bluuebunny/crossref_metadata_2025 huggingface dataset:
New Insights on Solar Wind Electrons at 1 AU: Collisionality, Heat Flux, and Thermal Force
Authors: Salem Chadi , Pulupa Marc , Verscharen Daniel , Yoon Peter
Published: March 2024

The origin and evolution of non-equilibrium characteristics of electron velocity distribution functions (eVDFs) in the solar wind are still not well understood. They are key in understanding heat conduction and energy transport in weakly collisional plasma, as well as in the scenario at the origin of the solar wind. Due to low collision rates in the solar wind, the electron populations develop temperature anisotropies and velocity drifts in the proton frame, as well as suprathermal tails and heat fluxes along the local magnetic field direction. These non-thermal characteristics are highly variable, and the processes that control them remain an open question.  We present here a recent work on enhanced measurements of solar wind eVDFs from Wind at 1AU. This work is based on a sophisticated algorithm that calibrates eVDFs with plasma Quasi Thermal Noise data in order to accurately and systematically characterize the non-thermal properties of the eVDFs, as well as those of their Core, Halo and Strahl components.  Indeed, the core, halo and strahl populations are fitted to determine their densities, temperatures and temperature anisotropies as well as their respective drift velocities with respect of the ion velocity (or solar wind speed).  The density, temperature and temperature anisotropy, as well as the parallel heat flux of the total eVDFs are also computed. We use a 4-year-long dataset composed of all these parameters at solar minimum to enable statistically significant analyses of solar wind electron properties. We estimate collisional proxies such as collisional age and Knudsen number, and discuss usually neglected effects. In addition to the total electron heat flux, we also compute the heat flux contributions from the core, halo and strahl and discuss the interplay between these three components.  We finally show estimates of the so-called Thermal Force, a drag or Coulomb friction between ions and the electron components that arises naturally from the non-thermal character of the eVDFs, even in the absence of current. This TF enhances the parallel electric field and plays an important, but usually neglected, role in two fluid energy transfers between electrons and ions. It is parallel to the heat flux that causes it, however its role in understanding the observed heat flux remains to be explored.  This statistically-significant work allows a local, quantitative measure of Coulomb coupling that maybe important with possibly other microphysical processes to locally control non-thermal properties.
Temporal and Spatial Patterns of Ice Supersaturation: A 3D climatology over the North Atlantic Region
Authors: Brast Nils , Li Yun , Rohs Susanne , Konjari Patrick , Rolf Christian , Krämer Martina , Petzold Andreas , Spichtinger Peter , Reutter Philipp
Published: March 2024

As the most important greenhouse gas in the Earth's atmosphere, the presence of water vapor in the upper troposphere and lower stratosphere (UTLS) is essential for influencing global radiation patterns and surface climate conditions. Even minor changes in water vapor levels within the mostly dry lower stratosphere (LS) can impact the vertical water vapor gradient, making it a crucial factor in the decadal variability of surface temperature.In condensed form, water holds significant importance for planetary radiation. Clouds play a dual role by reflecting incoming solar radiation into space and absorbing/emitting longwave radiation from the surface. Estimating the impact of cirrus clouds on the radiation budget is particularly challenging as it depends on a variety of factors, such as altitude, humidity and the microphysical properties of the cloud.During the lifetime of a cirrus cloud, the radiative impact can even change from a warming to a cooling effect and vice versa. For the formation of cirrus clouds, ice supersaturated regions (ISSRs) play an important role. However, the required amount of supersaturation is dependent on the nucleation mechanism, with at least ∼ 45% supersaturation for homogeneous freezing and as low as ∼ 20% for heterogeneous freezing.We present a statistical intercomparison of the In-service Aircraft for a Global Observing System (IAGOS) dataset with ERA5, the latest reanalysis product of the European Centre for Medium-Range Weather Forecasts (ECMWF). Furthermore, a machine learning based algorithm is developed to improve the accordance of relative humidity with respect to ice (RHi) of reanalysis data with in-situ measurements, enabling large scale analyses of water vapor in the UTLS region. With this tool, we build three-dimensional climatologies of RHi and ISSRs over the North Atlantic region and show their seasonal and regional variability. This will help foster a general understanding of the occurence of cirrus clouds and their impact on weather and climate.
Hydrological, biogeochemical, and ecological linkages at the land-sea margin: Insights from a coastal critical zone network
Authors: Michael Holly , Pratt Dannielle , Chin Yu-Ping , Fagherazzi Sergio , Gedan Keryn , Kirwan Matthew , Seyfferth Angelia , Slater Lee , Stotts Stephanie , Tully Katherine
Published: March 2024

Ghost forests and abandoned farms are stark indicators of ecological change along world coastlines, caused by sea level rise (SLR). These changes adversely affect terrestrial ecosystems and economies, but expanding coastal marshes resulting from SLR also provide crucial ecosystem services such as carbon sequestration and mediate material fluxes to the ocean. A US-NSF Critical Zone Network project was designed to understand the hydrological, ecological, geomorphological, and biogeochemical processes that are altering the functioning of the marsh-upland transition in the coastal critical zone. We have instrumented six sites in the mid-Atlantic region of the US, along the coastlines of the Atlantic Ocean, Delaware Bay, and Chesapeake Bay where marshes are rapidly encroaching into forests and farmland. Field observations, laboratory experiments, and modeling are revealing the drivers and impacts of coastal change, as well as feedbacks among competing processes that accelerate or reduce rates and magnitude of change. We discuss examples of processes and feedbacks and highlight the importance of interdisciplinary exploration and synthesis in advancing process understanding at the land-sea transition.
Harnessing decision timelines to improve understanding and integration of local and scientific knowledges across the Climate Services value chain
Authors: Rastogi Sumiran , Werner Micha , van den Homberg Marc
Published: March 2024

Climate services are increasingly being co-produced through a negotiation process between climate service providers, purveyors, and end users. Their different knowledge systems (scientific and local) determine to a large extent this process. Local knowledge, covers a range of different knowledges, and includes how individuals perceive their surroundings, validate new information such as coming from science-based climate services, and solve problems. As such, local knowledge holders can range from indigenous, rural, or urban communities to professionals working at various levels of governance and various positions across the climate services value chain (e.g., service providers and purveyors).Given the diversity of knowledges and knowledge holders, the actual integration of local knowledge in a climate service is challenging. In this research, we present an approach to collect, understand, and integrate local knowledge for climate services through the utilization of decision timelines. Decision timelines are effective tools for elucidating and understanding the decision-making process, allowing stakeholders to visualise changes and patterns over time (e.g., months, seasons, multiple years, etc). Through visual representation, decision timelines offer an effective way to understand links between different knowledges, stimulate discussions, co-design, and co-evaluate climate services with users. Traditionally such timelines have been limited to agricultural users to introduce the topic of climate information and how it relates to the key decisions that farmers need to make. However, in this research, we expand the scope of these timelines to different sectors (e.g., tourism, urban environment) and also to other actors in the climate services value chain (so not only the end user of a climate service). The timelines are instrumental to understand the decision-making over time and to elicit environmental and socio-economic cues (from local or scientific knowledge). Making timelines for those actors more upstream in the climate services value chain also allows to understand the co-production and knowledge management underpinning the governance process and climate service provision itself. We present examples from the different living labs that have been established in the I-CISK project (an EU research initiative), where these decision timelines have been used as a tool to elicit and understand local knowledge.
Heat Sensitive Epoxy Foam for Permeability Alteration in Fractured Geothermal Fields 
Authors: Or Dani , Parashar Rishi , Yang Ying , Bishwokarma Manish , Karra Satish
Published: March 2024

Geothermal energy plays a growing role in the transition to renewable and carbon free energy sources. A challenge for many geothermal fields is how to enhance water-rock heat exchange either by creation of new fractures, or by blocking short-circuiting large conduits. Here we report a novel approach for blocking large conduits (faults and large fractures) using heat sensitive epoxy resin foam designed to be transported as discrete resin droplets to specific regions that are then activated (foamed and cure) in-situ at targeted temperatures. In contrast with alternative methods for reducing geothermal rock permeability such as silicate gels or heat responsive polymer microbeads targeting small aperture fractures < 0.1 mm, the epoxy foam can reduce the permeability of fractures with apertures up to several millimeters. Results from laboratory 2-D glass fracture model provide insights by visualizing the transport phase and subsequent temperature-sensitive foaming and curing transformations with associated flow pathway blocking. Modeling results for transport and foaming in simple fracture networks considering rheological properties and foaming (volume expansion) behavior will be presented. On going activities of rheological resin characterization; tuning of the foaming-curing to different temperature ranges; and consideration of resin dispersion using small droplets for enhanced transport will be discussed.  
Deglacial temperature estimates from dual clumped-isotope measurements and fluid inclusion noble gas concentrations in a stalagmite from McLean’s Cave, western Sierra Nevada
Authors: de Wet Cameron , Wortham Barbara , Stolper Daniel , Mukhopadhyay Sujoy , Montañez Isabel
Published: March 2024

Clumped-isotope (Δ47) measurements from speleothem calcite have the potential to record formation temperatures with an uncertainty of ± 2°C but are strongly impacted by kinetic effects during mineral precipitation that lead to isotopic disequilibrium and erroneously high-temperature estimates. The application of dual clumped-isotope (Δ47-Δ48) measurements can identify the influence of kinetic effects and has the potential to provide temperature estimates that are corrected for the degree of isotopic disequilibrium, though this involves a decrease in precision (± 4.5°C). The concentration of noble gases in water that is trapped in fluid inclusions in speleothems is another independent estimate of paleo-temperatures that is based on the temperature dependence of noble gas solubility in freshwater systems. We combine these two newly emerging techniques by applying dual-clumped isotope (n = 15) and fluid inclusion noble gas measurements (n = 3) to a speleothem from McLeans Cave, located in the western foothills of the Sierra Nevada, that grew during the last deglaciation (~11 to 19 ka). We obtain temperature estimates using the noble gas measurements as well as using the Δ47 measurements for samples that do not exhibit isotopic disequilibrium in dual clumped-isotope space and compare these estimates with other western US temperature records from proxy records and climate model simulations. Many of the dual clumped-isotope samples, however do exhibit isotopic disequilibrium. We assess the degree to which disequilibrium can be corrected for using dual clumped-isotopes and test the sensitivity of these isotopic relationships to different published corrections to assess the implications for estimates of paleo-temperatures. Additionally, we compare the new dual-clumped isotope data with coeval d18O and d13C measurements, as well we previously collected measurements of d18O and d2H from fluid inclusions in the sample to investigate what processes may be driving the isotopic variability in both speleothem calcite and fluid inclusion water in this sample.
Attribution of hydrological trends and change points in the discharge of Mackenzie River during 1972-202
Authors: Shi John Xiaogang , Xu Jiayi , Yang Daqing
Published: March 2024

Due to the amplification of climate change in the polar regions, the changes in discharge are more pronounced for the Arctic rivers, which are relevant to other hydro-climatic indicators (e.g., precipitation, snowmelt, groundwater, and permafrost) in the river basin. To investigate the recent changes of river discharge in the Mackenzie River Basin (MRB) responding to climate change, this study used the Mann-Kendall trend test and correlation coefficient approach to examine the long-term variability in discharge at three gauges along the watercourses of MRB between 1972 and 2020, focusing on the inter-decadal trends and the occurrence of hydrological extremes. From the 1970s to 2000s, the discharge in the MRB has increased significantly. However, a reverse trend was shown in the 2010s that is more pronounced in winter and spring. Moreover, the analyses in annual discharge have revealed that the extremely low discharge in 1994/1995 is highly associated with the changes in snowfall, while the extremely high discharge events in 2012/13 and 2019/2020 are more influenced by the reduced sea ice extent and peatland burning over the last decades.
In Situ Signatures and Features of Modulational Instability of Ocean Waves
Authors: Babanin Alexander
Published: March 2024

Modulational instability of nonlinear waves in dispersive environments is known across a broad range of physical media, from nonlinear optics to waves in plasmas. Since it was discovered for the surface water waves in the early 60s, it was found responsible for, or able to contribute to the topics of breaking and rogue waves, swell, ice breakup, wave-current interactions and perhaps even spray production. Since the early days, however, the argument continues on whether the modulational instability, which is essentially a one-dimensional phenomenon, is active in directional wave fields (that is whether the realistic directional spectra are narrow enough to maintain such nonlinear behaviours).In the presentation, we will discuss distinct features of the evolution of nonlinear surface gravity waves, which should be attributed as signatures to this instability in oceanic wind-generated wave fields. These include: wave-breaking threshold in terms of average steepness; upshifting of the spectral energy prior to breaking; oscillations of wave asymmetry and skewness; energy loss from the carrier waves in the course of the breaking. We will also discuss the linear/nonlinear superposition of waves which is often considered a counterpart (or competing) mechanism responsible for breaking or rogue waves in the ocean. We argue that both mechanisms are physically possible and the question of in situ abnormal waves is a problem of their relative significance in specific circumstances.
The Canadian SWeeping Energetic Particle Telescope (SWEPT): Steerable Energy and Pitch Angle Resolved Energetic Particle Measurements on the Lunar Gateway
Authors: Fedosejevs Robert , Mann Ian , Tiedje Henry , Ozeke Louis , Gan Kai , Yu Bo , Barona David , Rowlands Neil , Caldwell Dwight , Smith Ken , Amjad Muhammad
Published: March 2024

The Canadian SWeeping Energetic Particle Telescope (SWEPT) targets an assessment of the pitch angle dependence of particular space radiation, and will address and characterize the energy and directional dependence of this space radiation in the lunar environment. The project focuses on an assessment of the fundamental plasma processes which accelerate the particles to create this severe radiation hazard for astronauts in deep space, and assess radiation risk mitigation. By using an innovative sweeping look direction to determine the angular and energy dependence of the radiation on the Lunar Gateway, the SWEPT can assess the temporally evolving solar energetic particle (SEP) radiation in the heliosphere, emitted in solar eruptions and accelerated at interplanetary shocks, as well as address the impacts of primary and secondary radiation hazards on the Lunar Gateway. The SWEPT will also contribute to the development of effective deep space radiation mitigation strategies, such as those based on the early arrival of solar energetic electrons in advanceof SEP protons for humans on the lunar surface or in the lunar vicinity.
Research on Data Mining-Based Precision Flood Control Scheduling Strategy for Reservoirs
Authors: Li Ningning , Tan Chao , Zhao Bikui , Huang Jing , Qin Yehongping
Published: March 2024

The accurate assessment of the relationship between reservoir outflow and downstream floods is often challenging in flood control scheduling of upstream reservoirs aimed at downstream flood protection. In this research, the Fengshuba Reservoir in the Dongjiang River Basin, China, is taken as the subject of study. Utilizing a dataset encompassing 62 years of daily measured flood processes, the MIC coefficient is employed to determine the correlation between the reservoir outflow process at different lag times and the flow at the downstream section. The flood propagation time is determined by identifying the lag time associated with the maximum MIC value. By utilizing the BPANN model, which incorporates the reservoir outflow process and the interval flood process as inputs, an accurate prediction of the downstream flood process is achieved, resulting in a closer approximation to reality in flood estimation at the downstream section. The model has been validated in the district between Fengshuba and Longchuan, exhibiting a certainty coefficient of 97% and a prediction qualification rate of nearly 90%. In comparison with the conventional Maskingen evolution method, the calculated outcomes provide enhanced support for flood control safety, enabling precise hourly control of downstream flood processes and upstream reservoir outflow processes.
The challenges of teaching climate change within the school science curriculum
Authors: Parry Sally
Published: March 2024

The issue of climate change is a critical topic.  In particular, for the current generation of school age children, who need to be fully informed with the facts. However, in the English national secondary curriculum climate change may not follow a coherent path as it is currently spread over various subjects. For example, the evidence for climate change placed in the Science curriculum and the impact in Geography.The argument has been made that the teaching of the causes and impacts of climate change should go beyond a basic understanding of how the climate system works. Within the Science curriculum, climate change is placed into the end of the GCSE Chemistry (ages 14-16) topics within a section on the Earth’s Atmosphere. The allocation of curriculum time within the exam syllabus suggests that no more than three hours teaching time should be used.  Another issue it that as Geography is not compulsory from the age of 14, the impacts are often taught well before the causes and the evidence. With the topic of climate change appearing at the end of the Chemistry GCSE curriculum, the implication is that it should be taught at the end of the course in year 11 (age 16).  A major barrier to the delivery is that in England, 32% of schools have insufficient numbers of Chemistry teachers. This shortage of chemistry teachers means there is a strong possibility that a non-specialist will be teaching climate change. Many schools move the topic into year 9 (age 14) as it perceived as easy to teach and easy for the students to understand. However, in the textbooks for example, where it is placed near the end of the book, the topic brings together concepts such as combustion and hydrocarbons.  These are concepts that the students have not yet been taught at the beginning of their GCSE course and so they may not be able to fully understand the evidence and causes for climate change at that stage.The new Natural History GCSE, which is planned to be offered from 2025, will address some of the issues, but it will be a non-compulsory subject.  It has been suggested that leaving environmental education to non-compulsory subjects and to the final years of secondary education tells the students that it is not important and is not something they need to know.   The other major issue is that schools will only be able to offer it if they have the staff with a background in biology, geography and chemistry.  As there is already a increasing shortage of teachers in these subjects, it would appear unlikely that many schools will be able to introduce it in the near future.
Variability in upper ocean properties around the South Orkney Islands, Antarctica
Authors: Renner Angelika , Menze Sebastian , Jones Elizabeth , Young Emma , Thorpe Sally , Murphy Eugene
Published: March 2024

The South Orkney Islands region is a highly productive environment situated between the Weddell Sea to the south and Scotia Sea to the north. Complex bathymetry around the island plateau strongly influences circulation and water mass exchanges. While the general, large-scale patterns in currents and hydrography are fairly well described, more detailed studies into spatial and temporal variability are mostly lacking, especially for the upper water column. In this study, we present hydrographic and ocean current observations from two surveys across the plateau conducted in January 2016 and 2019. The data confirm the dominant, topographically steered boundary current associated with the Weddell Front, which follows the continental slope around the southern edge of the South Orkney Plateau towards its northeastern side. During this passage, core characteristics of Weddell Sea water masses become eroded through interaction with other water masses. Where the Weddell Front first meets the plateau on its western side, large variability in currents is observed, possibly due to eddy activity and likely promoting mixing and water mass transformation. Differences in water mass characteristics between the two years are likely related to very different climatic conditions in the months prior to the surveys with opposing sea ice states, and large differences in regional winds, and air and sea surface temperatures. On the northwestern South Orkney Plateau, two canyons are particular hotspots for Antarctic krill, and the larger canyon was surveyed with high resolution, repeat transects. These repeated observations show high day-to-day variability in both currents and hydrography, possibly forced by short-term wind variability driving or restricting water exchange between the canyon and the deeper ocean. This suggests that the elevated krill abundance associated with the canyons may be due to several mechanisms, including retention by the local currents, interactions between the currents and krill behaviour, and potentially increased phytoplankton growth due to additional nutrient availability driven by the highly dynamic environment.
Neural Network Driven Early Warning System for Groundwater Flooding: A Comprehensive Approach in Lowland Karst Areas
Authors: Tabbussum Ruhhee , Basu Bidroha , Gill Laurence
Published: March 2024

Enhancing flood prediction is imperative given the profound socio-economic impacts of flooding and the projected increase in its frequency due to the impacts of climate change. In this context, artificial intelligence (AI) models have emerged as valuable tools, offering enhanced accuracy and cost-effective solutions to simulate physical flood processes. This study addresses the development of an early warning system for groundwater flooding in the lowland karst area of south Galway, Ireland, employing neural network models with Bayesian regularization and scaled conjugate gradient training algorithms. The lowland karst area is characterised by several groundwater fed, intermittent lakes, known as turloughs that fill when the underlying karst system becomes surcharged during periods of high rainfall. The training datasets incorporate several years of field data from the study area and outputs from a highly calibrated semi-distributed hydraulic/hydrological model of the karst network. Inputs for training the models include flood volume data from the past 5 days, rainfall data, and tidal amplitude data over the preceding 4 days. Both daily and hourly models were developed to facilitate real-time flood predictions. Results indicate strong performance by both Bayesian and Scaled Conjugate Gradient models in real-time flood forecasting. The Bayesian model shows forecasting capabilities extending up to 45 days into the future, with a Nash-Sutcliffe Efficiency (NSE) of 1.00 up to 7 days ahead and 0.95 for predictions up to 45 days ahead. The Scaled Conjugate Gradient model offers the best performance up to 60 days into the future with NSE of 0.98 up to 20 days ahead and 0.95 for predictions up to 60 days ahead, coupled with the advantage of significantly reduced training time compared to the Bayesian model. Additionally, both models exhibit a Co-efficient of Correlation (r) value of 0.98 up to 60 days ahead. Evaluation measures such as Kling Gupta Efficiency reveal high performance, with values of 0.96 up to 15 days ahead for both Bayesian and Scaled Conjugate Gradient models, and 0.90 up to 45 days ahead in the future. The integration of diverse data sources and consideration of both daily and hourly models enhance the resilience and reliability of such an early warning system. In particular, the Scaled Conjugate Gradient model emerges as a versatile tool. It balances predictive accuracy with reduced computational demands, thereby offering practical insights for real-time flood prediction, and aiding in proactive flood management and response efforts.
Land-Atmosphere Coupling Simulation and Its Role in Subseasonal-to-Seasonal Prediction
Authors: Lim Yuna , Molod Andrea , Koster Randal , Santanello Joseph
Published: March 2024

Land-atmosphere (L-A) coupling can significantly contribute to subseasonal-to-seasonal (S2S) prediction. During periods of strong L-A coupling, land-atmosphere feedbacks are expected to enhance the memory of the system and therefore also the predictability and prediction skill. This study aims to evaluate S2S prediction of ambient surface air temperature under conditions of strong versus weak L-A coupling in forecasts produced with NASA’s state-of-the-art GEOS S2S forecast system. Utilizing three L-A coupling metrics that together capture the connection between the soil and the free atmosphere, enhanced prediction skill for surface air temperature is observed for 3-4 week boreal summer forecasts across the eastern Great Plains when strong L-A coupling is detected at this lead by all three indices. The forecasts with strong L-A coupling in these “hot spot” regions exhibit warm and dry anomalies, signals that are well simulated in the model. Overall, this study provides insight into how better capturing relevant L-A coupling processes might improve prediction on subseasonal-to-seasonal timescales.
Grounding Zone Processes at Thwaites Glacier from ICESat-2 Data and Ice-Ocean Modelling
Authors: Das Indrani , Goldberg Daniel , Scambos Ted
Published: March 2024

It is now well accepted that ice shelves and grounding zones experience changes in elevation synchronous with ocean tides, atmospheric loading and other processes. Recent studies have demonstrated that tidal pumping at the grounding zone can cause a transient migration of the grounding line hundreds of meters upstream relative to the grounded zone at low tide. As the grounded edge shifts inland, ocean intrusion leads to enhanced basal melting and grounding zone retreat, as demonstrated by previous InSAR-based studies on Thwaites Glacier in the Amundsen Sea Embayment. In this work, we use ICESat 2 elevation profile data spanning the Thwaites Glacier grounding zone and demonstrate the uplift of grounding zone topography in high tides with ocean intrusion ranging from ~1–9 km inland. The uplift of surface topography in high tides and our inferred ocean intrusion underneath the ice is heterogenous both in the along-track direction and along the width of the grounding zone. This work using ICESat 2 provides evidence in support of similar InSAR-based observations of the dynamic grounding zone and permits an independent assessment of the scale and volume of ocean water intrusion underneath Thwaites Glacier. 
Optimal network designs of in situ atmospheric CO2 stations over continental France
Authors: D'Angeli Carla , Lauvaux Thomas , Matajira Rueda David , Abdallah Charbel , Bazzi Hassan , Ciais Philippe , Lopez Morgan , Ramonet Michel , Rivier Léonard
Published: March 2024

The global Stocktake, a fundamental component of the Paris Agreement tracking progress on national mitigation actions, collects the Nationally Determined Contributions (NDCs) generated through the means of annual national inventories. Greenhouse gases (GHG) inventories are prone to uncertainties, especially when considering sub-national scales, sub-annual frequencies, or the natural component of GHG budgets, lacking verification and transparency. Atmospheric observations assimilated through the inverse approach can help constrain both the natural and anthropogenic components of national carbon budgets. Here, we aim at quantifying the carbon dioxide (CO2) fluxes over continental France by combining atmospheric greenhouse gas concentrations from the ICOS (Integrated Carbon Observation System) measurement network and a high-resolution inversion system.We present an assessment of the observational constraint from the current ICOS network. We also determine the optimal locations and number of additional stations to monitor CO2 fluxes from human activities and different ecosystems. The CO2 concentration measurements influenced by surface CO2 fluxes are analyzed using a Lagrangian Particle Dispersion (LPDM) model. LPDM is run backward in time with meteorological inputs from the Weather Research Forescating (WRF) model, at 3km resolution over continental France. We infer the origin of the CO2 using the TNO high-resolution fossil fuel inventory and biogenic CO2 fluxes produced by the Vegetation Photosynthesis Respiration Model (VPRM). The VPRM model simulates both the CO2 uptake from photosynthesis and the release from respiration using meteorological re-analysis products and surface remote sensing data.We start by evaluating the improved model performances at high resolution compared to low resolution simulations. Then we analyze the influence of biogenic and fossil fuel sources at each tower of the ICOS network, and finally we explore which areas are constrained by atmospheric stations using different criteria: by ecosystem type, by land cover, and in terms of net carbon fluxes and fossil fuel emissions. We discuss here how our future inversion system could help constrain the regional distribution of CO2 fluxes, sub-annual variations at seasonal and monthly timescales to track current climate change impacts (forest fires, droughts), and the effects of emission mitigation policies.
Remote sensing techniques for habitat condition mapping: deadwood monitoring using airborne laser scanning data
Authors: Walicka Agata , Bladt Jesper , Moeslund Jesper Erenskjold
Published: March 2024

Deadwood is a vital part of the habitat for many threatened species of animals, plants and fungi. Thus, presence of deadwood is an important indicator for the probability that a given site harbors threatened species. Nowadays, field work is the most common method for monitoring dead trees. However, it is time consuming, costly and labor-intensive. Therefore, there is a need for an automatic method for mapping and monitoring deadwood. The combination of fine-resolution remote sensing and deep learning techniques have a potential to provide exactly this. Unfortunately, due to the typical location of lying deadwood under the canopy, this is a challenging task as the visibility of the lying trees is limited notably with optical remote sensing techniques. Therefore, laser scanning data seems to be the most appropriate for this purpose as it can penetrate the canopy to some extent and hence gather data from a forest floor.In this work we aim at the development of methods enabling detection of lying deadwood at the national scale in protected forests and we focus on the presence of deadwood in 15-meter-radius circular plots. To achieve this goal, we use Airborne Laser Scanning (ALS) data that is publicly available for the whole Denmark and, as a reference, almost 6000 forestry plots acquired as a part of the Danish national habitats monitoring program. The binary classification into plots that contain deadwood and the ones that do not is performed using SparseCNN deep neural network. In this study we showed that it is possible to detect plots having deadwood with an overall accuracy of around 61%. However, the accuracy of the classifier depends on the volume of the deadwood present in a plot.  
From the UN Agenda 2030 to the organisation of a mega sustainable event: the case study of Paris 2024 Olympics.
Authors: D'Ercoli Celeste
Published: March 2024

In 2015, with the publication of the UN Agenda, sport has been recognized as instrumental for sustainable development. The Agenda consists of guidelines for the future and is in line with the recommendations of the 2020 Olympic Agenda: in fact, the International Olympic Committee (IOC) believes that sports and the Olympics can help develop the majority of the Agenda goals.The next Olympics will be held in Paris in 2024 and will be the first organized according to the sustainability principles set up by the Agenda. This case is supposed to mark a turning point in the history of the Olympics. However, these objectives remain fairly vague in that they are not defined by concrete criteria.Here we develop a method that starting from the analysis of the Agenda goals provides a series of requirements to discretise and evaluate quantitatively the long-term sustainability of the event. This study investigates, with particular focus on the urban and architectural aspects, the relations between the event and the host city, between people and context and between event and environment. Much importance is given to public infrastructures, the wellbeing of visitors and athletes and the needs of the host city. We study the Olympic venues, assessing how many of them already exist, are temporary, or have been built for the event, as well as which materials were used in the realization [fig.1]. We pay attention to the legacy of the event, which implies planning from the beginning the future of the city after the Games. In fact, the Olympics in Paris are part of a wider process of expansion of the city: the construction of a large infrastructure network, the Grand Paris Express, and the redevelopment of the suburban district of Seine Saint-Denis [fig.2].With this method, we can easily analyse results of studies and field research, like visits to the building site, and evaluate the impact of the event. This study is the beginning of a process that allows us to analyse and compare different Olympic editions within a single coherent framework.
Absence of Winter Warming in Eurasia following large, tropical volcanic eruptions during the Last Millennium
Authors: Tejedor Ernesto , Polvani Lorenzo , Steiger Nathan , Vuille Mathias , Smerdon Jason
Published: March 2024

In this investigation, we reassess the hypothesis that volcanic eruptions lead to surface warming in Eurasia during winter. This reevaluation is grounded in contemporary modeling studies that propose internal climatic variations might dominate over the volcanic-forced responses. Our analysis is centered on the Last Millennium (LM), where we combine model output, instrumental observations, tree-ring records, and ice cores, and build a new temperature reconstruction that specifically targets the boreal winter season. Utilizing the latest advancements in volcanic forcing reconstructions, we pinpoint 20 volcanic events over the LM with volcanic stratospheric sulfur injections (VSSI) exceeding those of the 1991 Pinatubo eruption.Our analysis indicates that among the 20 major volcanic events identified, only seven resulted in warmer surface temperature anomalies in Eurasia during the initial winter following the eruption. In scrutinizing the 13 occurrences that exhibit cold post-eruption anomalies, we observe no direct correlation between the extent of winter cooling and the mass of volcanic stratospheric sulfur injections (VSSI), suggesting that significant internal climatic variability is the probable driver of these cold anomalies.Moreover, we compare our new temperature reconstruction with two independent reconstructions, and successfully harmonize our results with those of prior research. Moving beyond the observational uncertainties and the conflation of eruptions from different latitudes and different post-eruption winters, our study challenges previous assertions of post-eruption winter warming that largely stemmed from the superposed epoch analysis, which involved averaging the effects of smaller eruptions with larger ones. Our comprehensive observational findings, encompassing the entire LM and corroborating many recent climate modeling studies, suggest that substantial low-latitude volcanic eruptions, such as the 1991 Mount Pinatubo eruption, do not lead to any notable surface warming during the winter months in Eurasia.
Assessment of liquefaction susceptibility under complex stratigraphic conditions: the case of Terre del Reno (FE)
Authors: Giallini Silvia , Fortunato Carolina , Sirianni Pietro , Baris Anna , Caciolli Maria Chiara , Fabozzi Stefania , Gaudiosi Iolanda , Mancini Marco , Martelli Luca , Modoni Giuseppe , Moscatelli Massimiliano , Paolella Luca , Simionato Maurizio , Spacagna Rose Line , Stigliano Francesco , Tentori Daniel , Varone Chiara
Published: March 2024

The phenomenon of liquefaction is nowadays sufficiently understood in terms of phenomenology and predisposing conditions. However, a better assessment of liquefaction risk is necessary to mitigate its effects and guide land-use planning choices, particularly in the context of post-earthquake reconstruction.This evidence comes from some recent events (e.g., New Zealand, 2010-2011; Emilia-Romagna 2012; Palu, 2018), in which liquefaction induced effects were, in some instances, considerably more severe than expected. This is the case of Terre del Reno (Emilia-Romagna region, Italy) which experienced significant liquefaction phenomena during the 2012 Emilia-Romagna earthquake sequence, characterized by two main events: Mw 6.1 and 5.9. In this area sand eruptions, settlements, lateral spreading, and ground fractures were observed, resulting in extensive and irregularly distributed damage to structures and infrastructure.This study deals with the evaluation of liquefaction susceptibility and development of liquefaction hazard map in complex stratigraphic condition through an integrated method and multilevel approach. The study area is characterized by complex geologic conditions and abrupt slope changes, typical of riverbank-channel systems.The analysis of liquefaction potential was conducted using simplified semi-empirical methods. The safety factor against this phenomenon was estimated at different depths, relying on  soil properties obtained from penetrometric tests and seismic input. In addition to the calculation of liquefaction potential, the study also addressed the phenomenon of lateral spreading due to liquefaction. To date, the delimitation and representation of area prone to lateral spreading is not yet ruled by guidelines for the mitigation of liquefaction risks. Therefore, this study employed an empirical methodology based on original criteria and procedures to establish the perimeter of such areas.The cross-analysis between the prediction of indicators of liquefaction potential and the evidence of damage found following the May 20, 2012 earthquake (Mw 6.1) showed a clear correlation between slope and damage frequency, suggesting the possibility of applying an empirical method to define the probability of lateral spreading occurrence.
Realisation of primary mixtures of CO2 in air at known isotopic composition
Authors: Rolle Francesca , Durbiano Francesca , Pavarelli Stefano , Pennecchi Francesca Romana , Sega Michela
Published: March 2024

The monitoring of the increasing levels of CO2 in atmosphere, together with the discrimination between the natural and anthropogenic sources of CO2, is of utmost importance to support climate change studies and the reduction of the CO2 emissions from human activities in the close future. The involvement of the metrological community is essential to achieve the comparability of results over space and time, to assure accuracy and metrological traceability, linking all the individual measurement results to common and stable reference standards.The availability of sound and affordable reference materials for the measurement of the isotopic composition of CO2 at ambient amount fraction is foreseen to support the researchers operating in the isotope measurement field, by means of spectroscopic techniques, to assure the metrological traceability for the determination of the isotopic composition of CO2 in air. Reference gas mixtures at known isotopic composition produced by means of primary methods, such as gravimetry, represent a good opportunity for this purpose.At INRiM, the Italian National Metrology Institute, the realization of gaseous reference materials of CO2 in air at known δ13C-CO2 started within the European Joint Research Project (JRP) 16ENV06 SIRS, and continued with the JRP 19ENV05 STELLAR.The reference mixtures are realized by the gravimetric method, following the ISO standard 6142-1, in high-pressure cylinders of aluminum alloy, obtaining low preparation uncertainties of 0.33 % for the CO2 amount fraction at atmospheric level. These mixtures are prepared from parent mixtures at higher amount fraction, realized at INRiM from different pure CO2 sources.Non Dispersive Infrared Spectroscopy (NDIR ABB URAS 14, Switzerland) is used to verify the mixtures for their amount fraction values while Fourier Transform Infrared Spectroscopy (FTIR Thermo Scientific Nicolet iS50, USA) is used for the δ13C-CO2 value assignment. The δ13C-CO2 values of the gravimetric mixtures span in the range from +1.3 ‰ to -42 ‰.Recently, a Cavity Ring-Down Spectrometer (CRDS G2131i Picarro, USA) was acquired to double-check the isotopic composition of the prepared mixtures. Preliminary tests were carried out for the metrological characterization of the instrument, followed by the set-up of the analytical methodology for the confirmation of the isotopic composition of some mixtures prepared within the STELLAR project and sent to other project partners for analysis in the past two years. The results of the tests carried out are presented in this work, together with some future perspectives for the realization of primary reference mixtures of CO2 in air at know isotopic composition on a larger scale. 
Patterns, controls and predictions of water and land resources nexus in a typical inland river basina: A green-blue water perspective
Authors: Zhu Meng , Feng Qi , Liu Wei , Zhang Chengqi , Zhang Jutao
Published: March 2024

The underlying surface structure is being reshaped by climate change and human activities, which in turn affects the hydrological processes in inland river basins, with significant consequences for coupling patterns of water and land resources in inland river basins of arid and semi-arid regions. However, current studies of coupling pattern of water and land resources analysis focus on available water and visible land resources in the districts, so that there is an urgent need for research on the simulation and prediction for water and land resources coupling of the micro-scale. Therefore, this study firstly evaluated and predicted the land resources by MCE-CA-Markov model and soil quality index function with environment factors and socio-economic factors, then generalized and simulated the water resources by SWAT, and construct the Water-Land Nexus Model for water conservation and water consumption zones to clear the impact mechanisms of water and land resources nexus in inland river basins. The results show that the nexus index of water and land resources present a decreasing distribution from water conservation area to water consumption area of the Shiyang River Basin, with that being lower than 0.1 (mainly in the water consumption area). The coupling index of water and land resources of Shiyang River Basin decreases from 0.1105 in 1980 to 0.1071 in 2000. In 2020-2050, the water conservation area exhibit an increasing trend, but that of the water consumption area is decreasing. The Geo-detector results show that soil quality index, blue water resource and DEM are the main factors influencing the coupling of water and land resources in Shiyang River Basin, follow by precipitation, temperature and green water resource, and the effects of POP and GDP could be negligible. Furthermore, the interactions between natural and socio-economic factors are stronger than the ones within each other, indicating that natural factors are the main influences on water-land nexus and it is important to consider the interactions of nature along with the human activities.