bluuebunny/crossref_metadata_2025 huggingface dataset:
Polluted clouds at air pollution hot spots help to better understand anthropogenic impacts on Earth’s climate
Authors: Trofimov Heido , Toll Velle
Published: February 2023

It is unclear to what extent the cooling effect of anthropogenic air pollution particles, known as aerosols, counteract the warming effect of greenhouse gases. In particular, it is uncertain how strong the cooling effect caused by aerosol-induced changes in cloud properties is. Clouds and precipitation can form in the Earth's atmosphere thanks to aerosols. However, cloud thickness, coverage, and lifetime may be perturbed when anthropogenic activities add additional aerosols to clouds, leading to the formation of more numerous, but smaller droplets. We show that it is possible to quantify these perturbations by comparing the properties of polluted clouds at air pollution hotspots with those of nearby unpolluted clouds. There are large-scale polluted cloud areas around the world that are hundreds of kilometres in size, yet surrounded by distinctively less polluted cloud areas. We show that such strong anthropogenic cloud perturbations occur intermittently and only under favourable meteorological conditions. We challenge the assumption of a unidirectional increase in cloud thickness in current climate models and show that, on average, cloud thickness does not increase in response to aerosols. This suggests that the cooling effect of anthropogenic aerosols on Earth's climate may not be as strong as previously thought. Our results will ultimately lead to more reliable climate projections.
Negative Emissions based on Photoelectrochemical Methods: Surface Investigation of Potential Catalysts
Authors: Lörch Daniel , Euchner Holger , Mohamed Aya , Bogdanoff Peter , May Matthias
Published: February 2023

Mitigating climate change is one of the greatest challenges humanity has to face in the next decades. For this purpose, negative emissions – the active removal of large amounts of carbon dioxide from the atmosphere (~10Gt/a) – are indispensable, meaning that highly efficient methods for carbon dioxide removal have to be developed.1In our work we aim to design a photoelectrochemical system that uses solar energy to drive a catalytic process that converts carbon dioxide into long term stable storage products such as oxalate or carbon flakes. Here, we present first results of electrochemical and spectroscopic investigations on two promising catalytic processes for carbon dioxide conversion which are based on metallic cerium and a GaInSn–based liquid metal alloy. The determination of the conversion efficiency allows for an estimation of the area demand of a large-scale deployment of our artificial photosynthesis-based process to meet the carbon dioxide reduction goals.Apart from developing catalytic processes that result in high solar to carbon efficiencies, our work aims to improve the knowledge on the solid/liquid interface between catalyst and electrolyte. This is done by applying a combination of well established electrochemical methods like Cyclic Voltammetry or Chronoamperometry and operando Spectroscopy based on Raman and Reflection Anisotropy Spectroscopy. This is expected to allow for monitoring and controlling changes at the catalytic surfaces, like the formation of potentially catalyst poisoning species such as cerium fluoride. Since surface processes play a crucial role in the carbon dioxide conversion, understanding and controlling them might pave the way for improvements on the conversion efficiency. This would further reduce the area requirements of our system, which in turn would ease the suspected land-use conflict potential caused by climate change mitigation measures.
Integrated analysis of Multifunctional Fruit production landscapes to promote ecosystem services and sustainable land-use under climate change (MultiFruit): Approaches and first results of soil sampling campaign
Authors: Grimm Mark , Sut-Lohmann Magdalena , Raab Thomas , Heinrich Martina
Published: February 2023

Beginning in 2020 the research of the MultiFruit cluster seeks to optimize food production and the provision of ecosystem services in multifunctional landscapes. Joining agricultural production with the provision of ecosystem services and the preservation of biological diversity, the outcomes of this project aim to provide comprehensive findings to farmers, and the agricultural community as a whole, that are also applicable in the face of climate change. Active apple orchards located in greater Brandenburg, Germany of both organic and conventional management practices have been selected as the sites of research. The present state of organic apple orchards in Germany can best be described as organic “conventionalization”; high yielding orchards with little to no plant diversity, with the major differences being the substitution of synthetic fertilizers, pesticides, herbicides, and fungicides with organic alternatives certified by the Federal Office of Consumer Protection and Food Safety (Bundesamt für Verbraucherschutz und Lebensmittelsicherheit). The project implements an interdisciplinary approach, with researchers of ecology, economics, soil and microbial sciences. The ecological subproject is investigating how local management measures and the surrounding landscapes affect natural pest control by beneficial insects. The soil group are investigating the toxicological and soil health impacts of conventional and organic practices through analysis of both plant and soil material collected from the orchards. Microbial studies seek to provide information on the microorganisms that promote the growth, health, and performance of fruit trees. The economic studies aim to assess the costs and benefits of management measures and resulting pest control services for fruit growers and society as a whole. The overall expected outcome of this cluster is to maximize ecosystem services provided by the orchards while optimizing yield and maintaining soil and orchard health.  Here we show the preliminary results of the 2021 field campaign related to the soil group. The processed plant and soil material was analyzed at our laboratory and total elemental concentration of all constituents was determined using Microwave assisted MP-AES for select metals and cations (Zn, Cu, Fe, Al, Mg, Ca, K). These results, in conjunction with measured soil properties (pH, EC, Scheibler carbonate measurement, Total N, Total C) aid in the effort to determine the effects of the various management practices on the soil health and the mobility and translocation of metals and cations within the plant tissues.
In situ chemical composition and density measurements of Earth’s thermosphere, exosphere, and ionosphere with CHESS
Authors: Fausch Rico , Moeller Gregor , Belkhiria Aziz , Kneib Jean-Paul , Wurz Peter
Published: February 2023

The Constellation of High-performance Exosphere Science Satellites (CHESS) mission is a dedicated CubeSat mission designed to analyse the upper atmosphere of Earth in situ. The status of this dynamic region is driven by external and internal forces, causing variations in temperature, the chemical composition, total number density, and their altitude profiles. Although such measurements are key for our understanding of the origin and evolution of the habitable atmosphere of Earth, the community lacks updated, local, detailed measurements. Recent technological advancements in instrumentation enable sensitive in situ measurements of the exosphere–thermosphere–ionosphere region with small satellites. On one hand, the miniaturisation of a high-performance mass spectrometer enables measurements of the chemical composition and density. On the other hand, a new generation of dual-frequency Global Navigation Satellite System (GNSS) receivers enable precise orbit determination. From the knowledge of the evolution of the orbits, the atmospheric drag and hence, the density can be derived complementary. Additionally, the GNSS receivers provide the dispersive line-of-sight total electron content from the linear combination of dual-frequency carrier phase measurements that can be converted into total column density between the spacecraft in low Earth orbit and the satellites of the GNSS in higher orbits. Thanks to the elliptic orbit of the spacecraft, the altitude profiles of these number density measurements of species can be converted into exospheric temperatures. Measuring with a constellation will allow for overcoming the space-time degeneracy to analyse the drivers and mechanisms including basic physics in detail. The CHESS mission is scheduled for launch in early 2026. Once available, the collected data will also be compared with atmospheric escape data on, for example, Venus and Mars to provide insights into the different evolution of these rocky, initially comparable planets.
The International Methane Emissions Observatory (IMEO): Bringing together policy-relevant methane emissions data
Authors: Zavala-Araiza Daniel , Schwietzke Stefan , Calcan Andreea , Irakulis Loitxate Itziar , Randles Cynthia , Demeter Meghan , Guanter Luis , Caltagirone Manfredi , Hamburg Steven P.
Published: February 2023

To fill gaps in knowledge and refine global understanding of the location and magnitude of methane emissions across sectors, integration and use of data from a range of sources is needed. As countries and industry establish ambitious mitigation targets, accurate and measurement-based emission estimates are critical to accelerate emission reductions and assess progress by tracking changes in emissions over time.The International Methane Emissions Observatory (IMEO) was launched in 2021 at the G20 summit and is hosted by the United Nations Environment Program (UNEP). IMEO is providing reliable, public, policy-relevant data to facilitate actions to reduce methane emissions.IMEO is collecting and integrating diverse methane emissions data streams, including satellite remote sensing data, science studies, inventories, and measurement-based industry reporting to establish a global, centralized public record of empirically verified methane emissions.In this work, we will summarize (i) IMEO’s current efforts to integrate spatio-temporally dynamic methane emissions data (ii) details of the Methane Alert and Response System (MARS) -a recently-launched system for satellite-based detection, attribution, and monitoring of methane sources to notify emitters and assist mitigation efforts, (iii) insights from measurement campaigns across the world, and (iv) activities for the direct engagement with relevant stakeholders to accelerate mitigation of methane emissions.
Modelling a complex lowland irrigation channel network to optimize management operation under future scenarios of climate change
Authors: Farina Gabriele , Milanesi Luca , Pilotti Marco
Published: February 2023

Irrigation in northern Italy takes advantage of the Maggiore, Como, Iseo, Idro and Garda pre-alpine lakes, whose management rules and structures allow to stock rain and snowmelt outside the irrigation season and share it among the downstream users during late spring and summer. Consorzio Irrigazioni Cremonesi founded in 1883 (CIC in the following) is the most important irrigation consortia in the province of Cremona (northern Italy) in terms of amount of discharged water for irrigation purposes and manages a channel network that dates back to the 16th century. The maximum discharge derived from the Oglio river and the Adda river by CIC is 57.8 m3/s transported to the different withdrawal points (271) by an open channel network with a length of approximately 261 km. The water distribution provided by CIC is regulated by a complex and rigid timetable of the water turn, which defines the amount of water delivered to each user and the time duration. The intakes of the channel network are provided by the regulation of pre-alpine Lake Iseo and Lake Como, whose level regulation dates back to 1930 and was defined by law considering a set of conflicting constraints as well as the water demand of the irrigated areas. The water distributed by CIC provides a set of ecological services that go beyond simple irrigation.  Although the management of these Lakes is expected to change under the effects of the climate change, on the other hand the management of the irrigation water system is very stiff, being based on pure historical custom and relying on the practical experience of a small group of people. Accordingly, it is likely that this traditional management will become unsuitable in the future and practical experience could be of little use in search of new optimized water distribution frameworks. To manage this transition, CIC is building a mathematical model of the channel network that will be used to test different management options, following the reduction of available discharge caused by different conditions of the lake. The mathematical model, based on the one-dimensional formulation of the Saint-Venant equations, should be able to perform long time simulations for a set of complex interconnected channels in order to capture the different regulations of the gates in correspondence of the withdrawal points along the channel and to take into account the large number of structures which affect the flow along the channel network.
Towards Laser Ranging in Future Gravimetric Missions
Authors: Müller Vitali , Misfeldt Malte , Müller Laura , Weberpals Martin , Voss Kai , Nicklaus Kolja , Heinzel Gerhard
Published: February 2023

The next generation of gravimetric satellite missions will likely  utilize a single laser-based instrument to track distance variations between the satellites in a pair. These variations are used to derive the monthly average of Earth’s gravity field. Mission studies and technology developments are ongoing at NASA/USA, DLR/Germany and at the European Space Agency (ESA) in order to advance the successful technology demonstrator aboard GRACE-FO, the Laser Ranging Instrument (LRI), to a primary instrument with appropriate redundancy. The new instruments should of course incorporate learned lessons from the development as well as in-orbit operation of the instrument on GRACE-FO.The new generation of instruments is expected to have similar noise requirements as in GRACE-FO, since laser ranging observations are usually not limiting the monthly gravity field maps. Design changes in the future LRI are carefully assessed in order to ensure that the actual in-flight precision can reach the same level as in the LRI aboard GRACE-FO, which has shown at high frequencies a noise of 200 pm/√Hz, i.e. is able to resolve changes in the 200 km distance as small as single atoms over short time scales. Efforts focus in particular on an improved knowledge of the LRI scale factor, i.e. the absolute laser frequency, because the current approach of correlating KBR and LRI range can not be employed in future missions.In this presentation we address the LRI technology and some of the trade-offs that have been performed in the design of future instruments in the context of the above studies. Moreover, we discuss the limiting performance aspects for tone errors and noise and summarize the learned lessons and their potential relevance for future missions.
Increasing ENSO variability synchronizes tree growth in subtropical forests
Authors: Su Jiajia , Gou Xiaohua , HilleRisLambers Janneke , Zhang David , Zheng Wuji , Xie Mingmei , Manzanedo Rubén
Published: February 2023

Rising El Niño–Southern Oscillation (ENSO) variability is expected to influence Earth’s forest ecosystems, through changes in how coordinated annual tree growth is across large spatiotemporal scales. However, the mechanisms by which changes in ENSO variability affect tree growth remains poorly understood, especially in understudied subtropical forests. We use a newly built tree ring network collected from 4,028 trees at 144 forest locations across East Asian subtropical forests (EASF) at subcontinental scales (∼2,000 km), to assess long-term influences of ENSO on the spatiotemporal variability in tree radial growth across China. Our results demonstrate a west-east dipole pattern of synchronized tree growth in EASF moisture-limited tree populations, with positive growth responses to El Nino in southeastern China, and negative growth responses in the southwestern China. Specifically, trees grew more in El Niño years in eastern populations, but less in western populations. This pattern likely results from the contrasting effects of ENSO on drought limitation along a longitudinal gradient. Our results also show that increasingly severe El Niño/La Niña years have caused a sharp rise in tree growth coherence over past 150 years in these moisture-limited populations. A further increase in climate variability, as is expected with climate change, could destabilize subtropical forest ecosystems by synchronizing tree growth to an unprecedented level. In all, our results highlight the need for further research on the ecological implications of rising synchrony, given its increasing relevance to global forest ecosystems in a time of rising climate variability.
Polar sea-salt aerosols in CMIP6 models
Authors: Lapere Rémy , Thomas Jennie L. , Marelle Louis , Ekman Annica M. L. , Frey Markus M. , Lund Marianne T. , Makkonen Risto , Ranjithkumar Ananth , Salter Matthew E. , Samset Bjørn H. , Schulz Michael , Sogacheva Larisa , Yang Xin , Zieger Paul
Published: February 2023

We present an inter-comparison of simulated sea-salt aerosols (SSA) in CMIP6 models, including an evaluation against station observations in the Artic and Antarctic regions and satellite data. Drivers of model diversity are investigated. Historical and future trends are also explored and connected to their driving mechanisms. Additionally, the sensitivity of the polar radiative budget to SSA in CMIP6 models is quantified and put in relation to present-day uncertainties and future trends. Comparisons suggest (i) a large inter-model spread in SSA surface concentrations mostly driven by the diversity in source functions, (ii) an important overestimation of SSA surface concentrations compared to measurement stations but reasonable agreement with optical depth from satellite data, (iii) difficulties in properly capturing the annual cycle of SSA at both poles, particularly at higher latitude. A generally increasing trend in SSA concentrations is found in CMIP6 over the last decades and in future scenarios. CMIP6 models show that SSA contribute to cooling the poles significantly, implying possible uncertainties of several W/m2 in the present-day polar radiative budget.
Sediment connectivity and connectivity of proglacial environments: Spatio-temporal pattern of sediment deliver from hillslopes coupling to proglacial margins
Authors: Bayens Mathilde , Lane Stuart
Published: February 2023

In a context of climate change, water yield, sediment supply and transport capacity have been increasing since the early 1980s in Alpine catchments experiencing rapid glacier recession. Over the next few decades the increasing extent of deglaciated terrain will interact with changing magnitude and frequency of sediment mobilizing extreme events (e.g. debris flows).In permafrost-dominated regions rising temperatures are also changing the response of slope stability to extreme precipitation events. It is not only the frequency of the events that is likely to change but also the seasonality as climate warming reduces winter snow accumulation and leads to an earlier onset of snow-free conditions. In the same way, even if the overall frequency of debris flows events remains low, magnitude may increase if larger volumes of sediment are mobilized. There is emerging evidence that these changes can be seen in increasing sediment yield from mountain basins.What is perhaps less frequently considered in periglacial environments especially is the role played by connectivity as an influence upon the ways in which the signals of changing climate propagate through river catchments. Through erosion and deposition, sediment transport leads to modification of the landscape and thus the ease with which sediment can move though the landscape, that is the degree of connectivity. For instance, glacier recession leads to sidewall debuttressing and fall in local base level leading to intense erosional processes on sidewalls (e.g. gully development) which increase potential connectivity from upstream to downstream.Following these processes, the project focus on the relative importance of the sources, sinks and pathways of sediments in the hillslopes that form after deglaciation as compared with other drivers of sediment flux (e.g. rivers) in proglacial margins. This is being achieved by combining passive environmental seismometry to quantify sediment transport events and static and dynamic connectivity analyses to understand where sources are and the role played by connectivity in modifying source-to-sink sediment transfers.
North Atlantic Drift Sediments Constrain Eocene Tidal Dissipation and the Evolution of the Earth-Moon System.
Authors: De Vleeschouwer David , Penman Donald , D'haenens Simon , Wu Fei , Westerhold Thomas , Vahlenkamp Maximilian , Cappelli Carlotta , Agnini Claudia , Kordesch Wendy , King Daniel , van der Ploeg Robin , Pälike Heiko , Kirtland-Turner Sandra , Wilson Paul , Norris Richard D. , Zachos James C. , Bohaty Steven , Hull Pincelli
Published: February 2023

Cyclostratigraphy and astrochronology are leading methods for determining geologic time. While this technique is dependent on the accuracy of astronomical calculations, the chaos of the solar system limits the confidence of these calculations when applied to ancient periods. High-resolution paleoclimate records, such as those found in Middle Eocene drift sediments from the Newfoundland Ridge (Integrated Ocean Drilling Program Sites (IODP) Expedition 342), offer a unique opportunity to reverse this approach. These sediments, with their high sedimentation rates and distinct lithological cycles, provide an ideal setting for this type of study. However, the stratigraphies of IODP Sites U1408-U1410 are complex and contain several hiatuses. We have overcome this challenge by creating a composite of the two sites and constructing a conservative age-depth model. This has allowed us to create a reliable chronology for this high-resolution sedimentary archive. We have used two different techniques to extract astronomical components (g-terms and precession constant) from proxy time-series, which have produced consistent results. Our study has found that astronomical frequencies are up to 4% lower than those reported in astronomical solution La04. These results provide new constraints on the variability of g-term on million-year timescales, as well as evidence that the g4-g3 "grand eccentricity cycle" may have had a 1.2-Myr period around 41 Ma, instead of its current 2.4-Myr periodicity. Our estimates of the precession constant also confirms previous indications of a relatively low rate of tidal dissipation in the Paleogene. The Newfoundland Ridge drift sediments thus offer a reliable means of reconstructing astronomical components, providing a new target for future astronomical calculations.
Coherence-based Amplification of Rayleigh Waves from Urban Anthropogenic Noise recorded with Distributed Acoustic Sensing
Authors: Ehsaninezhad Leila , Wollin Christopher , Schwarz Benjamin , Krawczyk Charlotte
Published: February 2023

At a local scale, e.g. in urban settlements, seismic subsurface characterization requires implementing experiments at high spatial resolution. Distributed acoustic sensing (DAS) provides the opportunity of using pre-existing fiber optic cables as dense receiver arrays, thus potentially reducing the effort for active seismic surveying in urban areas. Due to their small footprint, passive experiments appear particularly appealing. However, extracting coherent signals in an urban environment, i.e. in the presence of anthropogenic activity in the receivers' vicinity, remains a challenge. In this study, we present results from combining the well known technique of Multichannel Analysis of Surface Waves (MASW) with the coherency-based enhancement of wavefields. The investigation is based on a DAS dataset acquired along a major road in Berlin, Germany. We analyse a 4.5 km long straight subsegment of a dark fiber that was sampled at 8 m intervals with 1000 Hz over a period of 15 days. After temporal decimation and the interferometric analysis, clear causal and a-causal branches of Rayleigh-surface waves emerge in the virtual shot gathers. In the further processing, we employ coherence-based enhancement of wavefields to amplify the Signal to Noise Ratio of the virtual shot gathers. Compared to the traditional workflow of ambient-noise tomography the modified one yields improved dispersion curves particularly in the low-frequency part of the signal. This leads to an increased investigation depth along with lower uncertainties in the inversion result. The final velocity model reaches depths down to 300 m. We show that the application of coherence-based enhancement of the virtual shot gathers in the MASW-workflow may significantly relax the necessity of collecting long baselines for passive tomography in urban environments.
Saltwater upwelling quantified by density-driven 3D flow and transport simulations for a study area in Brandenburg, Germany
Authors: Chabab Elena , Kühn Michael , Kempka Thomas
Published: February 2023

Inland salinisation due to the upwelling of highly mineralised deep waters formed by leaching of Upper Permian salt diapirs is a typical phenomenon in the North German Basin. In the German State of Brandenburg, the local absence of the regionally most important aquiclude, the Lower Oligocene Rupelian Clay, separating deep saline waters from the overlying freshwater aquifers, is considered to be the main cause of local salinisation in the freshwater column.The present study uses density-driven 3D flow and transport simulations to assess saltwater upwelling across Quaternary window sediments in the Rupelian for an area in southeastern Brandenburg with detectable salt concentrations in the freshwater column. Previous simulations along a 55 km long transect in Brandenburg using a 2D model have already demonstrated the potential negative impact of groundwater extraction, the use of the deep subsurface as a storage reservoir or lower precipitation rates and decreasing groundwater levels as a consequence of global climate change on the degree of upper aquifer salinisation (Chabab et al., 2022; Tillner et al., 2016; Wetzel et al., 2016).The presented simulation results show that 3D flow strongly affects the temporal and spatial distribution of upper aquifer salinisation due to the varying extent of layers and erosion windows in the Rupelian Clay. The location of groundwater extraction sites, hydraulically conductive faults and spatial variations in groundwater recharge additionally influence the location and degree of shallow aquifer salinisation, and must therefore be carefully considered. Depending on topographic gradients and density variations occurring due to differences in pressure and temperature, convective cells with descending ﬂow and freshwater lenses in the saltwater column also develop locally. We show that 3D flow simulations are essential for site-specific analysis to represent the dynamics of the system with many different hydrogeologic interacting and controlling factors. LiteratureChabab, E., Kühn, M., Kempka, T. (2022): Upwelling mechanisms of deep saline waters via Quaternary erosion windows considering varying hydrogeological boundary conditions. Advances in Geosciences, 58, 47-54.Tillner, E., Wetzel, M., Kempka, T., Kühn, M. (2016): Fault damage zone volume and initial salinity distribution determine intensity of shallow aquifer salinisation in subsurface storage. Hydrology and Earth System Sciences, 20, 1049-1067.Wetzel, M., Kühn, M. (2016): Salinization of Freshwater Aquifers Due to Subsurface Fluid Injection Quantified by Species Transport Simulations. Energy Procedia, 97, 411-418.
Colloids movement at the wetting front during infiltration to sand
Authors: Min Xinying , Brindt Naaran , Jung Sunghwan , Steenhuis Tammo
Published: February 2023

Both preferential flow and colloid-sized particles facilitate groundwater pollution in the vadose zone. Preferential flow in sandy soils that overlays most aquifers is through unstable finger-like features. Studying colloid movement in these preferential flow paths is a crucial step toward better strategies for dealing with this pollution. In this study, we aimed to examine how the wetting front of fingers affects colloid mobilization and movement in dry sands. We postulate that the discontinuous pressure at the finger front results in the wetting front to move one pore at a time, causing high pore velocities with increased interfacial contact angles according to the Hoffman-Jiang equation. In a series of flow cell infiltration experiments, we used a high-speed camera (500 fps) to capture the colloid movement at the wetting front as water infiltrated acid-washed sands (2 mm in diameter). Four hundred and fifty milligrams of the sand particles were packed in a 0.6 x 0.2 x 2 cm channel and flushed with red-colored deionized water at 10 μl/min. Colloids were introduced by applying to the sand hydrophilic blue carboxylated microspheres (10.3 μm) or water-repellent polystyrene microspheres (10.2 μm) at a concentration of spheres/gram of sand before cell packing. Frame-by-frame image analysis was used to determine the position and velocity of the colloid movements, wetting front, and the advancing front contact angle. The results of the different experiments showed that the water velocity in the pore behind the front, based on the colloid velocity, is often quite different from the wetting front velocity and lacks a direct connection to it. In some cases, the wetting front advancement speed was 20 mm/s, four times faster than colloids. In others, the velocity of colloids could achieve around 10 mm/s while the wetting front’s velocity was 2 to 3 times less. The results also show that the changes in contact angle between the wetting front and particle surface are consistent with the Hoffman theory and are close to the value derived from the Hoffman Jiang equation. It confirmed that the change in contact angle during infiltration should be considered when studying water and colloid transport in sands.

 

 
OSCAR: validation of 2D total surface current vector fields during the SEASTARex airborne campaign in Iroise Sea, May 2022.
Authors: McCann David , Martin Adrien , Macedo Karlus , Gommenginger Christine , Marié Louis , Carrasco Alvarez Ruben , Meta Adriano , Martin Iglesias Petronilo , Casal Tania
Published: February 2023

OSCAR (Ocean Surface Current Airborne Radar) is a new airborne instrument which provides unique 2D synoptic views of ocean and atmosphere dynamics (currents, waves, winds) below km-scale. OSCAR is a Ku-band (13.5 GHz) SAR system with Doppler and scatterometry capabilities in three azimuth look directions. The OSCAR instrument features an along-track interferometric (ATI) baseline in two lines-of-sight squinted 45° fore and aft from the broadside direction. The fore and aft antenna pairs provide interferometric Doppler measurements in two views angularly separated by 90 degrees. This ensures two orthogonal measurements of the ocean surface motion velocity that enable the retrieval of the total ocean surface current vector. In addition, backscatter measurements from the broadside antenna in the zero-Doppler direction serve to retrieve wind direction and wind speed, which are critical to correctly measure total ocean surface currents.In each line-of-sight, the ocean surface motion sensed by the microwave radar (after correcting for navigation and geometry) has two constituents: the total ocean surface current – consisting of all currents contributing to actual horizontal transport of water – and a measurement bias associated with the Doppler signature of the surface scatterers responsible for the backscatter, a term known as Doppler wave bias or Wind-wave induced Artefact Surface Velocity — WASV (Martin et al., 2016). The WASV is caused by the phase velocity of the surface scatterers responsible for the microwave backscatter (e.g. Bragg waves) and the effect of the orbital motion of longer ocean waves. The magnitude of the WASV can reach 0.5-1 m/s and is, at first order, a function of the wind direction. A number of geophysical model functions (GMFs) have been published in recent years to correct this effect.In May 2022, OSCAR was flown during the SEASTARex campaign over Iroise Sea (French Brittany). The campaign consisted of three flights on three different days, including acquisitions over a well-instrumented site with ground truth measurements of total ocean surface current fields from a WERA HF radar, supported by data from an X-band marine radar, stereo-video and a down-looking ADCP. Here, we present the first results of the validation of the OSCAR retrieved current fields against data from independent ground truth sensors and models.
Unreported VOC emissions from road transport including from electric vehicles
Authors: Cliff Samuel , Lewis Ally , Shaw Marvin , Lee James , Flynn Michael , Andrews Stephen , Hopkins Jim , Purvis Ruth , Yeoman Amber
Published: February 2023

There are widespread policy assumptions that the phase-out of gasoline and diesel internal combustion engines will over time lead to much reduced emissions of Volatile Organic Compounds (VOCs) from road transport and related fuels. However, the use of real-world emissions measurements from a new mobile air quality monitoring station demonstrated a large underestimation of alcohol-based species in road transport emissions inventories. Scaling of industry sales statistics enabled the discrepancy to be attributed to the use of ancillary solvent products such as screenwash and deicer which are not included in internationally applied vehicle emission methodologies. A fleet average non-fuel non-exhaust VOC emission factor of 58 ± 39 mg veh−1 km−1 was calculated for the missing source, which is greater than the total of all VOCs emitted from vehicle exhausts and their associated evaporative fuel losses. These emissions are independent of the vehicle energy/propulsion system and therefore applicable to all road vehicle types including those with battery-electric powertrains. In contrast to predictions, vehicle VOC emissions may actually increase given a predicted growth in total vehicle kilometers driven in a future electrified fleet and will undergo a complete VOC respeciation due to the source change.
Water-Energy-Food nexus in Algeria; Ain Temouchent case study
Authors: Mostefaoui Leila
Published: February 2023

Given the complexity of the interactions between water, energy, and food, any alteration to one sector can have impacts on the other sectors of the system.(Sušnik et al., 2018).Scientists are increasingly recognizing the need for an integrative approach to planning and managing resources. Hoff explained that several factors have influenced the demand for water, energy, and food, and listed the following; population growth, sustainable development, climate change, degradation, and scarcity of resources.(Hoff & Ulrich, 2017)Algeria is ranked 1st among the Arab countries which have exceeded two-thirds of the way to achieving the SDGs (Dahan et al., 2019.), but according to Hoff (Hoff & Ulrich, 2017), the countries in the MENA region have not made remarkable progress in adopting the nexus approach due to several constraints such as lack of experience and insufficient management planning. ((Hoff & Ulrich, 2017).  As part of establishing the nexus approach in Algeria, we have selected the region of Ain Temouchent as a case study known for its agricultural vocation.Ain Temouchent is located on located in the northwestern of Algeria, 520 km from the capital Algiers, and a hundred kilometers from the border Moroccan. And limited: to the North, by the Mediterranean Sea, to the South West, by Tlemcen, to the South East, Sidi Bel Abbes, and, to the east, by Oran. The region area is about 2,376 km² with a façade sea of 84 km and the population is over 406,000. The agricultural sector represents 15.22%, and the construction sector employs 14.19% of the employed population. The region of Ain-Temouchent is characterized by a Mediterranean climate with a hot summer and a temperate winter. The intensification of agricultural production in this region has led to the overexploitation of groundwater resources, and the establishment of a combined cycle thermal power station has accentuated its path towards a more considerable development, following its satisfaction in electrical energy. The establishment of a reverse osmosis desalination plant (Benisaf Water Company) with a production capacity of 200,000m3/day significantly alleviated the crisis situation, but its energy consumption and environmental impact raise several questionsConsidering all these segments, one of the objectives of the study is to determine the key links between segments of the Nexus and understand the dynamics between them using System Dynamics Modeling. ((Aliyev et al., 2019))This work aims to determine the links between water, food, and energy and to analyze the dynamics between them, also to propose solutions and recommendations for developing effective policies for the region. 
Exploring the water structure on atmospheric particle surfaces
Authors: Ammann Markus , Yang Huanyu , Boucly Anthony , Artiglia Luca , Kiselev Alexei
Published: February 2023

Water is prevalent on all atmospheric particle surfaces, independent of material, phase state or water vapor saturation ratio. Under subsaturated relative humidity conditions, water occurs as reversibly adsorbed layers on solid surfaces or as concentrated aqueous solutions in aqueous particles, exhibiting different composition at the interface than in the bulk. The hydrogen bonding structure at these interfaces is affected by interactions with the substrate on solid surfaces and by ions and ionic or neutral surfactants on aqueous solutions. The water structure and its interplay with hydrated substrate features, hydrated free ions or neutral solutes or surfactant head groups are playing a key role in many chemical and physical processes at these interfaces. We have developed X-ray photoelectron spectroscopy (XPS) and electron yield near edge X-ray absorption fine structure (NEXAFS) spectroscopy to explore the interfacial water structure in situ. We will present examples of the structure of adsorbed water on different Feldspar surfaces, on silver iodide and titanium dioxide. We will also show cases related to the water structure on aqueous solutions containing salts or different surfactant species.
Global perspective of changes in the terrestrial hydrologic cycle using different data products
Authors: Dutta Riya , Markonis Yannis
Published: February 2023

Changes in the terrestrial hydrologic cycle determine the future availability of water around the world, affecting various aspects of society. Accurate estimation of these changes is essential for effective implementation of water management policies. A major source of uncertainty in such estimates is the data products used for analysis. This study provides a global perspective of changes in water availability in terms of Precipitation minus Evapotranspiration (P-E) using three data sources, namely reanalysis (ERA5-Land), hydrological modelling (TerraClimate), and simulations of eight Global Climate Models (GCMs; CMCC-CM2, CNRM-CM6, EC-Earth3P, ECMWF-IFS, HadGEM3-GC31, IPSL-CM6A, MPI-ESM1, and MRI-AGCM3 ). The period of analysis (1960-2014) is divided into two epochs, and the magnitude of change is analyzed by the percent change in the mean and increasing/decreasing trend over the 55-year period. In general, all three data products successfully capture the climatological mean of P-E with comparatively higher values for the equatorial regions. However, when comparing the intensity of changes the results provided by the three data sources differ significantly, especially for regions at higher latitudes. Projections from various GCMs show significant rise in the precipitation for the higher latitudes, which will also affect the extent of P-E and increase the uncertainty over the changes in water availability. It is critical to find reliable data sources for the historical period to increase confidence in future projections and to successfully implement various bias correction techniques wherever necessary. 
Emission potential estimation in landfill by coupled particle filter
Authors: Wang Liang , Heimovaara Timo
Published: February 2023

The emission potential, represented by the total chloride mass in a landfill waste body in this paper, is a key factor in controlling long-term pollutant emissions from landfills. However, the direct measurement of pollutant mass in subsurfaces is usually hard to perform. Traditional model optimization methods use history matching to get the initial emission potential, which gives the best fit for the whole measurement series. However, the estimation at the latest time step is not as reliable as sequential data assimilation, which is a recursively updating method. This study investigates the feasibility of using a weakly coupled particle filtering approach to estimate emission potential. A flow-concentration coupled travel time distribution model is used to simulate the flow transport in the landfill. The weekly coupled particle filter framework assimilates leachate outflow volume and concentration measurements separately to estimate corresponding states in the landfill. The mass states are the product of the evaluated leachate volume and concentration states. Our results show that the uncertainty in chloride mass is quantified with less uncertainty, and the prediction results are also improved. These results indicate that it's promising to use outflow measurement series for emission potential estimation.
Drivers of alleviated PM2.5 and O3 concentrations in China from 2013 to 2020
Authors: Wang Peng , Shao Tian , Zhang Hongliang
Published: February 2023

China is in fronting severe air pollution due to rapid industrialization and urbanization, which significantly threatens public health. Since 2013, the Chinese Government has implemented “Clean Air Action” with consecutive emission control policies to improve air quality. The “Clean Air Action” Phase I (2013-2017) and Phase II (2018-2020) mainly targeted alleviating the fine particulate matter (PM2.5) and ozone (O3) concentrations, respectively. However, it remains unclear how these policies have impacted air quality since most previous studies merely focus on Phase I. In addition, meteorology plays an important role in air pollution formation. It is urgent to conduct a compressive study to evaluate the response of air quality in China to changes in metrology and emissions. In this study, we applied the Community Multiscale Air Quality (CMAQ) model to investigate variations of air quality in China during “Clean Air Action” Phase I and Phase II (from 2013-2020). Results show that PM2.5 is significantly reduced (up to 40%) across China from 2013 to 2020 except in summer when the rising PM2.5 is predicted in Southern China due to the enhanced atmospheric oxidation capacity. On average, the O3 concertation also decreases (-7%) from 2013-2020, but a 3% increase of O3 is found in the Beijing-Tianjin-Hebei (BTH) region. Emission changes play a dominant role in the reduction of PM2.5 (over 95%). For O3, the contributions from meteorology and emissions to O3 reduction are 46% and 54%, respectively. The unfavorable meteorological conditions such as high-temperature even facilitate the co-occurrence of high PM2.5 and O3. Our results suggest that a more effective emission abatement strategy should be formulated, aiming to synergistic control O3 and PM2.5.
Integrated Source to Sink palaeogeological maps at pluri-basins-scale, understandings and predictions
Authors: Lasseur Eric , Ortiz Alexandre , Fillon Charlotte , Briais Justine , Guillocheau Francois , Uzel Jessica , Frasca Gianlucca , barbarand Jocelyn , Loget Nicolas , Castellort Sebastien , Calassou Sylvain
Published: February 2023

The knowledge acquired on the exhumation of the Pyrenean chain and the evolution of the adjacent foreland basins makes this Alpine-type domain a good laboratory to better constrain a full sediment routing system in a compressive context and to apprehend the driving processes controlling the sediment routing in space and time. This integrated approach aims at enhancing our basin mastering approach as well as improving our predictions of reservoir properties.This Source-to-Sink study seeks to understand the evolution of sedimentary routing from the Source (orogenic relief, craton, basin recycling) through the transfer zone (peripheral or internal to the basin) to the final sink (flexural basin, deep turbiditic margin). Within this new cartography, we propose to compile the data over the entire peri-Pyrenean domain. We produced large scale quantitative and qualitative maps to better observe and interpret the tectonic, climatic and surface processes impacts of the SRS behavior.These maps include kinematic reconstructions of the Iberian-European-Mediterranean system, restored sequential cross-sections, history/magnitude of exhumation by thermochronology, source tracking, characterization of weathering and erosion surfaces, synthesis of the major structures activity, paleogeographic reconstructions, analysis of sedimentary geometries and transport directions as well as the quantification of volumes preserved in the basins. Their interpretation is combined with a time representation along the routing system, linking classical basin wheeler diagram representation to source erosion and lithologies to obtain a continuous view on the sediment journey.The time steps chosen for these 5 maps account for the different stages of tectono-sedimentary evolution of the peri-Pyrenean system at the early-, syn- and post-orogenic stages. The compilations carried out compare exhumed domains and sedimentation zones in terms of fluxes and volumes and make it possible to map the routing systems and point out the main drivers for the surface evolution during the construction/destruction cycle of an orogen.Research work financed and carried out as part of the BRGM-TOTAL Source-to-Sink program