bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate ambition, background scenario or the model? Attribution of the variance of energy-related indicators in global scenarios
Authors: Al Khourdajie Alaa , Skea Jim , Green Richard
Published: March 2024

 HighlightsWe attribute variation across global climate mitigation scenarios to three factors
The three factors are climate ambition, scenario background and model choice
Many indicators are well-explained by the average effects of one or two factors
We also calculate the residual not explained by these average effects
This shows which indicators give outliers for some specific input combinations
AbstractWe attribute variations in key energy sector indicators across global climate mitigation scenarios to climate ambition, assumptions in background socioeconomic scenarios, differences between models and an unattributed portion that depends on the interaction between these. The scenarios assessed have been generated by Integrated Assessment Models (IAMs) as part of a model intercomparison project exploring the Shared Socio-economic Pathways (SSPs) used by the climate science community. Climate ambition plays the most significant role in explaining many energy-related indicators, particularly those relevant to overall energy supply, the use of fossil fuels, final energy carriers and emissions. The role of socioeconomic background scenarios is more prominent for indicators influenced by population and GDP growth, such as those relating to final energy demand and nuclear energy. Variations across some indicators, including hydro, solar and wind generation, are largely attributable to inter-model differences. Our Shapley-Owen decomposition gives an unexplained residual not due to the average effects of the other factors, highlighting some (such as the use of carbon capture and storage (CCS) for fossil fuels, or adopting hydrogen as an energy carrier) with outlier results for particular ambition-scenario-model combinations. This suggests guidance to policymakers on these indicators is the least robust.Graphical AbstractKeywordsEnergy transition, climate change mitigation, Integrated Assessment Models, Shapley-Owen decomposition
Investigating hydrothermal alteration in Copahue volcano (Argentina/Chile) using muography and laboratory measurements on rock samples
Authors: Tramontini Matias , Rosas-Carbajal Marina , Zyserman Fabio I. , Besson Pascale , Marteau Jacques , Heap Michael
Published: March 2024

Muography is a non-invasive geophysical method that relies on the detection of muons, which are subatomic particles generated by the interaction of cosmic rays with the Earth's atmosphere. The physical quantity estimated by this method is the opacity, which represents the amount of matter traversed by muons along their trajectories, resulting in energy loss and scattering for the particles. Thus, absorption muography consists of deploying a muon detector targeting the volcano and registering the muons traversing it per unit of time and trajectory. From these data, radiographs of average density of extensive rock volumes can be obtained using a single measuring instrument and from a singular measurement position.Copahue volcano is located in the Andes mountain range and is considered the highest-risk volcano in Argentina due to its proximity to two towns situated within an 8 km radius of the volcano's crater. Additionally, the region attracts a significant number of tourists, leading to a substantial increase in the population of both localities. The latest eruptive cycle, initiated in 2012, has maintained a near-continuous state of activity, marked by ash emissions, crater explosions, and seismic activity. In this work, we study the hydrothermal alteration at Copahue volcano through a combination of muography and laboratory measurements of the chemical and physical properties of rock samples.The muography dataset was acquired by installing a muon detector on the eastern flank of Copahue volcano, situated at an altitude of approximately 2500 meters above sea level. For the laboratory analyses, we collected rock blocks with the objective of representing a diverse spectrum of alteration stages within Copahue volcano. Through this selection process, we captured variations in mineralogical composition, geochemical signatures, and physical properties that correspond to different stages of hydrothermal alteration. We carried out a series of examinations on the rock samples extracted from the targeted flank, such as X-ray diffraction (XRD) and inductively coupled plasma mass spectrometry (ICP-MS) analyses that identified mineralogical compositions and geochemical signatures associated with hydrothermal processes. We also carried out additional measurements, including density, porosity, permeability, thermal properties, and uniaxial compressive strength, contributing to a comprehensive understanding of the physical properties of the samples. In addition, we performed microscopic examinations using a scanning electron microscope (SEM) to study the microstructural changes induced by hydrothermal alteration. This integrative approach, between muography and detailed laboratory measurements on rock samples, aims to reveal correlations between subsurface density variations and hydrothermal alteration observed at the microscopic and macroscopic scales.
Inferring the Interstellar Magnetic Field Direction from Energetic Neutral Atom Observations of the Heliotail
Authors: Kornbleuth Marc , Opher Merav , Dayeh Maher , Sokol Justyna , Turner Drew , Baliukin Igor , Dialynas Kostas , Izmodenov Vladislav
Published: March 2024

Determining the magnitude and direction of the interstellar magnetic field (BISM) is a longstanding problem. To date, some methods to infer the direction and magnitude have utilized best fit models to the positions of the termination shock and heliopause measured by Voyager 1 and 2. Other models use the circularity of the IBEX Ribbon assuming a secondary energetic neutral atom (ENA) mechanism. Previous studies have revealed that the BISM organizes the orientation of the heliotail with respect to the solar meridian. Here, we propose a new way to infer the direction of the BISM based on ENA observations of the heliotail. IBEX observations of the heliotail have revealed high-latitude lobes of enhanced ENA flux at energies >2 keV. Analyses showed that the high latitude lobes are nearly aligned with the solar meridian, while also exhibiting a rotation with solar cycle. We show using steady state solar wind conditions that the inclination of the lobes reproduced with commonly used values for the angle (αBV) between BISM and the interstellar flow in the hydrogen deflection plane (40 deg. < αBV < 60 deg.) is inconsistent with the IBEX ENA observations. We report that 0 deg. < αBV < 20 deg. is required to reproduce the heliotail lobe inclinations observed by IBEX. Additionally, we find that the variation of the solar magnetic field magnitude with solar cycle causes the longitudinal rotation of the lobes observed by IBEX by affecting the inclination of the lobes.
Can endogenic CO2 inflate radiolytic H2O2 in Europa’s Chaos?
Authors: Raut Ujjwal , Protopapa Silvia , Mamo Bereket D , Villanueva Geronimo , Cartwright Richard J , Teolis Benjamin D , Retherford Kurt D , Blaney Diana L
Published: March 2024

Recent JWST observations reveal a higher abundance of endogenic CO2 at Tara Regio, a prominent leading hemisphere chaos (Villanueva et al., 2023; Trumbo and Brown, 2023). Prior findings from Keck also show an excess of H2O2 in the same region (Trumbo et al., 2019). Could the emplacement of the ocean-derived CO2 onto Europa’s surface influence radiolytic chemistry to boost peroxide yields in these enigmatic chaos regions? Increased H2O2 at fractured chaos terrains where ocean-surface exchange is more likely is exciting from a habitability stance, as it may facilitate oxidant delivery to the subsurface ocean.We present laboratory results that show H2O2 synthesis increases by 2-3 folds in the presence of trace amounts of CO2 (< 3 %) when compared to radiolysis of pure water ice. We also discuss correlations between CO2 and H2O2 abundances in the JWST datasets to determine whether Europa’s endogenous CO2 indeed conspires to inflate H2O2 at Tara Regio and possibly other chaos terrains. These JWST observations combined with emerging laboratory measurements set the stage for detailed mapping of CO2 (via its 2.7 and ~4.23-4.29 µm absorptions) and H2O2 (via its 3.5 µm absorption) with MISE (Europa Clipper) and MAJIS (JUICE) at unprecedented spatial resolution.References:Villanueva, G. L. et al., (2023) Science, 381, 1305–1308 
Trumbo, S. K and Brown, M. E. (2023) Science, 381, 1308–1311
Trumbo, S. K. et al. (2019) Astronomical Journal, 158, 127
Isotopic and elemental ratios in the open and closed porosity for two Antarctic firn cores (D47 and Little Dome C) of very different surface characteristics. 
Authors: Landais Amaelle , Harris Stuart Romilly , Orsi Anais , Jacob Roxanne , Teste Gregory , Prié Frédéric , Brückner Louisa , Martinerie Patricia , Emmanuel Witrant , Elise Fourré , Emilie Capron , Daniel Baggenstos , Hubertus Fischer , Jochen Schmitt
Published: March 2024

Understanding the processes during gas trapping in ice is essential to accurately interpret the gas records in ice cores. As a consequence, it is very desirable to have firn core and firn air sampling campaigns associated with deep ice coring. We know that elemental fractionation occurs during bubble close-off, hence largely affecting the δO2/N2 measurements further used to date the ice cores on orbital timescales. A recent study also suggested that this elemental fractionation can be linked to surface characteristics (i.e. temperature and / or accumulation rate). The aim of this study is to investigate the elemental and isotopic fractionation of N2 and O2 during bubbles close-off at two sites of very different characteristics (D47 located at the edge of the East Antarctic plateau with high temperature and accumulation rate and Little Dome C at the center of the East Antarctic plateau with low accumulation and accumulation rate). For this study, we did measurements both in the open and closed porosity of the firn in the lock-in zone. The D47 lock-in zone extends over nearly 20 m and, over these 20 m,  strong signals of increasing δO2/N2 (+ 7 permil) and decreasing δ15N (-0.05 permil) are observed with increasing depths. At Little Dome C, the site of the Beyond EPICA deep ice core, the lock-in depth is much thinner (a few meters thick only) and fractionation much smaller. We discuss how these signals relate to the signals measured in the closed porosity in both sites and present some perspectives for the interpretation of the gas records in the deep ice cores.   
Observations from a constantly changing nearshore zone in a mixed sediment bay 
Authors: Townsend Dominique , Leyland Julian , Kassem Hachem , Thompson Charlie , Townend Ian
Published: March 2024

There has been limited exploration of the nearshore zone of mixed sediment beaches despite being widespread globally.  Our work aims to build a more complete picture of coastal change by looking at seabed evolution from the very upper reaches of the swash zone, down to the edge of the nearshore zone, at a variety of timescales. Bathymetry surveys, completed using both traditional and automated surface vessels collected single and multibeam sonar data over a 19-year period, were complimented by a shorter period of weekly radar sea surface roughness images which are indicative of nearshore bed morphology. Additionally, grab samples were collected from across the nearshore to show the bed sediments composition variation over a year, providing valuable insight on bed response to varying hydrodynamic conditions. Process based analysis gave long and cross shore drift rates to help understand the observed changes. 

We found that the nearshore zone experiences significantly larger volumetric bed changes in comparison to the upper beach but were limited to approximately +/-0.3 m, which is equivalent to the upper error limits of the surveyed data. The depth of closure, a term used to mark the offshore point of no change over a defined time scale, varied across the mixed sediment bay at both seasonal  (ranging between –4.7 and –8.4 metres Ordnance Datum(mOD)) and decadal (ranging between –7.3 and –8.2 mOD) timescales, yet was consistently shallower than all predictive equations of this depth. Moreover, our results indicate a loss of volume in the nearshore zone over time which is coupled with a simultaneous steepening of the upper beach for two thirds of the frontage.  The observed steepening poses questions for the current ‘hold the line’ management strategy, which is achieved through active beach management works, and accommodation space.  
Overall, our observations highlight the substantial sediment transport occurring within the predominantly sandy nearshore zone and demonstrate evidence of impacts to the upper shingle beach. Consequently, to ensure the sustainability of management practices in the upper beach, a comprehensive understanding of the nearshore dynamics becomes imperative. The presented findings emphasize the necessity of integrating nearshore considerations into coastal management strategies, providing a more holistic and effective approach to making sustainable management decisions. 
The Magnetosphere Aurora Reconnection Boundary Layer Explorer (MARBLE):  Understanding How Magnetic Reconnection Generates the Aurora
Authors: Dorelli John , Bard Christopher
Published: March 2024

Understanding the connection between magnetospheric dynamics and the aurora has remained one of the most challenging problems in Heliophysics for the last fifty years. One of the more exciting developments in the last two decades was the discovery that Alfvén waves play a significant role, comparable to static electric fields, in accelerating magnetospheric electrons to energies capable of generating auroral arcs during periods of high auroral activity. This discovery has revealed a direct connection between the universal process of magnetic reconnection and the generation of the aurora, but understanding this connection poses some significant challenges for global magnetosphere models. Presently, there does not exist a magnetosphere model capable of simulating the coupling of magnetic reconnection to Earth’s ionosphere on a global scale. The MARBLE project will fill this significant gap by developing a new “collisionless Hall MHD” model capable of following plasma particles and waves from their birth at reconnection sites deep in the magnetosphere all the way to the auroral zone in Earth’s ionosphere. To achieve this goal, MARBLE will be designed from the ground up to make optimal use of the most advanced computer hardware, including large clusters of Graphics Processing Units (GPUs). MARBLE will also embrace Open Science principles at every stage of its development. In addition to being released to the community under an open source license, MARBLE will establish a community driven development approach with transparency, inclusivity, collaboration, and reproducibility as core values. A key goal of the project, consistent with NASA’s Open Science initiative, is to make it possible for non-experts in computational plasma physics to play a meaningful role in the development and validation of the most advanced global magnetosphere models.
Eco-evolutionary Modelling of Global Vegetation Dynamics and the Impact of CO2 during the late Quaternary: Insights from Contrasting Periods 
Authors: Zhao Jierong , P.Harrison Sandy , Prentice Iain Colin
Published: March 2024

Changes in climate have had a significant impact on global vegetation patterns during the Quaternary. However, variations in CO2 levels also play a key role in shaping vegetation dynamics by influencing plant water-use efficiency, and consequently, the competitive success of employing the C3 and C4 photosynthetic pathways. In this study, we use an eco-evolutionary optimality (EEO) based modelling approach to examine the respective impacts of climate fluctuations and CO2-induced alterations on vegetation shifts. We consider two distinct periods, the Last Glacial Maximum (LGM, 21,000 years before present) and the mid-Holocene (MH, 6,000 years before present) and compare these to contemporary conditions. The LGM, characterised by generally colder and drier climate, had a CO2 level close to the minimum threshold for effective C3 plant operation. In contrast, the MH had warmer summers, increased monsoonal rainfall in the northern hemisphere, with CO2 levels lower than the present day. We simulate vegetation changes at the LGM and the MH using a light-use efficiency model that simulates gross primary production (GPP) coupled to an EEO model that simulates leaf area index (LAI) and C3/C4 competition. We show that low CO2 at the LGM is as important as climate in reducing tree cover, increasing the abundance of C4 plants and lowering GPP. Global GPP is also lower than today in the MH (although increased compared to the LGM), reflecting CO2 constraints on plant growth despite the positive impacts of warmer and/or wetter climates experienced in the northern hemisphere and tropical regions on plant growth. These results emphasise the importance of taking account of impacts of changing CO2 levels on plant growth in order to simulate ecosystem changes correctly.
Simulating CO2 seasonal cycle amplitude in northern high latitudes with an eco-evolutionary optimality model
Authors: Cai Wenjia , Prentice Iain Colin , Hooghiem Joram
Published: March 2024

Land-atmosphere carbon exchanges and feedbacks constitute one of the largest uncertainties in future climate projections. Seasonal variations in atmospheric CO2 content depend on uptake by photosynthesis and release by autotrophic and heterotrophic respiration, providing an atmospheric signal of land ecosystem activity. Large increases in the seasonal cycle amplitude (SCA) of CO2 have occurred since the 1950s, especially in northern high latitudes. However, land surface and dynamic vegetation models have produced a wide range of magnitudes for the SCA, and have generally underestimated its increase. We explored the controls of the SCA by using a parameter-sparse eco-evolutionary optimality (EEO) model, the ‘P model’, combined with generic representations of plant and decomposer respiration, to simulate seasonal cycles and decadal trends of net ecosystem exchange (NEE). Simulated NEE fields were used to model near-surface CO2 concentrations during the satellite era, with the help of the atmospheric chemistry-transport model TM5. The P model has previously been shown to reproduce trends of gross primary production (GPP) at flux sites with long records. Our model set-up also generated a realistic simulation of global net terrestrial carbon uptake, comparable with results produced by more complex dynamic vegetation models; and allowed us to attribute causes to observed SCA increases at high-latitude CO2 monitoring stations.
World climate simulation
Authors: Thabet Soumaya
Published: March 2024

The IPCC experts attribute unequivocal human influence to the observed climate change. The global temperature has increased by approximately 1.1 degrees celsius compared to the preindustrial era, with negative impacts on worldwide populations and ecosystems.A world climate simulation is an in-person role-playing excercice of the UN climate change negotiations. The simulation aims to rise awarness among students about the issue of climate change by having them take on roles of responsability, allowing them to become active participants during the mock UN summit. Participants work in groups, with each group representing a specific nation, negociating bloc or an interest group. To achieve the objective of staying below 2 degrees celsius of warming above the preindustrial levels, participants must discuss strategies, negociate, make decisions and collaborate to propose greenhouse gaz emissions reductions, land use changes and climate finance pledges. They can predict the impact of their proposals on the global temperature by using a computer simulation of the dynamics of the climate C-ROADS.The project unfolds in three parts :Understanding climate change : students engage in activities about the reality of climate change and its origins.
Negociating at the international level : preparing for negociation and participating in a negociation simulation.
Taking action locally and globally for the climate : discovering projects to take action for the climate.
Landslides on the growing folds of the Kura fold-and-thrust belt (Azerbaijan, Georgia)
Authors: Břežný Michal , Pánek Tomáš , Havenith Hans-Balder , Tibaldi Alessandro
Published: March 2024

Rising hillslopes in the active fold-and-thrust regions present new landslide-prone slopes. However, studies investigating landslides in newly formed fold-and-thrust belts are limited. In this research, we analyse landslide occurrences in the Kura fold-and-thrust belt, a geologically active region at the southern edge of the Greater Caucasus. This area has experienced significant tectonic shaping over the last 2-3 million years, affecting Miocene to Quaternary sediments. Using satellite imagery, we identified about 1600 landslides, a quarter of which are active. These landslides, although occupying less than 1% of the land, are predominantly found at higher elevations and areas with greater relief. They mainly occur in regions elevated by tectonic forces, especially on steep anticlines and valley slopes cut by active faults. Our findings lead to a conceptual model for the temporal evolution of landslide patterns in weak sediment-based fold-and-thrust belts: 1) Initially, slow deformations at thrust fronts lead to landslides in deep valleys intersecting the uplifting hanging walls. 2) As anticlines rise and steepen, they become more prone to planar sliding when dip slopes exceed friction angle, and valley development creates additional dip slopes resulting in widespread landslides. 3) Finally, erosion lowers relief, forming badlands and reducing landslide occurence.
Unveiling the Activity of a Young Fault: Insights from the 2021 Maduo Earthquake
Authors: Yao Wenqian , Liu_Zeng Jing , Klinger Yann , Hu Guiming , Shao Yanxiu , Liu Xiaoli , Qin Kexin , Liu Zhijun , Wang Zijun , Gao Yunpeng , Han Longfei
Published: March 2024

Faults grow through fault lengthening and slip accumulation, which are episodic processes related to the repetition of earthquakes. It is most often recorded in geomorphology. Meanwhile, the activity and seismic hazard of the ‘slow-moving’ faults are often overlooked due to their weak imprints in landforms, especially at their initial formation stage. The 2021 Mw 7.4 Maduo earthquake triggered a ~158-km long surface rupture along the poorly-known and geomorphically subtle Jiangcuo fault, which is one of the distributed faults in the Bayan Har block and splays that merge with the Kunlun Pass fault. The slip rate of the Jiangcuo fault is thus crucial for comprehending how the strain is distributed between the major and subsidy faults in the complete fault system of the Bayan Har block, as well as the broader deformation process at a large scale. In this study, we present three sites where the Jiangcuo fault left-laterally displaces Holocene geomorphic features (e.g., terraces, fans, and channels). Through the detailed interpretations of high-resolution Digital Elevation Models (DEMs), field investigations, and credible Optically Stimulated Luminescence (OSL) dating of displaced geomorphic features, we document an average left-lateral slip rate of 2.1 ± 0.2 mm/yr since ~12 ka of the Jiangcuo fault. Furthermore, we conservatively updated existing slip rates of the large strike-slip faults (East Kunlun fault, Ganzi-Yushu-Xianshuihe fault) bounding the Bayan Har block. Synthesizing the slip rate of the Jiangcuo fault with the updated rates of the bounding faults, our findings suggest that the Jiangcuo fault accommodates ∼10% of the total deformation in the Bayan Har block. This study provides valuable insights into the impact of younger faults on regional deformation processes.
System of devices for accumulation of excess heat in the natural water-permeable layer and for its recovery – modeling results
Authors: Solecki Marek L. , Solecki Tadeusz , Stopa Jerzy M. , Wiśniowski Rafał , Hajto Marek , Smulski Rafał
Published: March 2024

A system of devices for accumulating excess heat in a natural water-permeable layer and for its recovery, applicable in underground heat storage, especially in its effective use, is presented. This system ensures high efficiency and low thermal inertia, and at the same time eliminates the disadvantage of the known method of storing heat in natural water-permeable layers - Aquifer Thermal Energy Storage (ATES), which consists in the impossibility of using it in water-permeable layers with low water content or with significant dynamics of water flow in the area designated as heat storage.The system of devices for accumulating excess heat in the natural water-permeable layer and for its recovery is a heat accumulator filled with water, which is a closed area separated from the water-permeable layer using anti-filtration walls, which are also a thermally insulating partition.The system includes a surface heat exchanger and extraction and discharge wells located in the battery area, used to accumulate and remove heat, equipped with deep-well pumps. The extraction and discharge wells also contain multi-level temperature and water level measurement probes, signal-connected to the control, measurement, and control equipment that controls the operation of deep-well pumps and controllable valves located on the hydraulic lines connecting the well system with the heat exchanger.The solution can be used as a seasonal heat and/or cold storage using geotechnical structures such as sheet piling, as well as a dedicated solution for storing excess heat/cold to support existing urban heating systems.The device concept has obtained the European patent EP4063780B1.The results of modeling the heat storage operation performed in the Petrel and Eclipse software by Schlumberger are presented.
Three decades of changing nutrient stoichiometry from source to sea on the Swedish west coast
Authors: Peacock Michael , Futter Martyn , Jutterström Sara , Kothawala Dolly , Moldan Filip , Stadmark Johanna , Evans Chris
Published: March 2024

European ecosystems have been subject to extensive shifts in anthropogenic disturbance, primarily through atmospheric deposition, climate change, and land management. These changes have altered the macronutrient composition of aquatic systems, with widespread increases in organic carbon (C), and declines in nitrogen (N) and phosphorus (P). Less well known is how these disturbances have affected nutrient stoichiometry, which may be a more useful metric to evaluate the health of aquatic ecosystems than individual nutrient concentrations. The Swedish west coast has historically experienced moderate to high levels of atmospheric deposition of sulfate and N, and eutrophication. In addition, coastal waters have been darkening with damaging effects on marine flora and fauna. Here, we present three decades of macronutrient data from seven watercourses (plus additional lakes) along the Swedish west coast, including headwaters and river mouths, across a range of land covers, and with catchments ranging 0.037 – 40000 km2.We find a high degree of consistency between these diverse sites, with widespread increasing trends in organic C, and declines in inorganic N and total P. These trends in individual macronutrients translate into large stoichiometric changes, with a doubling in C:P, and increases in C:N and N:P by 50% and 30%, showing that freshwaters are moving further away from the Redfield Ratio, and becoming even more C rich, and depleted in N and P. These changes were not restricted to headwaters but were also evident in larger rivers and at river mouths. Although recovery from atmospheric deposition is linked to some of these changes, land cover also appears to have an effect; lakes buffer against C increases, and decreases in inorganic N have been greatest under arable land cover. Taken together, our findings show that freshwater macronutrient concentrations and stoichiometry have undergone substantial shifts during the last three decades, and these shifts can potentially explain some of the detrimental changes that adjacent coastal ecosystems are undergoing. Our findings are relevant for all European and North American waters that have experienced historically high levels of atmospheric sulphate and N deposition, and provide a starting point for understanding and mitigating against the trajectories of long-term change in aquatic systems.
Understanding CMIP6 Inter-model Spread of Projected Change in Tropical Sea Surface Salinity
Authors: Pang Shanshan , Vialard Jérôme , Lengaigne Matthieu , Wang Xidong
Published: March 2024

Here, we analyze projected tropical sea surface salinity (SSS) changes in 32 Coupled Model Intercomparison Projects phase 6 (CMIP6) global climate models historical simulations and representative concentration pathway 8.5 (SSP5-8.5) scenario. A robust “fresh gets fresher” pattern emerges by the end of the twenty-first century, with fresher tropical Indian and Pacific Oceans and saltier tropical Atlantic Ocean. We examine the inter-model diversity in this pattern using Empirical Orthogonal Function (EOF) analysis. The first two EOFs explain 45% of the total variance. EOF2 (22%) is a modulation of the multi-model mean SSS change, associated with the tropical-average warming intensity (r=0.61). Higher climate sensitivity leads to a more pronounced El Niño-like (positive IOD-like) warming pattern and stronger rainfall in the equatorial and north subtropical Pacific (west Indian) Ocean, leading to local freshening. In the equatorial Atlantic, an enhanced warming leads to more evaporation through the Clausius–Clapeyron relation, and a stronger SSS saltening. The “fresh gets fresher” SSS pattern inter-model diversity is thus more a response to the SST pattern diversity through the “warmer gets wetter” mechanism than an evidence of the “wet gets wetter” intensification of the hydrological cycle. EOF1 (25%) is characterized by saltening in the Indian Ocean and freshening in the Pacific Ocean, associated with changes in the inter-hemispheric relative SST gradient (r=0.55). Enhanced warming in the south hemisphere shifts the precipitation south, reducing total rainfall and saltening the Indian Ocean, while increasing rainfall and freshening the south Pacific Ocean. Overall, we find a strong influence of SST changes on the rainfall distribution, which influences SSS with some effects related to transport by the oceanic circulation.
Exploring Catchment Regionalization through the Eyes of HydroLSTM
Authors: De La Fuente Luis , Gupta Hoshin , Condon Laura
Published: March 2024

Regionalization is an issue that hydrologists have been working on for decades. It is used, for example, when we transfer parameters from one calibrated model to another, or when we identify similarities between gauged to ungauged catchments. However, there is still no unified method that can successfully transfer parameters and identify similarities between different regions while accounting for differences in meteorological forcing, catchment attributes, and hydrological responses.Machine learning (ML) has shown promising results in the generalization of its results at temporal and spatial scales for streamflow prediction. This suggests that ML models have learned useful regionalization relationships that we could extract. This study explores how the HydroLSTM representation, a modification of traditional Long Short-Term Memory, can learn meaningful relationships between meteorological forcing and catchment attributes. One promising feature of the HydroLSTM representation is that the learned patterns can generate different hydrological responses across the US. These findings indicate that we can learn more about regionalization by studying ML models.
A new record of the earliest planktonic foraminifera Conoglobigerina sp. and Globuligerina sp. from the Middle Jurassic (Bajocian) D4 unit of the Dhruma Formation in Saudi Arabia
Authors: Korin Asmaa , Prayudi Sinatrya , Kaminski Michael
Published: March 2024

The Mesozoic Shaqra group has been the subject of numerous previous studies because of its 13 petroleum-producing reservoirs dispersed across different formations. Several geologists thoroughly examined the Dhruma Formation, the second formation of the Shaqra group, from a petrographic and sedimentological standpoint. However, other than the report by Kaminski et al. (2018), there are only a few micropaleontological investigations of the marly units within this formation, and no thorough evaluation of the maximum flood surfaces utilizing microfossil contents, such as planktonic foraminifera, has been carried out. The diversity, quantity, and preservation mode of planktonic foraminifera in older rocks could give insight into changes in past sea level or in other words the maximum flood surfaces (MFS). These free-floating foraminifera replace shallow-water species during transgressions as sea levels rise; their numbers peak at the maximum flood surface when sufficient water depths and nutrient-rich waters provide them with an ideal depositional environment. To provide new evidence for high-resolution sequence stratigraphy, we are attempting to trace the maximum flood surfaces within the carbonates and marl units of the Dhruma formation by examining their microfossil content. The material under consideration was collected from a marly D4 unit exposure (~15 m thick) located on Highway Road no. 5395, southwest Riyadh City, about 1 km from a Saudi poultry farm (N24°12'48'', E46° 14'5''E). The samples were obtained from the lower marly limestone part of the D4 Unit and examined using traditional micropaleontological procedures and the acetolysis technique. The main new finding of this study is that, as previously noted in Unit D5, the bottom part of Unit D4 contains the low-spired species Globuligerina sp. and the high-spired variant Conoglobigerina sp. Alongside the planktonic foraminifera, there is a benthic foraminiferal assemblage consisting of a mixture of smaller agglutinated species (Haplophragmoides and Nautiloculina) and calcareous species (polymorphinids and nodosariids). This assemblage suggests conditions on an open sea shelf and characteristics of a Middle Jurassic foraminiferal content from a marly carbonate unit. Considering their small size, calcareous benthic foraminifera indicate the presence of an oligotrophic depositional environment for Unit D4. The D4 Unit of the Dhruma Formation contains planktonic foraminifera, which provides a novel correlation tool for determining a new maximum flooding surface between the J20 and J30 maximum flooding surfaces in the Middle East.
A Comparison of the Effectiveness of Regulated OGI Leak Detection and Repair (LDAR) Surveys and Aerial Measurements in the Real-World
Authors: Wilde Shona , Tyner David , Conrad Bradley , Johnson Matthew
Published: March 2024

Periodic comprehensive or screening leak detection and repair (LDAR) surveys are a central part of many current regulations, which are intended to reduce unintentional methane emissions caused by leaking infrastructure.  In principle, by swiftly identifying and repairing leaks, emissions of methane, a potent greenhouse gas, are reduced.  The primary tools used for comprehensive LDAR surveys are Optical Gas Imaging (OGI) cameras.  While OGI can be effective for detecting and visualizing methane leaks, its extension to quantitative measurement (QOGI) is notoriously imprecise.  Moreover, studies have shown considerable variation in the performance of OGI in practice, where successful use is heavily dependent on the skill of the operator. Manual OGI surveys are also time consuming and labour intensive.  Implementing and maintaining an effective LDAR program that involves multiple OGI surveys per facility can be costly, potentially disrupting routine operations while requiring the deployment of trained personnel to each site.  Although operators are obligated to address and verify the repair of identified leaks, there is also still potential that significant leaks may be allowed to persist if they are not initially detected.  Consequently, despite the substantial costs involved, the full potential of methane reduction benefits may not be realized.  By contrast, aerial surveys have the potential to overcome many of the negatives associated with OGI surveys. In particular, aerial surveys can permit large numbers of sites to be surveyed per day at significantly lower cost per site, reducing overall compliance costs, labour requirements, and improving safety through reduced risks.  However, there remains no objective way to assess the relative performance of aerial surveys in complementing or replacing LDAR surveys under different scenarios.  In the context of emerging regulations, this is an especially important topic.This work seeks to directly compare the effectiveness of conventional OGI surveys and aerial measurement under real-world conditions.  At an identical set of approximately 500 operating oil and gas sites in British Columbia, Canada, we compare and contrast detected and quantified sources in regulated LDAR surveys with parallel aerial surveys completed using Bridger Photonics’ Gas Mapping LiDAR (GML) technology.  The publicly reported LDAR reports are parsed to analyze patterns in detected emissions on 1 and 3 times per year deployments which are contrasted with aerial measurements at the same set of sites.  This direct contrast under real world conditions gives one of the first large scale tests of LDAR and aerial performance in practice, helping to provide quantitative guidance for the design of potential alternative LDAR programs under emerging regulatory scenarios.
Decadal predictions of temperature, precipitation and streamflow considering their covariability
Authors: Lima Carlos , Kwon Hyun-Han , Lall Upmanu
Published: March 2024

The significance of decadal predictions of climate for successful adaptation is now well understood. The focus is quickly shifting from end of 21st century predictions to decadal predictions, given that they should be much better constrained by emissions scenarios and the high economic present value of capital investments in infrastructure and loss reduction over the next decade. We evaluate the efficacy of current seasonal to decadal (S2D) predictions of temperature, precipitation and streamflow in specific contexts, considering both the external forcing and internal dynamical variability at the relevant time scales. Both global and selected regional scales are considered. We compare and enhance the predictions from state of the art S2D models, the CMIP6 models using statistical/machine learning tools with model generated and empirical data. Insights from these experiments are presented.
Acknowledgment: This work was supported by Korea Environment Industry & Technology Institute (KEITI) through Water Management Program for Drought, funded by Korea Ministry of Environment (MOE) (2022003610003).                      
Moist bias in the Pacific upper troposphere and lower stratosphere (UTLS) in climate models affects regional circulation patterns
Authors: Ploeger Felix , Birner Thomas , Charlesworth Edward , Konopka Paul , Müller Rolf
Published: March 2024

Water vapour in the UTLS is a key radiative agent and a crucial factor in the Earth's climate system. Here, we investigate a common regional moist bias in the Pacific UTLS during northern summer in state-of-the-art climate models. We demonstrate, through a combination of climate model experiments and satellite observations that the Pacific moist bias amplifies local longwave cooling which ultimately impacts regional circulation systems in the UTLS. Related impacts involve a strengthening of isentropic potential vorticity gradients, strengthened westerlies in the Pacific westerly duct region, and a zonally displaced anticyclonic monsoon circulation. Furthermore, we show that the regional Pacific moist bias can be significantly reduced by applying a Lagrangian, less diffusive transport scheme and that such a model improvement could be important for improving the simulation of regional circulation systems, in particular in the Asian monsoon and Pacific region. 
Parameterizing mesoscale eddy buoyancy transport over sloping topography
Authors: Nummelin Aleksi , Isachsen Pål Erik
Published: March 2024

Models that do not resolve the mesoscale eddies tend to parameterize their impacts such that the parameterized transport of buoyancy and tracers reduces the large-scale available potential energy and spreads tracers. However, the parameterizations used in the ocean components of current generation Earth System Models (ESMs) rely on an assumption of a flat ocean floor even though observations and high-resolution modelling show that eddy transport is sensitive to the potential vorticity gradients associated with a sloping seafloor. Using a hierarchy of model complexities, we show that (i) the buoyancy transport coefficient diagnosed from idealized eddy-resolving simulations is indeed reduced over bottom slopes (ii) such reduction can be skillfully captured by a mixing length parameterization by introducing the topographic Rhines scale as a length scale (iii) implementing such a modified `GM' parameterization in non-eddying simulations enhances the strength of thermal wind currents over the bottom slopes.  Testing the new parameterization in realistic global coarse-resolution simulations shows that the impact of topography is most pronounced at high latitudes, enhancing the mean flow strength and reducing temperature and salinity biases. Reducing the buoyancy transport coefficient further with a mean-flow dependent eddy efficiency factor, has notable effects also at lower latitudes and leads to reduction of global mean tracer biases. We find that most of the tracer bias reduction follows from changing the buoyancy transport coefficient (GM), but we also discuss the impact of applying similar changes to the tracer mixing coefficient (Redi).
Real-time forecasts of unrest at Campi Flegrei, Southern Italy, 2013-2023.
Authors: Kilburn Christopher , Newland Eric , Pino Nicola Alessandro , Carlino Stefano , Danesi Stefania
Published: March 2024

Large volcanic calderas can take decades or more to return to activity after centuries in repose. Their reawakening frequently triggers several, intermittent episodes of unrest before magma finally erupts. The non-eruptive episodes can divide scientific opinion about the cause of unrest and its outcome. The Campi Flegrei caldera is a remarkable example. Fifteen kilometres across, it is Europe’s largest active caldera and supports a population of more than 360,000 people to the west of Naples in southern Italy. It has been episodically restless since 1950, for the first time in four centuries. Uplifts in 1950-52, 1969-72, 1982-84 and since 2004 have created a caldera-wide bulge that, close to its centre, has raised the coastal town of Pozzuoli by more than 4 m, while tens of thousands of small earthquakes have shaken the volcano to depths of 4 km.The behaviour is consistent with repeated rupture of the crust. The most recent rupture developed between 2013 and 2023. The rate of local volcano-seismic earthquakes evolved from an exponential increase, through a constant rate to a hyperbolic increase with time. This is the classic pre-rupture sequence for elastic-brittle rock being extended under an approximately constant rate of supplied stress.We used changes in the sequence to forecast the approach to rupture in real-time. Observations followed the forecast trend through the first nine months of 2023, by which time the increase in seismicity was expected to continue until early 2024. Instead, the rupture sequence culminated in October 2023, since when the rates of seismicity have decayed. The end of rupturing was brought forward by an increase in the number of larger magnitude earthquakes, which accelerated rates of stress loss compared with previous months. Uplift had also slowed by December 2024.  Each rupture sequence increases the amount of damage in the crust. Other factors being equal, therefore, if any new magma can reach the shallow crust in the near future, it is likely to meet a lower resistance to eruption than has been the case since unrest began in 1950.
Land-atmosphere coupling induced local moist convection initiation in central Europe
Authors: Breuninger Noah , Warrach-Sagi Kirsten
Published: March 2024

In Europe, extreme weather events are expected to increase noticeably in frequency, duration, and intensity with the continued warming of the planet's climate. Land-atmosphere feedbacks have been shown to play an important role in the exacerbation of events such as heat waves and droughts. Due to the important role of convective events in local weather an improved understanding of the role that land-atmosphere feedback plays in the development of convection initiation is required.The heated condensation framework (HCF) enables the quantification of land-atmosphere coupling strength and local convection events in dependence of the temperature and moisture profiles from the ground to the planetary boundary layer height. The HCF is applied to the hourly data from the Weather Research and Forecasting (WRF) model application of the University of Hohenheim (UHOH) within the decadal km-scale regional climate simulations within CORDEX-FPS convection.The analysis reveals the Po-Valley area as a hotspot of land-atmosphere coupling-induced local convection initiation in central Europe. Further strong wet and dry soil anomalies impact the number of local convection initiation events throughout the studied domain.
An enhanced algorithm for co-registering individual trees extracted from airborne LiDAR and aerial photographs
Authors: Xu Yi , Wang Tiejun , Skidmore Andrew
Published: March 2024

As fine-resolution remotely sensed data rapidly evolves, individual trees are increasingly becoming a prevailing unit of analysis in many scientific disciplines such as forestry, ecology, and urban planning. Fusion of airborne LiDAR and aerial photography is a promising means for improving the accuracy of individual tree mapping. However, local misalignments between these two datasets are frequently ignored. Solving this problem using traditional pixel-based image registration methods requires extensive computation and is extremely challenging on large scales. In our earlier research, we proposed an approach that involved determining the optimal offset vector for a local area and using it to rectify the spatial positions of all individual trees in that area. Although the approach is effective in addressing mismatch issues, it still exhibits large errors for some trees and is susceptible to changes in scale. Here, we propose an enhanced algorithm by constructing a data structure called a k-dimensional tree (also known as K-D Tree) to efficiently search for each tree’s unique offset vector and assigning the closest determined offset vector to candidate trees that lack corresponding counterparts in the reference data. The enhanced algorithm significantly improves the matching accuracy of individual trees, elevating it from 0.861 ± 0.152 to 0.911 ± 0.126 (p < 0.01, t-test). Moreover, it substantially reduces the computational time by approximately 70% and successfully overcomes limitations associated with scale changes. The example data, source code, and instructions for the enhanced algorithm are publicly available on GitHub*.*https://github.com/XUYIRS/Individual_trees_matching