scholarly journals A Lagrangian Tool for Simulating the Transport of Chemical Pollutants in the Arabian/Persian Gulf

2021 ◽  
Author(s):  
Raúl Periáñez
Keyword(s):  
Persian Gulf ◽  
Fast Response ◽  
Ocean Model ◽  
Lagrangian Model ◽  
Transfer Coefficients ◽  
Dynamic Approach ◽  
Chemical Pollutants ◽  
Baroclinic Circulation ◽  
Chemical Pollutant ◽  
Release Processes

A rapid-response Lagrangian model for simulating the transport of a chemical pollutant in the Arabian/Persian Guls is described. The model is well suited to provide a fast response after an emergency due to an accident or a deliberate spill. Baroclinic circulation was obtained from HYCOM ocean model and tides were calculated using a barotropic model. The interactions of pollutants with sediments (uptake/release processes) were described using a dynamic approach based on kinetic transfer coefficients and a stochastic numerical method. Some examples of model applications are shown.

scholarly journals A Lagrangian Tool for Simulating the Transport of Chemical Pollutants in the Arabian/Persian Gulf

Modelling ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 675-685
Author(s):  
Raúl Periáñez
Keyword(s):  
Persian Gulf ◽  
Rapid Assessment ◽  
Distribution Patterns ◽  
Fast Response ◽  
Ocean Model ◽  
Lagrangian Model ◽  
Transfer Coefficients ◽  
Geochemical Behaviour ◽  
Chemical Pollutant ◽  
Set Up

A rapid-response Lagrangian model for the use in simulation of the transport of a chemical pollutant in the Arabian/Persian Gulf is described. The model is well suited to the provision of a fast response after an emergency due to an accident or a deliberate spill. It is easy to set up for any situation since only requires the modification of a few input files specifying the pollutant properties and release characteristics. Running times are short, even on a desktop PC, which makes it appropriate for a rapid assessment of a hypothetical accident occurring in the region. Baroclinic circulation was obtained from an HYCOM ocean model, and tides were calculated using a barotropic model. The interactions of pollutants with sediments (uptake/release processes) were described using a dynamic approach based on kinetic transfer coefficients and a stochastic numerical method. Some examples of model applications are shown, showing the influence of the geochemical behaviour of the pollutant in its distribution patterns.

scholarly journals A numerical study of the response of tropical Pacific SST to atmospheric forcing

MAUSAM ◽  
2021 ◽  
Vol 48 (4) ◽  
pp. 657-668
Author(s):  
XIAOMING LIU ◽  
JOHN M. MORRISON ◽  
LIAN XIE
Keyword(s):  
Ocean Circulation ◽  
Numerical Study ◽  
Ocean Model ◽  
Tropical Pacific ◽  
The Other ◽  
Atmospheric Forcing ◽  
Transfer Coefficients ◽  
Low Wind Speed ◽  
Sensitivity Tests ◽  
The Tropical Pacific

Two sets of atmospheric forcing from NCEP/NCAR 40-year reanalysis project, one based on monthly averaged climatological data and the other on 1982-83 monthly averaged data, are used to derive the global Miami Isopycnic Coordinate Ocean Model (MICOM). These two runs are referred to as the climatological experiments and 1982-83 El Nino experiments. Sensitivity tests of tropical Pacific SST to different bulk parameterizations of air-sea heat and momentum fluxes are carried out in the two experiments. Primary results show that constant transfer coefficients                          (1.2 × 10-3) for heat flux greatly overestimate the tropical Pacific SST, whereas the Liu-Katsaros-Businger (Liu et al. 1979) method can significantly improve the SST simulation especially under very low-wind speed conditions. On the other hand, Large and Pond (1982) formulation of the drag coefficient made little difference on the tropical Pacific SST simulation although it might modify the surface ocean circulation. The SST seasonal cycle and interannual variability of tropical Pacific SST are also examined in this study. Since SST is the most important oceanic parameter that provides the link between the atmosphere and the ocean, this evaluation of different parameterization schemes may facilitate future studies on coupling ocean-atmospheric numeric models.    

scholarly journals Integrated transcriptomics and metabolomics reveal signatures of lipid metabolism dysregulation in HepaRG liver cells exposed to PCB 126

2018 ◽  
Author(s):  
Robin Mesnage ◽  
Martina Biserni ◽  
Sucharitha Balu ◽  
Clément Frainay ◽  
Nathalie Poupin ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Fatty Liver ◽  
Polychlorinated Biphenyl ◽  
Expression Profiles ◽  
Human Populations ◽  
Limited Information ◽  
Chemical Pollutants ◽  
Pcb 126 ◽  
Heparg Cell Line ◽  
Chemical Pollutant

AbstractChemical pollutant exposure is a risk factor contributing to the growing epidemic of nonalcoholic fatty liver disease (NAFLD) affecting human populations that consume a Western diet. Although it is recognized that intoxication by chemical pollutants can lead to NAFLD, there is limited information available regarding the mechanism by which typical environmental levels of exposure can contribute to the onset of this disease. Here we describe the alterations in gene expression profiles and metabolite levels in the human hepatocyte HepaRG cell line, a validated model for cellular steatosis, exposed to the polychlorinated biphenyl (PCB) 126, one of the most potent chemical pollutants that can induce NAFLD. Sparse partial least squares classification of the molecular profiles revealed that exposure to PCB 126 provoked a decrease in polyunsaturated fatty acids as well as an increase in sphingolipid levels, concomitant with a decrease in the activity of genes involved in lipid metabolism. This was associated with an increased oxidative stress reflected by marked disturbances in taurine metabolism. A gene ontology analysis showed hallmarks of an activation of the AhR receptor by dioxin-like compounds. These changes in metabolome and transcriptome profiles were observed even at the lowest concentration (100 pM) of PCB 126 tested. A decrease in docosatrienoate levels was the most sensitive biomarker. Overall, our integrated multi-omics analysis provides mechanistic insight into how this class of chemical pollutant can cause NAFLD. Our study lays the foundation for the development of molecular signatures of toxic effects of chemicals causing fatty liver diseases to move away from a chemical risk assessment based on in vivo animal experiments.

High-Throughput Analytical Techniques for Determination of Residues of 653 Multiclass Pesticides and Chemical Pollutants in Tea, Part II: Comparative Study of Extraction Efficiencies of Three Sample Preparation Techniques

2013 ◽  
Vol 96 (2) ◽  
pp. 432-440 ◽  
Author(s):  
Chun-Lin Fan ◽  
Qiao-Ying Chang ◽  
Guo-Fang Pang ◽  
Zeng-Yin Li ◽  
Jian Kang ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Green Tea ◽  
High Speed ◽  
Extraction Efficiency ◽  
Preparation Technique ◽  
Test Results ◽  
Chemical Pollutants ◽  
Chemical Pollutant ◽  
Three Stages

Abstract This paper reports a study of the extraction efficiency for the multiresidue pesticides and chemical pollutants in tea with three methods over three stages. Method 1 adopts the Pang et al. approach: the targets were extracted with 1% acetic acid in acetonitrile and cleaned up with a Cleanert TPT SPE cartridge; Method 2 adopts the QuEChERS approach: the targets were cleaned up dispersively with graphitized carbon and primary-secondary amine (PSA) sorbent; Method 3 adopts the relatively commonly used approach of hydration for solid samples, with tea hydrated before being extracted through salting out with acetonitrile and the cleanup procedures identical to those of Method 1. The three stages comprised two phases of comparative tests on spike recoveries of 201 pesticides and chemical pollutants from different teas and a third phase on determination of the content of the 201 pesticides and chemical pollutants from aged tea samples. In stages I and II, test results of the spike recoveries of 201 pesticides and chemical pollutants demonstrated that 91.4% of the pesticide and chemical pollutant recoveries fell within the range of 70–110%, and 93.2% of the pesticides and chemical pollutants had RSD < 15%, with no marked difference obtained by Method 1 and Method 2 regardless of whether it was green tea or woolong tea, or GC/MS or GC/MS/MS was used for analysis. For pigment removal, Method 1 was superior to Method 2; in terms of easy operation, Method 2 outweighed Method 1. However, Method 3 obtained relatively low recoveries, with 94% of pesticide and chemical pollutant recoveries less than 70%, which proved that Method 3 was not applicable to the determination of multiresidue pesticides and chemical pollutants in tea. Stage III made a comparison of Method 1 and Method 2 for the extraction efficiency of pesticides and chemical pollutants in 165-day-aged samples of green and woolong tea. Test results showed that 94% of the pesticide and chemical pollutant content in the aged tea samples was recovered with Method 1, more than 10% higher than with Method 2 (30–50% higher on average). For green tea, 193 (GC/MS/MS) and 197 (GC/MS) pesticides and chemical pollutants accounted for 96.5% (GC/MS/MS) and 98.0% (GC/MS) with Method 1 higher than with Method 2. For woolong tea, 191 (GC/MS/MS) and 194 (GC/MS) pesticides and chemical pollutants accounted for 95% (GC/MS/MS) and 96% (GC/MS/MS) with Method 1, higher than with Method 2, respectively. In other words, there were definite differences in the test results for aged tea samples between Method 1 and Method 2, which suggests that Method 1 was capable of extracting more residual pesticides and chemical pollutants from the precipitated 165-day-aged tea samples. The reason can be traced to the possibility that Method 1 (high-speed homogenizing) has better extraction efficiency than Method 2 (vortex and oscillation). Therefore, Method 1 was chosen as the sample preparation technique for multiresidue pesticide and chemical pollutant analysis in tea.

Transient Forced Convection Heat Transfer to Helium During a Step in Heat Flux

1983 ◽  
Vol 105 (2) ◽  
pp. 350-357 ◽  
Author(s):  
P. J. Giarratano ◽  
W. G. Steward
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Forced Convection ◽  
Carbon Film ◽  
Convection Heat Transfer ◽  
Fast Response ◽  
Operating Conditions ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Forced Convection Heat Transfer

Transient forced convection heat transfer coefficients for both subcritical and supercritical helium in a rectangular flow channel heated on one side were measured during the application of a step in heat flux. Zero flow data were also obtained. The heater surface which served simultaneously as a thermometer was a fast response carbon film. Operating conditions covered the following range: Pressure, 1.0 × 105 Pa (1 bar) to 1.0 × 106 Pa (10 bar); Temperature, 4 K–10 K; Heat Flux, 0.1 W/cm2−10 W/cm2; Reynolds number, 0–8 × 105. The experimental data and a predictive correlation are presented.

scholarly journals NUMERICAL SIMULATION OF TROPICAL CYCLONES AND STORM SURGES IN THE ARABIAN SEA

2018 ◽  
pp. 11
Author(s):  
Mohsen Soltanpour ◽  
Zahra Ranji ◽  
Tomoyo Shibayama ◽  
Sarmad Ghader ◽  
Shinsaku Nishizaki
Keyword(s):  
Tropical Cyclones ◽  
Persian Gulf ◽  
Arabian Sea ◽  
Storm Surges ◽  
Ocean Model ◽  
Gulf Of Oman ◽  
The Persian Gulf ◽  
The Impact ◽  
Landfall Location ◽  
Good Agreement

Winds, waves and storm surges of Gonu and Ashobaa, as two recent cyclones in the Arabian Sea and Gulf of Oman, are simulated by a system of WRF-FVCOM-SWAN. The employed models are separately calibrated using the available data. Surges are found to be highly dependent on coastal geometry and landfall location, rather than the storm intensity. Comparisons at different stations reveal that the results of models are in a good agreement with measured parameters. Negative surges are also observed in the enclosed basins of the Persian Gulf and Red Sea. The calibrated atmosphere-wave-ocean model can be utilized for the prediction of extreme events, expected to increase in future due to the impact of the climate change.

How Environmental Effects on Child Health Are Recognized

PEDIATRICS ◽  
1974 ◽  
Vol 53 (5) ◽  
pp. 792-799
Author(s):  
Robert W. Miller
Keyword(s):  
Cerebral Palsy ◽  
Case Reports ◽  
Human Beings ◽  
Older Children ◽  
Chemical Pollutants ◽  
Chemical Pollutant ◽  
Minamata Bay ◽  
Vinyl Plastic ◽  
Harmful Effects ◽  
Kyushu District

There is no doubt that the fetus and child have special susceptibility to the harmful effects of chemical pollutants. EPIDEMIOLOGIC CASE REPORTS Example 1 "Strange incidents occurred in villages along Minamata Bay in [the] Kyushu district in Japan, in which many cats went mad and died. These incidents were the prelude to [an] epidemic of a mysterious disease in human beings."1 In this way Japanese scientists began their account of the link between the ailment, now known as Minamata disease, and pollution of water with methylmercury. Initially, a degenerative neurological disease was observed only in older children and adults. Apparently no one thought of possible fetal effects. In consequence, they went unnoticed for several years before it was realized that an epidemic of cerebral palsy had paralleled the illness in adults and older children. This was the first evidence that a chemical pollutant could harm the human fetus. Methylmercury was identified as the cause of the epidemic by looking back into the histories of affected persons. The frequency and seriousness of the effect was greatest in the families of fishermen. It had been noted that fish in the Bay swam erratically. Fishermen sold their best catch and used the sickest looking fish as food for their families. Twenty-three children developed cerebral palsy after intrauterine exposure. Six percent of births during the interval were affected, as compared with 0.5% elsewhere in Japan. Although brain damage in the children was severe, only one of their mothers showed signs of the disease. The methylmercury came from waste flushed into the Bay by a factory that made vinyl plastic.

A Modeling Study of Circulation and Eddies in the Persian Gulf

2010 ◽  
Vol 40 (9) ◽  
pp. 2122-2134 ◽  
Author(s):  
Prasad G. Thoppil ◽  
Patrick J. Hogan
Keyword(s):  
Persian Gulf ◽  
Spatial Scales ◽  
Baroclinic Instability ◽  
Mesoscale Eddies ◽  
Ocean Model ◽  
Coastal Current ◽  
Basin Scale ◽  
Strait Of Hormuz ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Persian Gulf

Abstract The circulation and mesoscale eddies in the Persian Gulf are investigated using results from a high-resolution (∼1 km) Hybrid Coordinate Ocean Model (HYCOM). The circulation in the Persian Gulf is composed of two spatial scales: basin scale and mesoscale. The progression of a cyclonic circulation cell dominates the basin-scale circulation in the eastern half of the gulf (52°–55°E) during March–July. This is primarily the consequence of density-driven outflow–inflow through the Strait of Hormuz and strong stratification. A northwestward-flowing Iranian Coastal Current (ICC; 30–40 cm s−1) between the Strait of Hormuz and north of Qatar (∼52°E) forms the northern flank of the cell. Between July and August the ICC becomes unstable because of the baroclinic instability mechanism by releasing the potential energy stored in the cross-shelf density gradient. As a result, the meanders in the ICC evolve into a series of mesoscale eddies, which is denoted as the Iranian coastal eddies (ICE). The ICE have a diameter of about 115–130 km and extend vertically over most of the water column. Three cyclonic eddies produced by the model during August–September 2005 compared quite well with the Moderate Resolution Imaging Spectroradiometer (MODIS) SST and chlorophyll-a observations. The remnants of ICE are seen until November, after which they dissipate as the winter cooling causes the thermocline to collapse.

scholarly journals Ventilation dynamics of the Oxygen Minimum Zone in the Arabian Sea

2019 ◽  
Author(s):  
Henrike Schmidt ◽  
Rena Czeschel ◽  
Martin Visbeck
Keyword(s):  
Summer Monsoon ◽  
Persian Gulf ◽  
Arabian Sea ◽  
Sea Water ◽  
Ocean Model ◽  
Western Basin ◽  
Eastern Basin ◽  
Persian Gulf Water ◽  
Core Thickness ◽  
Oxygen Minimum

Abstract. Oxygen minimum zones (OMZs) in the open ocean occur below the surface in regions of weak ventilation and high biological productivity. Very low levels of dissolved oxygen affect marine life and alter biogeochemical cycles. One of the most intense but least understood OMZs in the world is located in the Arabian Sea in a depth range between 300 to 1000 m. Within the last decades observations suggest a decreasing oxygen trend. Thus, an improved understanding of the crucial processes is necessary for a reliable assessment of the future development of the Arabian Sea OMZ. This study uses a combination of observational data as well as reanalysis velocity fields from the ocean model Hycom (Hybrid Coordinate Ocean Model) to explore the ventilation dynamics of the Arabian Sea OMZ. Our results show that the OMZ features a strong seasonal cycle with regional differences that is correlated with the monsoon system: In the eastern basin, the OMZ is strongest during the winter monsoon with a core thickness of 1000 m depth and oxygen values of less than 5 µmol/kg. Ventilation during that phase is dominated by Persian Gulf water, that clockwise circles the perimeter of the basin and enters the OMZ from the north. During the summer monsoon ventilation from the southeast leads to higher oxygen values indicating a reverse flow along the Indian coast in the intermediate layer compared to the southeastward surface currents. The seasonal cycle in the western basin has the same seasonality as the one in the eastern basin with a core thickness of 900 m during the winter monsoon. The oxygen supply during the summer monsoon is weaker compared to the eastern basin and correlates with the ventilation of Persian Gulf (Red Sea) water during the summer monsoon (autumn inter-monsoon) phase. As the interior exchange between the eastern and western basin is weak, the more pronounced OMZ in the eastern basin is explained by prolonged ventilation time scales. For the eastern (western) basin Persian Gulf water needs 2–3 (1–2) years and Red Sea water 7–8 (3–4) years to ventilate the OMZ.

scholarly journals Mesoscale variability in the Arabian Sea from HYCOM model results and observations: impact on the Persian Gulf Water path

Ocean Science ◽  
2015 ◽  
Vol 11 (5) ◽  
pp. 667-693 ◽  
Author(s):  
P. L'Hégaret ◽  
R. Duarte ◽  
X. Carton ◽  
C. Vic ◽  
D. Ciani ◽  
...  
Keyword(s):  
Persian Gulf ◽  
Arabian Sea ◽  
Meteorological Data ◽  
Mesoscale Eddies ◽  
Ocean Model ◽  
Water Masses ◽  
Dimensional Structure ◽  
Persian Gulf Water ◽  
The Persian Gulf ◽  
Sea Of Oman

Abstract. The Arabian Sea and Sea of Oman circulation and water masses, subject to monsoon forcing, reveal a strong seasonal variability and intense mesoscale features. We describe and analyze this variability and these features, using both meteorological data (from ECMWF reanalyses), in situ observations (from the ARGO float program and the GDEM – Generalized Digital Environmental mode – climatology), satellite altimetry (from AVISO) and a regional simulation with a primitive equation model (HYCOM – the Hybrid Coordinate Ocean Model). The model and observations display comparable variability, and the model is then used to analyze the three-dimensional structure of eddies and water masses with higher temporal and spatial resolutions than the available observations. The mesoscale features are highly seasonal, with the formation of coastal currents, destabilizing into eddies, or the radiation of Rossby waves from the Indian coast. The mesoscale eddies have a deep dynamical influence and strongly drive the water masses at depth. In particular, in the Sea of Oman, the Persian Gulf Water presents several offshore ejection sites and a complex recirculation, depending on the mesoscale eddies. The associated mechanisms range from coastal ejection via dipoles, alongshore pulses due to a cyclonic eddy, to the formation of lee eddies downstream of Ra's Al Hamra. This water mass is also captured inside the eddies via several mechanisms, keeping high thermohaline characteristics in the Arabian Sea. The variations of the outflow characteristics near the Strait of Hormuz are compared with variations downstream.

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