bluuebunny/crossref_metadata_2025 huggingface dataset:
Intercomparison and sensitivity assessment of lake primary production models for remote sensing
Authors: Wydler Jonas , Werther Mortimer , Minaudo Camille , Damm Alexander , Odermatt Daniel
Published: February 2023

Lakes are highly biodiverse ecosystems and are providing a wide range of ecosystem services to human wellbeing such as drinking water, water for irrigation, access to fisheries and recreational areas. Anthropogenic activities threaten these services both through local impacts on water bodies (e.g. eutrophication) and globally (e.g. climate change). The trophic state and the aquatic carbon cycle are sensitive indicators to evaluate the state and health of lake ecosystems. Monitoring the spatial and temporal dynamics of primary production is therefore a high priority in lake research.Primary production can be assessed in several ways. The most common approach involves the incubation and measurement of labelled carbon isotopes in lake water samples that are exposed to certain light conditions. Alternatively, primary production can be estimated using diel variations in oxygen concentration or fast repetition rate fluorometry. Both approaches are accurate but can hardly be used to cover large spatial heterogeneities. For global assessments, only bio-optical primary production models based on remote sensing data allow a consistent upscaling in a cost-efficient manner.A wide range of bio-optical primary production models exist and have been applied to lakes. Generally, these models describe the availability of light in the water column and the efficiency of the algae particles to absorb photon energy and to use this energy for subsequent carbon assimilation. The main challenges related to such approaches are to accurately the retrieve required information from satellite data and to precisely estimate sensible model parameters. The upcoming hyperspectral mission Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) by NASA will help to improve the accuracy of primary productivity estimates.This contribution aims to improve understanding of sensitivities and validity of available bio-optical primary production models to eventually maximise the benefits of improved information retrievals from PACE. We particularly reviewed state-of-the-art primary production models for remote sensing data of oceans and lakes, provided an overview of relevant model inputs and calculated Sobol sensitivity indices for a range of input parameters and models. Our results facilitate future applications of primary production models to hyperspectral PACE data and will particularly help to identify most sensitive input variables, to improve empirical model parameterizations and to guide the selection of suited models for freshwater systems.
Earth's Magnetic Field Models from Comprehensive Inversion of 9 Years of Swarm, CSES, and CryoSat Data
Authors: Tøffner-Clausen Lars
Published: February 2023

The ESA Swarm DISC (Data, Innovation, and Science Cluster), a consortium of several research institutions, has been established with a goal of deriving science products by combination of data from the three ESA Swarm spacecraft as well as other spacecraft. Here we present the results of the Comprehensive Inversion (CI) magnetic field modelling by the Swarm DISC team at DTU Space and NASA Goddard. The CI chain takes full advantage of the Swarm constellation by doing a comprehensive co-estimation of the magnetic fields from Earth's core, lithosphere, ionosphere, and magnetosphere together with induced fields from Earth's mantle and oceans using single and dual satellite gradient information from Swarm supplemented by scalar data from the Chinese CSES (China Seismo-Electromagnetic Satellite), the platform magnetometers onboard CryoSat-2, as well as data from ground based magnetic observatories.
Internal tides off the Amazon shelf: importance to structure ocean's temperature during two contrasted seasons
Authors: Assene Fernand , Koch-Larrouy Ariane , Dadou Isabelle , Tchilibou Michel , Morvan Guillaume , Chanut Jérôme , Vantrepotte Vincent , Allain Damien , Tran Trung-Kien
Published: February 2023

Tides and internal tides (IT) in the ocean can significantly affect local to regional ocean temperature and even sea surface temperature (SST), via processes such as vertical mixing, vertical advection and transport of water masses. Offshore of the Amazon River, IT have already been detected and studied; however, their impact on temperature, SST and associated processes are not known in this region. In this work, we use high resolution (1/36°) numerical simulations with and without the tides from an ocean circulation model (NEMO) which explicitly resolves the internal tides (IT), to assess how they can affect ocean temperature in the studied area. We distinguish the analysis for two contrasted seasons, from April to June (AMJ) and from August to October (ASO), since the seasonal stratification off the Amazon River modulates the IT’s response and their influence in temperature.  The IT are well reproduced by the model, and are in good agreement with observations, for both their generation and their propagation. The simulation with tides is in better agreement with satellite SST data compared to the simulation without tides. During ASO season, stronger meso-scale currents, deeper and weaker pycnocline are observed in contrast to the AMJ season. Results show that the observed coastal upwelling during ASO season is well reproduced by the model including tides, whereas the no-tide simulation is too warm by +0.3 °C at sea surface. In the subsurface above the thermocline, the tide simulation is cooler by -1.2 °C, and warmer below the thermocline by +1.2 °C compared to the simulation without the tides. The study further highlights that the IT induce vertical mixing on their generation site along the shelf break and on their propagation pathways towards the open ocean. This process explains the cooler temperature at the ocean surface and in the subsurface water above the thermocline and a warming in the deeper layers (below the thermocline). The surface cooling induced in turn an increase of the net heat flux from the atmosphere to the ocean surface, which could induce significant changes in the local and even for the regional tropical Atlantic atmospheric circulation and precipitation. We therefore demonstrate that IT, mainly via vertical diffusivity along their propagation pathways of approximately 700 km offshore, and tides over the continental shelf, play a key role on the temperature structure off the Amazon River mouth, particularly in the coastal cooling enhanced by IT.  
Mid-Pleistocene volcano-tectonic fragmentation of the Turkana-Suguta Megalake
Authors: Junginger Annett , Kuebler Simon , Rosca Carolina , Owen R. Bernhard , Deino Alan , Feibel Craig , Trauth Martin. H. , Vonhof Hubert
Published: February 2023

The East African Rift System (EARS) is a key location for studying Plio-Pleistocene paleoclimate and hominin inhabitance. The region experienced profound reorganization during this interval as a response to volcanism, tectonics and climate change, and arguably detailed spatiotemporally coherent climate datasets could provide evidence of causal links between geologic change and hominin evolution.  However, continued tectonism, erosion, burial and volcanism obscures much of this information. Despite its rich fossil record, the Turkana basin in the northern Kenya Rift is no exception. It has been hypothesized that Lake Turkana and paleo-Lake Suguta to its south formed one 530-650 km long mega-lake before 221 ka ago, and was a major barrier for E-W dispersal of hominids and other terrestrial fauna. Here we present new information on basin development based on paleolandscape modeling and 87Sr/86Sr analysis on microfossils of newly discovered paleo-lake sequences in the Suguta Valley, permitting reconstruction of volcano-tectonic processes 900-700 ka ago. Contrary to previous assumptions, results suggest that two to three lakes separated by tectono-volcanic barriers formed instead of one mega-lake. These results have implications for previously formulated hypotheses about mega-lakes preventing W-E migration and exchange and suggest that during the early Middle Pleistocene E-W migrations were possible.
Muon Paleotopometry – Measuring crustal thickness variations with muons?
Authors: Raab Gerald , Gosse John , Hidy Alan
Published: February 2023

Understanding topographic relief evolution and its changes over hundreds of thousands to million-year timescales remains challenging. Recent approaches usually combine numerical modelling of terrestrial cosmogenic nuclide (TCN) exposure ages on strath terraces, exhumation histories based on thermochronology, drainage basin evolution, and basin stratigraphy. However, even when combined, these methods are unable to measure the rate changes with precisions needed to differentiate climate from tectonic drivers over multiple glacial cycles and longer timescales.Muon-paleotopometry is a new approach that may address the methodological gap in determining relief generation. Muon-paleotopometry utilizes the dependence of cosmic ray muon flux on crustal shielding depth. The spatial pattern of concentrations of multiple muon-induced TCN measured along a near-horizontal transect under valleys and peaks relates directly to the history of changes (positive or negative) in crustal thickness. It enables paleotopometry above the sample datum over an isotope-specific monitoring duration. By sampling at depths of hectametres, long-lived TCNs are not sensitive to minor short-term (<105-yr) changes owing to cut and fill terraces or transgressions for instance, but short-lived isotopes may provide constraints on this. The method uses concentration differences among samples, so is not significantly impacted by limitations in knowledge of muon flux and interactions at those depths. Early proof-of-concept investigations at Dalhousie (M. Soukup, Hon. Thesis, 2017) provided encouraging results to allow for the current large-scale relief investigation of the European Alps.
Tectono-magmatic and kinematic evolution of the Africa-Europe plate boundary: from Cadomian subduction to Western Mediterranean tectonics
Authors: Mouthereau Frédéric , Angrand Paul
Published: February 2023

Processes driving orogenic styles and long-term isostatic versus dynamic support of the topography have been largely debated in domains of plate convergence. The tectonic evolution of orogens reflect the interactions between mantle flow driving plates and the inherited rheology and composition of moving plates. Here we show that the tectono-magmatic evolution of the European lithospheric mantle and structure, which inherits past subduction/collision (e.g. Cadomian, Variscan) and rifting events (Tethys/Atlantic), control first-order crust-mantle coupling, plate-mantle coupling, defining Alpine-type orogens. The lack of thermal relaxation needed to maintain rheological contrasts over several hundreds of millions of years requires high mantle heat ﬂux below Central Europe since at least the Permian. A combination of edge-driven convection on craton margins and asthenospheric ﬂow triggered by rift propagation during the Atlantic and Tethys rifting is suggested to be the main source of heat. Timing and rates of exhumation recorded across Western Europe during the Cenozoic convergence reveal an additional control by the architecture of Mesozoic rifted margins that defined a complex array of small continental blocks with European affinity (e.g. S-Iberia, Ebro/Sardinia-Corsica) caught between the East European and West African cratons, and Adria. By 50 Ma the acceleration of orogenic exhumation, from the High Atlas to the Pyrenees, occurred synchronously with the onset of extension and magmatism in the West European Rift. Extension marks the onset of distinct orogenic evolution between Western Europe (Iberia) and the Alps (Adria) in the east, heralding the opening of the Western Mediterranean. While the details of the Cenozoic topographic history of peri-Mediterranean orogens are understood to be controlled by the rheology and architecture of rifted margins combined with changing large-scale kinematic boundary conditions (e.g. Atlas, Betics, Pyrenees, Alps), their post-10 Ma, quaternary to current surface and tectonic evolution appears to illustrate increasing control by magmatism and flow at the asthenosphere-lithosphere boundary.
Climate change impact on water budget and hydrological extremes across Peru
Authors: Fernandez-Palomino Carlos Antonio , Hattermann Fred F. , Krysanova Valentina , Vega-Jácome Fiorella , Lavado Waldo , Bronstert Axel
Published: February 2023

Peru is already facing a number of challenges related to climate change, including retreating glaciers and more severe droughts and floods. Therefore, a countrywide analysis of current and future hydroclimatic conditions is crucial to formulate adaptation strategies in water resource development. This study aims to evaluate the effects of climate change on the distribution of water budget components and streamflow variability across Peru. For that, we bias-adjusted and statistically downscaled CMIP6 climate projections of 10 climate models under two Shared Socioeconomic Pathways (SSP1-2.6 and SSP5-8.5) to obtain a range of possible future regional climatic conditions. These selected scenarios span a range of possible future options from the sustainable pathway (SSP1-2.6, with 2.6 W/m2 by the year 2100) to fossil-fueled development (SSP5-8.5, with 8.5 W/m2 by the year 2100). The adjusted climate data were fed into the hydrological model, Soil and Water Assessment Tool (SWAT), to simulate and analyze future hydroclimatic conditions. SWAT was calibrated and validated at 72 discharge stations against mean, high and low water flows. Climate projections suggest a warmer climate and diverging changes in precipitation, with a drier response over the lowlands of the Upper Amazon related to a substantial reduction in precipitation during June-November and a wetter response over the tropical Andes due to precipitation increases during September-March. Projected changes in hydrological conditions show lower water availability over lowlands and higher water availability along the Andean basins in the future. The projections for hydrological extremes indicate that Peru might face excessive water exposure during floods along the Andean catchments and water scarcity during droughts over the Amazon lowlands in the future, particularly under the fossil-fueled development (SSP5-8.5) scenario. The results of this study provide information to planners and decision-makers for formulating adaptation strategies for sustainable water management under climate change in Peru.
Keywords: water resources, climate change, CMIP6, hydrological extremes, Peru, Andes, Amazon
Dairy sector greenhouse gas and ammonia emissions estimates based on seasonal measurements from 200 farms in California
Authors: Li Nathan , Moore Daniel , Yi Hongming , Tao Lei , McSpiritt James , Wendt Lars , Sevostianov Vladislav , Robles Nidia Rojas , Hopkins Francesca , Zondlo Mark
Published: February 2023

We report facility-scale emissions measurements of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ammonia (NH3) from over 200 farms in California, representing 2.4% of the total dairy cow population of the United States. The dairy industry—and its 270 million cattle—are responsible for a significant proportion of global greenhouse gas and reactive nitrogen emissions. Open-path laser spectrometers mounted on top of an electric vehicle were used to conduct measurements downwind of facilities. Emission rates and associated uncertainties for each facility were quantified using in-plume observations and an inverse Gaussian plume atmospheric dispersion model with Bayesian inference. A subset of 53 farms were revisited quarterly to investigate seasonal variability and changes in management practices. 24 farms were sampled multiple times a week on different days for select seasons in order to capture inter-day variability. We partnered with 6 farms for intensive 24-hour measurements to study diurnal variability in emissions. 
Measurements of emissions were compared with national and state emissions inventories, and they were also evaluated against bottom-up estimates using activity data from the Vista-CA database. The median of the top-down CH4 emissions agreed with the median of facility-level bottom-up emissions to within 8%. Measured N2O emissions were 2.5 times higher than current inventories. N2O was responsible for about 15% of total greenhouse gas emissions in terms of CO2-equivalents (CO2e). NH3 was 40% lower than the values indicated by the 2017 US EPA national emissions inventory (NEI). 
For N2O, we found that emissions were dominated by large emission events (≈30 kg N2O hr-1) with high spatial and temporal variability. These events are potentially not captured by shorter measurement campaigns that focus only on a few farms. The top 10% largest N2O emission events were responsible for 58% of total N2O emissions. Focused studies on such events may elucidate potential opportunities for reduction of N2O emissions. 
For CH4, 14 out of the 207 dairies that we sampled had verified anaerobic digestion systems installed for manure management. The effectiveness of these systems for reducing methane emissions will be evaluated by comparing emissions from farms with digesters to emissions from farms without digesters.
Perturbed Roughness Sublayer affecting the law of thewall modeled by a "co-spectral link"
Authors: Bohbot-Raviv Yardena , Katul Gabriel George
Published: February 2023

 Fully developed turbulent flows near walls, regardless of their roughness, are commonly studied based on the law of the wall originally proposed by Prandtl and von Karman in the early part of the 20th century. The derivation of the law of the wall has traditionally been based on theoretical and scaling arguments, under which a balance between dissipation and production (negligible advection terms) of turbulent kinetic energy and a nearly constant shear stress with distance from the wall are assumed in a thin layer of fluid, accommodating about 10% of the boundary layer (i.e., separation of scales). One of the hallmarks of this theory is the von-Karman constant (=0.4) valid across many wall-roughness and boundary layer flow configurations. In many situations, however, the separation of scales required to observe a log-layer is hardly realizable, especially in tall and fully rough canopy flows as in submerged aquatic vegetation and urban centres under certain atmospheric conditions. In recent years, several spectral- and co-spectral -based theories have revealed a "link" between the law of the wall and the energy spectrum of turbulent eddies. This link is exploited here to examine the roughness sublayer of a rough canopy boundary layer. A simplified co- spectral model and data collected from wind tunnel experiments allows to examine the roughness sublayer correction to the law of the wall and test the effect of finite Reynolds number and intermittency on the von-Karman constant, from which the scales dominating the law of the wall in the roughness sublayer are revealed.
Transport and fate of wollastonite weathering products through soil and subsoil under realistic irrigation/rainfall conditions
Authors: Khalidy Reza , Chiang Yi Wai , Santos Rafael M.
Published: February 2023

Deemed an inexpensive and low-energy method for mitigating atmospheric CO2 levels, enhanced rock weathering offers a long-term stable sink of soil carbon by converting alkaline earth metals into stable carbonates. Several silicate-rich minerals (e.g., basalt, olivine, and wollastonite) have been a matter of particular interest of researchers investigating the applicability of this approach for sequestrating atmospheric CO2 in agricultural and urban soils. Several field-scale and laboratory-scale experiments have been conducted in our research group investigating the impact of the wollastonite amendment on the agricultural soil of Ontario. This includes monitoring pedogenic carbonate formation and migration in soil and subsoil systems (through collecting shallow and deep samples down to 1-meter profiles) as well as the effect on various plant growths in soils amended with crushed wollastonite.The water (e.g., rainfall or irrigation water) infiltrating the porous medium of soil could transport and relocate solid particles over the vertical profile of the soil. Accordingly, when crushed silicate minerals (e.g., wollastonite) is applied to topsoil, the recurring introduction of water leads to the dissolution of mineral as well as downward migration of weathering products which could be settled in subsoil layers. Furthermore, the dissolution of wollastonite alters the chemical properties (e.g., pH, EC, etc.) of migrating water, which finally find its way to the water table below the soil medium. In the present study, we have looked into evidence of the vertical distribution of weathering products in soils amended with crushed wollastonite, whose relatively rapid weathering rate helps in the shorter-term to inform what occurs in the longer-term with slower weathering minerals. The experimental setup includes soil columns with and without wollastonite enrichment, located under two situations of lab environment (with regular hand-operated irrigation) and outdoor (with natural rainfall-fed). We also investigated the leachate collected from the bottom of columns in term of physiochemical properties.The current study is part of the analytical and modelling framework we are developing in order to account for newly formed pedogenic carbonate as a qualified implementation for carbon capture credits. Such verified methods would encourage private and governmental entities to contribute to meeting emissions reduction goals and encourage the adoption of enhanced rock weathering as a reliable negative emissions technology.
Improving the satellite retrieval of surface solar irradiance during an eclipse
Authors: Roy Arindam , Hammer Annette , Schroedter-Homscheidt Marion , Lezaca Jorge , Azam Faiza , Lünsdorf Ontje , Heinemann Detlev , Saint-Drenan Yves-Marie
Published: February 2023

Solar eclipse causes high magnitude fluctuations in the Surface Solar Irradiance (SSI) for a short duration and consequently reduces the output of solar PV systems. Grid operators try to estimate the impending loss in PV power generation prior to the occurrence of an eclipse in order to schedule conventional generators for compensating the loss. The worldwide installed capacity of grid connected solar PV systems is expected to steeply rise in the coming decade as a result of the various policy initiatives aimed to tackle the climate change. In future electric supply networks with a high penetration of solar PV systems, such large ramps in generation could impact the stability of the network. Although a solar eclipse is a purely deterministic phenomenon, it’s impact on the satellite retrieval of Surface Solar Irradiance (SSI) is complicated due to the possibility of cloud presence in the regions affected by the eclipse. The extraterrestrial solar irradiance is reduced by the moon during an eclipse. On the one hand this causes clouds to appear darker and they get assigned lower reflectance values than they should have in reality. This leads to predicting higher values for the solar irradiance under these clouds than expected. On the other hand, the eclipse also reduces the clear sky irradiance reaching the earth surface. We developed a method to make corrections for both of these effects on the High Resolution Visible (HRV) channel images from Meteosat-11 The results are validated against ground measurements of irradiance provided by BSRN, IEA-PVPS, DTN and the National Weather Services networks. The validation is performed for sites with locations across Europe and for the last two eclipses.  
Molecular simulation of stripping of crude oil by CO2 in tight reservoirs
Authors: Wang Qian , Shen Jian , Jie Bai , Glover Paul W.J. , Lorinczi Piroska
Published: February 2023

Tight oil reservoirs are often oil-wet and contain surface adsorbed layers of hydrocarbon. Improvement of production lies in part in the ability to produce this adsorbed oil for its own sake and to unblock small pores that can improve the relative permeability of the reservoir. In this paper we have used molecular modelling and simulation first to study the formation of adsorbed oil films made from n-alkanes of 5 different molecular weights (nC7, nC12, nC18, nC22, nC25) on an hydroxylated ->-SiO2 surface, and then to examine the process of stripping oil from these layers using carbon dioxide, nitrogen and water. It was found that all n-alkanes but nC12 formed a monolayer oil film, while nC12 formed a three-layer oil film. Molecular weight, length and flexibility of the n-alkane were all factors in oil film formation. It was found that flooding with CO2 is able to strip all of the modelled n-alkanes from the α-SiO2 surface effectively. The time required to strip the n-alkane was longer for n-alkanes with higher molecular weights. The stripping process was divided into three stages: (i) CO2 diffusion and dissolution, (ii) competitive adsorption, and (iii) oil film push-off. A fourth stage was recognized only for light n-alkanes, and which involved the dissolution of CO2 in mobilized n-alkane, leading to improvements in its mobility. Comparative simulations using nC12 showed that N2 and H2O exhibit no efficacy in stripping n-alkanes from surface adsorbed oil films. The efficacy of CO2 was attributed to (i) it being a polar molecule that is attracted to the hydroxylated silica surface, (ii) its miscibility in n-alkanes, and (iii) that it is in a supercritical state at reservoir conditions. The failure of N2 arises because it is a non-polar molecule with no affinity for the surface and exists as an immiscible gas at reservoir conditions. Water was ineffective, because, though polar, it is immiscible in the oil layer and so cannot access the rock surface. Consequently, CO2-flooding is expected to be particularly effective in improving production from tight oil-wet clastic reservoirs.Key words: tight reservoir; pore throats; CO2 flooding; oil film stripping; molecular simulation
Characteristics of Recent Column-Compound Extremes in the Global Ocean
Authors: Wong Joel , Gruber Nicolas , Münnich Matthias
Published: February 2023

Marine extreme events can be detrimental to organisms and ecosystems across the global ocean. Marine heatwaves (MHW), ocean acidity extremes (OAX) and low oxygen extremes (LOX) occur everywhere, superimposed on the already changing trends of temperature, pH, and oxygen. When such extremes concurrently occur in the vertical column, the habitable space for marine organisms can be severely reduced. We use daily output from a hindcast simulation with the Community Earth System Model coupled with Biological Elemental Cycling (CESM-BEC) for the period 1961-2020 to characterise such compound extremes. Extreme conditions are identified on a moving baseline with the 95th or 5th percentile, and an additional absolute threshold of 150 μM for low oxygen conditions. To investigate compound events in the vertical dimension, at least 50 m out of the top 300 m is required to be extreme with respect to each stressor. Such an event is termed a column-compound extreme event (CCX). On average, 1% of the global ocean volume is occupied by CCXs and up to 5% at maximum. On a fixed baseline these values increase to 8% and 27% respectively. CCXs decrease habitable space by up to 75% and have high intensity index of more than 2 in many regions around the globe. El Niño-Southern Oscillation events are found to be strongly associated with CCXs in the tropical and subtropical Pacific, but also other ocean basins through teleconnections. The global volume of CCXs is expected in increase in the future, exacerbating impacts and reducing habitable space of marine organisms.
On the effect of ocean surface waves on air-sea interactions: results from in-situ and remote measurements in the Gulf of Mexico.
Authors: Ocampo-Torres Francisco J. , Osuna Pedro , Rascle Nicolas G. , García-Nava Héctor , Díaz Méndez Guillermo , Esquivel-Trava Bernardo , Villarreal-Olivarrieta Carlos E. , Mora-Escalante Rodney E.
Published: February 2023

Ocean surface wave full directional spectrum is estimated directly from measurements obtained with a spar buoy and from synthetic aperture radar images of the sea surface. These two techniques complement each other to provide us with a rather comprehensive view of the dynamical behaviour of surface waves. We focus our study in sea state conditions under varying winds, when frequently mixed sea and swell systems are encountered. These conditions are characterized by non-equilibrium wind-wave systems. Direct measurements of ocean-atmosphere momentum fluxes obtained from dedicated air-sea interaction spar buoy are also analyzed. The aim is to better understand the ocean-atmosphere momentum transfer behaviour and uppermost ocean currents under rapidly varying wind field. Atmospheric cold front passage through the measuring buoy imposed a unique wind-wave system information, especially under the occurrence of cases when swell propagation opposes locally generated wind-waves. Of particular importance is the analysis of the wave field making use of synthetic aperture radar images of the sea surface. The wave and wind fields to both sides of the atmospheric front are analyzed. From the buoy measurements fetch-limited wind sea growth is also determined, where slanting fetch is to be considered as very relevant. In particular, wind acceleration effect on wave growth is addressed, during specific cases when wind direction prevailed relatively constant. Wind-wave growth rate is somewhat greater than stationary conditions, as it can be observed also in some laboratory experiments at least for the early stages of the growth process. 
Hydro-environmental Modelling of the Impacts of Turbine Layout and Design Considerations of Tidal Range Schemes
Authors: Leech Catherine , Ahmadian Reza
Published: February 2023

IntroductionModelling potential sites for tidal range energy across the world Neill et al, (2018) estimate a theoretical annual output of 25,880 TWh across 11 countries. The predictability, availability and sustainability of tidal range energy makes it an ideal alternative to fossil fuels for producing baseload power whilst boosting the marine energy industry. Despite the presence of this plentiful resource across many countries, the development of Tidal Range Structures (TRSs) has so far been limited to a handful of locations globally due to technical, financial and environmental concerns. The environmental impacts of TRSs must be addressed in order for this technology to be actualised.MethodWhilst most research into TRSs deploys numerical modelling, this research adds to the body of knowledge using physical modelling to investigate the hydro-environmental impacts of varying TRS designs. A 1:5000 scale model was built in the Hydro-environmental Research Centre at Cardiff University to test the effects of varying turbine spacing in TRS seawalls as well as comparing the impact of different shaped TRSs with the same area. Acoustic Doppler Current Profilers were used to record velocity, whilst water level data was obtained using pressure cells and fluorescent dye was injected into the TRS and filmed in order to visualise flow.ResultsResults showed that velocity patterns are most influenced by turbine spacing and that tight spacing leads to the greatest impact on baseline conditions due to concentrated wake effects. Wider spacing promotes slower circulation which would enable other activities to take place within TRSs but may lead to issues with water quality if flows are too slow to facilitate effective flushing. Both square and rectangular TRS designs showed similar results within the TRS but a rectangular TRS leads to greater blockage effects outside. This emphasises the need for site specific design to take coastal conditions into account. Overall, turbine spacing has a greater impact on flow conditions than the number of turbines, and central placement with wider spacing was found to be best for maintaining natural conditions.AcknowledgmentsThis research is funded as part of the Water Informatics Science and Engineering Centre for Doctoral Training under a grant from the Engineering and Physical Sciences Research Council, grant number EP/L016214/1.ReferencesNeill, et al. (2018) Tidal range energy resource and optimization – Past perspectives and future challenges. Renewable Energy, 127, 763-778.
The rheology of magma feeding the February-September 2021 lava fountains at Etna volcano (Italy)
Authors: Cáceres Francisco , Taddeucci Jacopo , Colombier Mathieu , Terán Javiera , Flores Joaquin , Hess Kai-Uwe , Vossen Caron E.J. , Dingwell Donald B.
Published: February 2023

All magmas form crystals upon cooling and volatile loss, following shifts in the melt liquidus during both decompressive ascent and eruption. Crystallisation modifies the melt chemistry and adds solid particles (crystals) in suspension in a magma. Both changes increase the bulk viscosity of the magma, potentially affecting the final eruptive style. Hence, it is crucial to understand the complete evolution of viscosity in a magmatic system in order to properly constrain its role in the evolution of a magma from depth to surface.Here we measured the viscosity of magma feeding five events of lava fountaining at Etna volcano, Italy, during a period of seven months in 2021. All measurements were performed using remelted lapilli samples of trachybasalt composition (47-48 wt.% SiO2, 5.37-5.78 wt.% Na2O+K2O), originally collected during or immediately after each explosive event. Rheology analyses were performed at superliquidus conditions between 1198-1490°C in a concentric cylinder rheometer. The results show low viscosity variations - up to 0.14 log units at 1198°C - in time among the explosive events. These results are consistent with calorimetric analyses performed in both the remelted and natural samples. Additionally, pre-eruptive crystal contents vary between 21-53% of mainly clinopyroxene, plagioclase, olivine and orthopyroxene, as well as some oxide minerals, while interstitial melt compositions show an enrichment of up to 7 wt.% in SiO2 and more than 2 wt.% in Na2O+K2O after microlite crystallisation, which affects the magma bulk viscosity. Further analyses will help constrain such evolution of magma bulk viscosity. These results help to better constrain the minimum viscosity for the pre-eruptive magmas, as well as the shifts in bulk viscosity that the magmas experienced during ascent and eruption before quenching in air, potentially affecting the eruptive behaviour.
Chronic exposure to non-eruptive volcanic activity as cause of pulmonary oxidativestress and apoptosis in mice
Authors: Camarinho Ricardo , Linhares Diana , Garcia Patrícia , Rodrigues Armindo
Published: February 2023

Volcanogenic air pollution studies and their effects on the respiratory system are still outnumbered by studies regarding the effects of anthropogenic air pollution, representing an unknown risk to human population inhabiting volcanic areas worldwide (either eruptive or non-eruptive areas).This study was carried out in the Azorean archipelago of Portugal, in areas with active non-eruptive volcanism. The hydrothermal emissions within the volcanic complex of Furnas (São Miguel Island) are responsible for the emission of nearly 1000 tons of CO2 per day, along with H2S, the radioactive gas –radon, among others. Besides the gaseous emissions, metals (e.g., Hg, Cd, Al, Ni) and particulate matter are also released into the environment. We test the hypothesis whether chronic exposure to hydrothermal emissions causes pulmonary oxidative stress, using Mus musculus as a surrogate species. M. musculus were live-captured in: two villages with hydrothermal emissions and one village without any type of volcanic activity. Immunohistochemical evaluations were performed to access the level of pulmonary oxidative stress using an OxyIHCTM Oxidative stress detection kit, and the detection of terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) was used to evaluate apoptosis in lung tissues. Mice chronically exposed to hydrothermal emissions presented increased levels of oxidative stress and amount of apoptotic cells. We demonstrate, for the first time, the high oxidative stress potential in the lungs of mice chronically exposed to hydrothermal emissions. This study also highlights the Mus musculus as a useful bioindicator for future biomonitoring programs in these types of volcanic environments.
Competition between source and loss processes of radiation belt seed, source, and relativistic electrons induced by a magnetic cloud event
Authors: Zou Zhengyang , Zuo Pingbing , Ni Binbin , Zhou Wentao , Wei Jiayun
Published: February 2023

We study the competition between source and loss processes of radiation belt source (~10 keV), seed (~100 keV), and relativistic (> 1 MeV) electrons during a typical magnetic cloud event on 19-10 July 2016 that triggered a moderate geomagnetic storm. Across the interplanetary (IP) shock, the relativistic electrons experienced a “one-kick” energization at lower L-shells while having a moderate dropout at higher L-shells. The dropout continued enhancing during the storm main phase. However, the seed electrons had a light decrease after the shock and increased to a little more than the pre-event level in the main phase, while source electrons continued increasing during the whole event time. Further analysis demonstrates that the loss processes (e.g., magnetopause shadowing connected with ULF-induce outward transport) were competing with the source processes (e.g., shock-induced energization for relativistic electron, substorm ejections as well as accelerations via wave-particle interactions), which are strongly sensitive to electron energy and L-shells. By quantitatively comparing the PSD change in (Energy vs. L*) space during different stages of the storm, we find that L*= ~ 4 and Ek = 102 – 102.5 keV could be typical values that the source and the loss processes arrived in the dynamic equilibrium. By tracing the temporal evolutions of source, seed, and relativistic electrons in response to a magnetic cloud event, the present study gives quantitative and comprehensive insight into the competition between source and loss mechanisms for radiation belt electrons, which would be valuable to further investigations in magnetic cloud-radiation belt coupling.
Bacterial and fungal communities along temperature and aridity gradients are linked with soil functions across global biomes
Authors: Donhauser Jonathan , Jordaan Karen , Han Xingguo , Doménech Pascual Anna , Casas-Ruiz Joan Pere , Romaní Anna M. , Frossard Aline , Ramond Jean-Baptiste , Priemé Anders
Published: February 2023

Changes in temperature and water availability under global warming will alter soil bacterial and fungal community structures and thus ecosystem functioning across the globe. We sampled large-scale temperature and aridity gradients across Greenland, Europe, Spain, the Swiss Alps and South Africa to understand microbial long-term adaptation to climatic conditions in soils and to predict microbial responses to climate change. We found that bacterial communities from South African soils were distinct from those in European and Greenlandic soils, largely explained by high relative abundances of Firmicutes. Conversely, fungal communities additionally differed between European and Greenlandic soils and thus seem to be more affected by oceans acting as geographical barrier compared to bacteria. Interestingly, bacterial communities in hyperarid soils from Northern Greenland clustered with hyperarid soils from Southern Spain and South Africa indicating that these communities share taxa adapted to low water availability despite their distinct geographical origin and temperature regimes. Within regional gradients in Europe and Greenland microbial community structures sequentially shifted along the gradients of temperature and aridity, whereas in the South African gradient soil physicochemical properties such as pH and texture that were not related with aridity were important drivers of microbial community structures. Shifts in fungal and bacterial community structures along climatic gradients occurred in parallel with changes in microbial functions, such as extracellular enzyme activities, greenhouse gas fluxes as well as abundances of functional genes involved in soil carbon and nitrogen cycling. Collectively, our results suggest that alterations in microbial community structures along climatic gradients, which serve as a proxy for climate change over time, translate into an alteration in ecosystem services provided by the community members. Moreover, at the global scale our study indicates that bacterial communities are mainly controlled by environmental conditions whereas fungal communities are more influenced by geographic barriers.
Cosmic Ray Soil Moisture Sensors as an Asset to Space Weather Monitoring Activities
Authors: Baird Fraser , Ryden Keith
Published: February 2023

Cosmic Ray Sensors (CRS) are used worldwide to measure soil moisture at intermediate scales, exploiting the neutrons produced in the air showers created by cosmic ray particles interacting with the atmosphere. Neutron Monitors also exploit these atmospheric neutrons, but they are shielded from local soil moisture variations so that information about the cosmic ray flux near Earth can be deduced from their observations. Neutron monitors remain the state of the art for observing variations in high-energy cosmic rays and are critically important to understanding ground-level enhancements of atmospheric radiation caused by high energy solar energetic particles.This contribution explores how the UK CRS network (COSMOS-UK) can complement the neutron monitor network in monitoring these ground-level enhancements, as well as other space weather-driven variations in the ground-level neutron flux. Observations of such variations using COSMOS-UK are presented and discussed, and the sensitivity of COSMOS-UK to ground-level enhancements is also shown. Finally, the prospects and challenges of improving the space weather utility of CRS networks are discussed.
Co-Creating Digital Twins for Planning of Water Resources and Housing Development
Authors: Rico Carranza Eduardo , Mijic Ana , Whyte Jennifer
Published: February 2023

The potential to deliver better, more efficient and sustainable cities has motivated recent research on Digital Twins (DTs) that seek to support planning decisions by displaying analytical evidence to inform collaborative design actions. Prior research identifies different types of DT tools and gives recommendations for their use, but it has not been grounded in engaged research that co-designs DTs with planning users from the context description and problem formulation stage. We report on a research project to co-create DTs with local government planners to visualize interactions between water resources and housing development. We describe co-creating two different DTs starting from the context and problem for water management and assess the steps against these three categories. While engaging with the field we built on prior studies to identify a set of categories relevant to co-creating and assessing DTs: context, governance, spatial and technical definition.  By recording the steps of the DT design process, and contrasting the results with the theoretical proposals, we develop a three-step framework for the co-creation of DTs. This step-by-step framework, illustrated by examples, provides a contribution to the literature on the co-design of DT, and we conclude by discussing implications for practitioners and areas for further research.  
Machine learning-based emulation of land cover effects at sub-hectometric scale using crowd-sourced weather observations
Authors: Covaci Andrei , Vergauwen Thomas , Top Sara , Caluwaerts Steven , De Cruz Lesley
Published: February 2023

Traditional weather stations monitor the weather above short grass, which is a standardized environment. Such an environment is far from representative of where most people live. Moreover, despite advances in urban climate modelling, even state-of-the-art weather forecasts and climate scenarios do not account for the hyperlocal influence of land cover on meteorological variables.To bridge this gap, we have constructed several machine learning models to translate 2-meter temperature measurements from standardized to different rural and urban environments. The input features of these models are the land cover fractions: impervious, green and water around a target station, and the interpolated open-field 2-meter temperature and wind values at the target location. The target feature for these models is the temperature data from the Flemish crowd-sourced VLINDER-network, which consists of calibrated stations positioned in unconventional locations. These models were trained on data from a limited set of VLINDER-stations and evaluated on unseen data of previously used and unused VLINDER-stations. We found that a random forest model yields the best results and had the highest interpretability of how the features interacted with the model. The results of the simple artificial neural networks are not robust, making these models less reliable.We explore the addition of more features related to the urban environment such as building height, sky view factor and variables related to radiation. Finally, we investigate how to prevent possible overfitting due to insufficient variation in the land cover in the training data by including other data sources.
On the properties of greenCu: continental, organized shallow clouds
Authors: Dror Tom , Koren Ilan , Altaratz Orit , Chekroun Michael D. , Silverman Vered
Published: February 2023

Prevalent over the world’s oceans and continents, shallow clouds still comprise a main aspect of the uncertainty related to cloud feedback and climate sensitivity. Compared to shallow clouds over the ocean, confined to specific marine environments, shallow cumulus (Cu) over land occur in diverse locations throughout the globe.

Motivated by an intriguing observation regarding the universality of continental shallow Cu fields regardless of their geographical location, we explore their similarities. We combine satellite observations, along with machine learning classification and numerical modelling to show that these cloud fields share many important properties, such as the patterns they form and their tendency to form over and near forests and vegetated lands, thus termed greenCu.
Moreover, we show that in spite of their occurrence in different climatic regions, from the tropics to mid- and high-latitudes, greenCu fields are associated with similar large-scale meteorological conditions.