Статті в журналах: "Eastern Arabian Sea"

1

Saraswat, Rajeev, S. R. Kurtarkar, R. Yadav, A. Mackensen, D. P. Singh, S. Bhadra, A. D. Singh, et al. "Inconsistent change in surface hydrography of the eastern Arabian Sea during the last four glacial–interglacial intervals." Geological Magazine 157, no. 6 (November 15, 2019): 989–1000. http://dx.doi.org/10.1017/s0016756819001122.

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AbstractThe eastern Arabian Sea is influenced by both the advection of upwelled water from the western Arabian Sea and winter convective mixing. Therefore, sediments collected from the eastern Arabian Sea can help to understand the long-term seasonal hydrographic changes. We used the planktonic foraminifera census and stable isotopic ratio (δ18O) from sediments drilled during the International Ocean Discovery Program Expedition 355 to reconstruct surface hydrographic changes in the eastern Arabian Sea during the last 350 kyr. The increased abundance of Globigerina bulloides suggests enhanced advection of upwelled water during the latter half of MIS7 and the beginning of MIS6, as a result of a strengthened summer monsoon. A large drop in upwelling and/or advection of upwelled water from the western Arabian Sea is inferred during the subsequent interval of MIS6, based on the rare presence of G. bulloides. The comparable relative abundance of Neogloboquadrina dutertrei, G. bulloides and Globigerinoides ruber suggests that during the early part of MIS5, hydrographic conditions were similar to today. The upwelling decreased and winter convection increased with the progress of the glacial interval. A good coherence between planktonic foraminiferal assemblage-based monsoon stacks from both the eastern and western Arabian Sea suggests a coeval response of the entire northern Arabian Sea to the glacial–interglacial changes. The glacial–interglacial difference in δ18Osw-ivc was at a maximum with 4–5 psu change in salinity during Termination 2 and 3, and a minimum during Termination 4. The significantly reduced regional contribution to the glacial–interglacial change in δ18Osw-ivc during Termination 4 suggests a lesser change in the monsoon.

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2

Garzon, Francesco, Collin T. Williams, Jesse E. M. Cochran, Lyndsey K. Tanabe, Ameer Abdulla, Michael L. Berumen, Thamer Habis, Paul A. Marshall, Mattie Rodrigue, and Lucy A. Hawkes. "A multi-method characterization of Elasmobranch & Cheloniidae communities of the north-eastern Red Sea and Gulf of Aqaba." PLOS ONE 17, no. 9 (September 30, 2022): e0275511. http://dx.doi.org/10.1371/journal.pone.0275511.

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The Red Sea is particularly biodiverse, hosting high levels of endemism and numerous populations whose extinction risk is heightened by their relative isolation. Elasmobranchs and sea turtles have likely suffered recent declines in this region, although data on their distribution and biology are severely lacking, especially on the eastern side of the basin in Saudi Arabian waters. Here, we present sightings of elasmobranchs and sea turtles across the north-eastern Red Sea and Gulf of Aqaba collected through a combination of survey methods. Over 455 survey hours, we recorded 407 sightings belonging to 26 elasmobranch species and two sea turtle species, more than 75% of which are of conservation concern. We identified 4 species of rays and 9 species of sharks not previously recorded in Saudi Arabia and report a range extension for the pink whipray (Himantura fai) and the round ribbontail ray (Taeniurops meyeni) into the Gulf of Aqaba. High density of sightings of conservation significance, including green and hawksbill sea turtles and halavi guitarfish were recorded in bay systems along the eastern Gulf of Aqaba and the Saudi Arabian coastline bordering the north-eastern Red Sea, and many carcharhinid species were encountered at offshore seamounts in the region. Our findings provide new insights into the distribution patterns of megafaunal assemblages over smaller spatial scales in the region, and facilitate future research and conservation efforts, amidst ongoing, large-scale coastal developments in the north-eastern Red Sea and Gulf of Aqaba.

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3

Schmidt, Henrike, Rena Czeschel, and Martin Visbeck. "Seasonal variability of the Arabian Sea intermediate circulation and its impact on seasonal changes of the upper oxygen minimum zone." Ocean Science 16, no. 6 (November 27, 2020): 1459–74. http://dx.doi.org/10.5194/os-16-1459-2020.

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Abstract. Oxygen minimum zones (OMZs) in the open ocean occur below the surface in regions of weak ventilation and high biological productivity with associated sinking organic matter. Very low levels of dissolved oxygen alter biogeochemical cycles and significantly affect marine life. One of the most intense though poorly understood OMZs in the world ocean is located in the Arabian Sea between 300 and 1000 m of depth. An improved understanding of the physical processes that have an impact on the OMZ in the Arabian Sea is expected to increase the reliability of assessments of its future development. This study uses reanalysis velocity fields from the ocean model HYCOM (Hybrid Coordinate Ocean Model), which are verified with observational data, to investigate advective pathways of Lagrangian particles into the Arabian Sea OMZ at intermediate depths between 200 and 800 m. In the eastern basin, the vertical expansion of the OMZ is strongest during the winter monsoon, revealing a core thickness 1000 m deep and oxygen values below 5 µmol kg−1. The minimum oxygen concentration might be favoured by a maximum water mass advection that follows the main advective pathway of Lagrangian particles along the perimeter of the basin into the eastern basin of the Arabian Sea during the winter monsoon. These water masses pass regions of high primary production and respiration, contributing to the transport of low-oxygenated water into the eastern part of the OMZ. The maximum oxygen concentration in the western basin of the Arabian Sea in May coincides with a maximum southward water mass advection in the western basin during the spring intermonsoon, supplying the western core of the OMZ with high-oxygenated water. The maximum oxygen concentration in the eastern basin of the Arabian Sea in May might be associated with the northward inflow of water across 10∘ N into the Arabian Sea, which is highest during the spring intermonsoon. The Red Sea outflow of advective particles into the western and eastern basin starts during the summer monsoon associated with the northeastward current during the summer monsoon. On the other hand, waters from the Persian Gulf are advected with little variation on seasonal timescales. As the weak seasonal cycle of oxygen concentration in the eastern and western basin can be explained by seasonally changing advection of water masses at intermediate depths into the Arabian Sea OMZ (ASOMZ), the simplified backward-trajectory approach seems to be a good method for prediction of the seasonality of advective pathways of Lagrangian particles into the ASOMZ.

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4

Clift, Peter D., Dhananjai K. Pandey, and Denise K. Kulhanek. "Climate–tectonic interactions in the eastern Arabian Sea." Geological Magazine 157, no. 6 (June 2020): 829–33. http://dx.doi.org/10.1017/s0016756820000461.

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5

Ahmed, Ayaz, Mangesh Gauns, Siby Kurian, Pratirupa Bardhan, Anil Pratihary, Hema Naik, Damodar M. Shenoy, and S. W. A. Naqvi. "Nitrogen fixation rates in the eastern Arabian Sea." Estuarine, Coastal and Shelf Science 191 (May 2017): 74–83. http://dx.doi.org/10.1016/j.ecss.2017.04.005.

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6

Zhang, Jijung. "Living planktonic foraminifera from the eastern Arabian Sea." Deep Sea Research Part A. Oceanographic Research Papers 32, no. 7 (July 1985): 789–98. http://dx.doi.org/10.1016/0198-0149(85)90115-3.

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7

Zajonz, Uwe, Edouard Lavergne, Sergey V. Bogorodsky, and Friedhelm Krupp. "Biogeography of the coastal fishes of the Socotra Archipelago: Challenging current ecoregional concepts." PLOS ONE 17, no. 4 (April 29, 2022): e0267086. http://dx.doi.org/10.1371/journal.pone.0267086.

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The Socotra Archipelago, located in the eastern Gulf of Aden, has a unique marine environment, which combines tropical and ‘pseudo-temperate’ elements. An updated species inventory recently considered its coastal fish diversity the highest among Arabian ecoregions, necessitating to re-assess the ichthyogeographic position of the island group. The main aim of this study is to describe the distributional biogeography of its coastal fish fauna in relation to contemporary ichthyogeographic and ecoregional concepts. Inferences are drawn with regard to the marine biogeographic arrangement and ecoregional partitioning of the Arabian region. The main datasets comprise eight and twenty selected families including 404 and 898 species, respectively, from Arabian ecoregions. The Socotra Archipelago has close affinities to a putative ecoregion in the eastern Gulf of Aden that extends to southern Oman. It is more closely related to the Arabian Sea coast of Oman than to ecoregions in the Red Sea and a putative ecoregion in the western Gulf of Aden. The Gulf of Aden does not represent a consistent ecoregion in ichthyogeographic terms, because its eastern and western parts are less closely related to one another than to other ecoregions. The Socotra Archipelago and the eastern Gulf of Aden should therefore not be assigned to a joined province with Red Sea ecoregions. The coastal fish faunas of the southern Red Sea have close affinities with those of the western Gulf of Aden. The Arabian/Persian Gulf is least related to the other Arabian ecoregions. The authors posit the Socotra Archipelago as a distinct ecoregion, either on its own or in combination with affiliated mainland areas. This best reflects the ichthyogeographic data and the exceptionally high levels of fish and overall marine diversity. Two alternative ecoregional delineations are proposed, serving as working hypotheses for onward research.

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8

U., ABDUL JALEEL K., USHA V. PARAMESWARAN, ANAGHA BIJU, PARTHASARATHI S., and ANAS ABDULAZIZ. "First report of brittle stars (Echinodermata: Ophiuroidea) from a seamount in the eastern Arabian Sea." Zootaxa 5285, no. 3 (May 17, 2023): 578–84. http://dx.doi.org/10.11646/zootaxa.5285.3.8.

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This paper reports two species—Ophiozonella molesta (Koehler, 1904) and Ophiothamnus venustus Matsumoto, 1915, from a seamount in the Eastern Arabian Sea. This forms the first ever report of Ophiothamnus venustus from the Indian Ocean, and the first verified report of Ophiozonella molesta from Indian waters. This is the first ever work to document benthic invertebrates from seamounts in the Arabian Sea.

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9

Tiwari, Manish, Ashutosh K. Singh, and Rengaswamy Ramesh. "High-Resolution Monsoon Records Since Last Glacial Maximum: A Comparison of Marine and Terrestrial Paleoarchives from South Asia." Journal of Geological Research 2011 (August 23, 2011): 1–12. http://dx.doi.org/10.1155/2011/765248.

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Agricultural production and the availability of fresh water in Indian subcontinent critically depend on the monsoon rains. Therefore it is vital to understand the causal mechanisms underlying the observed changes in the Indian monsoon in the past. Paleomonsoon reconstructions show that the water discharge from the Ganges-Brahmaputra River system to the Bay of Bengal was maximum in the early to mid-Holocene; data from the Western Arabian Sea and Omanian speleothems indicate declining monsoon winds during the Holocene, whereas records from the South West Monsoon (SWM) precipitation dominated eastern Arabian Sea show higher runoff from the Western Ghats indicating gradually increasing monsoon precipitation during the Holocene. Thus there exists considerable spatial variability in the monsoon in addition to the temporal variability that needs to be assessed systematically. Here we discuss the available high resolution marine and terrestrial paleomonsoon records such as speleothems and pollen records of the SWM from important climatic regimes such as Western Arabian Sea, Eastern Arabian Sea, Bay of Bengal to assess what we have learnt from the past and what can be said about the future of water resources of the subcontinent in the context of the observed changes.

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10

BALAKRISHNAN, T. K., A. K. JASWAL, S. S. SINGH, and H. N. SRIVASTAVA. "Principal component analysis of monthly mean Area surface temperature over the Arabian Sea, Bay of Bengal and north Indian Ocean for two Contrasting sets of monsoon years." MAUSAM 44, no. 1 (December 31, 2021): 69–76. http://dx.doi.org/10.54302/mausam.v44i1.3778.

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The spatial distribution and temporal variation of the monthly mean SSTA over the Arabian Sea, Bay of Bengal and the north Indian Ocean were investigated for a set of contrasting years of monsoon over the period 1961-80 for months April through July using Empirical Orthogonal Function (EOF) technique with a view to identify regions that are significantly related to the monsoon rainfall. Over 75% of the total variance is, explained by the first mode EOF. SSTA over the north and northeast Arabian Sea during pre-monsoon months were found to be possible indicators of the ensuing monsoon activity. The higher eigen vectors in May over northeast Arabian Sea may signal good monsoon and vice versa. In June there is a marked contrast in the distribution of SST over the Arabian Sea between the two sets of the years the eastern Arabian Sea IS warmer for the deficient monsoon years while the entire Arabian Sea except over the extreme north Arabian Sea is cool during good monsoon years. There is formation of SSTA over the equatorial Indian Ocean area close to Indonesian island commencing from May which is more marked in June and is positively correlated with seasonal rainfall activity over India.

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11

REJOMON, G. "BIOGEOCHEMICAL SIGNIFICANCE OF EDDIES OF THE EASTERN ARABIAN SEA." Applied Ecology and Environmental Research 11, no. 2 (May 30, 2013): 237–48. http://dx.doi.org/10.15666/aeer/1102_237248.

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12

Mahanty, Madan Mohan, Latha Ganeshan, and Raguraman Govindan. "Soundscapes in shallow water of the eastern Arabian Sea." Progress in Oceanography 165 (July 2018): 158–67. http://dx.doi.org/10.1016/j.pocean.2018.06.004.

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13

Shailaja, M. S., and R. Sen Gupta. "DDT residues in fishes from the eastern Arabian Sea." Marine Pollution Bulletin 20, no. 12 (December 1989): 629–30. http://dx.doi.org/10.1016/0025-326x(89)90402-5.

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14

Sasmal, S. K. "Optical classification of waters in the eastern arabian sea." Journal of the Indian Society of Remote Sensing 25, no. 2 (June 1997): 73–78. http://dx.doi.org/10.1007/bf03025905.

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15

SINGH, O. P., and H. R. HATWAR. "Response of sea state to the monsoon onset." MAUSAM 56, no. 1 (January 19, 2022): 59–64. http://dx.doi.org/10.54302/mausam.v56i1.859.

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Utilizing the buoy meteorological data of Arabian Sea collected during the onset phase of ARMEX an attempt has been made to examine the influence of monsoon onset 2003 on the surface parameters. The peaking and collapse of warm pool during monsoon onset 2003 has been compared with the normal peaking and collapse conditions and it has been found that the collapse of warm pool during the onset of 2003 monsoon was very gradual. As a matter of fact the evaporative cooling in the warm pool region was quite subdued during 2003 monsoon onset which shows that the sudden collapse of warm pool should be expected to occur only when onset vortex is formed which did not happen during 2003.The roughness of sea (wave height) increased over the southeastern Arabian Sea about 2-3 days before the monsoon onset showing that the swells are reliable precursors of monsoon onset. There was a steep fall in SLP throughout the eastern Arabian Sea (8° - 20° N) about a week before the monsoon onset over Kerala on 8 June. All buoys from DS7 to SW1 registered this type of SLP change. After the sudden fall on 1 June the SLPs over the eastern Arabian Sea remained almost steady and unimpacted by the monsoon onset on 8 June or subsequent advance along the west coast.

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16

Saravanan, Ponnusamy, Anil K. Gupta, Hongbo Zheng, Mruganka K. Panigrahi, Sameer K. Tiwari, Santosh K. Rai, and Muthusamy Prakasam. "Response of shallow-sea benthic foraminifera to environmental changes off the coast of Goa, eastern Arabian Sea, during the last ∼6100 cal yr BP." Geological Magazine 157, no. 3 (October 14, 2019): 497–505. http://dx.doi.org/10.1017/s0016756819000979.

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AbstractWe have analysed a 6100-year record of benthic and planktonic foraminifera from inner neritic sediments from Core SK291/GC13, off the Goa coast, eastern Arabian Sea, to understand the response of benthic foraminifera to shallow-marine processes. The benthic foraminiferal assemblage is dominated by Nonion cf. asterizans, Ammonia beccarii, A. gaimardii and Virgulinella fragilis, which have been selected on the basis of a population of 10% or more in any three samples analysed. The planktonic foraminiferal population is sporadic and rare, with Globigerinoides ruber as the predominant species showing a variable trend. The foraminiferal proxies combined with total organic carbon (wt%) and δ13C and δ18O values of Ammonia gaimardii suggest distinct variations, indicating changes in productivity and salinity in the shallow eastern Arabian Sea. The coastal waters off Goa were relatively warmer and less saline between 6100 and 4600, or perhaps to 4200, calibrated years before the present (cal yr BP), corresponding to a stronger monsoon in South and East Asia. The shallow sea was cooler from ~4200 to 2600 cal yr BP in the study area, coinciding with a lower sea surface temperature in the northeastern Arabian Sea and an arid phase in the Indian subcontinent. From 2900 to 2600 cal yr BP the study core exhibits the impacts of short-term cold events, which have earlier been observed in the northeastern Arabian Sea, off Pakistan. During the Little Ice Age, the shallow sea off Goa was less productive.

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17

Ali, Syed Haroon, Osman M. Abdullatif, Lamidi O. Babalola, Fawwaz M. Alkhaldi, Yasir Bashir, S. M. Talha Qadri, and Ali Wahid. "Sedimentary facies, depositional environments and conceptual outcrop analogue (Dam Formation, early Miocene) Eastern Arabian Platform, Saudi Arabia: a new high-resolution approach." Journal of Petroleum Exploration and Production Technology 11, no. 6 (May 15, 2021): 2497–518. http://dx.doi.org/10.1007/s13202-021-01181-7.

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AbstractThis paper presents the facies and depositional environment of the early Miocene Dam Formation, Eastern Arabian platform, Saudi Arabia. Deposition of Dam Formation (Fm.) was considered as a restricted shallow marine deposition. Few studies suggest the role of sea-level change in its deposition but were without decisive substantiation. Here, we describe the facies and high-resolution model of Dam Fm. under varying depositional conditions. The depositional conditions were subjected to changing relative sea level and tectonics. High-resolution outcrop photographs, sedimentological logs, and thin sections present that the mixed carbonate–siliciclastic sequence was affected by a regional tectonics. The lower part of Dam Fm. presents the development of carbonate ramp conditions that are represented by limestones and marl. The depositional conditions fluctuated with the fall of sea level, and uplift in the region pushed the siliciclastic down-dip and covered the whole platform. The subsequent rise in sea level was not as pronounced and thus allowed the deposition of microbial laminites and stromatolitic facies. The southeast outcrops, down-dip, are more carbonate prone as compared to the northwest outcrop, which allowed the deposition of siliciclastic-prone sedimentation up-dip. All facies, architecture, heterogeneity, and deposition were controlled by tectonic events including uplift, subsidence, tilting, and syn-sedimentary faulting, consequently affecting relative sea level. The resulting conceptual outcrop model would help to improve our understanding of mixed carbonate–siliciclastic systems and serve as an analogue for other stratigraphic units in the Arabian plate and region. Our results show that Dam Fm. can be a good target for exploration in the Northern Arabian Gulf.

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18

RAMAMURTHI, K. M. "On the activity of the Arabian Sea monsoon." MAUSAM 23, no. 1 (January 27, 2022): 11–14. http://dx.doi.org/10.54302/mausam.v23i1.5119.

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In connection with the activity of the Arabian Sea monsoon, Ramage's postulate regarding the relationship between the intensity of the heat low over West Pakistan and the monsoon rains was examined and it was found that the heat low does not contribute to the strengthening. If the low level monsoon flow. The effects of monsoon perturbations are found to extend from sea level and are therefore considered directly responsible for strengthening the low level monsoon flow. A method of Identifying the effects of perturbations of active as well as weak Arabian Sea monsoon is postulated. This brought out that active Arabian Sea monsoon is associated with two cyclonic vertices which in the mean are lacated over the Gulf of Cambay (Gujarat low) and the northern parts of east coast 'eastern low' respectively and extend from sea level upwards affecting the wind flow practically throughout the entire troposphere. The reason for the cyclonic circulation associated with the Gujarat low not being obvious in lower tropospheric levels is discussed. The importance .of contribution to northerly meridional flow along the west coast at upper tropospheric levels by the perturbations of strong monsoon is highlighted. The strength of upper level east wind maximum over south Peninsular India is found to be less during strong than in weak monsoon. This goes against the hypothesis regarding the role of release of latent heat in causing the summer time easterly jet. The effects of perturbations of weak Arabian Sea monsoon are found to be just the reverse of those of strong monsoon. Certain aspects of the transformation of airmass over the east Arabian Sea are also discussed.

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19

Anoop, T. R., V. Sanil Kumar, P. R. Shanas, G. Johnson, and M. M. Amrutha. "Indian Ocean Dipole modulated wave climate of eastern Arabian Sea." Ocean Science Discussions 12, no. 5 (October 27, 2015): 2473–96. http://dx.doi.org/10.5194/osd-12-2473-2015.

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Abstract. Intrinsic modes of variability have a significant role in driving climatic oscillations in the ocean. In this paper, we investigate the influence of inter-annual variability, the Indian Ocean Dipole (IOD), on the wave climate of the eastern Arabian Sea (AS). Using measured, modeled and reanalysis wave data and reanalysis wind data, we show that the IOD plays a major role in the variability of wave climate of the study region due to the IOD induced changes in equatorial sea surface temperature and sea level pressure. Inter-annual variability in the wave climate over the eastern AS during the IOD is due to the modification of winds from the northern AS. The change in wind field over the AS due to IOD influences the generation or dissipation of wave field and hence causes the decrease in northwest short period waves during positive IOD and increase during negative IOD.

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20

Kaviani, Ayoub, Anne Paul, Ali Moradi, Paul Martin Mai, Simone Pilia, Lapo Boschi, Georg Rümpker, Yang Lu, Zheng Tang, and Eric Sandvol. "Crustal and uppermost mantle shear wave velocity structure beneath the Middle East from surface wave tomography." Geophysical Journal International 221, no. 2 (February 21, 2020): 1349–65. http://dx.doi.org/10.1093/gji/ggaa075.

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SUMMARY We have constructed a 3-D shear wave velocity (Vs) model for the crust and uppermost mantle beneath the Middle East using Rayleigh wave records obtained from ambient-noise cross-correlations and regional earthquakes. We combined one decade of data collected from 852 permanent and temporary broad-band stations in the region to calculate group-velocity dispersion curves. A compilation of >54 000 ray paths provides reliable group-velocity measurements for periods between 2 and 150 s. Path-averaged group velocities calculated at different periods were inverted for 2-D group-velocity maps. To overcome the problem of heterogeneous ray coverage, we used an adaptive grid parametrization for the group-velocity tomographic inversion. We then sample the period-dependent group-velocity field at each cell of a predefined grid to generate 1-D group-velocity dispersion curves, which are subsequently inverted for 1-D Vs models beneath each cell and combined to approximate the 3-D Vs structure of the area. The Vs model shows low velocities at shallow depths (5–10 km) beneath the Mesopotamian foredeep, South Caspian Basin, eastern Mediterranean and the Black Sea, in coincidence with deep sedimentary basins. Shallow high-velocity anomalies are observed in regions such as the Arabian Shield, Anatolian Plateau and Central Iran, which are dominated by widespread magmatic exposures. In the 10–20 km depth range, we find evidence for a band of high velocities (>4.0 km s–1) along the southern Red Sea and Arabian Shield, indicating the presence of upper mantle rocks. Our 3-D velocity model exhibits high velocities in the depth range of 30–50 km beneath western Arabia, eastern Mediterranean, Central Iranian Block, South Caspian Basin and the Black Sea, possibly indicating a relatively thin crust. In contrast, the Zagros mountain range, the Sanandaj-Sirjan metamorphic zone in western central Iran, the easternmost Anatolian plateau and Lesser Caucasus are characterized by low velocities at these depths. Some of these anomalies may be related to thick crustal roots that support the high topography of these regions. In the upper mantle depth range, high-velocity anomalies are obtained beneath the Arabian Platform, southern Zagros, Persian Gulf and the eastern Mediterranean, in contrast to low velocities beneath the Red Sea, Arabian Shield, Afar depression, eastern Turkey and Lut Block in eastern Iran. Our Vs model may be used as a new reference crustal model for the Middle East in a broad range of future studies.

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21

Anoop, T. R., V. Sanil Kumar, P. R. Shanas, J. Glejin, and M. M. Amrutha. "Indian Ocean Dipole modulated wave climate of eastern Arabian Sea." Ocean Science 12, no. 2 (March 7, 2016): 369–78. http://dx.doi.org/10.5194/os-12-369-2016.

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Abstract. Intrinsic modes of variability have a significant role in driving the climatic oscillations in the oceanic processes. In this paper, we investigate the influence of an inter-annual mode of variability, the Indian Ocean Dipole (IOD), on the wave climate of the eastern Arabian Sea (AS). Using measured, modeled and reanalysis wave data and reanalysis wind data, we show that the IOD plays a major role in the variability of wave climate of the study region. Due to the IOD-induced changes in equatorial sea surface temperature and sea level pressure, the winds from the northern AS gets modified and cause inter-annual variability in the wave climate over the eastern AS. The changes in wind field over the AS due to the IOD influence the generation or dissipation of the wave field and hence cause a decrease in northwest short-period waves during positive IOD and an increase during negative IOD.

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22

Sanil Kumar, V., and T. R. Anoop. "Directionality and spread of shallow water waves along the eastern Arabian Sea." Annales Geophysicae 31, no. 10 (October 25, 2013): 1817–27. http://dx.doi.org/10.5194/angeo-31-1817-2013.

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Abstract. The directional characteristics of shallow water waves are described based on measured data during 2011 at two locations spaced at 350 km along the eastern Arabian Sea. Study shows that, for high swells (significant wave height > 1 m) approaching almost parallel to the coast, the difference between mean and principal wave direction at spectral peak is negligible. The directional spreading of wind-sea-dominated wave spectrum is less than that of the swell-dominated spectrum. Average value of the ratio of the directional width at twice the peak frequency and that at the peak frequency is 1.9 indicating that the directional width increased at higher frequency. Even though both locations studied are along the eastern Arabian Sea, there are more northwest waves due to shamal events and local winds found at the northern location (27%) than at the southern location (7%).

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23

Sarkar, Ashish, R. Ramesh, B. L. K. Somayajulu, R. Agnihotri, A. J. T. Jull, and G. S. Burr. "High resolution Holocene monsoon record from the eastern Arabian Sea." Earth and Planetary Science Letters 177, no. 3-4 (April 30, 2000): 209–18. http://dx.doi.org/10.1016/s0012-821x(00)00053-4.

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24

Kumar, V. Sanil, P. R. Shanas, and K. K. Dubhashi. "Shallow water wave spectral characteristics along the eastern Arabian Sea." Natural Hazards 70, no. 1 (August 1, 2013): 377–94. http://dx.doi.org/10.1007/s11069-013-0815-7.

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25

Shankar, D., S. S. C. Shenoi, R. K. Nayak, P. N. Vinayachandran, G. Nampoothiri, A. M. Almeida, G. S. Michael, M. R. Ramesh Kumar, D. Sundar, and O. P. Sreejith. "Hydrography of the eastern Arabian Sea during summer monsoon 2002." Journal of Earth System Science 114, no. 5 (October 2005): 459–74. http://dx.doi.org/10.1007/bf02702023.

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26

Behara, Ambica, P. N. Vinayachandran, and D. Shankar. "Influence of Rainfall Over Eastern Arabian Sea on Its Salinity." Journal of Geophysical Research: Oceans 124, no. 7 (July 2019): 5003–20. http://dx.doi.org/10.1029/2019jc014999.

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27

Kumar, V. Sanil, Jesbin George, Udhaba Dora, and Muhammed Naseef. "Surface wave dynamics off Mumbai coast, north-eastern Arabian Sea." Ocean Dynamics 69, no. 1 (October 23, 2018): 29–42. http://dx.doi.org/10.1007/s10236-018-1230-0.

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28

Varghese, Sijo P., D. K. Gulati, N. Unnikrishnan, and A. E. Ayoob. "Biological aspects of silky shark Carcharhinus falciformis in the eastern Arabian Sea." Journal of the Marine Biological Association of the United Kingdom 96, no. 7 (October 21, 2015): 1437–47. http://dx.doi.org/10.1017/s0025315415001575.

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Reproduction, diet and growth of silky shark Carcharhinus falciformis in the eastern Arabian Sea are described based on 473 specimens collected from the gillnet-cum-longline landings at the Cochin fisheries harbour during 2012–2014. The reproductive biology of 215 males and 258 females was examined while 113 stomachs were sampled to study the diet. The von Bertalanffy growth parameters estimated using length-based models were asymptotic length (L∞) = 309.80 cm, growth coefficient (K) = 0.10 year−1 and age at zero length (t0) = −2.398 year. The sex ratio was significantly skewed to females. Seasonality in reproduction was not evident and in males, sexual maturity was attained at 201–223 cm total length (LT) with the size at maturity (LT50) occurring at 217.0 cm, whereas in females sexual maturity was attained at 224–231 cm LT and LT50 occurs at 226.5 cm. In total 114 embryos, in the length range of 12.2–65.1 cm were recovered from 15 pregnant females. Numbers of embryos in females were in the range of 3–13, averaging 7.6. Silky sharks of the eastern Arabian Sea feed primarily on swimming crab Charybdis smithii, with juveniles feeding principally on swimming crabs, while adults feed on actively swimming prey like squids and teleost fishes. This preliminary information on the reproduction, diet and growth should be useful to identify management strategies for silky sharks in the eastern Arabian Sea.

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Bange, H. W., M. O. Andreae, S. Lal, C. S. Law, S. W. A. Naqvi, P. K. Patra, T. Rixen, and R. C. Upstill-Goddard. "Nitrous oxide emissions from the Arabian Sea: A synthesis." Atmospheric Chemistry and Physics 1, no. 1 (December 28, 2001): 61–71. http://dx.doi.org/10.5194/acp-1-61-2001.

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Abstract. We computed high-resolution (1º latitude x 1º longitude) seasonal and annual nitrous oxide (N2O) concentration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured between December 1977 and July 1997. N2O concentrations are highest during the southwest (SW) monsoon along the southern Indian continental shelf. Annual emissions range from 0.33 to 0.70 Tg N2O and are dominated by fluxes from coastal regions during the SW and northeast monsoons. Our revised estimate for the annual N2O flux from the Arabian Sea is much more tightly constrained than the previous consensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on measurements in locally restricted features in combination with insufficient seasonal data coverage leads to considerable uncertainties of the concentration fields and thus in the flux estimates, especially in the coastal zones of the northern and eastern Arabian Sea. The overall mean relative error of the annual N2O emissions from the Arabian Sea was estimated to be at least 65%.

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MATHEW, B., P. V. HAREESH KUMAR, and R. R. RAO. "Mixed layer variability at selected locations in the Arabian Sea during pre and summer monsoon seasons : Observations and simulations." MAUSAM 54, no. 4 (January 19, 2022): 917–28. http://dx.doi.org/10.54302/mausam.v54i4.1592.

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Observed short term (few days to few weeks) variability of mixed layer depth (MLD) and temperature (MLT) at selected locations in the Arabian Sea during pre and summer monsoon seasons is discussed. In the Arabian Sea, pre monsoon season is generally characterized by fair weather conditions with occasional thunder squalls. In the eastern Arabian Sea, SST is above 30° C, which is assumed to be the part of the Indian Ocean warm pool, and is characterized by the diurnal range of about 1.5° C. During the monsoon season, maximum cooling (>l° C) and deepening (5075 m) of the mixed layer is noticed in the central Arabian Sea during the onset phase. On the contrary, the mixed layer shoals in the coastal zones due to upwelling. Miller's one dimensional mixed layer model is used to simulate the observed mixed layer variability. The model simulated MLT and MLD variations reasonably well on a synoptic scale. Whenever advective processes (horizontal and vertical) and large amplitude waves dominate, significant departures are noticed between the observed and simulated values.

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31

Cobb, Matthew Adam. "THE RECEPTION AND CONSUMPTION OF EASTERN GOODS IN ROMAN SOCIETY." Greece and Rome 60, no. 1 (March 12, 2013): 136–52. http://dx.doi.org/10.1017/s0017383512000307.

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The Roman Empire received goods from eastern lands through a variety of overland routes crossing the Arabian Peninsula and Mesopotamia, and through seaborne trade via the Red Sea and the Indian Ocean. In particular, the sea routes that utilized the monsoon winds of the Indian Ocean enabled a significant volume of goods to be imported from the East on ships that may often have been of several hundred tons' capacity. The scale of the trade was significant enough for Pliny to claim that 100 million sesterces were being sent annually to India, China, and Arabia. The veracity of these figures has come in for some debate, especially with the publication of a document known as the Muziris Papyrus, which reveals that a shipment of nard, ivory, and textiles received at one of the Egyptian Red Sea ports in the second centuryadwas valued at the equivalent of roughly 7 million sesterces. It is nevertheless clear, particularly from the archaeological and numismatic evidence, that Roman trade with the East peaked in the first and second centuriesad,followed by subsequent decline and a limited revival in the Late Roman period.

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Weijermars, Ruud. "Plio-Quaternary Movement of the East Arabian Block." GeoArabia 3, no. 4 (October 1, 1998): 509–40. http://dx.doi.org/10.2113/geoarabia0304509.

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ABSTRACT New data presented herein support the previously suggested existence of an East Arabian Tectonic Block in Saudi Arabia. However, the East Arabian Tectonic Block is not exclusively bound by grabens, as was previously thought, but also by strike-slip faults and transpressive folds (in what is named here the Mughrah-Al-Kharj Transpression Zone), which laterally grade into the transtensive Central Arabian Graben System. Evidence for Plio-Quaternary strike-slip motion is presented here for the first time and supports previous contentions that graben formation occurred in Plio-Quaternary time. These new observations allow the development of a tectonic model that succinctly explains the deformation along the margins of the East Arabian Block. With the importance of regional fault structures thus recognized, even some major faults of tectonic dimensions start to emerge in the Eastern Province of Saudi Arabia. For example, radar images from the Space Shuttle Endeavour confirm that the Nisah Fault extends eastward along Wadi As-Sahba, over a total distance of 250 kilometers, which was previously undemonstrable. The Sahba Fault is made visible beneath the Ad-Dahna Sand Sea by virtue of the sand-penetrating capability of the L-band radar. Five to eight kilometers of left-lateral strike separation is visible on either side of Wadi As-Sahba which truncates the southern end of the Ghawar field. The graben structure of the Nisah Fault System had been reported before, but its eastward continuation and any strike separation were not established until now. Furthermore, the Nisah-Sahba Fault System may extend further eastward, beneath alluvial gravels, for an additional 200 kilometers to join a known lineament at the southern end of Qatar. Further extension towards the Gulf into the 600-kilometer long Trans-Arabian Gulf Fault is also suggested here for the first time. Field evidence presented here indicates that a substantial part of the motion of the Central Arabian Graben System took place in the Plio-Quaternary and may continue at present. This has been inferred from a study of the wadi (flood valley) system on the Jubaila and Hanifa outcrops in the vicinity of the graben structures to the south of Riyadh. In fact, an 8-kilometer long section of a mature stream channel, known as Sha’ib al-Miklaf, which was formerly discharging intermittent wadi drift and torrential run-off waters into Wadi Hanifa, has now been cut off from its former catchment area by the graben tectonics. As a result Sha’ib al-Miklaf now lies idle between the active wadis of the Awsat Graben and the Nisah Graben. The occurrence of recent fault motion in the Arabian Platform is further supported by changes in thickness of the Ad-Dahna Sand Sea across the Sahba Fault, as well as by truncation of mega-barchanoids in the Jafurah Sand Sea across the Jaub lineament. Not surprisingly, some modern seismicity in the Eastern Province of Saudi Arabia may be attributed to motion on the Nisah-Sahba Fault System.

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RAO, GANDIKOTA VENKATA, and TAI-HWA HOR. "Momentum exchange between cloud bands and the Low level flow in the Arabian Sea." MAUSAM 41, no. 2 (February 22, 2022): 72–75. http://dx.doi.org/10.54302/mausam.v41i2.2538.

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Vertical distribution of momentum fluxes u ‘W’ and V' W' were computed in convective bands over the Arabian Sea, using the data gathered mainly by the NCAR's Electra on 24 June .1979. In the above u was along the direction of growth and v was orthogonal to u, right handed. The results revealed that, in the Eastern Arabian Sea (EAS) the vertical transport of; TWi was countergradient below 3 km, In the Central Arabian Sea (CAS), the, u’ w’ profile was against the vertical momentum gradient throughout the cloud layer (similar to EAS). The dominant terms for the generation of momentum flux were the same as those in the EAS. An evaluation of the kinetic energy conversion showed that the large-scale flow received its kinetic energy from the cloud bands over the CAS but transferred its energy to the BAS cloud bands.

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Tozuka, Tomoki, Motoki Nagura, and Toshio Yamagata. "Influence of the Reflected Rossby Waves on the Western Arabian Sea Upwelling Region." Journal of Physical Oceanography 44, no. 5 (April 24, 2014): 1424–38. http://dx.doi.org/10.1175/jpo-d-13-0127.1.

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Abstract The sea surface temperature (SST) in the western Arabian Sea upwelling region is known to influence the amount of precipitation associated with the Indian summer monsoon. Thus, understanding what determines the SST in this region is an important issue. Using outputs from an ocean general circulation model with and without strong damping in the eastern equatorial Indian Ocean, this study examines how the reflection of semiannual Kelvin waves at the eastern boundary of the Indian Ocean may influence the western Arabian Sea upwelling region. The downwelling Kelvin waves generated in boreal spring are reflected at the eastern boundary and reach the western equatorial Indian Ocean as reflected Rossby waves about 6 months later. The resulting westward current along the equator in the western equatorial Indian Ocean transports warmer water to the western Arabian Sea upwelling region. Thus, the SST in this region becomes colder especially in boreal fall without the reflected Rossby waves. These results are further supported by the analysis of the mixed layer temperature balance. Surprisingly, vertical processes do not contribute to the SST difference, even though the thermocline becomes shallower without the downwelling Rossby waves. This is because the mixed layer is shoaling rapidly from September to November, and there is basically no entrainment of water from below. In contrast, the reflected Rossby waves do not have large impacts on the SST in other seasons mainly because the zonal SST gradient is not as strong and/or the amplitude of Rossby waves is weaker.

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35

Zolina, Olga, Ambroise Dufour, Sergey K. Gulev, and Georgiy Stenchikov. "Regional Hydrological Cycle over the Red Sea in ERA-Interim." Journal of Hydrometeorology 18, no. 1 (December 21, 2016): 65–83. http://dx.doi.org/10.1175/jhm-d-16-0048.1.

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Abstract The major sources of atmospheric moisture over the Red Sea are analyzed using ERA-Interim for the 1979–2013 period. The vertical structure of moisture transports across the coastlines has been computed separately for the western and eastern coasts of the Red Sea. The vertical structure of the moisture transport from the Red Sea to the continents is dominated by a breeze-like circulation in the near-surface layer and the Arabian high above 850 hPa. The lower-layer, breeze-like circulation is acting to export the moisture to the northwest of Africa and to the Arabian Peninsula and contributes about 80% of the moisture exports from the Red Sea, dominating over the transport in the upper layer, where the moisture is advected to the Arabian Peninsula in the northern part of the sea and to the African continent in the southern part. Integrated moisture divergence over the Red Sea decreased from the early 1980s to 1997 and then increased until the 2010s. Associated changes in the moisture export were provided primarily by the increasing intensity of the breeze-associated transports. The transports above the boundary layer, while being strong across the western and the eastern coasts, have a smaller effect on the net moisture export. The interannual variability of the moisture export in the near-surface layer was found to be closely correlated with the variability in sea surface temperature, especially in summer. Implications of the observed changes in the moisture advection for the hydrological cycle of the Middle East are discussed.

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36

D’Souza, Maia L., Isha Bopardikar, Dipani Sutaria, and Holger Klinck. "Arabian Sea Humpback Whale (Megaptera novaeangliae) Singing Activity off Netrani Island, India." Aquatic Mammals 49, no. 3 (May 15, 2023): 223–35. http://dx.doi.org/10.1578/am.49.3.2023.223.

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Arabian Sea humpback whales (Megaptera novaeangliae), listed as “Endangered” on the International Union for Conservation of Nature’s Red List, remain resident throughout the year in the waters of the Arabian Sea and constitute a genetically isolated population. In the eastern Arabian Sea, information on humpback whales off the Indian coast has largely been limited to stranding records, local ecological knowledge, and opportunistic visual sighting data. These data, along with information from a long-term study off Oman, suggest that humpback whales migrate across the Arabian Sea into Indian territorial waters from October to March. To study the presence of Arabian Sea humpback whales in Indian waters more comprehensively, passive acoustic monitoring (PAM) was initiated along the west coast of India in 2019. Male humpback whales produce complex songs with a stereotyped structure; these songs are shared within a population, and song patterns are known to evolve progressively over time. In this article, a structural analysis of humpback whale song recorded over four days off the coast of Netrani Island, Karnataka, India, in December 2019 is presented. Time-frequency features of 2,641 individual call units were analysed. Call units had a fundamental frequency bandwidth ranging from 149.98 to 541.65 Hz, with a duration ranging from 1.19 to 5.5 s. The call units were used to identify phrases and themes required to construct the structure of the song, which can potentially help identify the population to which singing individuals belong. This study indicates the need for a long-term PAM program across the Arabian Sea to compare whale songs across the region. Simultaneous recordings over multiple seasons will best assess population connectivity, seasonal occurrence, and movement patterns within and between populations across the Arabian Sea and the Indian Ocean.

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Nandkeolyar, Neha, Mini Raman, G. Sandhya Kiran, and Ajai. "Comparative Analysis of Sea Surface Temperature Pattern in the Eastern and Western Gulfs of Arabian Sea and the Red Sea in Recent Past Using Satellite Data." International Journal of Oceanography 2013 (June 4, 2013): 1–16. http://dx.doi.org/10.1155/2013/501602.

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With unprecedented rate of development in the countries surrounding the gulfs of the Arabian Sea, there has been a rapid warming of these gulfs. In this regard, using Advanced Very High Resolution Radiometer (AVHRR) data from 1985 to 2009, a climatological study of Sea Surface Temperature (SST) and its inter annual variability in the Persian Gulf (PG), Gulf of Oman (GO), Gulf of Aden (GA), Gulf of Kutch (KTCH), Gulf of Khambhat (KMBT), and Red Sea (RS) was carried out using the normalized SST anomaly index. KTCH, KMBT, and GA pursued the typical Arabian Sea basin bimodal SST pattern, whereas PG, GO, and RS followed unimodal SST curve. In the western gulfs and RS, from 1985 to 1991-1992, cooling was observed followed by rapid warming phase from 1993 onwards, whereas in the eastern gulfs, the phase of sharp rise of SST was observed from 1995 onwards. Strong influence of the El Niño and La Niña and the Indian Ocean Dipole on interannual variability of SST of gulfs was observed. Annual and seasonal increase of SST was lower in the eastern gulfs than the western gulfs. RS showed the highest annual increase of normalized SST anomaly (+0.64/decade) followed by PG (+0.4/decade).

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Anu, A. P., Elizabeth Shani N. X., and M. Harikrishnan. "Warmest Sea Surface Temperature Event in the South Eastern Arabian Sea over the Decade using Satellite and INS Sagardhwani Observations." Defence Science Journal 69, no. 2 (March 6, 2019): 109–14. http://dx.doi.org/10.14429/dsj.69.14221.

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South Eastern Arabian Sea is well known for its prolonged and warmer sea surface temperature (>30 °C) events generally known as Arabian Sea mini warm pool occurring during the pre-monsoon periods (March-May). To study the intensity and spatial extent of the warm pool, ten years (2007-2016) of satellite-derived weekly averaged SST and in-situ data measured from INS Sagardhwani are used. The analysis is done based on the precondition ‘sea surface temperature > 30 °C’ and lasts more than a week. These analysis demonstrate the existence of a strong inter-annual variability. It is also identified that the sea surface temperature in the year 2016 is the hottest over the decade with maximum spatial coverage and prolonged period of occurrence. These anomalous events are also explained in terms of variabilities of the atmospheric water vapour and wind at the sea surface.

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Maheswaran, P. A., S. Satheesh Kumar, and T. Pradeep Kumar. "Intra annual Variability of the Arabian Sea high salinity water mass in the South Eastern Arabian Sea during 2016 17." Defence Science Journal 69, no. 2 (March 6, 2019): 149–55. http://dx.doi.org/10.14429/dsj.69.14217.

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Intra-annual variability of the Arabian Sea high salinity water mass (ASHSW) in the South Eastern Arabian Sea (SEAS) and Gulf of Mannar (GoM) are addressed in this paper by utilisng the monthly missions carried out onboard INS Sagardhwani during 2016-17. Our observations revealed that the ASHSW was evident along the SEAS irrespective of seasons, whereas in the GoM the presence of ASHSW was observed during winter. The processes such as downwelling/up-welling, coastal currents, intrusion of low saline waters, stratification are clearly affects the spreading of the ASHSW. The characteristics such as core salinity value, depth and thickness of ASHSW exhibited remarkable spatio-temporal variability. Lateral mixing with the low saline waters in the region during winter reduces its core salinity. The intrusion of low saline waters was clearly seen upto 15 ON but the intrusion of low saline waters is not flowing through the GoM. The interface between the ASHSW and the prevailing low saline waters showed strong horizontal gradients of salinity. The presence of the ASHSW makes difference in the SLD and the below layer gradient which is sufficient to complicate or influence sound transmission. The spatio temporal variability of the ASHSW and its acoustic relevance are documented in this paper.

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40

Dutta, Koushik, Ravi Bhushan та B. L. K. Somayajulu. "ΔR Correction Values for the Northern Indian Ocean". Radiocarbon 43, № 2A (2001): 483–88. http://dx.doi.org/10.1017/s0033822200038376.

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Apparent marine radiocarbon ages are reported for the northern Indian Ocean region for the pre-nuclear period, based on measurements made in seven mollusk shells collected between 1930 and 1954. The conventional 14C ages of these shells range from 693 ± 44 to 434 ± 51 BP in the Arabian Sea and 511 ± 34 to 408 ± 51 BP in the Bay of Bengal. These ages correspond to mean ΔR correction values of 163 ± 30 yr for the northern Arabian Sea, 11 ± 35 yr for the eastern Bay of Bengal (Andaman Sea) and 32 ± 20 yr for the southern Bay of Bengal. Contrasting reservoir ages for these two basins are most likely due to differences in their thermocline ventilation rates.

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41

Ali, Shehata, and Abdullah S. Alshammari. "Genesis of gabbroic intrusions in the Arabian Shield, Saudi Arabia: mineralogical, geochemical and tectonic fingerprints of the Neoproterozoic arc magmatism." Geological Magazine 158, no. 9 (April 12, 2021): 1639–56. http://dx.doi.org/10.1017/s0016756821000182.

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AbstractThe Arabian Shield of Saudi Arabia represents part of the Arabian–Nubian Shield and forms an exposure of juvenile continental crust on the eastern side of the Red Sea rift. Gabbroic intrusions in Saudi Arabia constitute a significant part of the mafic magmatism in the Neoproterozoic Arabian Shield. This study records the first detailed geological, mineralogical and geochemical data for gabbroic intrusions located in the Gabal Samra and Gabal Abd areas of the Hail region in the Arabian Shield of Saudi Arabia. Geological field relations and investigations, supported by mineralogical and geochemical data, indicate that the gabbroic intrusions are generally unmetamorphosed and undeformed, and argue for their post-collisional emplacement. Their mineralogical and geochemical features reveal crystallization from hydrous, mainly tholeiitic, mafic magmas with arc-like signatures, which were probably inherited from the previous subduction event in the Arabian–Nubian Shield. The gabbroic rocks exhibit sub-chondritic Nb/U, Nb/Ta and Zr/Hf ratios, revealing depletion of their mantle source. Moreover, the high ratios of (Gd/Yb)N and (Dy/Yb)N indicate that their parental mafic melts were derived from a garnet-peridotite source with a garnet signature in the mantle residue. This implication suggests that the melting region was at a depth exceeding ∼70–80 km at the garnet stability field. They have geochemical characteristics similar to other post-collisional gabbros of the Arabian–Nubian Shield. Their origin could be explained by adiabatic decompression melting of depleted asthenosphere that interacted during ascent with metasomatized lithospheric mantle in an extensional regime, likely related to the activity of the Najd Fault System, at the end of the Pan-African Orogeny.

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42

Johnson, Glejin, V. Sanil Kumar, Sajiv Philip Chempalayil, Jai Singh, Premanand Pednekar, K. Ashok Kumar, G. Udhaba Dora, and Rajamanickam Gowthaman. "Variations in Swells along Eastern Arabian Sea during the Summer Monsoon." Open Journal of Marine Science 02, no. 02 (2012): 43–50. http://dx.doi.org/10.4236/ojms.2012.22006.

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Vipindas, P. V., R. K. M. Mujeeb, T. Jabir, T. R. Thasneem, and A. A. Mohamed Hatha. "Diversity of sediment bacterial communities in the South Eastern Arabian Sea." Regional Studies in Marine Science 35 (March 2020): 101153. http://dx.doi.org/10.1016/j.rsma.2020.101153.

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Amrutha, M. M., and V. Sanil Kumar. "Short-term statistics of waves measured off Ratnagiri, eastern Arabian Sea." Applied Ocean Research 53 (October 2015): 218–27. http://dx.doi.org/10.1016/j.apor.2015.09.009.

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45

Narvekar, P. V., and S. Y. S. Singbal. "Dissolved aluminium in the surface microlayer of the eastern Arabian sea." Marine Chemistry 42, no. 2 (April 1993): 85–94. http://dx.doi.org/10.1016/0304-4203(93)90239-k.

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46

Varna, M., A. K. Jithin, and P. A. Francis. "Characteristics and dynamics of mesoscale eddies in the eastern Arabian sea." Deep Sea Research Part II: Topical Studies in Oceanography 207 (February 2023): 105218. http://dx.doi.org/10.1016/j.dsr2.2022.105218.

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47

Murthy, P. G. K., G. S. Sharma, V. V. James, and K. V. Suseela. "Internal wave characteristics in the eastern Arabian Sea during summer monsoon." Journal of Earth System Science 101, no. 4 (December 1992): 317–27. http://dx.doi.org/10.1007/bf02893007.

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PATTANAIK, DR. "Variability of convective activity over the Bay of Bengal and the Arabian sea." MAUSAM 59, no. 4 (October 1, 2008): 479–90. http://dx.doi.org/10.54302/mausam.v59i4.1276.

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The present study is an attempt to examine seasonal and interannual variability of convective activity over the north Indian Ocean. The monthly mean Outgoing Long-wave Radiation (OLR) data obtained from National Oceanic and Atmospheric Administration (NOAA) polar orbiting spacecraft are used in this study for a period of 26 year (1979 to 2004). The period has been divided into two groups of 13 years each with period (i) from 1979 to 1991 and period (ii) from 1992 to 2004. The monthly and seasonal variation of convective activity along with its linear trends analysis during four seasons [winter, Jan-Feb (JF); pre-monsoon, Mar-May (MAM); monsoon, Jun-Sep (JJAS); & post-monsoon, Oct-Dec (OND)] are performed. The difference of seasonal OLR anomalies in winter season between period (ii) & period (i) indicate increase in convective activity during recent period [period (ii)] compared to that of period (i) over the south Arabian Sea & south Bay of Bengal and just the opposite occurred over the rest regions associated with a significant decreasing trend of convective activity over the north and central Arabian Sea (at 99.9% level and 99% level respectively). During MAM the Bay of Bengal and the eastern part of Arabian Sea are relatively more convective during the recent period compared to the former period with significant increasing trend of convective activity over central Bay of Bengal (99% level) and northern (95% level) Bay of Bengal. The convective activity increases mainly over the southern parts of the Arabian Sea (dominated in the month of July) and some parts of southern and eastern Bay of Bengal in recent period compared to that of former period during the monsoon season and is associated with significant increasing trend (at 95 % level) of convective activity over the north Bay of Bengal. The post monsoon season also shows significant (at 95% level) increasing trend in convective activity over south Arabian Sea.

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VAN WAEREBEEK, KOEN, MICHAEL GALLAGHER, ROBERT BALDWIN, VASSILI PAPASTAVROU, and Samira Mustafa Al-Lawati. "Morphology and distribution of the spinner dolphin, Stenella longirostris, rough-toothed dolphin, Steno bredanensis and melon-headed whale, Peponocephala electra, from waters off the Sultanate of Oman." J. Cetacean Res. Manage. 1, no. 2 (September 1, 1999): 167–77. http://dx.doi.org/10.47536/jcrm.v1i2.464.

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The morphology of three tropical delphinids from the Sultanate of Oman and their occurrence in the Arabian Sea are presented. Body lengths of four physically mature spinner dolphins (three males) ranged from 154- l78.3cm (median 164.5cm), i.e. smaller than any known stock of spinner dolphins, except the dwarf forms from Thailand and Australia. Skulls of Oman spinner dolphins (11 = I0) were practically indistinguishable from those of eastern spinner dolphins (Stenella longirosrris orientalis) from the eastern tropical Pacific, but were considerably smaller than skulls of populations of pantropical (Stene/la longirostris longirostris) and Central American spinner dolphins (Stenella !ongirostris centroamericana). Two colour morphs (CM) were observed. The most common (CMI) has the typical tripartite pattern of the pantropical spinner dolphin. A small morph (CM2), so far seen mostly off Muscat, is characterised by a dark dorsal overlay obscuring most of the tripartite pattern and by a pinkish or white ventral field and supragenital patch. Two skulls were linked to a CMI colour morph, the others were undetermined. It is concluded that Oman spinner dolphins should be treated as a discrete population, morphologically distinct from all known spinner dolphin subspecies. Confirmed coastal range states off the Arabian Peninsula include the United Arab Emirates, the Sultanate of Oman, Yemen, Somalia, Djibouti, Saudi Arabia, Sudan and Egypt. The taxonomic position of two damaged dolphin calvariae from Oman has been the issue of much debate. This paper discusses the cranial characteristics that allow positive identification as rough-toothed dolphin (Steno bredanensis) and melon-headed whale (Peponoceplwla electro) respectively. The calvariae represent the first confirmed specimen records of these dolphin species for the Arabian Sea sensu lato.

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SINGH, A. D., S. DAS, and K. VERMA. "Impact of climate induced hypoxia on calcifying biota in the Arabian Sea : An evaluation from the micropaleontological records of the Indian margin." MAUSAM 62, no. 4 (December 16, 2021): 647–52. http://dx.doi.org/10.54302/mausam.v62i4.388.

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High biological productivity combined with the poor ventilation produces severe oxygen depletion (hypoxia) in upper intermediate waters of the Arabian Sea. The naturally developed Arabian Sea oxygen minimum zone (OMZ) is one of the most pronounced low oxygen ocean environments known today. The OMZ impinges the Indian margin where oxygen concentration reaches values less than 0.05 ml/l leading denitrification. In recent studies, it has been observed that the OMZ strength has varied considerably in the past, in tune with the global climate change. But the effect of changes in natural mid-water hypoxic environment on the marine biota particularly of the eastern Arabian Sea is unknown. Here, we analyzed 30,000 yr record of temporal changes in two major groups of marine calcifying microfauna pteropods secreting aragonitic shells and foraminifera secreting calcitic shells in terms of abundance and diversity variations. This study will provide an insight into our understanding of potential impact of rising atmospheric CO2 on marine ecosystem.

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