Inhibition of mixed-layer deepening during winter in the northeastern Arabian Sea by the West India Coastal Current

2015 ◽  
Vol 47 (3-4) ◽  
pp. 1049-1072 ◽  
Author(s):  
D. Shankar ◽  
R. Remya ◽  
P. N. Vinayachandran ◽  
Abhisek Chatterjee ◽  
Ambica Behera
Keyword(s):  
Mixed Layer ◽  
Arabian Sea ◽  
Coastal Current ◽  
The West

Consequences of inhibition of mixed-layer deepening by the West India Coastal Current for winter phytoplankton bloom in the northeastern Arabian Sea

2016 ◽  
Vol 121 (9) ◽  
pp. 6583-6603 ◽  
Author(s):  
V. Vijith ◽  
P. N. Vinayachandran ◽  
V. Thushara ◽  
P. Amol ◽  
D. Shankar ◽  
...  
Keyword(s):  
Mixed Layer ◽  
Arabian Sea ◽  
Phytoplankton Bloom ◽  
Coastal Current ◽  
The West

scholarly journals Erratum to: Inhibition of mixed-layer deepening during winter in the northeastern Arabian Sea by the West India Coastal Current

2016 ◽  
Vol 48 (11-12) ◽  
pp. 4109-4110
Author(s):  
D. Shankar ◽  
R. Remya ◽  
P. N. Vinayachandran ◽  
Abhisek Chatterjee ◽  
Ambica Behera
Keyword(s):  
Mixed Layer ◽  
Arabian Sea ◽  
Coastal Current ◽  
The West

scholarly journals Origins of Coupled Model Biases in the Arabian Sea Climatological State

2018 ◽  
Vol 31 (5) ◽  
pp. 2005-2029 ◽  
Author(s):  
Motoki Nagura ◽  
J. P. McCreary ◽  
H. Annamalai
Keyword(s):  
Mixed Layer ◽  
Persian Gulf ◽  
Arabian Sea ◽  
Coupled Model ◽  
Sea Surface Salinity ◽  
Western Boundary ◽  
Coastal Current ◽  
Surface Cooling ◽  
Surface Salinity ◽  
High Salinity Water

This study investigates biases of the climatological mean state of the northern Arabian Sea (NAS) in 31 coupled ocean–atmosphere models. The focus is to understand the cause of the large biases in the depth of the 20°C isotherm [Formula: see text] that occur in many of them. Other prominent biases are the depth [Formula: see text] and temperature [Formula: see text] of Persian Gulf water (PGW) and the wintertime mixed-layer thickness (MLT) along the northern boundary. For models that lack a Persian Gulf (group 1), [Formula: see text] is determined by the wintertime MLT bias [Formula: see text] through the formation of an Arabian Sea high-salinity water mass (ASHSW) that is too deep. For models with a Persian Gulf (group 2), if [Formula: see text] > MLT (group 2B), PGW remains mostly trapped to the western boundary and, again, [Formula: see text] directly controls [Formula: see text]. If [Formula: see text] MLT (group 2A), PGW spreads into the NAS and impacts [Formula: see text] because [Formula: see text] > 20°C; nevertheless [Formula: see text] still influences [Formula: see text] indirectly through its impact on [Formula: see text]. The thick wintertime mixed layer is driven primarily by surface cooling [Formula: see text] during the fall. Nevertheless, variations in ΔMLT among the models are more strongly linked to biases in the density stratification (jump) across the bottom of the mixed layer than to [Formula: see text] biases. The jump is in turn determined primarily by sea surface salinity biases (ΔSSS) advected into the NAS by the West India Coastal Current, and the source of ΔSSS is the rainfall deficit associated with the models’ weak summer monsoon. Ultimately, then, ΔD20 is linked to this deficit.

TEMPERATURE VARIABILITY AT SENUNU BAY, WEST SUMBAWA

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Syamsul Hidayat ◽  
Mulia Purba ◽  
Jorina Waworuntu
Keyword(s):  
Layer Thickness ◽  
Mixed Layer ◽  
Cross Correlation ◽  
Sea Surface ◽  
Thermocline Depth ◽  
Kelvin Wave ◽  
The West ◽  
Sea Bottom ◽  
Annual Period ◽  
Regional Processes

The purposes of this study were to determine the variability of temperature and its relation to regional processes in the Senunu Bay. The result showed clear vertical stratifications i.e., mixed layer thickness about 39-119 m with isotherm of 27°C, thermocline layer thickness about 83-204 m with isotherm of 14–26°C, and  the deeper layer from the thermocline lower limit to the sea bottom with isotherm <13°C. Temperature and the thickness of each layers varied with season in which during the Northwest Monsoon the temperature was warmer and the mixed layer was thicker than those during Southeast Monsoon. During Southeast Monsoon, the thermocline layer rose  about 24 m. The 2001, 2006, and 2009 (weak La Nina years),  the Indonesia Throughflow (ITF) carried warmer water, deepening thermocline depth and reducing upwelling strength.  In 2003 and 2008 thickening of mixed layer occurred in transition season  was believed  associated with the  arrival of Kelvin Wave from the west. In 2002 and 2004 (weak El Nino period,) ITF carries colder water shallowing thermocline depth and enhancing upwelling strength. In 2007 was believed to be related with positive IODM where the sea surface temperature were decreasing due to intensification of southeast wind which induced strong upwelling. The temperature spectral density of mixed layer and thermocline was influenced by annual, semi-annual, intra-annual and inter-annual period fluctuations. The cross-correlation between wind and temperature showed significant value in the annual period.  Keywords: temperature, thermocline, variability, ENSO, IODM.

Observed variability of the West India Coastal Current on the continental shelf from 2010–2017

2021 ◽  
Vol 130 (2) ◽  
Author(s):  
Anya Chaudhuri ◽  
P Amol ◽  
D Shankar ◽  
S Mukhopadhyay ◽  
S G Aparna ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Coastal Current ◽  
The West

Prehistoric Man Round Bombay

1932 ◽  
Vol 7 (1) ◽  
pp. 35-42 ◽  
Author(s):  
K. R. U. Todd
Keyword(s):  
Arabian Sea ◽  
Maximum Height ◽  
The West ◽  
Fishing Village ◽  
Red Earth ◽  
The Hill ◽  
Steep Hill

The purpose of this paper is to put on record the discovery of various sites, containing traces of prehistoric man, in the neighbourhood of Bombay.The area of greatest importance is that of Worli. It is a cotton milling suburb of Bombay, distant some 4 miles from the Fort, and is situated on low lying marshy ground and bounded to the West by a low steep hill having a maximum height of 100 ft. O.D., and consisting of igneous basalt overlying amygdaloidal trap with a dyke of F.W. strata between. This dyke contains fossils of marsh tortoises, frogs and plants resembling bulrushes. The basalt is capped with red earth which is decomposing trap, and contains nodules of agate and blocks of chert. West of the hill is the Arabian Sea. The northern extremity of this hill ends in a spur which juts out into the sea, and here is the fishing village of Koliwada, consisting of mud huts.

Seasonal variations of the dinoflagellate algae Noctiluca scintillans abundance in the western Arabian Sea and the northern Black Sea

2021 ◽  
Author(s):  
Sergey Piontkovski ◽  
Khalid Al Hashmi ◽  
Yuliya Zagorodnaya ◽  
Irina Serikova ◽  
Vladislav Evstigneev ◽  
...  
Keyword(s):  
Black Sea ◽  
Mixed Layer ◽  
Algal Blooms ◽  
Arabian Sea ◽  
Temporal Dynamics ◽  
The Black Sea ◽  
Northeast Monsoon ◽  
Major Peak ◽  
Noctiluca Scintillans ◽  
Upper Mixed Layer

&lt;p&gt;Seasonal variability is a powerful component of the spatio-temporal dynamics of plankton communities, especially in the regions with oxygen-depleted waters. The Arabian Sea and the Black Sea are typical representatives of these regions. In both, the dinoflagellate Noctiluca scintillans (Macartney) Kofoid &amp; Swezy, 1921, is one of the abundant plankton species which forms algal blooms. Sampling on coastal stations in the upper mixed layer by the plankton nets with the 120-140 &amp;#181;m mesh size was carried out in 2004-2010. Monthly data were averaged over years. A comparison of seasonal patterns of Noctiluca abundance pointed to the persistence of a bimodal seasonal cycle in both regions. The major peak was observed during spring in the Black Sea and during the winter (Northeast) monsoon in the Arabian Sea. The timing of the second (minor) peak was different over regions as well. This peak was modulated by advection of seasonally fluctuating velocity of coastal currents which transport waters enriched by nutrients by coastal upwelling. The abundance of Noctiluca of the major peak (with the concentration around 1.5*10&lt;sup&gt;6&lt;/sup&gt; cells m&lt;sup&gt;-3&lt;/sup&gt;) was from one to two orders as much high in the western Arabian Sea compared to the northern Black Sea. The remotely sensed chlorophyll-a concentration during the time of the major seasonal peak exhibited a fivefold difference over these regions. In terms of nutrient&lt;sub&gt;&lt;/sub&gt;concentration in the upper mixed layer (in particular, nitrates and silicates), a difference of about one order of magnitude was observed.&lt;/p&gt;

scholarly journals Amino acid composition and <i>δ</i><sup>15</sup>N of suspended matter in the Arabian Sea: implications for organic matter sources and degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7689-7702 ◽  
Author(s):  
B. Gaye ◽  
B. Nagel ◽  
K. Dähnke ◽  
T. Rixen ◽  
N. Lahajnar ◽  
...  
Keyword(s):  
Organic Matter ◽  
Amino Acid ◽  
Water Column ◽  
Residence Time ◽  
Mixed Layer ◽  
Suspended Matter ◽  
Arabian Sea ◽  
Monsoon Season ◽  
Sediment Traps ◽  
Surface Mixed Layer

Abstract. Sedimentation in the ocean is fed by large aggregates produced in the surface mixed layer that sink rapidly through the water column. These particles sampled by sediment traps have often been proposed to interact by disaggregation and scavenging with a pool of fine suspended matter with very slow sinking velocities and thus a long residence time. We investigated the amino acid (AA) composition and stable nitrogen isotopic ratios of suspended matter (SPM) sampled during the late SW monsoon season in the Arabian Sea and compared them to those of sinking particles to understand organic matter degradation/modification during passage through the water column. We found that AA composition of mixed layer suspended matter corresponds more to fresh plankton and their aggregates, whereas AA composition of SPM in the sub-thermocline water column deviated progressively from mixed layer composition. We conclude that suspended matter in deep waters and in the mixed layers of oligotrophic stations is dominated by fine material that has a long residence time and organic matter that is resistant to degradation. SPM in areas of high primary productivity is essentially derived from fresh plankton and thus has a strong imprint of the subsurface nitrate source, whereas SPM at oligotrophic stations and at subthermocline depths appears to exchange amino acids and nitrogen isotopes with the dissolved organic carbon (DOC) pool influencing also the δ15N values.

On Abnormally Strong Currents Observed on the Northern Coast of Peru during the 2015-2016 El Niño

2021 ◽  
Vol 8 (4) ◽  
pp. 205-210
Author(s):  
Chang-Woong Shin ◽  
Dimitri Gutiérrez
Keyword(s):  
Mixed Layer ◽  
El Niño ◽  
El Nino ◽  
Current Data ◽  
Kelvin Waves ◽  
Coastal Current ◽  
Northern Coast ◽  
El Niño Event ◽  
Strong Current ◽  
The Impact

The northern coast of Peru is a region that can rapidly detect the impact of an El Niño. To investigate the effects of the 2015-2016 El Niño on the oceanographic environment of the northern coast of Peru, the temperature and current data obtained from moored equipment at an oil platform were analyzed. Strong coastal along-shore currents of more than 0.60 m·s-1 were observed three times, although the mean current speed was 0.10 m·s-1 flowing toward the south-southwest. After the first strong current, the bottom temperature increased and the mixed layer deepened and remained there during the El Niño event. The temperature reached a maximum after the strong coastal current, then decreased gradually. An analysis of wind and sea surface height anomalies revealed that the coastal strong current was caused by Kelvin waves and the deepening of the mixed layer was not related to local winds, but to coastal Kelvin waves from the equator during the El Niño event.

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