bluuebunny/crossref_metadata_2025 huggingface dataset:
Connecting the interior to the atmosphere: should atmospheres of warm rocky planets differ for stagnant-lid and mobile surface regimes?
Authors: Noack Lena , Brachmann Caroline
Published: March 2024

Many factors influence the long-term evolution of the atmosphere of a rocky planet, including star-planet interactions and late accretion of volatiles. However, for planets where gravity is low enough for a primordial atmosphere to escape (i.e. roughly Earth-size and smaller), the main factor driving the atmospheric evolution will be volcanic outgassing from the interior. While for planets in the habitable zone, where liquid water may exist that could allow for an Earth-like carbon-silicate cycle, planets closer to their host star have been suggested to have Venus-like, thick CO2-dominated atmospheres. Our study focusses on the question, how basic planetary parameters such as size, core mass fraction, and surface regime (either stagnant-lid or mobile, such as plate tectonics) may impact the atmosphere, specifically the range of atmospheric pressures as well as their composition, for warm planets where condensation of water as well as an efficient carbon cycle can be excluded. We show, that planets with a stagnant lid tend to be hotter in their interior due to the isolating behaviour of the lithosphere, but at the same time tend to have much reduced outgassing efficiencies. At the same time, since volcanic outgassing at the surface of a planet is directly influenced by partial pressures in the atmosphere, compositional variations appear between stagnant-lid or mobile-lid planets, as well as between low-mass and high-mass rocky planets.Observations with JWST looking at warmer planets (i.e. inside the inner boundary of the habitable zone) might therefore give first-order indications on the outgassing efficiency (coupled with the erosion efficiency of the atmosphere) and surface regime of these rocky planets.
Post-mortem pteropod degradation in the Southern Atlantic twilight zone
Authors: Sulpis Olivier , Chaurand Perrine , Kruijt Anne , Cala Ben , Peijnenburg Katja TCA , van Dijk Robin , van der Burg Daniëlle , Humphreys Matthew
Published: March 2024

Part of the carbon taken up by the ocean is transformed into biogenic particulate matter, that eventually leaves the surface ocean, settling toward the seafloor. Planktonic organisms secreting a calcium carbonate (CaCO3) shell occupy a key, but ambivalent role in this scheme. First, the precipitation of their shell generates CO2, thereby reducing the ocean CO2 sink, while the sinking of their shell constitutes a direct export of carbon to the deep ocean. Meanwhile, the dissolution of their shells generates alkalinity, which in turn boosts the capacity of seawater to take up more CO2 from the atmosphere. CaCO3 is present in the ocean under two main mineral forms: calcite (relatively stable) and aragonite (relatively soluble). Aragonite, produced in today’s oceans mostly by pteropods, a group of pelagic snails, has a very poorly understood role in the marine carbon cycle, and key questions remain unanswered: what controls their soft parts degradation and shell dissolution in the upper kilometer of the water column? How do both processes interact? During the BEYΩND expedition that took place in March 2023 across the Southern Atlantic, we sampled pteropods using a multinet at 5 different depth ranges in the upper kilometer. Retrieved pteropods were representative of different life stages (adults, juveniles), some still well preserved, some dead with various stages of decomposition. Individuals were then preserved into ethanol, and later scanned with a micrometric resolution using microtomography. From the scans, the post-mortem degradation of the different body parts can be appreciated, shell micro-ornamentations can be seen, and possibly gut contents, which may influence dissolution and degradation processes. From the collected scans, a reactive transport model is then applied to predict in 3D the rates at which both organic matter degradation and aragonite dissolution occur, as well as how they interact.
Understanding coastal response to sea level rise in Northern Italy: the Holocene history of the Tagliamento river delta
Authors: Gerats Wouter , Donders Timme , van der Vegt Maarten , Fontana Alessandro , Stouthamer Esther , Cohen Kim
Published: March 2024

Many deltas worldwide are at the risk of drowning under projected future rates of sea-level rise. Understanding the morphodynamic response of deltas through stages in the Holocene, is crucial to know their current state and determine their future and to take effective action.To understand the relation of coastal-plain morphology and substrate with history of vegetation cover, sediment supply, tides and salinity gradients, between vegetation cover, sediment supply and coastal morphology we examine the history of the Tagliamento river delta in Northern Italy, a backbarrier coastal system with large lagoonal areas. This river mouth is one of the morphologically intact in Europe, even though it has experienced a long history of human presence. We combine a large dataset of 4,000 core descriptions with detailed proxy-analyses of multiple cores to map accretion surfaces in time and link them to past changes in vegetation, sea level and climate. Lithology, pollen data and C-14 ages provide quantitative information on infill rates and landscape change and human influence. Resulting geologic transects and paleogeographic maps show the 3D infill history of the former lagoon and provide constraints on sediment fluxes and degree of marine ingression. First results from pollen analysis and sedimentology show clear local and region changes in vegetation cover but relatively late and low direct human influence. Further work will attempt to confront the reconstructions with idealized model simulations of sediment budgets and geomorphology at selected moments in time.
Estimating the impact of irrigation and groundwater pumping on regional hydroclimate using an Earth System Model
Authors: Satoh Yusuke , Pokhrel Yadu , Kim Hyungjun , Yokohata Tokuta
Published: March 2024

Irrigation is an anthropogenic forcing to the Earth-system that alters the water and heat budgets at the land surface, leading to changes in regional hydro-climate conditions over a range of spatiotemporal scales. These impacts of irrigation are anticipated to escalate in the future due to increased food demand and the pervasive effects of climate change. Thus, it is imperative to better understand the nature, extent, and mechanisms through which irrigation affects the Earth's system. However, despite its increasing importance, irrigation remains a relatively nascent component in the Earth-system modeling community, necessitating advancements in modeling and a deepened understanding.Our research aims to improve the quantitative understanding of the impacts of irrigation and groundwater use as anthropogenic drivers on regional climate and environmental changes. To this end, we developed an improved Earth-system modeling framework that is based on MIROC-ES2L (Hajima et al 2020 GMD) coupled with hydrological human-activity modules (Yokohata et al. 2020 GMD). This model enables the simulation of a coupled natural-human interaction including hydrological dynamics associated with irrigation processes. Employing this Earth-system model, we carried out a numerical experiment in T85 spatial resolution, utilizing an AMIP style set-up. Here, our ensemble simulation allows for statistical quantification of the irrigation impact differentiating them from the uncertainties arising due to natural variability.Through our investigation, we have identified specific regions and seasons where irrigation exerts a discernible influence on regional hydro-climate. Notably, our results show substantial disparities—larger than or comparable to inter-annual variability—between simulations incorporating and excluding the irrigation process, particularly in heavily irrigated regions such as Pakistan and India. Our model demonstrates that the introduction of moisture into the soil through irrigation alters the hydrological balance of the land surface, consequently influencing the overlying atmosphere. Conversely, we found significant uncertainty in the impact estimate for some regions, even those heavily irrigated, such as the central United States and eastern China, indicating the challenges of robustly estimating irrigation impacts with limited samples. This underscores the necessity for an appropriate statistical approach to evaluate the impact of irrigation, considering the inherent variability. Furthermore, our study delves into estimating regional variations in the contributions of groundwater and surface water use to these impacts. Emphasizing the importance of a more nuanced understanding of regional characteristics in irrigation impact assessments, our research underscores the significance of coupled earth system models in comprehending and predicting the intricate interplay between human activities and the Earth's climate system.
Natural carbon sequestration process into shallow sill intrusions – numerical modelling, land-based and IODP drilling investigations
Authors: Galerne Christophe , Jörg Hasenclever , Cheviet Alban , Bach Woflgang , Lenhardt Nils , Zhang Junli , wiggers Christin , Kahl Wolf-Achim , Kopf Achim , Buatier Martine , Götz Annette
Published: March 2024

Permanent carbonate mineralisation in basalt is a promising solution for Carbon Capture and Storage of anthropogenic greenhouse gases without the risk of leakage. While this process is known to occur at relatively low temperatures below 100°C, new research on Large Igneous Provinces (LIPs) and young rift basins suggests that much of the thermogenic gases mobilised during contact metamorphism can remain trapped and mineralised in the sills that mobilised them. This discovery is the result of two distinct drilling investigations on land (KARIN) and at sea (IODP Exp 385). It shows that basalts may not only trigger the sudden release of thermogenic gas, but also represent an important carbon sink. The two examples of carbonate trapping in sills presented here are from the Karoo and Guaymas basins. Results indicate that a large fraction of epimagmatic fluids charged with thermogenic gas systematically penetrated inside the sills during cooling. Our numerical solutions suggest that in both cases the higher permeability of the sill acquired during cooling and crystallisation compared to that of its host, ultimately dictates the fate of the thermogenic gas that accumulated in the igneous bodies.
Large scale atmospheric circulation patterns in DeepMIP simulations
Authors: Kelemen Fanni Dora , Meijer Niels , Ahrens Bodo
Published: March 2024

Paleoclimate models help us understand the complex influence of high CO2 concentration and other boundary conditions on large scale atmospheric circulation patterns. Based on meridional heat transport analysis we investigate different phenomena, such as the Hadley cell, the monsoon and extratropical cyclones, in simulations from the Deep-Time Model Intercomparison Project (DeepMIP). For the analysis we compare preindustrial and early Eocene simulations at a range of CO2 levels (1x, 3x and 6x preindustrial values), which are targeting the climate of the Early Eocene Climatic Optimum (EECO; 53-49 Ma).Meridional heat transfer analysis shows asymmetric changes due to rising CO2 concentrations in the northern and southern Hadley cells’, which we investigate further. In the DeepMIP simulations, the global monsoon systems transport more latent heat from the subtropics to the higher latitudes, which shows a more intensive hydrological cycle than in present day climate.  Though, the global area influenced by monsoons is smaller in the early Eocene than today due to the differences in paleogeography. Fossil pollen and isotopic records from the Paleocene-Eocene Thermal Maximum (PETM) from arid Central Asia show that rainfall temporarily doubled and that monsoon expanded into the continental interior during these extreme hyperthermal conditions. This is not well captured in the DeepMIP simulations and suggests that even more mechanisms strengthened the development of East Asian monsoon, such as orbital forcing and vegetation feedbacks, that should be considered in future simulations. At the midlatitudes, cyclones’ climatology was also likely different in the Eocene, especially over Eurasia, which was more fragmented, and marginal seas influenced the cyclogenesis through land-sea thermal contrast. The analysis identifies the processes that are affected by the Eocene boundary conditions and that are sensitive to the CO2 increase, which has high relevance to our future climate projections.
Long-term (2015-2023) observations of tropospheric BrO from two research sites in Antarctica
Authors: Prados-Roman Cristina , Gómez-Martín Laura , Puentedura Olga , Adame Jose Antonio , Navarro-Comas Mónica , Ochoa Héctor , Yela Margarita
Published: March 2024

Reactive halogens compounds (i.e., those containing bromine, iodine, chlorine) are known to be key species for the oxidizing capacity of the atmosphere affecting e.g. the lifetime of relevant species such ozone, HOx or NOx and also to have an impact on the climate through interactions with other trace gases and aerosols.In the polar regions reactive halogens play a particular role since e.g. the auto-catalytic release of bromine from sea ice into the atmosphere may lead to the depletion of tropospheric ozone even below instrumental detection limit and, also, to the deposition of toxic mercury into the polar ecosystem.In order to infer vertical profiles of relevant tropospheric trace gases, within the framework of several nationally funded projects (including the current GARDENIA project) and in collaboration with the Argentinian National Antarctic Direction, INTA has being performing multi-axis DOAS (MAXDOAS) observations from Antarctica for nearly a decade. One of the gases retrieved through the MAXDOAS technique is bromine monoxide (BrO), a reactive form of bromine.The work presented herein expands the 1-year study of Prados-Roman et al. (2018) to a 8-year study of the presence of tropospheric BrO at two research sites in Antarctica: Belgano II (77°52' S, 34°7' W) and Marambio (64°13' S, 56°37' W). We will present tropospheric BrO data from the two research sites that expands from 2015 to last year 2023, with values as high as nearly 40 pmol/mol. We will discuss the tropospheric BrO vertical and  latitudinal distribution as well its seasonal evolution throughout all these years.Note that a similar work but based on observations of iodine monoxide from Antarctica will be presented at EGU2024 in the work of Puentedura et al. (2024).
Spatio-temporal characteristics of floods in the largest basin of the Indian Peninsula
Authors: Pandey Shreejit , Swarnkar Somil , Kundu Soumya
Published: March 2024

The intensification of the hydrological cycle is a consequence of the rising global temperatures caused by global warming. This has worsened extreme hydrological occurrences, including floods. Flooding is a substantial global hazard that endangers human livelihoods, infrastructure, and economies. Furthermore, the combination of rising temperatures and human activities has significantly modified the flood patterns that have been documented worldwide by several scientists. More precisely, a substantial area of the Indian sub-continent is greatly impacted by regular instances of flooding. Previous studies have indicated an increase in both the magnitude and frequency of flood events in the Indian river basins during the past several decades. The Godavari River Basin (GRB), which is the biggest peninsular basin in India with an area of 312,812 square kilometers, has been prone to frequent and devastating flood events in recent decades. Nevertheless, the comprehensive flood attributes, such as the maximum intensity, total amount, and length, in the GRB remain unidentified. Hence, in this study, we have employed the peak-over-threshold and Master Recession Curve (MRC) techniques to evaluate the flood features in the GRB. We have utilized the daily recorded water flow information obtained from the Central Water Commission (CWC) from 21 gauging stations in the Godavari River Basin (GRB). The 21 gauging stations are categorized into four main geographical zones. The results of our research indicate that there are notable differences in the regional flood characteristics of the GRB in terms of both spatial and temporal scales. The majority of stations in the GRB exhibit substantial fluctuations in flood characteristics after 1995. More precisely, the western GRB exhibits a notable decrease in the amount, length, and intensity of floods after 1995. The data suggest that human actions have a significant role in the flood generation process in the western GRB area. The conclusions derived from this research will be valuable to policymakers and many stakeholders in their efforts to reduce flooding and promote equitable growth in the GRB.
AI based 3D P- & S-wave velocity model for the Alpine mountain chain from Local Earthquake Tomography
Authors: Braszus Benedikt , Rietbrock Andreas , Haberland Christian , Ryberg Trond
Published: March 2024

We present a new 3D P & S-wave model based on Local Earthquake Tomography (LET) of the European Alpine mountain chain using data from a total of more than 1100 broadband stations of the AlpArray Seismic Network and additional permanent and temporary stations. We use "SeisBench - A toolbox for machine learning in seismology" to assess the performance of the most commonly used AI pickers and find PhaseNet to be the most suitable. Our final data set comprises 2374 events of Ml >= 1.5 yielding 89,000 Pg-, 64,000 Pn-, 41,000 Sg- & 23,000 Sn-phases. Initially, we include observations from
CMIP6 models overestimate the North Atlantic eddy-driven jet persistence 
Authors: Ossó Albert , Ennemoser Florian
Published: March 2024

Persistent fluctuations in the latitudinal position of the North Atlantic jet stream are associated with extreme weather anomalies, particularly over Europe. Therefore, it is crucial to understand how the jet stream persistence might change in response to increased greenhouse gases to deliver useful regional climate projections. This study examines the persistence of the North Atlantic jet stream latitudinal fluctuations in CMIP6 and ERA5. We found that CMIP6 models consistently overestimate the persistence compared to ERA5 during the historical period. This discrepancy appears linked to too weak transient eddies over the NATL in CMIP6 models.By the end of the XXI century, CMIP6 models forced with the SSP585 scenario project a reduction of the jet fluctuations persistence of about 10% during the summer season. The evidence suggests this reduction is linked to a slower NATL jet during the summer months.        
Grey alder and birch as an admixture in Norway spruce stands: Effects on soil nitrogen and carbon pools
Authors: Soronen Päivi , Jämtgård Sandra , Myllymäki Mari , Smolander Aino
Published: March 2024

Norway spruce monocultures in the boreal region are vulnerable to the effects of climate change and unfavourable in terms of soil fertility. Introducing broadleaved tree species to these forests may increase not only the resilience of the forest ecosystem to climate change but also enhance soil productivity and carbon (C) stock. We studied how grey alder, having symbiosis with N2-fixing Frankia, and birch affect soil nitrogen (N) and carbon pools as an admixture in Norway spruce stands in Southern Finland.Study sites were three 40–60-year-old Norway spruce (Picea abies (L.) Karst.) -dominated stands with both grey alder (Alnus incana) and birch (both Betula pendula and Betula pubescens) as an admixture and a 20-year-old spruce stand with an admixture of grey alder. The forest type was a relatively fertile Oxalis acetosella – Vaccinium myrtillus type (OMT) on the two older (60 yr) sites and a slightly less fertile Vaccinium myrtillus type (MT) on the two younger sites (20–40 yr), applying the Finnish forest type classification. We took the soil samples at a 50–100 cm distance from 3–8 stems of the different tree species for the determinations of soil C and N stocks from all sites and for additional characterisation of organic matter only from the 60-year OMT sites. Soil diffusive N fluxes were measured using in situ microdialysis sampling and the subsequent laboratory analyses of plant-available N compounds.On average, forest floor N stock was larger under the canopy of alder versus birch or spruce. C-to-N ratios of forest floor and topmost 10 cm mineral soil layer were lower under alder versus spruce. Soil C stock was affected by tree species only at the 40-year MT site, where alder had a higher forest floor C stock than birch or spruce. Differences in diffusive N fluxes between tree species were non-significant, and we observed inconsistent trends at different sites. C mineralisation rate tended to be lower under alder versus spruce on the two 60-year OMT sites, and the amount of microbial biomass N was lower under alder versus birch. Microbial biomass C-to-N ratio and forest floor thickness were lower under birch than spruce on one of the 60-year OMT sites.The results point towards complex interactions and dynamics between tree species in mixed forests. Although we observed tree-species-induced spatial variation in soil properties, the distribution of above- and belowground litter and root activities in mixed stands reduces the differences between tree species. We found tree species to affect N stocks and C-to-N ratios most strongly, alder altering soil properties of spruce stands more than birch.
Unravelling the sources of uncertainty in glacier runoff in the Patagonian Andes (40–56° S) 
Authors: Aguayo Rodrigo , Maussion Fabien , Schuster Lilian , Schaefer Marius , Caro Alexis , Schmitt Patrick , Mackay Jonathan , Ultee Lizz , Leon-Muñoz Jorge , Aguayo Mauricio
Published: March 2024

Glaciers are retreating globally and are projected to continue to lose mass in the coming decades, directly affecting downstream ecosystems through changes in glacier runoff. Estimating the future evolution of glacier runoff involves several sources of uncertainty in the modelling chain, which have not been comprehensively assessed on a regional scale. In this study, we used the Open Global Glacier Model (OGGM) to estimate the evolution of each glacier (area > 1 km2) in the Patagonian Andes (40–56° S), which together represent 82% of the glacier area of the Andes. We used different glacier inventories (n = 2), ice thickness datasets (n = 2), historical climate datasets (n = 4), general circulation models (GCMs; n = 10), emission scenarios (SSPs; n = 4), and bias correction methods (BCMs; n = 3) to generate 1,920 possible scenarios over the period 1980–2099. For each scenario and catchment, glacier runoff and melt time series were characterised by ten glacio-hydrological metrics. We used the permutation feature importance of random forest regression models to assess the relative importance of each source on the metrics of each catchment. Considering all scenarios, 30% ± 13% of the glacier area has already peaked in terms of glacier melt (year 2020), and 18% ± 7% of the glacier area will lose more than 80% of its volume this century. In terms of glacier melt metrics, future sources of uncertainty (GCMs, SSPs and BCMs) were the main source for only 18% ± 21% of the total glacier area. In contrast, the reference climate was the main source in 78% ± 21% of the glacier area, highlighting the importance of the choices we made in the calibration procedure. The results provide a basis for prioritising future efforts to reduce glacio-hydrological modelling gaps in poorly instrumented regions, such as the Patagonian Andes.
The impact of convection on the climate of TRAPPIST-1e in global stretched-mesh simulations
Authors: Sergeev Denis , Boutle Ian , Lambert Hugo , Mayne Nathan , Bendall Thomas
Published: March 2024

Convective processes are crucial in shaping exoplanetary atmospheres but are computationally expensive to simulate directly. A novel technique of simulating moist convection, especially on tidally locked exoplanets such as those orbiting TRAPPIST-1, is to use a 3D general circulation model (GCM) with a global stretched mesh. This allows us to locally refine the model resolution to a km-scale and resolve deep convection without relying on parameterization. We explore the impact of explicit vs parameterized convection on the climate of TRAPPIST-1e, a confirmed rocky exoplanet in the habitable zone and a primary candidate for atmospheric characterization. We show allowing for explicit convection in a stretched-mesh simulation results primarily in changes in cloud distribution and precipitation on a planetary scale. Nevertheless, the overall climate state is close to that produced with parameterized convection and a non-stretched mesh. Additionally, these novel simulations shed more light on the bistability of the atmospheric circulation on TRAPPIST-1e. Our methodology opens an exciting and computationally feasible avenue for improving our understanding of fine-scale 3D mixing in exoplanetary atmospheres.
Revisiting excitation of length-of-day using recent GRACE/GRACE-FO, SLR, SLR+GRACE/GRACE-FO gravity solutions and geophysical models
Authors: Śliwińska-Bronowicz Justyna , Nastula Jolanta , Wińska Małgorzata , Partyka Aleksander
Published: March 2024

Variations in Earth’s rotation, encompassing polar motion (PM) and the length-of-day (LOD) changes, result from a variety of factors influencing mass distribution and movement. These factors include the redistribution of air and water masses within the climate system and the solid Earth, and exchanges of angular momentum between the core and mantle. The ability to differentiate between these diverse sources is crucial for comprehending processes occurring at or near the Earth's surface, as well as within its interior.Fluctuations in the low-degree spherical harmonic coefficients of Earth's gravitational potential are linked to the redistribution of mass on a large scale within and on the planet. Observing changes in these coefficients provides a means to investigate the movement of mass within the Earth system. The degree-2 order-0 coefficient (C20) of geopotential holds particular significance for Earth rotation studies since C20 variations (ΔC20) are directly linked to the corresponding excitations of LOD. ΔC20 can be determined from various methods, of which Satellite Laser Ranging (SLR) measurements have the longest tradition. Launching Gravity Recovery and Climate Experiment (GRACE) in 2002 and GRACE Follow-On (GRACE-FO) in 2018 brought new measurements of changes in the Earth's gravitational field, including estimates of the ΔC20. However, estimates of ΔC20 from GRACE/GRACE-FO have limitations due to orbital geometry, the relatively short distance between the two satellites, and tide-like aliases. In practice, GRACE/GRACE-FO computing centres replace ΔC20 with an estimate from SLR measurements. Combining GRACE/GRACE-FO and SLR observations could enhance the accuracy of determining low-degree coefficients of geopotential, including ΔC20, ΔC21, and ΔS21.In this study, we reassess the excitation of LOD over the period 2002–2023, estimated from five different data sources: SLR, GRACE/GRACE-FO, a combination of SLR+GRACE/GRACE-FO, geodetic observations, and geophysical fluid models. To each of the time series we apply the same processing to isolate long-period, seasonal and non-seasonal short-term fluctuations. For every component, we conduct a comparative analysis aiming to evaluate the consistency among various estimates and identify discrepancies between the series. We show that combining GRACE/GRACE-FO with SLR data improves the consistency between ΔC20-derived and observed LOD excitation for the studied oscillations.
Research and Development of Satellite-borne Scanning Array for Hyper-multispectral Radiowave Imaging (SAMRAI)
Authors: Maeda Takashi , Kobayashi Yuta , Trung Nguyen Tat , Yano Tsutomu , Tomii Naoya
Published: March 2024

Scanning Array for hyper-Multispectral RAdiowave Imaging (SAMRAI) is a passive interferometric radiometer. In this respect, it is similar to MIRAS on board the SMOS satellite launched by ESA, but it realizes ultra-wideband (1-41 GHz) and high-frequency-resolution (27 MHz) microwave spectrum measurement. We believe that SAMRAI is the world's first microwave hyperspectral radiometer.JAXA will continue to operate the satellite-borne microwave radiometer AMSR series for more than 30 years, including AMSR3 currently under development. The design has remained largely unchanged for 30 years, and various issues are becoming apparent. In particular, the radio frequency interference (RFI) contaminating the natural-origin signals is a serious problem, and we believe that microwave hyperspectral measurement is essential for identifying and isolating RFI signals. This was a big motivation for developing SAMRAI. However, microwave hyperspectral measurement must have new possibilities, such as making it possible to measure the frequency characteristics of the emissivity of the Earth surface.SAMRAI's key technologies are:1) ultra-highspeed A/D conversion equivalent to 80 GSPS (SPS : samples per second)2) ultra-wideband antenna (1 - 41 GHz) as an element of a phased array antenna (PAA) system3) on-board data processing for an interferometer using FPGA including mitigation of grating lobesSAMRAI was first developed to be mounted on a helicopter (aircraft-borne SAMRAI), and its performance is currently being confirmed. Based on performance confirmation of the aircraft-borne SAMRAI, the final goal is to develop the satellite-borne SAMRAI and launch it in 2027.Here, we presents the detail of the technical points of SAMRAI, the performance confirmation results of the observation experiment by the aircraft-borne SAMRAI and investigation of a new algorithm for geophysical value retrieval based on microwave spectrum measurement.
Numerical modelling of the lahars generated during the 2015 eruption at Volcán Villarrica (Chile)
Authors: Kmetyko Silvio , Mergili Martin , Palma José Luis
Published: March 2024

The Villarrica or Rukapillan is one of the most active volcanoes in South America. In Chile it is the volcano with the highest risk to human life and infrastructure. An eruption on 3rd of March 2015 triggered several lahars that affected four different valleys, where they caused the destruction of touristic infrastructure and parts of the local road network. Adequate numerical simulations of such events can build an important basis for risk management. Various software tools are available to accomplish such task, each of which has its potentials and limitations. This work compares two sets of numerical simulations of the lahars that occurred in the valley Zanjón Seco during the 2015 eruption. The first set is conducted with r.avaflow, a physically-based open-source simulation framework for mass flows and process chains which runs in the GRASS GIS environment. The second is realized with Laharz, a statistically-based tool which runs in an ArcGIS environment. Strengths and weaknesses of both simulation tools in regard to the adequate reconstruction of the observed lahar events reproducing such volcanic hazards are discussed. For this purpose, the model outputs are evaluated against the lahar deposits mapped in the valley and qualitatively compared with each other.
Sensitivity of climate effects of hydrogen to leakage size, location, and chemical background
Authors: Skeie Ragnhild Bieltvedt
Published: March 2024

When hydrogen is used as an energy carrier, some hydrogen will leak into the atmosphere during production, storage, transport, and end use. Hydrogen itself is not a greenhouse gas, but via chemical reactions in the atmosphere, the leaked hydrogen will affect the atmospheric composition of methane, ozone, and stratospheric water vapor and hence radiation in the atmosphere. A recent multi-model study found the Global Warming Potential over a 100-year time horizon (GWP100) to be 11.6 ±2.8 (one standard deviation). In this study, a chemistry transport model (OsloCTM3) is used to investigate the sensitivity of the calculated GWP100 due to the size of the hydrogen perturbation, the location of the hydrogen perturbation as well as the chemical composition of the background atmosphere.The hydrogen perturbation of an additional 0.1, 1, 10 and 100 Tg yr-1 of anthropogenic hydrogen emissions gave GWP values that differed by only 0.4. To test the sensitivity of the location of the perturbation, 1 Tg yr-1 was added to seven different sites around the world. Perturbations at sites that are further away from dry deposition areas (such as middle of the ocean and in Antarctica) resulted in feedback factor larger than one. The GWP values were enhanced compared to perturbations at sites influenced more by dry deposition where feedback factor was less than one. The difference in GWP100 between the two most extreme sites was 4, less than the width of the ± one standard deviation range from the multi-model GWP100 study.The hydrogen economy is expected to grow, and in the future, the atmospheric composition might be different than the 2010 atmosphere used to calculate GWP100 in the multi-model study. To check the sensitivity to this the GWP100 is calculated with the perturbations on top of three different 2050 atmospheres using different SSP scenarios. The three different SSPs had different combinations of NOx to CO emission ratios and methane levels that both influence the atmospheric lifetime of hydrogen. The atmospheric lifetime increased in all the scenarios, and in SSP4-3.4 by as much as ~1 year. However, the dominant control on the total lifetime of hydrogen is the soil sink. Thus, future changes to the soil sink should be investigated, with a focus on how it influences the calculated GWP.
Effects of Heatwaves on European Ground Level Ozone Pollution in Recent Years
Authors: Drysdale Will , Nelson Beth , Wilson Sam , Lee James
Published: March 2024

Heatwaves are phenomena that are occurring with increasing frequency, a trend which is expected to continue over the coming century as the effects of climate change continue to be felt, as has been well documented in the IPCC’s AR6 synthesis report. Heatwaves are of direct concern to human health due to exposure to extreme heat, but also for their secondary impacts including those on air pollution. A heatwave describes a period of hot weather where the air temperature exceeds a climatological average for that region, for example the UK’s Met Office defines these based on the average temperature in a region for the 15th July 1991 - 2020. The meteorology surrounding heatwaves is usually characterised by stagnant conditions, allowing air pollutants to remain closer to their sources and allowing secondary pollutants to form there. Tropospheric ozone is one of these air pollutants, created through the reactions of nitrogen oxides and volatile organic compounds and is harmful to human health.As a part of the World Meteorological Organisation’s Air Quality and Climate Bulletin (2023), we included a short report on the effects of the July 2022 heatwave on ozone concentrations measured across several hundred air quality monitoring stations which were located primarily in urban and rural background locations in Europe. Here we present an extended analysis examining heatwave events over the last decade and their contribution to the number of extreme ozone events experienced at these sites.
Testing the efficacy of grain size-sorted sediment for biomarker analysis to reconstruct palaeoclimate
Authors: Hingley Joe , Bray P. Sargent , Foster Gavin , Whiteside Jessica , Wade Bridget , Inglis Gordon
Published: March 2024

Following the announcement of the retirement of the JOIDES Resolution drilling platform, it has become even more important to efficiently utilise the finite resource of marine sediment stored in IODP repositories. Marine sediments processed for inorganic geochemical analysis are often separated into fine (0.63 µm) fractions to help isolate benthic and planktonic foraminifera. However, organic matter can be associated with different particle size fractions and may have experienced different transport and diagenetic processes. Previous studies have suggested that sieving sediments into different size fractions does not affect the distribution of isoprenoidal [1,2] and branched glycerol dialkyl glycerol tetraethers (GDGTs) [3]. However, this has never been systematically investigated across a wide range of sample types (e.g., age, depositional environment, thermal maturity). It is also unclear whether size processing affects other lipid biomarker proxies (e.g., leaf waxes, alkenones).Here we test whether processing marine sediments into different size fractions influences lipid distributions by separating sediments into fine ( 0.63 µm) fractions and comparing these to corresponding bulk un-sieved sediments. Temperature reconstruction using the marine sea surface temperature proxy TEX86 shows relatively minimal deviation (average ±0.12 TEX86 units, or ~2-3 °C) between the bulk un-sieved sediment (i.e,. control) and fine (10 °C). We also analysed leaf wax derived n-alkanes extracted from the marine sediment to evaluate the impact on terrestrial biomarkers. The average chain length shows similar deviation in both the fine (±0.21 units) and coarse (±0.21 units) fractions relative to the bulk sediment, suggesting that either fraction is suitable for interpreting first-order changes in vegetation type.  Moving forward, our results suggest that the fine fraction of grain size-sorted sediment yield similar lipid distributions compared to the bulk un-washed sediment. However, coarse fractions often show large deviations from the bulk sediment across different proxies, perhaps making these unsuitable for biomarker-based climate reconstruction.References[1] Zachos et al., Geology, 34, 9, pp 737-740 (2006)[2] Xiao et al., Global Biogeochemical Cycles, 37, e2022GB007648 (2023)[3] Peterse and Eglinton, Frontiers in Earth Science, 5, 49 (2017)
Quirquincho and Pampeano-Chaqueño Highs: forebulge or Palaeozoic structures?
Authors: Cortassa Valentina , Ondrak Robert , Back Stefan , del Papa Cecilia , Rossello Eduardo
Published: March 2024

The Andean Foreland Basin in the Chaco-Pampean Plain of North-West Argentina is thought to have been tectonically inactive during the Cenozoic. However, re-interpreted industry seismic-reflection data and borehole information document a complex tectonic history in the subsurface at least until Palaeogene times. Data synopsis and re-analysis reveal two regionally extensive and approximately NW-SE-oriented basement highs beneath the flat present-day surface, the Quirquincho (or Rincón Caburé) High and the Pampeano-Chaqueño High. These large geological structures were described previously, but the mechanism that elevated these features relative to the surrounding stratigraphy and the timing of uplift has remained elusive.This study documents and describes of the Quirquincho and Pampeano-Chaqueño Highs and their relationship to the depocenters around and the sedimentary successions of the Chacoparanaense, Salta Rift and Andean Foreland Basins. We studied palaeo-basin morphology, stratigraphy, stratal terminations and distance to the Andes to unravel viable mechanisms that influenced the genesis of the two structural highs. The work presented is based on the re-interpretation of a large set of subsurface information (2D seismic-reflection profiles and well reports) using a regional approach that considers the Chacoparanaense, Salta Rift and Andean Foreland Basins as a complex lateral arrangement of basins varying in activity through time, depending on their relative location concerning orogens and rifted ocean margins.Our research reveals that the Quirquincho and Pampeano-Chaqueño Highs were elevated features from the Late Palaeozoic to the Palaeogene, strongly influencing the deposition of Mesozoic and Palaeogene sediments. The tectonic mechanism controlling the rise of the Quirquincho and Pampeano-Chaqueño Highs was initially flexural deformation in the foreland of the Gondwanide orogen in the Permian, subsequently influenced in the Mesozoic by the opening of the Southern Atlantic Ocean.
Understanding the methane cycle in heavily populated semi-closed Bays: a case study of Tokyo Bay and the Baltic Sea
Authors: Owari Satoko , Ketzer Marcelo , Gilbert Alexis , Stranne Christian , Chang Cheng , Yu Changxun
Published: March 2024

Methane is an important greenhouse gas, and global methane emission has been estimated separately from the perspective of anthropogenic and natural factors. However, in heavily populated semi-closed bays, methane emissions may be governed by both or even significantly amplified by human activities. One of the main factors mitigating methane emission from marine sediments to seawater and the atmosphere is the anaerobic oxidation of methane (AOM). The sulfate-rich zone acts as a barrier to methane release from the subseafloor because sulfate-dependent AOM removes sulfate and methane dissolved in interstitial water in a 1:1 molar ratio. Due to significant riverine inputs of freshwater and restricted water exchange, the seawater in some of the semi-closed bays is potentially fresher and has lower sulfate concentration, leading to a less effective AOM barrier for methane. Furthermore, the influx of nutrient-rich wastewater to densely populated semi-enclosed bays frequently leads to severe eutrophication, greatly enhancing biological productivity, anoxia, and the accumulation of organic-rich sediments in these systems. The objective of this study is to gain a deeper understanding of how the methane cycle is changed by anthropogenic activities in two case studies, with geochemical datasets collected from Tokyo Bay and the Baltic Sea, both known as heavily populated semi-closed bays.We conducted sediment coring at the entrance of Tokyo Bay and offshore Stockholm in the Baltic Sea. Two cores (2.5 m in length) from Tokyo Bay and six cores (4 to 6 m in length) from the Baltic Sea were recovered, respectively. Organic matter in the surface of 1 m of sediment, which may have been strongly influenced by recent anthropogenic activities, showed 1.5 to 2% and 1.5 to 3.6% of total organic carbon (TOC) in Tokyo Bay and the Baltic Sea, respectively. These results indicate the Baltic Sea has a higher potential to generate more methane than the Tokyo Bay. The sulfate concentration at the seafloor was 27 mM in Tokyo Bay and 4 mM in the Baltic Sea and decreased with depth due to the AOM reaction reaching 0 mM at 2.5 mbsf in both bays. The thickness of the sulfate reduction zone was the same in both bays, even though they have a large difference in sulfate concentration in the bottom seawater. The iodine concentration, which has been used as a tracer for methane due to its close association with organic matter, increased with depth up to 74 µM at 2.5 mbsf in Tokyo Bay and 63 µM at 4.5 mbsf in the Baltic Sea. The iodine flux in Tokyo Bay was two times higher than in the Baltic Sea, indicating the possibility of strong methane flux from deeper sediments, which may not directly derive from Anthropocene organic-rich sediment. We will discuss and compare the details of the geochemical datasets in both Bays in the presentation.
Vary me a river: investigating the impacts of climate variability on hydropower and electricity systems planning in Switzerland
Authors: Haddad Yann Yasser , Gudmundsson Lukas , Raycheva Elena , Savelsberg Jonas , Wechsler Tobias , Zappa Massimiliano , Hug Gabriela , Seneviratne Sonia Isabelle
Published: March 2024

Clean and renewable energy systems play a pivotal role in climate change mitigation strategies. Nevertheless, climate change constitutes a threat to current and future supply of clean energy.  In this study, we investigate how climate variability affects hydropower production and electricity systems planning in Switzerland. As the “water tower of Europe”, Switzerland encompasses a wide range of hydro-climatological conditions and showcases a high share of hydropower in its energy mix, making it a relevant case study.Focusing on all hydropower plants with a capacity > 300 kW, we used daily runoff simulations from the PREVAH model, at 500 m resolution spanning 1991-2022, to estimate water availability and hydropower production for each power plant. The climate-impacted hydropower production time series are then given as input to Nexus-e, an integrated electricity systems modeling framework. This enables us to model the future state of the electricity system in Switzerland while considering climate variability.Our method provides an accurate estimation of national hydropower generation and its variations. The integration of climate informed inputs into Nexus-e yields strong impacts on simulated investments in renewable energy and economic indicators such as power prices and imports/exports. Notably, in case of a projected decrease in hydropower generation due to increased drought occurrence, an increase in wind turbine and alpine PV capacity is needed to meet electricity demand. This scenario poses several societal and political questions regarding the implementation of a resilient energy system for Switzerland in the context of increasing changes in the climate system and pressure on ecosystems and biodiversity.
Ensemble streamflow probability prediction at the sub-seasonal to seasonal (S2S) timescale
Authors: Li Lingfeng , Wu Huan , Lu Lujiang , Chen Weitian
Published: March 2024

Sub-seasonal to seasonal (S2S) weather forecasting is widely regarded as a big challenge because of less predictability than short-term and seasonal forecasts, which significantly impedes the streamflow forecasts at the same time scale. In this study, we propose an integrated numerical and statistical approach to improve the accuracy of S2S streamflow forecasting based on a physically based hydrological model, i.e., the Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model with a Bayesian joint probability (BJP) model. The DRIVE model provides S2S streamflow simulations by leveraging physical processes, while the BJP model could mitigate the issue of over-fitted flood peaks and partially correct under-fitted flows. The main strategy to reduce the streamflow prediction uncertainty is through optimizing the integration of hydrological model simulations and statistical predictions. We applied the integrated DRIVE-BJP model to the Pear River Basin during the 2020-2022 time period and performed the validation according to observations at 24 hydrological stations located within the river basin. The results show the proposed ensemble approach yields significant improvements compared to the single BJP or DRIVE model. This study of fusion of the DRIVE and BJP models to enhance the sub-seasonal flood prediction, showing promising practical values in flood early warning and water resource management.Key words: S2S, ensemble streamflow forecast, DRIVE model, BJP model, Pearl River basin