bluuebunny/crossref_metadata_2025 huggingface dataset:
A Tsunami Generated by a Strike-Slip Event: Constraints From GPS and SAR Data on the 2018 Palu Earthquake
Authors: Simons Wim , Broerse Taco , Shen Lin , Nijholt Nicolai , Kleptsova Olga , Hooper Andrew , Pietrzak Julie , Morishita Yu , Naeije Marc , Lhermitte Stef , Govers Rob , Vigny Christophe , Visser Pieter , Riva Riccardo
Published: February 2023

A devastating tsunami struck Palu Bay in the wake of the 28 September 2018 Mw = 7.5 Palu earthquake (Sulawesi, Indonesia). With a predominantly strike-slip mechanism, the question remains whether this unexpected tsunami was generated by the earthquake itself, or rather by earthquake-induced landslides. In this study we examine the tsunami potential of the co-seismic deformation. To this end, we present a novel geodetic data set of Global Positioning System and multiple Synthetic Aperture Radar-derived displacement fields to estimate a 3D co-seismic surface deformation field. The data reveal a number of fault bends, conforming to our interpretation of the tectonic setting as a transtensional basin. Using a Bayesian framework, we provide robust finite fault solutions of the co-seismic slip distribution, incorporating several scenarios of tectonically feasible fault orientations below the bay. These finite fault scenarios involve large co-seismic uplift (>2 m) below the bay due to thrusting on a restraining fault bend that connects the offshore continuation of two parallel onshore fault segments. With the co-seismic displacement estimates as input we simulate a number of tsunami cases. For most locations for which video-derived tsunami waveforms are available our models provide a qualitative fit to leading wave arrival times and polarity. The modeled tsunamis explain most of the observed runup. We conclude that co-seismic deformation was the main driver behind the tsunami that followed the Palu earthquake. Our unique geodetic data set constrains vertical motions of the sea floor, and sheds new light on the tsunamigenesis of strike-slip faults in transtensional basins.
The role of CO2 degassing in the seismogenic process of the Apennines, Italy
Authors: Di Luccio Francesca ,   The FURTHER Team
Published: February 2023

An accurate survey of old and new datasets allowed us to probe the nature and role of fluids in the seismogenic processes of the Apennines mountain range in Italy. Geodynamics, geophysical and geochemical observations highlight differences between the western and eastern domains of the Apennines, and the main characteristics of the transition zone, which spatially corresponds with the overlapping Tyrrhenian and Adriatic Mohos. Tomographic images exhibit a large hot asthenospheric mantle wedge that intrudes beneath the western side of the Apennines and disappears at the southern tip of the southern Apennines. This wedge modulates the thermal structure and rheology of the overlying crust as well as the melting of carbonate-rich sediments of the subducting Adriatic lithosphere. As a result, CO2-rich fluids of mantle-origin have been recognized in association with the occurrence of destructive seismic sequences in the Apennines. The stretched western domain of the Apennines is characterized by a broad pattern of emissions from CO2-rich fluids that vanishes beneath the axial belt of the chain, where fluids are instead trapped within crustal overpressurized reservoirs, favoring their involvement in the evolution of destructive seismic sequences in that region. In the Apennines, areas with high mantle He are associated with different degrees of metasomatism of the mantle wedge from north to south. Beneath the chain, the thickness and permeability of the crust control the formation of overpressurized fluid zones at depth and the seismicity is favored by extensional faults that act as high permeability pathways. This study strongly relies on the multidisciplinary analysis of different datasets (both existing and newly acquired) with the most advanced methodologies to stimulate the knowledge of the fluid-related mechanisms of earthquake preparation, nucleation and space-time evolution. Ongoing and future investigations will include the continuous and simultaneous geochemical and geophysical monitoring at the scale of the outcropping seismogenic faults to properly decipher the link between earthquake occurrence, surface rupture and fluid release.
Better late than never: arrival of decadal predictions to the climate services arena
Authors: Solaraju-Murali Balakrishnan , Bojovic Dragana , Gonzalez-Reviriego Nube , Nicodemou Andria , Terrado Marta , Caron Louis-Philippe , Doblas-Reyes Francisco J.
Published: February 2023

Decadal prediction represents a source of near-term climate information that has the potential to support climate-related decisions in key socio-economic sectors that are influenced by climate variability and change. While the research to illustrate the ability of decadal predictions in forecasting the varying climate conditions on a multi-annual timescale is rapidly evolving, the development of climate services based on such forecasts is still in its early stages. This study showcases the potential value of decadal predictions in the development of climate services. We summarize the lessons learnt from coproducing a forecast product that provides tailored and user-friendly information about multi-year drought conditions for the coming five years over global wheat harvesting regions. The interaction between the user and climate service provider that was established at an early stage and lasted throughout the forecast product development process proved fundamental to provide useful and ultimately actionable information to the stakeholders concerned with food production and security. This study also provides insights on the potential reasons behind the delayed entry of decadal predictions in the climate services discourse and practice, which were obtained from surveying climate scientists and discussing with decadal prediction experts.
Models for the dynamic triggering of volcano seismicity at Sierra Negra, Galápagos Islands.
Authors: Dunn Eleanor , Bean Chris , Bell Andrew , Lokmer Ivan
Published: February 2023

Dynamic earthquake triggering is the process where local earthquakes are triggered by dynamic stress perturbations often from teleseismic earthquakes. Dynamic triggering from regional earthquakes can also trigger local volcanic seismicity. An understanding of dynamic triggering on volcanoes offers a window into volcano stress state and seismicity initiation, in general. Repeated episodes of dynamic triggering have been recorded at Sierra Negra, a large basaltic shield volcano on Isabela Island, Galápagos. Sierra Negra is a large elliptical summit caldera with a trap-door fault system and a 2km deep sill-like magma reservoir below the caldera. Sierra Negra erupted in June 2018, as part of a cycle of pre-eruption inflation, co-eruption deflation, and renewed post-eruption inflation. Dynamic earthquake triggering was observed at Sierra Negra following high magnitude teleseismic events that occurred from 2010-2018, with the number of dynamically triggered earthquakes increasing with increasing inflation of the magma reservoir. However, the locations and mechanisms of this dynamic triggering have not been determined. In this study, we aim to answer two questions: 1) is it possible to successfully interpret dynamic triggering on Sierra Negra and, 2) can dynamic triggering in Sierra Negra be used as a stress gauge? To interpret dynamic triggering, an STA/LTA detection algorithm has been designed which detects when a dynamically triggered event has happened. This provides insight into how regularly dynamic triggering occurs on Sierra Negra and how, if at all, it is related to teleseismic events. The detection algorithm has also been used to compare the dynamic triggering rate to the local seismic rate on Sierra Negra. We have also located where dynamic triggering occurs on Sierra Negra. To address question two; Peak Dynamic Strain (PDS) has been used as a threshold to detect when dynamic triggering occurs, PDS can be used to understand the stress state of Sierra Negra pre-, co- and post-2018 eruption. Looking forward we hope to understand the relationship between the location and timing of dynamic triggering, and its potential use in understanding volcano unrest state.
Doppler shifted auroral Lyman-alpha spectra observed by DMSP/SSUSI
Authors: Liou Kan , Paxton Larry , Zhang Yongliang , Schaefer Robert
Published: February 2023

Proton auroras are produced by energetic protons that precipitate, undergo charged exchange, and subsequently emit hydrogen lines before they are ionized again. When viewed from space, the spectral shape of proton auroras is expected to shift to longer wavelengths (red shift) due to the Doppler effect. Reports on space-based observations of Doppler shift of hydrogen Lyman-alpha spectral line associated with auroral proton precipitation are still rare. The Special Sensor Ultraviolet Spectrographic Imager (SSUSI) on board the Defense Meteorological Satellite Program (DMSP) series is a line scanning imaging spectrograph covering the far ultraviolet (FUV) spectrum from ~112 to 185 nm with 160 spectral bins. Under the spectragraph mode, SSUSI is supposed to be able to provide information about proton auroral precipitation. Here we present results from our first attempt to extract Doppler shift of Lyman-alpha spectral line of Hydrogen from the SSUSI data. We show red-shifted Lyman-alpha spectra observed by SSUSI whenever the DMSP satellite traverses the auroral oval, especially during geomagnetic active time. In general, a larger red shift appears in the nightside than dayside oval crossing and in the equatorward than poleward half of the oval. These are generally consistent with in situ auroral particle observations reported previously. Thus DMSP/SSUSI provides an alternative means to monitoring the energetic of proton precipitation.
Does the perspective of Global Mean Temperature decreasing after peak warming in an overshoot pathway matter for adaptation?
Authors: Lejeune Quentin , Kropf Chahan M , Schleussner Carl
Published: February 2023

Limited global gas emissions reductions would lead to exceeding 1.5˚C and even 2˚C of global warming compared to pre-industrial levels. Yet many emission scenarios included in the last IPCC report feature a decrease in Global Mean Temperature (GMT) after peak warming, even suggesting that levels compatible with the Long-Term Temperature Goal of the Paris Agreement could be reached again within the 21st century. In contrast with the prominence of overshoot pathways in the literature, their implications for adaptation planning have not been discussed. Many factors are taken into account when it comes to decision-making about adaptation, however it could be argued that the perspective of seeing in the future Global Mean Temperature decrease after peak warming constitutes a disincentive to deploy adaptation measures dimensioned against impacts to be expected at peak warming. In this study, we take the viewpoint of a decisionmaker who is trying to determine the extent to which they should adapt their assets to optimize costs. We assume that this decision is made in 2040, when global warming has just reached 1.5˚C and that the decisionmaker has full knowledge of the future evolution of GMT and resulting potential impacts from 1-in-100-year tropical cyclones on their assets. We consider three idealized pathways: two overshoot pathways in which GMT peaks in 2060 (at 1.65 or 1.8˚C) before coming back to 1.5 in 2080, and a third one in which it stabilizes at 1.65˚C as of 2060. We then compare the sum of the one-off costs of implementing adaptation measures and of the expected damages from tropical cyclones on the assets for two options: the decisionmaker decides to adapt against the level of damages expected at 1.5˚C, or at Peak Warming (1.65 or 1.8˚C). We also assess the sensitivity of the results to the evolving perceived value of the assets via a discount or growth (inflation) rate. We find that adapting to impacts at peak warming is more cost-efficient for adaptation measures characterized by high efficiency (effectiveness divided by costs), while adapting to impacts at 1.5˚C is more cost-efficient for measures with low efficiency. In contrast, which option is more cost-efficient does not depend on the GMT pathway, although the differences in total costs between the two options become stronger in pathways that reach higher levels of global warming. Higher discount rates constitute incentives to adapt to lower levels of global warming, whereas this is the opposite for higher growth rates. Overall, these results suggest that the perspective of decreasing GMT in the future plays a limited role in adaptation decisionmaking, and that it should not be perceived as an incentive not to deploy adaptation measures.
Life-cycle CO2 and Air Pollutant Emission Assessment of China’s Cement Industry under Planetary Boundaries
Authors: Cai Xingrui , Zheng Chaoyue , Meng Jing , Wang Xuejun
Published: February 2023

China is the world’s largest cement producer and consumer, contributing 58% of the world’s total cement production in 2020. The cement industry in China is associated with 4–5% of China’s total energy production and contributes 10–15% of national total CO2 emissions, ranking second only to the power industry, and also significant air pollutant discharges such as SO2, NOx and particulate matter (PM). Since China’s energy and environmental policies for the cement industry usually focus on specific energy/environment effects and a single manufacturing process, this study described the cradle-to-gate lifecycle covariation relationship of these effects and analyzed the potential transgression magnitude to related planetary boundaries to assist in designing low carbon and pollution industrial transition in Chinese cement industry. The multi-regional decomposition analysis model, the LMDI decomposition, and the SDA method were employed to identify the driving factors such as energy intensity, manufacturing technology, economic structure, intermediate demand and structure, and total demand. We found that the Chinese cement industry not only causes massive emissions directly but also imposes environmental burdens on other sectors through up- and downstream supply chains, especially in eastern and central regions. Scope 1 and 2 emissions decreased sharply for CO2, SO2, and PM thanks to stricter environmental regulations, but Scope 3 emissions of CO2 increased by approximately 30%, contributed by energy intensity and economic structural change. Although total emissions basically presented decline trends, several national and regional planetary boundaries might be transgressed under downscaling principles based on population, and gross value added. This work improves our understanding of lifecycle carbon emissions and pollution and related total environmental burden in terms of planetary boundaries, thus offering references for the implementation of energy conservation and environment policies in the Chinese cement industry.
Low-energy electron spectrometer to study the far environment of a dynamically new comet as a part of the Comet Interceptor payload
Authors: Prech Lubomir , André Nicolas , Lavraud Benoit , Verdeil Christophe , Fedorov Andrei , Vaverka Jakub ,   LEES Technical and Scientific Teams
Published: February 2023

Comet Interceptor is the ESA F1 space mission aiming to explore a comet very likely entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star, scheduled for launch in 2029 together with the ESA L-class Ariel spacecraft. Following the mission adoption in June 2022, the spacecraft and scientific payload development have advanced to the Phase C. In our contribution we present the status of development of the Low-energy electron spectrometer (LEES) that is a part of the Dust-Fields-Plasma multi-instrument suite deployed at the main spacecraft A (DFP-A).The DFP-A/LEES sensor will determine the thermal and suprathermal electron densities, temperatures, and the velocity distribution functions of the local plasma environment of both the solar wind and coma. It will also measure the local properties of negatively charged ions and dust, and detect photoelectrons resulting from neutral-plasma interactions in order to infer the magnetic connectivity between the cometary environment and the spacecraft. The LEES measurements are needed to understand the ionization sources of the cometary neutral gas as well as to infer the plasma boundaries of the induced magnetosphere of the comet. The electron spectrometer is a further miniaturized version of the top-hat analyser inherited from the Stereo, Maven and BepiColombo missions. We present the overall design, simulation of the spacecraft electromagnetic and particle environment influence to the LEES measurements and the intermediate results of testing of the LEES components to survive a potential harsh dust environment during the comet flyby.   
Ultra-slow transverse waves during continental extension: A numerical model of the rift-drift transition
Authors: Schettino Antonio , Ranalli Giorgio
Published: February 2023

Continental rifting is one of the four fundamental geological processes of the Wilson cycle. Rifting results from the continuous stretching of a continental mass and involves mechanical, thermodynamic, and rheological processes. It may last several tens Myrs and be followed by a catastrophic breakup stage (drifting), which determines cessation of continuous deformation and the final separation of a continent into two distinct tectonic plates that grow by accretion of oceanic lithosphere. To date, the transition to sea-floor spreading and the conditions for the development of a new ocean have not been fully understood. We present numerical experiments showing that a nonlinear viscoelastic model of the cratonic lithosphere, allowing accumulation of elastic strain over several Myrs, may explain the major features of the rift-drift transition. The model incorporates thermodynamic effects associated with viscous shearing, showing how thermal anomalies generated in the lithosphere during rifting play a major role in the break-up style. A fundamental result of the experiments is that extension is always accompanied by transverse material waves in the lithosphere, with wavelengths of the order of thousands km and periods of several tens kyrs. These waves induce an oscillating topography and could be responsible for high−frequency transgressive–regressive cycles in rift lakes. At sufficiently high extension rates, deformation localizes and these ultra-slow waves determine cyclic shear failure, with formation of X-shaped cross structures through the lithosphere that prelude to the final rupture. A comparison with the Red Sea evolution shows that onset of extension could be older than the widely accepted age of 27-30 Ma and that an older phase of uniform stretching without localization could have preceded the formation of a rift valley.
Fibre-optic dynamic strain borehole sensing at Etna volcano
Authors: Jousset Philippe , Currenti Gilda , Napoli Rosalba , Pulvirenti Mario , Pelligrino Daniele , Cunow Christian , Larocca Graziano , Bonaccorso Alessandro , Leto Giuseppe , Krawczyk Charlotte
Published: February 2023

Volcano monitoring has been experiencing significant improvements in recent years, yet eruption forecasting and scenarios have still lack of understanding, due to the poor observations in low amplitude events and hindered by surface external noise of similar amplitudes. Volcanic events have been shown to be accurately recorded with fiber optic techniques at the surface. In this study, we present preliminary results of fibre optic cable deployed in a new 200 m deep borehole on the southern flank of Etna at about 6 km away from the summit crater. This borehole has been designed primarily for the future deployment of a new strain sensor type. We benefited from the drilling of this new borehole to deploy a single-mode fibre optic cable. We connected an interrogator and recorded dynamic strain rate during several periods: first, in 2020 for several days during the completion of the borehole and the final stage of the drilling; second, in 2021 for several weeks during an active volcanic period; and in December 2022 during a quiet activity period of several months. We present a selection of records of noise while drilling, local volcano-tectonic earthquakes and volcanic events and tremor that occurred during those periods. These examples show the benefit of deploying a fibre in a borehole far from the active area and demonstrate the great variety of signals fibre optic can record is such configuration.
Antarctic firn air content depletion for different climate change scenarios
Authors: Veldhuijsen Sanne , van de Berg Willem Jan , Kuipers Munneke Peter , van den Broeke Michiel
Published: February 2023

Firn covers about 99% of the Antarctic ice sheet, providing, among other things, pore space in which most of the surface meltwater refreezes. Under anticipated future warming, surface melt, densification rates and the formation of impermeable ice layers are expected to increase, resulting in the depletion of reachable firn air content and consequently accelerated firn saturation by melt water. Firn saturation on Antarctica’s floating ice shelves is especially important, as this can potentially lead to their disintegration by hydrofracturing. On the other hand, snowfall is expected to increase as well, which will add pore space to the firn.       In this study, we simulate the historical (1950-present) and future (present until 2100) transient evolution of the Antarctic firn layer under three different climate change scenarios. For this we use the IMAU Firn Densification Model driven by outputs of the Community Earth System Model (CESM2), dynamically downscaled to 27 km resolution with the Regional Atmospheric Climate MOdel (RACMO), version 2.3p2. We analyze the dominant atmospheric and firn processes and investigate under which conditions firn air content depletion is expected to occur. We show that ice shelves around the Antarctic Peninsula and the Roi Baudouin ice shelf are most vulnerable to firn air content depletion, whereas strong firn air content loss on the Ross and Filchner-Ronne ice shelves is not expected to occur before 2100 under all climate change scenarios. We discuss potential reasons for the differences between this ‘transient’ modelling approach from recently applied ‘diagnostic’ studies.
Combining a novel in-situ sensor system with remotely sensed thermal infrared data to analyse spatial water temperature patterns in 3D
Authors: Loerke Eva , Geris Josie , Pohle Ina , Wilkinson Mark
Published: February 2023

To monitor aquatic habitats and understand physical and biogeochemical processes, the analysis of high-resolution spatial patterns in water temperature is of outmost importance. The spatial resolution of remotely sensed thermal infrared (TIR) data ranges from cm-scale for airborne to m- and km-scale for spaceborne observations, enabling the analysis of a variety of hydrological processes. However, while remotely sensed TIR data reflects temperatures emitted from the direct surface, the temperature of waterbodies may also vary significantly with depth. Hence, there are limits to relying purely on remotely sensed water temperature data to understand 3D water temperature patterns, leading to the need of high-resolution 3D water temperature data.Here, we combined a novel self-build in-situ sensor system with remotely sensed TIR data to explore high-resolution, natural and anthropogenically influenced 3D spatio-temporal patterns in river water temperature. The study site involved a ~780 m long stretch of a river in the Northeast of Scotland, with a smaller section (~50m long) that is influenced by cooling water being discharged from a local distillery. We applied our new observation system to gain a better understanding on the 3D extend of a thermal plume and how this local anomaly compares to and affects the overall thermal variability within the river. Three surveys were conducted (during April-June 2021) to measure the surface water temperature of the river with an UAV based TIR camera. We additionally installed the novel in-situ sensor system to measure 3D water temperature during each survey. The surveys were planned to acquire data under contrasting ambient conditions as well as at a time when no cooling water was being discharged, allowing us to also observe spatio-temporal thermal variability under natural conditions. While the acquired TIR datasets give an overall view of the thermal variability at the surface, subsets of the TIR datasets were merged with the corresponding data from the in-situ sensor system to spatially interpolate high resolution 3D water temperature of the area influenced by the thermal plume. The results show that (I) the combination of remote sensing and sensor system can detect pattern in 3D in high spatial resolution, (II) surface temperatures and their spatial patterns differ from temperatures and their spatial patterns at greater depth and (III) at this site, local anomalies due to cooling water releases do not alter the overall thermal variability within the river.The combination of the novel sensor system with remotely sensed TIR data has the potential to be used to observe a broad range of hydrological processes in natural and artificial aquatic environments and to contribute to the understanding of overall energy budgets, infiltration, limnology, groundwater surface water exchange or similar processes.
Antarctic Ice Sheet tipping points in the last 800,000 years
Authors: Chandler David , Langebroek Petra , Reese Ronja , Albrecht Torsten , Winkelmann Ricarda
Published: February 2023

Stability of the Antarctic Ice Sheet in the present-day climate, and in future warming scenarios, is of growing concern as increasing evidence points towards the prospect of irreversible ice loss from the West Antarctica Ice Sheet (WAIS) with little or no warming above present. Here, in transient ice sheet simulations for the last 800,000 years (9 glacial-interglacial cycles), we find evidence for strong hysteresis between ice volume and ocean temperature forcing through each glacial cycle, driven by rapid WAIS collapse and slow recovery. Additional equilibrium simulations at several climate states show this hysteresis does not arise solely from the long ice sheet response time, instead pointing to consistent tipping-point behaviour in the WAIS. Importantly, WAIS collapse is triggered when continental shelf bottom water is maintained above a threshold of 0 to 0.25°C above present, and there are no stable states for the WAIS in conditions warmer than present. Short excursions to warmer temperatures (marine isotope stage 7) may not initiate collapse (‘borrowed time’), while the more sustained interglacials (stages 11, 9, 5e) demonstrate an eventual WAIS collapse. Cooling of ca. 2°C below present-day is then required to initiate recovery. Despite the differing climatic characteristics of each glacial cycle, consistency between both the transient and equilibrium behaviour of the ice sheet through several cycles shows there is some intrinsic predictability at millennial time scales, supporting the use of Pleistocene ice sheet simulations and geological evidence as constraints on likely future behaviour.
Dispersed East Africa-Arabia volcanism fed by a star-shaped mantle plume head
Authors: Civiero Chiara , Lebedev Sergei , Celli Nicolas L.
Published: February 2023

Hot mantle plumes, the thermo-chemical instabilities rising from Earth’s deep mantle, are believed to form large, round heads, followed by narrow tails. The impact of a plume onto the continental lithosphere causes uplift, rifting, and flood basalt volcanism. The resulting large igneous provinces (LIPs) are thought to be emplaced rapidly above the plume head as it arrives and spreads, as a circle, beneath the plate. However, LIP eruptions often span up to tens of millions of years in time and are scattered unevenly over areas a few thousand kilometres across, which is inconsistent with this conventional view. Here, we use seismic waveform tomography and obtain clear images of interconnected corridors of hot, partially molten rock beneath the areas of uplift and volcanism in the East Africa-Arabia region. The spatial continuity of the hot rock corridors and the temporal continuity of the volcanism since ~45 million years ago suggest that we are witnessing an extant, integral plume head that was morphed into a three-pointed star by the topography of the lithosphere-asthenosphere boundary. Eruption ages and plate reconstructions indicate that the plume head spread south-to-north, and tomography shows it being currently fed by three upwellings beneath Kenya, Afar, and Levant. Star-shaped plume heads within thin-lithosphere valley systems can account for the enigmatic dispersed and protracted volcanism in LIPs and are, probably, an inherent feature of plume-continent interaction.
Mapping 21st Century global coastal land reclamation
Authors: Sengupta Dhritiraj , Rae Choi Young , Bo Tian Bo , Brown Sally , Meadows Michael , R Hackney Christopher , Banerjee Abhishek , Li Yingjie , Chen Ruishan , Zhou Yunxuan
Published: February 2023

Increasing population size and economic dependence on the coastal zone, coupled with the growing need for residential, agricultural, industrial, commercial, and green space infrastructure, are key drivers of land reclamation. Until now, there has been no comprehensive assessment of the global distribution of land use on reclaimed space at the coast. Here, we analyse Landsat satellite imagery from 2000 to 2020 to quantify the spatial extent, scale, and land use of urban coastal reclamation for 135 cities with popultions in excess of one million.  Findings indicate that 78% (106/135) of these major coastal cities have resorted to reclamation as a source of new ground, contributing a total of 253,000 ha of additional land to the Earth’s surface in the 21st century, equivalent to an area the size of Luxembourg. Reclamation is especially prominent in East Asia, the Middle East, and Southeast Asia, followed by Western Europe and West Africa. The most common land uses on reclaimed spaces are port extension (>70 cities), followed by residential/commercial (30 cities) and industrial (19 cities). While increased global trade and rapid urbanization have driven these uses, we argue that a city’s prestigious place-making effort to gain global reputation is emerging as another major driver underlying recent reclamation projects to create tourist and green spaces Meanwhile, the study suggests that 70% of recent reclamation has occurred in areas identified as potentially exposed to extreme sea level rise (SLR) by 2100 and this presents a significant challenge to sustainable development at the coast.  
A Statistical Study of Foreshock Environment under Radial IMF Conditions
Authors: Pi Gilbert , Salohub Anna , Xirogiannopoulou Niki , Němeček Zdeněk , Šafránková Jana
Published: February 2023

The foreshock is a turbulent region in front of the quasi-parallel bow shock. The reflected particles from the bow shock and interaction with oncoming waves in the solar wind create it. The foreshock is usually located at the dawn side. However, the foreshock region is relocate to the nose of the bow shock and covers all the dayside magnetospheric system when IMF points to radial or anti-radial directions. This change creates many unusual phenomena in the magnetospheric system, such as the magnetopause expansion, and generates the foreshock transients, such as spontaneous Hot Flow Anomalies (sHFA). Previous studies revealed that foreshock transients are preferred to occur under a radial IMF condition, however, what is the reason for this preference is still unclear. Using THEMIS and MMS data, the analysis presents a statistical analysis to reveal the foreshock characteristics under the radial IMF to check the reasons for the preference of foreshock transients. The primary solar wind parameters in the foreshock and/or solar wind under these conditions are revealed. The ULF wave behavior is also taken account.
High-resolution stable isotopic and trace element data of cryogenic cave carbonates from an alpine cave: preliminary results
Authors: Koltai Gabriella , Baldini James U.L. , Ottley Christopher J. , Iveson Alexander A. , Spötl Christoph
Published: February 2023

Coarsely crystalline cryogenic cave carbonates (CCC for short) are unique speleothems that precipitated in small water pools in cave ice via slow freezing. Their formation requires cave air temperatures very close to the 0°C isotherm. CCC have become increasingly important over the last decade and are one of the best terrestrial archives providing highly precise chronological constraints on paleo-permafrost degradation. Although a growing number of studies use CCCs as a time-marker of permafrost thawing, the details of their formation mechanism remain unanswered.CCC found at over a dozen sites in the ice-free parts of Eisriesenwelt (Tennengebirge, Eastern Alps) cover a wide spectrum of morphologies from skeletal crystals to more complex beak-like and hemispheric structures. At some sites one or two morphologies are dominant, while at other sites several different types occur together. The mechanisms of formation of many of the morphologies remain enigmatic.Here we present first results of high-resolution trace element (Mg, Sr, Ba, and U) and stable isotope (C and O) analyses of a white pea-like spherulite (~8 mm) and two beak-like aggregates (~12 and 15 mm in diameter) from Eisriesenwelt. The latter type shows an amber-coloured inner core, overgrown by more porous light brown to almost whitish calcite.Oxygen isotope ratios of one of the beak-like aggregates reduce progressively by 4.8‰ from the core towards the rim, while carbon isotope values increase by 2.1‰, reflecting the progressive freezing of the water. The dark brown calcite is characterized by low Mg, Sr, and Ba but high U values compared to the light brown calcite. Trace element analyses also indicate an increase in Mg and Sr towards the rim, whereas U shows the opposite trend. In the white hemispheric spherulite sample, oxygen isotope ratios show a larger (up to 2‰) intracrystalline variability, and a 5.8‰ decrease over the last 2 mm of the sample. In contrast, carbon isotope values vary only by 0.5‰. Mg values show an increasing trend through time, from core to rim. Sr, U, and Ba concentrations do not exhibit a clear pattern, except for a sharp change before the cessation of CCC growth. This is likely related to the presence of a thin (hundreds of 100µm), translucent calcite rim, expressed as an increase (decrease) in Mg, Sr, U (and Ba) concentrations. In both morphologies Ba follows a similar pattern as Sr, however Ba values decrease progressively before the cessation of CCC growth.Formation of CCC of the coarse crystalline variety has not been observed in-situ, limiting their significance as robust indicators of thawing conditions in ice caves. Studying individual CCC samples using a combination of high-resolution stable isotope and trace-element analyses is an important, but currently underdeveloped, approach to improving our understanding of CCC formation.
A high-resolution, operational pan-Arctic meltwater discharge database from 1950 to 202
Authors: Igneczi Adam , Bamber Jonathan
Published: February 2023

The Arctic has warmed about four times faster than the global average during the last four decades. One of the consequences of this intensive warming is increasing Arctic land ice loss. In particular, mass loss from the Greenland Ice Sheet has been estimated to have increased sixfold between 1980 and 2020. Glaciers and ice caps outside of Greenland, though receiving less attention, have also been reported to be losing mass at an increasing rate. This is caused by a combination of negative surface mass balance – due to decreasing snowfall and/or increasing melting and runoff – and increasing ice discharge. However, negative surface mass balance due to increasing melting and runoff has become the dominant cause of mass loss in Greenland and the Canadian Arctic during the last 10-15 years. This indicates the increasing role of meltwater discharge into fjords and coastal seas, influencing a wide-range of physical, chemical and biological processes and also the large-scale oceanic circulation. Despite recent advancements, no meltwater discharge data products are available that cover the entire Arctic at a high spatial (< 1 km) and temporal (sub-monthly) resolution. To fill this data gap, we use daily ~6km runoff data from a regional climate model, Modéle Atmosphérique Régional (MAR), for the period of 1950-2021 – covering Greenland, Arctic Canada, Iceland, Svalbard, and Arctic Russia. We employ a statistical downscaling algorithm that utilises a high resolution (250 m) DEM, land mask (Copernicus GLO-90), and ice mask (GIMP, RGI). A hydrological routing scheme is also applied to the downscaled runoff to provide meltwater runoff data at coastal outflow points. Meltwater components coming from non glacierized land, bare glacier ice, and glacierized area above the snowline are separated to aid further analyses. The software pipeline is designed to be fully operational so that it can be used to update the time series as soon as the input data are available, so providing a continuous time series for the entire Arctic within the framework of a project aimed to develop a holistic, integrated observing system for the Arctic (www.arctipassion.eu).
Last postglacial sea-level fluctuations control fluvial morphodynamics along the West Coast of Sumatra, Indonesia
Authors: Rohrmann Alexander , Fischer Alina , Hülscher Julian , Bernhardt Anne
Published: February 2023

The west Coast of central Sumatra is situated above the Sumatra subduction zone and is characterized by short (< 100 km) and very steep (> 20°) bed rock channels draining the volcanic arc towards the Indian Ocean. Incision and fluvial adaptation of these catchments are commonly attributed to tectonic uplift along the subduction zone and emplacement of magma bodies within the volcanic arc. Recent recognition of a regional sea-level high stand between 4,500 to 5,000 years ago and the low shelf depth of ~70 m below sea level, may indicate that base-level fluctuations had a stronger control on river network dynamics than previously thought. Here, we explore the impact of these processes on the fluvial morphology and the incision history of 31 catchments draining the volcanic arc of west-central Sumatra. Landscape evolution simulations using PyBadlands, geomorphic metrics of the normalized-steepness index, knickpoint detection and c-analysis derived from 30 m SRTM-satellite data demonstrate that the morphometric response of smaller catchments (drainage area: < 500 km2) is different from that of larger catchments (drainage area: > 500 km2). The reduction in overall drainage area due to the last postglacial sea-level rise forced smaller catchments to oversteepen to adjust to the new conditions. Instead, larger catchments responded by upstream drainage area expansion and capture of previously eastward flowing rivers, thus maintaining an overall lower gradient. Furthermore, the mid-Holocene high-stand and subsequent sea-level drop resulted in a major regional base-level fall and creation of a knickzone along the entire West Coast of Sumatra that is currently migrating up the fluvial network and is located at an elevation of around 200 m. Our results imply that (1) the tempo of fluvial incision between catchments along the West Coast of Sumatra may be out of phase with the uplift of the volcanic arc; (2) the drainage area reduction due to postglacial sea-level rise controlled fluvial catchment evolution; and (3) we observe a catchment size depended threshold at which catchments either oversteepen or incise headward to adjust for drainage area loss. This response should be applicable to all natural occurring fluvial bedrock channels that experience drainage area loss and should be modulated by runoff and erodibility. The process is exceptionally well visible in Sumatra as there exists no orographic rainfall gradient along the mountain front. Keywords: Postglacial sea-level rise, fluvial geomorphology, landscape evolution, erosion, subduction zone, SE Asia
Investigating the effect of a heavy rainfall episode on the Mw4.9 earthquake of 11 November 2019 at Le Teil (France)
Authors: Burnol André , Armandine Les Landes Antoine , Raucoules Daniel , Aochi Hideo , Maury Julie , Allanic Cécile , Bazargan-Sabet Behrooz
Published: February 2023

On 11 November 2019, the Le Teil Mw4.9 earthquake occurred in southeast France, in the vicinity of a surface quarry. We focus this work on the effect of hydraulic recharge linked to the infiltration of meteoric water in the fault zones in the period preceding the earthquake. In the reference simulation, we used the in situ soil moisture at 30 cm depth (Berzème station) as surface boundary conditions.We describe first the local 3D fault system from an updated geological model and the boundary conditions that are used to calculate the pressure variations at depth using a double permeability model.The movement of moisture in partially-saturated media is then simulated by the Compass code (1) during the period 2015-2019. A maximum overpressure takes place near the junction of the three-fault system at around 1,200 m depth. Moreover, the calculated increase in pore fluid pressure is maximum during 2015-2019 just before the earthquake of 11 November 2019. Additionally, the surface soil moisture (SSM) data acquired by the SMOS satellite (2) are used to extend the study period between 2010 and 2015.A sensitivity study carried out on the main hydraulic parameters allows us to estimate that the overpressure linked to the hydraulic recharge of the fault system is between 0.7 and 1 MPa at about 1200 m depth before the seismic event.Finally, we compare this result with the maximum Coulomb stress change linked to the mass withdrawal from the surface quarry over the two past centuries (3). The conclusion is that the hydraulic effect is about two and a half times larger than the cumulative effect of the mechanical stress release due to the mass removal from the surface quarry.(1) https://github.com/BRGM/ComPASS(2) Li, X., Wigneron, J.-P., et al.: The first global soil moisture and vegetation optical depth product retrieved from fused SMOS and SMAP L-band observations, Remote Sensing of Environment 282, 113272, 2022. https://doi.org/10.1016/j.rse.2022.113272(3) Maury, J., Guillon, T., Aochi, H., Bazargan, B., and Burnol, A.: Assessing the effect of mass withdrawal from a surface quarry on the Mw4.9 Le Teil (France) earthquake triggering, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2742, https://doi.org/10.5194/egusphere-egu22-2742, 2022.
Synergy of accelerometer, GNSS, InSAR and TLS measurements in the light of PROION Project
Authors: Nikolakopoulos Konstantinos , Kyriou Aggeliki , Sokos Efthimios , Bousias Stathis , Strepelias Elias , Groumpos Peter , Mpelogianni Vassiliki , Roumelioti Zafeiria , Serpetsidaki Anna , Paliatsas Dimitrios , Ganas Athanassios , Charalampoulou Vassiliki (Betty) , Athanasopoulos Theodoros
Published: February 2023

As infrastructure faces the consequences of climate change there is an urgent need for monitoring methodologies that can provide accurate and timely information to the stakeholders and decision makers in order to mitigate the risk and ensure the safety. According to the World Meteorological Organization the last decade has been recorded as the warmest period in human history. As a consequence, particularly high temperatures and frequent weather extremes (drought, floods, etc.) jeopardize the infrastructure safety. At the same time, the need for reliable, cost-efficient and globally applied infrastructure monitoring methodologies is even more crucial in areas with high seismicity and or volcanic activity.In this framework the current project, named “PROION”, focuses on the infrastructure monitoring in the “Enceladus” Hellenic supersite. Τhis very active tectonic and seismic area includes geographically:the urban centers of Athens, Corinth and Patras (> 50% of the country's population),
some of the most important archaeological monuments (Ancient Olympia and Mycenae) and
some very important infrastructures such as Mornos and Evinos dams, Rio-Antirrio Bridge etc.
The Enceladus Supersite area presents the highest seismicity in Europe, the highest recorded ground acceleration in Greece(0.77g) and a very high frequency of landslides.The aim of the project is the development of a platform for the continuous monitoring of high importance infrastructures such as public buildings and dams. The methodology combines instrumental and remote sensing measurements along with fuzzy logic networks methods and machine learning algorithms. Specifically, measurements obtained by three-axis accelerometers, low cost GNSS receivers and Persistent Scatterer Interferometry are fused and validated with high-precision 3D reference data derived from TLS surveys and UAV campaigns. The processing is based on soft computing algorithms while very accurate deformation maps are utilized for making decision about the current and the future state of each infrastructure. “PROION” project is financially supported by the European Union and the Hellenic government. «Acknowledgment:  This research has been co‐financed  by the European Union and Greek  national funds  through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call  RESEARCH – CREATE – INNOVATE (project code: T2EΔK-02396 Μultiparametric monitoring platform with micro-sensors of eNceladus hellenIc supersite)».
Preliminary assessment of burned area products in the detection of small fires: A case study of China
Authors: Lou Shuhan , Franquesa Magí , Bai Yuqi , Chuvieco Emilio
Published: February 2023

Previous studies have found that global burned area products based on coarse resolution sensors tend to miss small fires (<100 ha), particularly in those regions where burnings tend to be human-controlled.
We aimed to analyse the accuracy of small fire detection of current global burned area products in China. Most regions in China tend to have small fires due to strict forest and grassland fire suppression policies, as well as straw burning ban policies. According to Chinese government statistics from 2010 to 2019, there are more than 2000 forest fires every year, with an average size of 10.9 ha per fire. However, most of the studies on fire regimes and fire impacts in China used global burned area products with relatively coarser spatial resolutions, most likely leading to considerable uncertainty in the results.
Our assessment included burned area products with coarse spatial resolution sensors (MODIS, Sentinel-3) with relatively high temporal resolution (1 day) and those with medium resolution sensors (Landsat, Sentinel-2) with relatively low temporal resolution (> 5 days). A burned area reference dataset from Sentinel-2 (S2) images was built to validate those burned area products in China. The extent to which the difference in the spatial and temporal resolutions affecting the total burned area was measured based on the spatial and temporal intercomparison of burned area products.
Accuracy metrics, including both omission (undetected burned pixels) and commission errors (unburned pixels classified as burned), were used in this study. The preliminary results indicate that the ability of global burned area products to detect small fires needs to be improved. This work imposes the essential requirement of relatively high spatial and temporal resolution burned area products for small fires.