عنوان مقاله [English]
In the Northern Indian Ocean, monsoon reversing winds induce the variation in the characteristics of mixed layer depth (MLD). MLD as one of the most important quantities of the upper ocean plays a vital role in several physical, chemical, biological oceanographic and climatic phenomena. Using the most accurate bathymetry data with spatial resolution of 0.033deg and monthly temporal resolution using the MITgcm model and the use of a suitable criterion for the detection and diagnosis of MLD and BLT(Barrier Layer thickness) is one of the characteristics of this study. According to the results of this study, there is a significant change in MLD from summer monsoon to winter monsoon. In January/February, the southern coast of Iran and Pakistan toward its south, MLD varies from 125meters to 65meters. The highest values were found near the east coast of the North Indian Ocean, between 85 meters and 125 meters, and the lowest is about 85 meters near the western coast and near Oman. In July /August, from the southern coast of Iran and Pakistan toward its south, MLD varies from 15 meters to 45 meters. In general, during both the monsoons the MLDs on the eastern side of the ocean are deeper than the its western side. On the other hand, BLT has more presence in the area in the winter than summer. The causes of variations are can be found in factors such as precipitation, evaporation, wind stress, current inversions, pure surface heat during summer monsoon and winter monsoon.
 Vissa NK, Satyanarayana AN, Kumar BP. Comparison of mixed layer depth and barrier layer thickness for the Indian Ocean using two different climatologies. International Journal of Climatology. 2013 Nov 15;33(13):2855-70.
 Gregg MC. Structures and fluxes in a deep convecting mixed layer. Dynamics of the Ocean Mixed Layer. Hawaii Institute of Geophysics Special Publications. 1987 Jan 14;1:1-23.
 Sastry JS, D'souza RS. Oceanography of the Arabian Sea during southwest monsoon season, part I: thermal structure. Indian Journal of Meteorology and Geophysics. 1970;21:367-82.
 Han W, McCreary JP. Modeling salinity distributions in the Indian Ocean. Journal of Geophysical Research: Oceans. 2001 Jan 15;106(C1):859-77.
 Obata A, Ishizaka J, Endoh M. Global verification of critical depth theory for phytoplankton bloom with climatological in situ temperature and satellite ocean color data. Journal of Geophysical Research: Oceans. 1996 Sep 15;101(C9):20657-67.
 Lewis MR, Carr ME, Feldman GC, Esaias W, McClain C. Influence of penetrating solar radiation on the heat budget of the equatorial Pacific Ocean. Nature. 1990 Oct;347(6293):543.
 Thadathil P, Thoppil P, Rao RR, Muraleedharan PM, Somayajulu YK, Gopalakrishna VV et all. Seasonal variability of the observed barrier layer in the Arabian Sea. Journal of Physical Oceanography. 2008 Mar;38(3):624-38.
 Weller RA, Fischer AS, Rudnick DL, Eriksen CC, Dickey TD, Marra J et all. 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.
 Ramesh Babu V, Sastry JS. Summer cooling in the east central Arabian Sea-a process of dynamic response to the southwest monsoon. Mausam. 1984;35:17-26.
 Das VK, Gouveia AD, Varma KK. Circulation & Water Characteristics on Isanosteric Surfaces in the Northern Arabian Sea during February-April. Indian Journal of Marine Sciences. 1980;9:156-165.
 Krishna VV, Sadhuram Y, Babu VR. Variability of mixed layer depth in the northern Indian Ocean during 1977 and 1979 summer monsoon seasons. Indian Journal of Marine Sciences. 1988;17:258-264.
 Sprintall J, Tomczak M. Evidence of the barrier layer in the surface layer of the tropics. Journal of Geophysical Research: Oceans. 1992 May 15;97(C5):7305-16.
 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 1;112(C6).
 Jaffrés JB. Mixed layer depth seasonality within the Coral Sea Based on Argo Data. PloS one. 2013 Apr 11;8(4):e60985.
 Gill A. Atmospheric-ocean dynamics. New York: Academic Press; 1982. p.599-600.
 Adcroft A, Campin JM, Dutkiewicz S, Evangelinos C, Ferreira D et all. MITgcm user manual [Internet]. 2018 [update 2018 Jan 23; cited 2018 Feb 10]. Available from:http://mitgcm.org/public/r2_manual/final/online_documents/manual.html.
 Wyrtki K. Oceanographic atlas of the international Indian Ocean expedition. Amerind Publishing Co.; 1988.
 Defant A. Physical oceanography. Pergamon; 1961.
 Kara AB, Rochford PA, Hurlburt HE. Mixed layer depth variability over the global ocean. Journal of Geophysical Research: Oceans. 2003 Mar;108(C3).
 Ali A, Ahmed SN, Kazi LI, Tabrez M, Amjad S. Seasonal variation of mixed layer depth in the North Arabian Sea. Pakistan Journal of Marine Sciences. 1995;4(1):1-4.
 Prasad TG, Bahulayan N. Mixed layer depth and thermocline climatology of the Arabian Sea and western equatorial Indian Ocean. 1996;25:189-194.