نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکترا دانشکده علوم و فنون دریایی، گروه علوم غیر زیستی جوی و اقیانوسی، دانشگاه هرمزگان

2 دانشیار دانشکده علوم و فنون دریایی، گروه علوم غیر زیستی جوی و اقیانوسی، دانشگاه هرمزگان

3 استاد دانشکده علوم، گروه فیزیک، دانشگاه اصفهان

چکیده

در این مقاله تاثیر تبخیر بر لایه آمیخته اقیانوسی در حضور یا عدم حضور گردش لانگمویر و شکست موج با استفاه از شبیه سازی پیچک بزرگ بررسی و در تعریف شبیه سازی، از پارامترهای نزدیک به مونسون تابستانه دریای عربی استفاده شد. شبیه سازی برای 5/33 ساعت انجام و از خروجی های 5/9 ساعت ابتدایی صرف نظر شد و پارامترهای مختلف در یک بازه ی 24 ساعته مورد بررسی قرار گرفتند. در حضور تبخیر و واداشت باد و عدم حضور گردش لانگمویر و شکست موج، نوسانات روزانه TKE و SST با نوسانات روزانه شار گرمایی نهان تبخیر هم خوانی دارد و TKE نسبت به حالت عدم حضور تبخیر، بین 25 تا 100 درصد افزایش یافته است. در یک بازه ی 24 ساعته، تبخیر در حضور گردش لانگمویر و شکست موج، SST را حدودا 06/ سانتی گراد کاهش داده است و مطابق انتظار، کاهش دمای ناشی از تبخیر در حضور گردش لانگمویر و شسکت موج به میزان کم تری (حدودا 05/ سانتی گراد ) بوده است. مشاهده شد که تبخیر در غیاب شکست موج و گردش لانگمویر موجب کاهش اندک برش جریان و تولید برشی و افزایش نرخ اتلاف (به میزان تقریبی 2 برابر)، انتقال فشاری و انتقال تلاطمی TKE می شود. دو جمله اخیر بودجه TKE با نرخ اتلاف در نزدیکی سطح آب تعادل را برقرار می سازند و در این حالت است که امکان نوسانات روزانه نیمرخ TKE وجود دارد. با این وجود، مهمترین تاثیر به حساب آوردن تبخیر در حضور گردش لانگمویر و شکست موج در بودجه TKE، به کاهش تولید برشی در قسمت های میانی لایه ی آمیخته ی اقیانوسی خلاصه می شود. این نتیجه نیز بدست آمد که حضور یا عدم حضور گردش لانگمویر و شکست موج تاثیر چندانی بر نیمرخ شار گرمایی تلاطمی ندارد؛ درست مانند تبخیر که بر تولید تلاطمی استوکس بی تاثیر است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Sensitivity of the Oceanic Mixed Layer to the Surface Evaporation in the Presence of the Wind and Wave Forcing through the Large Eddy Simulation in the north Arabian Sea during Summer Monsoon

نویسندگان [English]

  • Iman Mehraby Dastenay 1
  • Hossein Malakooti 2
  • Smaeyl Hassanzadeh 3
  • Maryam Rahbani 2

1 Department of Marine and Atmospheric Science (non-Biologic), Faculty of marine sciences and technology, University of Hormozgan, Bandar Abbas, Iran

2 Department of Marine science and technology, University of Hormozgan, Bandar Abbas, Iran

3 Department of Physics, Faculty of Sciences, University of Isfahan, Isfahan, Iran

چکیده [English]

The effects of evaporation on the ocean mixed layer in the presence or the absence of Langmuir circulation (LC) and wave breaking (WB) is studied through the Large Eddy Simulation. We have used approximate parameters of summer monsoon for defining the experimental simulations. The simulations were conducted for 33.5 hours and we ignored the first 9.5 hours of results and the simulated parameters is investigated during 24 hours period. We can mention that there is a good matching between diurnal variations of TKE and SST with diurnal changes of latent heat flux in the presence of evaporation and absence of Langmuir circulation and wave breaking and TKE in this case increased between 25 to 100 percent related to the case on the absence of evaporation. Although, evaporation in the presence of LC and WB decreased SST, around 0.060 C in a 24 hours period, but as expected, it decreased SST in the case of presence of LC and WB less than it (0.050 C). Meanwhile, it was found that, evaporation in the absence of LC and WB causes a slight decrease in velocity shear and shear production and an increase in dissipation rate (approximately double), pressure transport, and TKE transport. These two terms of TKE budget balance with dissipation rate close to the sea surface and the diurnal changes of TKE profile is observable just in this case. However, the most effect of adding the presence of evaporation to the presence of LC and WB in TKE budget is summarized to decreasing of shear production in the middle part of ocean mixed layer. It is also found that, in the presence of evaporation, presence or absence of LC and WB doesn't affect the profile of turbulent heat flux; similar to the evaporation which doesn’t change the Stokes production.

کلیدواژه‌ها [English]

  • ocean mixed layer
  • Lungmuir circulation
  • Wave breaking
  • Latent heat flux
  • Arabian sea
  • monsoon

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