Discover the world's research
- 20+ million members
- 135+ million publications
- 700k+ research projects
Join for free
... To the best of the author's knowledge, a numerical study on free convection boundary-layer flow and heat transfer of Casson nanofluids over a vertical plate at low and high Prandtl numbers under the influence of thermal radiation and nanoparticle shape, size and type has not been investigated. Therefore, the present study focuses on a numerical study on free convection flow and heat transfer of Casson nanofluids over a vertical plate under the influence of thermal radiation using finite difference method [35][36][37][38][39][40][41][42][43]. ...
... Physical and thermal properties of the base fluid[36][37][38][39][40][41]. ...
... The physical, chemical, and biological characteristics of coastal waters form a gradient extending from land to ocean. While the characteristics of coastal waters at the seaward boundary typically do not significantly differ from those of ocean waters, this boundary is inherently variable with respect to distance from the shore (e.g., Exclusive Economic Zones), bathymetric structures [e.g., those coinciding with the continental shelf or slope; Gazeau et al. (2004); Pickard (1979)], biotic distributions or processes (Gibbs et al., 2006), hydrographic structures (Gibbs et al., 2006), etc. Adjacent to the landward boundary of coastal waters are the coastal inshore waters (CIW), specifically defined by this study as coastal waters between 0 and 200 m from the shoreline. As such, CIW represent <1% of coastal waters but constitute an ecosystem with distinct characteristics, due in part to their extremely dynamic physicochemical and biological processes. ...
-
![Eva Flo]()
Coastal inshore waters (CIW) are defined as the area of coastal waters between 0 and 200 m from the shoreline. They only represent < 1% of coastal waters, even though they are of main ecological, social, and economic importance. However, studies related to CIW are scarce and, thus, they are very poorly known and understood. The time series data base of the National Catalan Coastal Water Monitoring Program, conducted since 1990, has allowed characterizing the CIW in the NW Mediterranean Sea. CIW receive a larger influence of continental nutrient-rich freshwater inflows than outermost coastal waters. These influences trigger the primary production (chlorophyll-a concentration), which can enhance the eutrophication process. In addition, they are fluvial or urban. The fluvial continental influences are related to natural processes, such as fluvial inflows and submarine groundwater discharges, and are defined by a high freshwater content (inverse of salinity) and a high nitrate, and silicate concentrations. The urban ones are mainly related to urban inflows, thus of anthropogenic origin, and are defined by high phosphate, ammonia, and nitrite concentrations. During the study period (1990-2014), physicochemical and biological data analyses revealed great differences between CIW and outermost coastal waters, in space and time and at national and local scales. CIW showed significantly larger concentrations of dissolved inorganic nutrients and chlorophyll-a than outermost coastal waters. Within CIW, Fluvial continental influences occurred predominantly in coastal zones where rivers flow into, such as in the southwest where the Ebre river discharges, and urban continental influences occurred along the metropolitan Barcelona area and near mostly urban areas. Besides, fluvial continental influences decreased while urban continental influences increased with time. In addition, CIW showed higher variability and heterogeneity, especially at local scale. These evidences had allowed the creation of methods to assess pressures (nutrients) on land and on coastal waters and also the impact they drive (chlorophyll-a) on coastal waters, as required by the Water Framework Directive. The land uses simplified index (LUSI) method assesses the continental pressures measured on land and its influence on coastal waters, based on land uses and coastline morphology. The Phosphate-Ammonium-Nitrite (FAN) and FLUviality (FLU) indexes method, which is based on physicochemical variables, assesses the continental influences, the urban and fluvial ones, the water quality, and the anthropogenic component of the trophic state and the risks of eutrophication and cultural eutrophication on coastal waters. The chlorophyll-a method, which is based on chlorophyll-a concentration (phytoplanktonic biomass) and on salinity, assesses the ecological status of coastal waters and allows to assess the eutrophication on coastal waters. Merging the results of the FAN and FLU indexes and of the Chl-a methods allows to assess the cultural eutrophication on coastal waters. The integrated assessment of the Catalan coast, based on the jointly results of the created methods, revealed that the 42% of the water bodies are at risk of eutrophication, 19% are at risk of cultural eutrophication, 8% show eutrophication, and 2% show cultural eutrophication. Therefore, the assumption regarding the oligotrophy of the Mediterranean Sea is rejected in CIW of the Catalan Coast. The combined evidences of the characterization and assessments of the Catalan coastal waters provide a better understanding of the structure and functioning of coastal waters, especially of CIW, in the Mediterranean Sea, which is essential for decision-makers. In addition, scientific recommendations were provided to achieve in the future the integrated management of the Catalan coast, under the ecosystem approach.
... The area is directly influenced by the North Brazilian Current (NBC), the North Equatorial Sub-Current (NESC), the North Equatorial Counter-Current (NECC), and the North Equatorial Current (NEC) (Silveira et al., 2004). The NBC formation is related to a bifurcation in the northern direction of the southern branch of the South Equatorial Current (SEC) when it reaches the Brazilian continental margin between latitudes 10°S and 15°S (Schott et al., 2004;Talley et al., 2011). The NBC is known to be the largest surface flow component of the Southern Atlantic Overturning Circulation (AMOC); through the northward surface water transport and the inter-hemispheric oceanic heat exchange, it acts as a link between the northern and southern hemispheres and plays an important role in the equatorial counter-zonal current system and the global climate (Zhang et al., 2011). ...
This research addresses paleoclimatic variations using sedimentological, geochemical, and planktic foraminifera. The study was carried out in a survey core (ANP 1011) collected on the continental slope of the Icaraí Sub-basin (Ceará Basin), on the coast of the Municipality of Itapipoca, CE, Brazil. Particle size analysis, CaCO3 content, Ti/Ca and Fe/Ca ratios, and the analysis of foraminifera associations for biostratigraphic purposes were performed. Based on the relative abundance of planktic foraminifera, with indicators of warm and cold water throughout the studied cores, two biozones (Y: Upper Pleistocene and Z: Holocene), and two subzones (Z2 and Z1) were recognized. The data of sedimentological markers obtained confirmed the occurrence of more wet phases in northeastern Brazil during the early stages of the Holocene. The Ti/Ca and Fe/Ca ratios, as well as the geochemical and micropaleontological proxies, indicated a farther north displacement of the Intertropical Convergence Zone (ITCZ) in the Pleistocene–Holocene transition. This may have caused greater precipitation in the Northeastern region of Brazil, effectuating the entry of a high volume of terrestrial sediments directly into the ocean basin. Keywords: Quaternary biostratigraphy, marine sedimentation, ITCZ mobility, paleoclimate.
... The temperature and salinity profiles collected from Argo floats and Glider project allow us to confirm the water mass characteristics of the SCS (Fig. III.3a-h). We obtain the same characteristics of water masses in the zone as previous studies on SCS (Uu and Brankart 1997, Rojana-anawat et al. 2000, Saadon et al. 1999 and on Pacific (Pickard and Emery, 1990). In the upper layer (0-50 m), we observe both the Open Sea Water We observe some temperature profiles not following those DW characteristics both in Argo and model outputs, with temperature varying from 7-10°C below 700 m: they are located in the Sulu Sea. ...
- Bich Ngoc Trinh
The South China Sea (SCS) ocean dynamics play an important role at the local scale for the regional climate system, but also in global ocean circulation and climate. Surface waters of the global thermohaline circulation indeed transit from the Pacific to the Indian Oceans across the SCS through several interocean straits (the South China Sea Throughflow, SCSTF), and are significantly modified during this transit. Ocean dynamics moreover influences the SCS marine life through its role in the transport and mixing of the pelagic planktonic ecosystems' components. The general objective of this thesis is to contribute to the understanding of the SCS ocean dynamics and of their interactions with the other compartments of the regional system, by focusing on the functioning and variability of the SCS water, heat and salt budgets with the perspective to study their impact on the pelagic planktonic ecosystems. For that, a high resolution (4 km) configuration of a regional physical-biogeochemical ocean model covering the SCS with rigorously closed budgets is developed and used to perform and analyze simulations over the recent period 2009 - 2018. We first show by comparison with available satellite data and in-situ observations the ability of our physical simulation to reproduce the surface water masses and circulation characteristics as well as thermohaline vertical distribution, at the climatological, seasonal and interannual scales. We then examine the climatological average and seasonal cycle of all components involved in the water volume, heat and salt budgets over the SCS: internal variations and lateral, atmospheric and river fluxes. Water and salt inputs to the SCS are mostly related to the lateral inflow of Pacific water through the Luzon strait. About 1/2 of those inputs is released through the Mindoro strait to the Sulu sea, 1/4 through the Taiwan strait to the East China Sea and 1/4 through the Karimata strait to the Java Sea. Heat gain mostly comes for the Luzon lateral input (~ 3/4) and from the atmosphere (~1/4), and is equivalently released through the Mindoro, Taiwan and Karimata straits. Over the studied period, the SCS stores respectively 0.3% and 2.5% of the total salt and heat inputs. The seasonal cycle of water and salt budgets is mainly driven by the net lateral water flux through interocean straits, whereas the seasonal cycle of heat budget is mainly governed by the atmospheric heat flux. On the interannual time scale, water, heat and salt fluxes at Luzon and Mindoro straits are highly correlated together and show the strongest variability of all straits' transports, and high correlations with ENSO (El Niño Southern Oscillation) and PDO (Pacific Decadal Oscillation). The annual atmospheric water flux governs the interannual variability of SCS water budget: a variation of annual atmospheric freshwater input induces a mirror variation of lateral outflow so that the SCS volume hardly varies at the interannual scale. The SCS salt budget is regulated at the first order by the interannual variability of net lateral water flux, then by the salinity of the in/outflowing interocean waters. In particular, we show that the recent SCS saltening was mainly induced by the increase in the inflow of salty Pacific water which compensated a deficit of rainfall freshwater over the area. The heat budget interannual variability is driven first by the total lateral heat flux, itself driven by the variability of the temperature of the out/inflowing waters, then by the variability of the lateral water flux and surface heat flux. Water and salt budgets as well as the SCSTF are strongly affected by ENSO and PDO, whereas the heat budget is only affected by ENSO.
... Saat matahari, bulan dan bumi berada pada posisi sejajar, matahari dan bulan memberikan daya tarik yang besar terhadap bumi yang menciptakan pasang tinggi yang disebut pasang purnama (spring tides) dan terjadi dua kali dalam sebulan yaitu saat bulan purnama dan bulan baru (Talley et al., 2011). Pasang purnama terjadi setiap bulan, namun dalam setahun terjadi beberapa pasang purnama tertinggi yang disebut Perigean Spring Tide. ...
-
![Kautsar Fahreza Tandipanga]()
The purpose of this research was to: a) describe the perception of fish farmers to climate change, b) identify and map the impact of coastal flood due to climate change, c) estimate the economic losses of fish farmer due to climate change, and d) describe adaptation strategies of the fish farmer to address climate change impacts in Kalanganyar Village, Sidoarjo District. This is descriptive research was used both qualitative and quantitative approaches. Snowball sampling method was employed to choose 25 fish farmer households. Besides this, FGD also conducted to develop the participatory map. Perception and adaptation strategies were analysed using descriptive statistic. Estimation of economic losses was analysed using several methods, i.e. loss of production, replacement cost, and preventive expenditure. The spatial analysis also used to compose the participatory coastal flood impacts map. Result revealed that climate change has not entirely understood by fish farmers. However, their accounts of the changing climate parameters mostly converge to the increasing air temperature and sea level, and decreasing rainfall. Coastal flood due to climate change adversely affects the fish farmers by embankment breaching and loss of production. Estimate of economic losses in 2018 by the method of loss of production was the amount of Rp.572.483.181,82/fish farmer, replacement cost Rp.88.021.739,13/fish farmer, and preventive expenditure Rp.4.714.285,00/fish farmer, respectively. Fish farmers try to adapt in various ways, including river embankment heightening, livelihood diversification, mobilizing family members, change in stocking-harvest management, and frequently heightening the pond dykes. Some fish farmers could employ more than one adaptation strategy.
... Human civilization largely depends on the ocean resources for food, energy and security; transportation, navigation, and surveillance; climate, environment and weather conditions; industrial and commercial requirements. The ocean, being a fluid and an open thermodynamic system, has many similar properties as the atmosphere (Pickard and Emery, 1993), both, on the rotating frame of the earthas itpossesses several key dynamic properties (Pond and Pickard, 1993). Understanding of such properties is the subject of interest in the geophysical fluid dynamics. ...
- Binod Kumar Nath
-
![Dhanjit Deka]()
Floods are the most common natural hazards that can affect people, infrastructure and natural environment to a great extent. According to an investigation made by World Meteorological Organization (WMO) on the disasters caused by major types of natural hazards all over the world, floods occupy third place after cyclones and earthquakes ferocity by ranking (Pandharinath, et al., 2004). Floods cause large-scale damages to our socio-economic life as well as to the natural environment. Likewise, flood is a perennial problem and all kinds of common flood damages prevail in the study area of Lokrai Mouza, Darrang district of Assam. The study covers a wide range of database generated from both primary and secondary sources.The present study involves the use of survey of India topographical sheet (1967-68), satellite image (IRS-P6 LISS III) and other secondary data were used for the preparation of land use/land cover map and different kinds of analysis. The result shows that the agricultural practises as well as the socio-economic life of many villages in the study area are in highly vulnerable position due to havoc of flood. The study aims to find the frequency of flood, assess the LULC change, cause and impact of flood on public health and socio-economic life. It is expected that the findings of the study will help in proper planning and management for minimizing the damage of the flood in the study area.
... The temperature-salinity (TS) diagrams collected along the full glider tracks (23 January to 23 March 2019) are shown in Figure 14. The water masses sampled by the two instruments, known as the Indian Central Water, were formed and subducted in the Subtropical Convergence area of the southern gyre of the Indian Ocean [107,108]. The OML in this water mass was generally between 50 and 150 m in depth, with temperature between 25 ...
The international research program "ReNovRisk-CYCLONE" (RNR-CYC, 2017–2021) directly involves 20 partners from 5 countries of the south-west Indian-Ocean. It aims at improving the observation and modelling of tropical cyclones in the south-west Indian Ocean, as well as to foster regional cooperation and improve public policies adapted to present and future tropical cyclones risk in this cyclonic basin. This paper describes the structure and main objectives of this ambitious research project, with emphasis on its observing components, which allowed integrating numbers of innovative atmospheric and oceanic observations (sea-turtle borne and seismic data, unmanned airborne system, ocean gliders), as well as combining standard and original methods (radiosoundings and global navigation satellite system (GNSS) atmospheric soundings, seismic and in-situ swell sampling, drone and satellite imaging) to support research on tropical cyclones from the local to the basin-scale.
... Surface currents mainly flow northeastward in the northern Indian Ocean along the coast from Somalia to Oman (Johannessen et al., 1987). As the atmospheric center moves southward after September, the summer monsoon ceases and gradually changes to a northeast wind (Pickard and Emery, 1990). The winter monsoon usually starts in November and lasts until the next March, although its overall wind intensity is weaker than that of the summer monsoon (Webster, 1987). ...
Sixteen years of satellite observations are used to investigate frontogenesis, frontal variability and its impact on chlorophyll in the Arabian Sea. Large frontal probability (FP) and high chlorophyll mainly occur near the coast, e.g., near Somalia and Oman, and their values generally decrease with offshore distance. An empirical orthogonal function (EOF) is used to disentangle the spatial and temporal variability of fronts and chlorophyll. A prominent seasonal cycle of frontal activities is identified for the entire coastal region, peaking in summer when southwesterly winds prevail. The seasonality of chlorophyll is the same as that of wind and fronts near Somalia, which are largely impacted by monsoons. During summer, the southwest monsoon drives offshore Ekman transport and induces coastal upwelling off Somalia. This process transports subsurface cold water and nutrients to the surface layer, which generates fronts and enhances chlorophyll. Frontal activities can be used as an indicator to determine the chlorophyll level, at which high chlorophyll occurs when the FP exceeds 2%. A prominent dependence is also found in anomalous fields, in which strong winds can induce more frontal activities, which further introduces high chlorophyll. The impact of wind on frontogenesis can extend 1000 km offshore, and a simplified linear regression is applied to quantify their relationship. The variability in wind leads that in chlorophyll, with the lags increasing with distance, indicating horizontal offshore transport and advection of coastal water. In winter, the northeast wind is favorable for downwelling; thus, the frontal activities off Somalia are greatly reduced. However, strong wind during this period induces mixing and supplies nutrients off Oman, resulting in high chlorophyll, which extends southwestward along the coast. Thus, the relationship between chlorophyll and fronts was less pronounced, especially off Oman. In the upwelling regions, fronts act as an intermediate process that connects the wind forcing and responses of ecosystems. Frontal activities in the Arabian Sea are fundamentally important to improve our understanding of monsoon-related ocean dynamics and their impact on marine ecosystems.
Globally, reef manta rays (Mobula alfredi) are in decline and are particularly vulnerable to exploitation and disturbance at aggregation sites. Here, passive acoustic telemetry and a suite of advanced oceanographic technologies were used for the first time to investigate the fine-scale (5-min) influence of oceanographic drivers on the visitation patterns of 19 tagged M. alfredi to a feeding aggregation site at Egmont Atoll in the Chagos Archipelago. Boosted regression trees indicate that tag detection probability increased with the intrusion of cold-water bores propagating up the atoll slope through the narrow lagoon inlet during flood tide, potentially transporting zooplankton from the thermocline. Tag detection probability also increased with warmer near-surface temperature close to low tide, with near-surface currents flowing offshore, and with high levels of backscatter (a proxy of zooplankton biomass). These combinations of processes support the proposition that zooplankton carried from the thermocline into the lagoon during the flood may be pumped back out through the narrow inlet during an ebb tide. These conditions provide temporally limited feeding opportunities for M. alfredi, which are tied on the tides. Results also provide some evidence of the presence of Langmuir Circulation, which transports and concentrates zooplankton, and may partly explain why M. alfredi occasionally remained at the feeding location for longer than that two hours. Identification of these correlations provides unique insight into the dynamic synthesis of fine-scale oceanographic processes which are likely to influence the foraging ecology of M. alfredi at Egmont Atoll, and elsewhere throughout their range.
ResearchGate has not been able to resolve any references for this publication.
Source: https://www.researchgate.net/publication/236847160_Descriptive_Physical_Oceanography
0 Comments