Dominant Energy Source Research Articles

How to promote rural household energy transition in energy poverty area? Evidence from the Pumqu River Basin, Tibetan Plateau

Rural household energy transition from biomass energy to modern energy is essential for poverty alleviation and sustainable development. Existing studies have explored the determinants of rural household energy transition, but few of them consider household energy availability for modern energy, which is crucial for rural household energy consumption especially in energy poverty areas such as the Tibetan Plateau. This study establishes an analytical framework for exploring the determinants of rural household energy transition by considering household energy availability and household characteristics. By employing the Tobit model, the empirical analysis of Pumqu River Basin (PRB) of the Tibetan Plateau is conducted. The results show that (1) biomass energy is still the dominant energy source in the PRB, with 99.27% of users and 90.77% of rural household energy consumption. (2) The limited energy accessibility in the PRB plays a significant negative role in accelerating rural household energy transition. (3) Educational level of householder, per capita living space, the number of rural household appliances, and community organizations are the drivers for rural household energy transition, whereas per capita livestock number and per capita grassland areas are the constraints. The findings of this study can help decision makers formulate effective measures to promote rural household energy transition in energy poverty area. The framework introduced can be extended for application to examine the determinants of rural household energy transition in other regions.

The potential of 3D printing in facilitating carbon neutrality

At present, dramatically reduction of fossil fuel usage is regarded as a major initiative to achieve the carbon neutrality goal. Nevertheless, current energy policies are unlikely to achieve the climate goal without sacrificing economic development and people's livelihood because fossil fuels are currently the dominant energy source. As an environment-friendly manufacturing technology, three-dimensional printing (3DP) is flourishing and is considered beneficial to energy structure adjustment and industrial upgrading. Despite this, its potential to contribute to global carbon neutrality has not attracted enough attention. Herein, we explore the application of 3DP and its potential facilitating carbon neutrality from crucial sectors and applications including manufacturing, construction energy, livestock, and carbon capture and storage (CCS) technologies. The additive manufacturing and decentralized manufacturing characteristics of 3DP allow reducing greenhouse gas (GHG) emissions in manufacturing and construction sectors by optimized and lightweight designs, reduced material and energy consumption, and shortened transport processes. In addition, 3DP enables the precise manufacturing of customized complex structures and the expansion of functional materials, which makes 3DP an innovative alternative to the development of novel energy-related devices, cultured meat production technology, and CCS technologies. Despite this, the majority of applications of 3DP are still in an early stage and need further exploration. We call for further research to precisely evaluate the GHG emission reduction potential of 3DP and to make it better involved and deployed to better achieve carbon neutrality.

AN ANALYSIS OF THE SECURITY OF NATURAL GAS SUPPLY IN THE REPUBLIC OF CROATIA

In the global economy today energy certainly has a strategic importance, whereas in terms of energy supply and securing of primary energy sources a special role is played by crude oil and, to an increasing extent since the start of the new century, natural gas. In the past two decades the consumption of natural gas has been significantly rising and natural gas as energy source is gaining, like crude oil, a strategic importance. While oil is still a dominant energy source in the overall global consumption, which is not going to change in some decades to come, it is anticipated that the share of natural gas in the world energy consumption will go up by 2050 from the present 23 % to nearly 45 %. Securing oil and gas supply is hence a primary task of the energy policy of any country. Considering the fact that 70 % of its primary energy needs Croatia meets by using liquid and gaseous fuels, it is extremely important to review the needs, circumstances and situations concerning natural gas supply and to analyze the overall security of natural gas supply as a prerequisite for Croatia’s energy security as a whole.

The Wavelength Dependence of the Propagation of Near-Inertial Internal Waves

Abstract Wind-generated near-inertial internal waves (NIWs) are triggered in the mixed layer and propagate down into the ocean interior. Observational and numerical studies have shown the effects of background vorticity and high shear on propagating NIWs. However, the impacts of the background mean flow on NIWs as a function of the waves’ horizontal wavelength have yet to be fully investigated. Here, two distinct cases are analyzed, namely, the propagation of wind-generated, large-scale NIWs in negative vorticity and the behavior of small-scale NIWs in high shear. The propagation and energetics of the respective NIWs are investigated using a realistic eddy-resolving numerical simulation of the Kuroshio region. The large-scale NIWs display a rapid vertical propagation to depth in negative vorticity areas, while the small-scale NIWs are confined to shallower depths in high-shear regions. Furthermore, the dominant energy sources and sinks of near-inertial energy are estimated as the respective NIWs propagate into the ocean’s interior. The qualitative analysis of NIW energetics reveals that the wind triggers the generation of both the large-scale and small-scale NIWs, but the waves experience further amplification as they draw energy from the background mean flow upon propagation in negative vorticity and high-shear regions, respectively. In addition, the study demonstrates that small-scale NIWs can be induced independently by wind fluctuations and do not necessarily rely on straining nor refraction of large-scale NIWs by mesoscale motions.

Constraining the Carbon Budget of Peat Ecosystems: Application of Stoichiometry and Enthalpy Balances

AbstractWe consider how the stoichiometry and energy content of organic matter reservoirs and fluxes through and from a peatland enable the fluxes and storage of carbon within a peatland to be constrained. We include the elemental composition of the above‐ and below‐ground biomass, litter, the peat profile, and the dissolved and particulate organic matter within a blanket bog in northern England for which the C budget has previously been measured. The study shows, based only on the elemental composition, and calculation of oxidation and energy contents, that: (a) Dissolved organic carbon (DOC) in first‐order streams is significantly more oxidized than in peat pore water but that there was no significant difference in organic carbon oxidation state down the peat profile; (b) The occurrence and speciation of N uptake and release in the peatland with N used and recycled can be predicted; (c) The relatively high oxidation state of DOC in stream water acts as an endpoint for peat‐forming reactions; (d) Methanogenesis does not result in deep peat formation as its requirement for energy consumes too much organic matter to form residual peat at depth; (e) Sulfate reduction does occur during the formation of deep peat; (f) Organic matter elemental composition could be constrained to within three bounding equations though the proportions of carbon species could not be specified. (g) The formation of deep peat in this catchment could only be achieved if the dissolved organic matter (DOM) in the peat pore water is the dominant electron acceptor and energy source in the production of residual organic matter; however, it is unclear as to the flux of DOM up or down the peat profile.

Earth’s gradients as the engine of plate tectonics and earthquakes

The processes occurring on the Earth are controlled by several gradients. The surface of the Planet is featured by complex geological patterns produced by both endogenous and exogenous phenomena. The lack of direct investigations still makes Earth interior poorly understood and prevents complete clarification of the mechanisms ruling geodynamics and tectonics. Nowadays, slab-pull is considered the force with the greatest impact on plate motions, but also ridge-push, trench suction and physico-chemical heterogeneities are thought to play an important role. However, several counterarguments suggest that these mechanisms are insufficient to explain plate tectonics. While large part of the scientific community agreed that either bottom-up or top-down driven mantle convection is the cause of lithospheric displacements, geodetic observations and geodynamic models also support an astronomical contribution to plate motions. Moreover, several evidences indicate that tectonic plates follow a mainstream and how the lithosphere has a roughly westerly drift with respect to the asthenospheric mantle. An even more wide-open debate rises for the occurrence of earthquakes, which should be framed within the different tectonic setting, which affects the spatial and temporal properties of seismicity. In extensional regions, the dominant source of energy is given by gravitational potential, whereas in strike-slip faults and thrusts, earthquakes mainly dissipate elastic potential energy indeed. In the present article, a review is given of the most significant results of the last years in the field of geodynamics and earthquake geology following the common thread of gradients, which ultimately shape our planet.

Techno-Economic Analysis of a Wind-Energy-Based Charging Station for Electric Vehicles in High-Rise Buildings in Malaysia

Renewable energy sources have become necessary for long-term energy sustainability due to the increased demand for electric cars and worrisome rises in carbon dioxide emissions from traditional energy sources. Furthermore, transportation is one of the sectors that uses the most energy on the planet, accounting for 24% of overall consumption. Fossil fuels are still the dominant energy source for balancing global demand/supply dynamics. Supporting laws and regulations have enhanced the first phase of environmentally friendly energy-resource consumption. This has spurred the development of new solutions that cut greenhouse-gas emissions and reduce the air pollution produced by internal combustion engines that are fuelled by fossil fuels. Wind energy is one of the clean energy sources that may be utilised for this purpose. Wind energy has been used to power electric-car-charging infrastructure, generally in a hybrid mode with another renewable source. This research examines the possibility of using wind energy as a standalone energy source to support electric-vehicle-charging infrastructure. Using data from Malacca, Malaysia, and HOMER software, the project will build and optimise a standalone wind-powered charging station. An RC-5K-A wind turbine coupled to a battery and converter is the appropriate choice for the system. The findings demonstrate that the turbine can produce 214,272 kWh per year at the cost of USD 0.081/kWh, confirming wind’s future feasibility as an energy-infrastructure support source.

The BosWash Infrastructure Biome and Energy System Succession

The BosWash corridor is a megalopolis, or large urbanized region composed of interconnected transportation, infrastructure, physiography, and sociopolitical systems. Previous work has not considered the BosWash corridor as an integrated, holistic ecosystem. Building on the emerging field of infrastructure ecology, the region is conceptualized here as an infrastructure biome, and this concept is applied to the region’s energy transition to a post-fossil fueled heating sector, in analogy to ecosystem succession. In this conception, infrastructure systems are analogous to focal species. A case study for an energy succession from an aging natural gas infrastructure to a carbon-free heating sector is presented, in order to demonstrate the utility of the infrastructure biome framework to address climate and energy challenges facing BosWash communities. Natural gas is a dominant energy source that emits carbon dioxide when burned and methane when leaked along the process chain; therefore, a transition to electricity is widely seen as necessary toward reducing greenhouse gas emissions. Utilizing an infrastructure biome framework for energy policy, a regional gas transition plan akin to the Regional Greenhouse Gas Initiative is generated to harmonize natural gas transition within the BosWash infrastructure biome and resolve conflict arising from a siloed approach to infrastructure management at individual city and state levels. This work generates and utilizes the novel infrastructure biome concept to prescribe a regional energy policy for an element of infrastructure that has not previously been explored at the regional scale—natural gas.

Toward a Carbon-Neutral State: A Carbon–Energy–Water Nexus Perspective of China’s Coal Power Industry

Carbon neutrality is one of the most important goals for the Chinese government to mitigate climate change. Coal has long been China’s dominant energy source and accounts for more than 70–80% of its carbon emissions. Reducing the share of coal power supply and increasing carbon capture, utilization, and storage (CCUS) in coal power plants are the two primary efforts to reduce carbon emissions in China. However, even as energy and water consumed in CCUS are offset by reduced energy consumption from green energy transitions, there may be tradeoffs from the carbon–energy–water (CEW) nexus perspective. This paper developed a metric and tool known as the “Assessment Tool for Portfolios of Coal power production under Carbon neutral goals” (ATPCC) to evaluate the tradeoffs in China’s coal power industry from both the CEW nexus and financial profits perspectives. While most CEW nexus frameworks and practical tools focus on the CEW nexus perturbation from either an external factor or one sector from CEW, ATPCC considers the coupling effect from C(Carbon) and E(Energy) in the CEW nexus when integrating two main carbon mitigation policies. ATPCC also provides an essential systematic life cycle CEW nexus assessment tool for China’s coal power industry under carbon-neutral constraints. By applying ATPCC across different Chinese coal industry development portfolios, we illustrated potential strategies to reach a zero-emission electricity industry fueled by coal. When considering the sustainability of China’s coal industry in the future, we further demonstrate that reduced water and energy consumption results from the energy transition are not enough to offset the extra water and energy consumption in the rapid adoption of CCUS efforts. However, we acknowledge that the increased energy and water consumption is not a direct correlation to CCUS application growth nor a direct negative correlation to carbon emissions. The dual effort to implement CCUS and reduce electricity generation from coal needs a thorough understanding and concise strategy. We found that economic loss resulting from coal reduction can be compensated by the carbon market. Carbon trading has the potential to be the dominant profit-making source for China’s coal power industry. Additionally, the financial profits in China’s coal power industry are not negatively correlated to carbon emissions. Balance between the carbon market and the coal industry would lead to more economic revenues. The scenario with the most rapid reduction in coal power production combined with CCUS would be more sustainable from the CEW nexus perspective. However, when economic revenues are considered, the scenario with a moderately paced energy transition and CCUS effort would be more sustainable. Nevertheless, the ATPCC allows one to customize coal production scenarios according to the desired electricity production and emission reduction, thus making it appropriate not only for use in China but also in other coal-powered regions that face high-energy demands and carbon neutrality goals.

Morpho-kinematic Modeling of the Expanding Ejecta of the Extremely Slow Nova V1280 Scorpii

Knowledge of the morphology of nova ejecta is essential for fully understanding the physical processes involved in nova eruptions. We studied the 3D morphology of the expanding ejecta of the extremely slow nova V1280 Sco with a unique light curve. Synthetic line profile spectra were compared to the observed [O iii] λλ4959, 5007 and [N ii] λ5755 emission line profiles in order to find the best-fit morphology, inclination angle, and maximum expansion velocity of the ejected shell. We derive the best-fitting expansion velocity, inclination, and squeeze as km s−1, deg, and using [O iii] line profiles, and km s−1, deg, and using the [N ii] λ5755 line profile. A high inclination angle is consistent with the observational results showing multiple absorption lines originating from clumpy gases, which are produced in dense and slow equatorially focused outflows. Based on additional observational features such as optical flares near the maximum light and dust formation on V1280 Sco, a model of internal shock interaction between slow ejecta and fast wind proposed for the γ-ray emission detected in other novae seems to be applicable to this extremely slow and peculiar nova. Increasing the sample size of novae whose morphology is studied will be helpful in addressing long-standing mysteries in novae such as the dominant energy source to power the optical light at the maximum, optical flares near the maximum, clumpiness of the ejecta, and dust formation.

System approach to natural versus manufactured hydrogen: An interdisciplinary perspective on a new primary energy source

Hydrogen gas (H2) is currently widely investigated in the context of the energy transition as a means of storing energy production in particular from renewable and intermittent sources. However, such manufactured H2 is not a primary energy source but an energy carrier of other primary sources. The idea that natural H2 sources could exist on Earth and represent a potential source of primary energy had long been neglected in absence of empirical evidence. Recent geological surveys in many parts of the world provide increasing evidence that specific geological processes can lead to significant natural H2 generation. The objectives of this study are to synthetize information on natural H2 generation patterns based on geoscience literature and discuss societal implications, from an interdisciplinary perspective, of potential large-scale deployment of natural H2 operations. Based on current knowledge, we suggest that natural H2 presents contrasting features compared to current dominant energy sources, and may potentially contribute to a gradual emergence of energy system decentralization. We discuss differences and common features between natural and manufactured H2 systems and point out technical, social and economic opportunities and challenges. Overall, we argue that natural H2 is an emerging primary energy source with promising opportunities for the energy transition, and may involve a change of paradigm in the interplay between society and energy systems.

Correlation between the Production of Electricity by Offshore Wind Farms and the Demand for Electricity in Polish Conditions

Energy transition forcing a change in the structure of the electricity generation system is a particularly difficult task in countries such as Poland, where the dominant source of energy is fossil fuels. Due to the nature of renewable sources (stochastic and seasonally variable), it is necessary to study their impact on the power system. Much research was conducted on this subject. They consider modelling power systems in terms of dealing with an increasing amount of renewable energy sources, stabilization of electricity generation or environmental aspects. This article examines one of the key sources of future power systems—offshore wind turbines (OWT). The influence of offshore wind sources on the power system in the fields of stability of generation, methods of regulatory strategies, and economics were examined. One of the aspects that are less considered is the correlation of energy production in OWT with energy demand and with generation in other renewable energy sources, especially in the region of the southern Baltic Sea and the distribution of energy demand in countries such as Poland. The key aspect of the research is to fill this gap. The obtained results indicate that the average monthly power generation in OWT is strongly positively correlated with the demand, and the hourly average is positively correlated moderately. Correlation between generation in OWT and photovoltaic sources is very high negative, and between onshore and offshore wind turbines is highly positive. The study indicates that the OWT has a significant potential for the development and replacement of conventional sources, due to the very high capacity and a positive correlation with demand. Moreover, future offshore wind farms can cooperate with photovoltaic sources as these sources complement each other. On the other hand, a significant saturation of the system with offshore and onshore wind sources may pose a threat to the power system due to their positive correlation.

Emission profiles of volatile organic compounds from various geological maturity coal and its clean coal briquetting in China

Coal is a dominant energy source used in household cooking and warming in rural China. Its combustions generate a large quantity of gaseous and particulate phase's pollutants. In between, the volatile organic compounds (VOCs) is a critical class of chemical that shows strong environmental and health impacts. In this study, the VOC emission characteristics, influencing factors and briquette technology that affected the combustions of different maturity coals were investigated. Emission factors (EFs) of targeted non-methane VOCs (EFNMVOCs) for different coal samples ranged from 233 ± 89.8 to 1690 ± 722 mg/kg. The EFNMVOCs decreased with volatile content (VC). Besides, EFNMVOCs for the briquette coals showed 5.31–51.5% lower than that of the raw coals except the anthracite. Alkanes and alkenes are the two most dominated chemical groups, accounting for >50% of the total NMVOCs emissions. Coefficient of divergence (CD) values showed that a significant difference (>0.6) between the emissions of high-volatile and low-volatile raw coals, representing that the coal content should be sub-classified for either source apportionment or emission profile database development. Correlation analysis reported that VC is the most significant factor that correlated with EFNMVOCs (R = 0.78), while modified combustion efficiency (MCE) negatively correlated (R = −0.78). The calculations of ozone formation potentials (OFP) and secondary organic aerosol potentials (SOAP) deducted that alkenes and aromatics are the top two contributors to the formations of these secondary pollutants. In addition, the briquette technology has been proved to reduce both OFP and SOAP from coal combustions. Our results perceptibly support that the use of low VC coals could efficiently reduce the emissions of VOC and the formations of more environmental and health harm substances, and the application of briquetting technology also has a certain effect especially in bituminous coals. The key findings provide feasible solutions to improve regional air quality regarding residential coal combustion in northwest China.

Wave variability along the world’s continental shelves and coasts: Monitoring opportunities from satellite Earth observation

Insight on wave regimes along the world’s coastlines is important for virtually all coastal and nearshore marine activities, installations, planning and protection. Waves are pervasive and the dominant source of energy driving extreme sea levels, the transport of pollutants and sediments, erosion, and a major contributor to risks of flooding. We quantify the global spatio-temporal wave conditions along the world’s coasts and evaluate the needs for coastal Earth Observation strategies, with the aim, notably, that the derived scales of change can contribute to optimisation of these strategies. A global dominant timescale of 30 days is found in coastal wave variability that is, on average, spatially correlated just over the synoptic 5 degrees’ regional scale (≈ 550 km at the equator). This regional-scale dimension suggests that the timing and design of traditional field surveys and observations relevant to a vast array of coastal activities, and which may be expensive in terms of human resources, may be complemented by information gained from satellite Earth Observation that throws light on spatio-temporal scales of wave-energy change along the world’s coastlines.

Assessment of the Electricity System Transition towards High Share of Renewable Energy Sources in South Asian Countries

The progressive use of renewable energy sources to ensure a continuous and abundant energy supply is the significant target towards a sustainable and secure energy system. Previously, the countries that had relied on fossil fuel as a dominating energy source are now endorsing energy system transition towards renewable energy sources. In this study, a comparative assessment of the energy problems of South Asian countries is summarized. Nevertheless, there are many similarities and differences in the electricity supply system of these countries. Long-term planning for renewable energy development is suggested for a diverse population and dispersed geographical location considering all the significant challenges. However, appropriate schemes are imperative for integrating significant renewable energy sources. This study introduces a foresight plan of the electricity model according to the demand and supply balance for extensive technical analysis. The EnergyPLAN modeling tool was employed to work out a more ambitious VRE integration scenario than the official plans. The reference model was validated according to legitimate and authentic data, and then, the technically most feasible renewable energy-based alternate scenario was built. The additional grid integration cost of variable renewable energy was quantitatively investigated for comprehensive power system modeling for a real-time economic analysis. The results may be adapted and support developing more sustainable power generation serving 1787 million in South Asian countries.

Laboratory Performance Evaluation of Novel Bituminous Coal Pellet Combustion in an Automatic Heating Stove

Coal is China’s dominant energy source, among which bituminous coal is the most extensive and plentiful. Using bituminous coal resources to design a low-emission household fuel is very important for rural poverty areas. In this work, a new type of bituminous coal pellet (BCP) fuel using an automatic prototype pellet stove was designed for the first time. This study mainly shows the emission characteristic results of BCPs and some comparisons with other commercial solid fuels. Fuel property, PM2.5 morphology, and ash characteristics of the novel fuel were also assessed. In terms of fuel properties, BCPs had a cold compressive strength of 637.2 N, a heating value of 22.26 MJ/kg, and many fine pores in the cross-section for air entry. The real-time emissions of BCPs were stable during combustion. The emission factors of PM2.5 and CO of BCPs were 1.36–2.29 g/kg and 11.1–18.0 g/kg, which were significantly lower than those of bituminous chunk and bituminous briquette (p < 0.05). PM2.5 and CO reduced emissions by 83–90% and 61–76%, respectively, compared with raw coal chunk. According to the chemical composition and morphological characteristics, the PM2.5 from BCP combustion can be divided into fine particulates, molten char particles, and char fragmentation. The ash from BCPs had a higher melting temperature (over 1300 °C), with removable ash agglomeration. Overall, the results presented in this study highlight that turning bituminous coal into pellets and burning them in automatic stoves could noticeably reduce PM2.5 and CO emissions, effectively improving rural air quality.

A holistic environmental investigation of complementary energy in Alberta

AbstractAs Canada progresses toward its pledge of net-zero carbon emissions by the year 2050, it is worthwhile to thoughtfully examine the current energy landscape and how one might hope to achieve decarbonization within this timeframe. This examination is of particular importance in a fossil fuel producing region such as Alberta. Through an analysis of renewable energy strategies as well as the potential difficulties in this transition, an appropriate strategy may be devised. A combinatorial approach of wind, solar, and geothermal energy sources in the residential, commercial, and industrial spheres may serve as a transition measure, and eventually supplant fossil fuels as the dominant source of energy produced in Alberta with appropriate incentivization. Decarbonization is a pressing need given the imminent climate crisis the world is encountering, and these technologies are capable of serving as a step toward lower carbon emissions and ultimately curbing human-accelerated climate change.

Potential contributions of wind and solar power to China's carbon neutrality

China's goal of being carbon-neutral by 2060 requires a green electric power system dominated by renewable energy. However, the potential of wind and solar alone to power China remains unclear, hindering the holistic layout of the energy development plan. Here, after taking temporal matching of supply and demand (60 min), land use, and government policy into account and assuming lossless transmission, we demonstrate that deploying wind and solar capacity of 2495 and 2674 GW, respectively, within flexible and optimized grids can meet ∼67% of electricity demands by all society sectors for 2050 (∼6.3% curtailment rate), even without other costly power sources or storage. Spatially explicit configurations of the grids are provided simultaneously to support this achievement. The resulting green electricity supply of 10.4 PWh per year help secure China's carbon-neutral goal and reduces 2.08 Mt SO2 and 1.97 Mt NOx emissions annually. Our findings recommend policymakers accelerate exploiting complementary wind and solar power as the dominant source of energy.

Analyzing the future potential of defossilizing industrial specialty glass production with hydrogen by LCA

The glass industry is part of the energy-intensive industry, with most of the energy needed to melt the raw materials. To produce glass, temperatures between 1000 and 1600 °C are necessary. Presently, mostly fossil natural gas is the dominant energy source. As direct electrification is not always possible, in this paper a Life Cycle Assessment (LCA) for specialty glass production is conducted, where the conventional fossil-based reference process is compared to a hydrogen-fired furnace. This hydrogen can be produced on-site in an water electrolyzer, using not only the hydrogen for the combustion but also the produced oxygen. Hydrogen can be produced alternatively off-site in a large scale electrolyzer to facilitate economy of scale. For the transport and distribution of this hydrogen different options are available. A rather new option are liquid organic hydrogen carriers (LOHC), which bind the hydrogen in a chemical substance. However, temperatures around 300 °C are necessary to separate the hydrogen from the LOHC after transport. At the glass trough waste heat is available at the required temperature level to facilitate the dehydrogenation. The comparison is completed by the production of off-site hydrogen transported to the glass trough as conventional liquefied hydrogen in cooling tanks by truck or in hydrogen pipelines.In this assessment, to power the electrolyzers the national grid mix of Germany is used. A time frame from 2020 till 2050 and its changing energy system towards defossilisation is analyzed. Regarding climate change, on-site hydrogen production causes the least impact for specialty glass production in 2050. However, negative trade-offs for other environmental impact categories, e.g. Metal depletion, are recorded.

Generation Mechanisms of Mesoscale Eddies in the Mauritanian Upwelling Region

AbstractThe physical processes driving the genesis of surface- and subsurface-intensified cyclonic and anticyclonic eddies originating from the coastal current system of the Mauritanian upwelling region are investigated using a high-resolution (∼1.5 km) configuration of GFDL’s Modular Ocean Model. Estimating an energy budget for the boundary current reveals a baroclinically unstable state during its intensification phase in boreal summer and which is driving eddy generation within the near-coastal region. The mean poleward coastal flow’s interaction with the sloping topography induces enhanced anticyclonic vorticity, with potential vorticity close to zero generated in the bottom boundary layer. Flow separation at sharp topographic bends intensifies the anticyclonic vorticity, and submesoscale structures of low PV coalesce to form anticyclonic vortices. A combination of offshore Ekman transport and horizontal advection determined the amount of South Atlantic Central Water (SACW) in an anticyclonic eddy. A vortex with a relatively dense and low PV core will form an anticyclonic mode water eddy, which will subduct along isopycnals while propagating offshore and hence be shielded from surface buoyancy forcing. Less contribution of dense SACW promotes the generation of surface anticyclonic eddies as the core is composed of a lighter water mass, which causes the eddy to stay closer to the surface and hence be exposed to surface buoyancy forcing. Simulated cyclonic eddies are formed between the rotational flow of an offshore anticyclonic vortex and a poleward flowing boundary current, with eddy potential energy being the dominant source of eddy kinetic energy. All three types of eddies play a key role in the exchange between the Mauritanian coastal currents system and the adjacent eastern boundary shadow zone region.