mixed‐layer dynamics between the Arabian Sea and Bay of Bengal: One‐dimensional model results. Journal of Geophysical Research: Oceans. 2004 Mar;109(C3).

[32] de Boyer Montégut C, Mignot J, Lazar A, Cravatte S. Control of salinity on the mixed layer depth in the world ocean: 1. General description. Journal of Geophysical Research: Oceans. 2007 Jun;112(C6).

[33] McCreary JP, Kundu PK. A numerical investigation of sea surface temperature variability in the Arabian Sea. Journal of Geophysical Research: Oceans. 1989 Nov 15;94(C11):16097-114.

 [34] Maronga B, Gryschka M, Heinze R, Hoffmann F, Kanani-Sühring F, Keck M, et al. The Parallelized Large-Eddy Simulation Model )PALM) version 4.0 for atmospheric and oceanic flows: model formulation, recent developments, and future perspectives. Geoscientific Model Development Discussions 8 (2015), Nr. 2, S. 1539-1637. 2015 Feb 19.

[35] Deardorff JW. Stratocumulus-capped mixed layers derived from a three-dimensional model. Boundary-Layer Meteorology. 1980 Jun 1; 18(4):495-527.

[36] Moeng CH, Wyngaard JC. Spectral analysis of large-eddy simulations of the convective boundary layer. Journal of the Atmospheric Sciences. 1988 Dec; 45(23):3573-87.

[37] Saiki EM, Moeng CH, Sullivan PP. Large-eddy simulation of the stably stratified planetary boundary layer. Boundary-Layer Meteorology. 2000 Apr 1; 95(1):1-30.

[38] Fairall CW, Bradley EF, Hare JE, Grachev AA, Edson JB. Bulk parameterization of air–sea fluxes: Updates and verification for the COARE algorithm. Journal of climate. 2003 Feb;16(4):571-91.

[39] Findlater J. A major low‐level air current near the Indian Ocean during the northern summer. Quarterly Journal of the Royal Meteorological Society. 1969 Apr 1; 95(404):362-80.

[40] Yi X, Hünicke B, Tim N, Zorita E. The relationship between Arabian Sea upwelling and Indian Monsoon revisited in a high resolution ocean simulation. Climate dynamics. 2018 Jan 1;50(1-2):201-13.