bluuebunny/crossref_metadata_2025 huggingface dataset:
Tropical Land Temperature Change across Termination II and the Last Interglacial
Authors: Ding Hao , Krüger Yves , Carolin Stacy , Meckler Anna Nele
Published: March 2024

The general sequence of a late Pleistocene glacial termination has been well portrayed, where the high latitude regions of the Northern and Southern Hemisphere play essential but significantly different roles. The role of low latitude regions, however, is less well constrained. This is particularly true for time intervals prior to the last glacial period, and for glacial inceptions where our current understanding hinges on marine proxy records that are prone to uncertainties regarding the season and water depth the signals represent, as well as non-thermal influences. Additional, precisely dated and accurate temperature records from the tropics are therefore essential to constrain the amplitude and timing of tropical temperature change in comparison with the high latitudes.Here we provide a new record for tropical land temperature from Northern Borneo across Termination II, the Last Interglacial, and the glacial inception between marine isotope stages (MIS) 5e and 5d, spanning approximately from 145 to 107 ka. The temperatures are based on nucleation-assisted fluid inclusion microthermometry (Krüger et al., 2011), currently considered the most precise paleothermometer for stalagmites. This approach has the advantage that it does not rely on empirical calibration and that the resulting temperatures are not seasonally biased.Our record shows that the temperature, which was corrected for sea-level induced cave altitude changes, increased from 19.6 ± 0.4 °C (2SEM) to 24.0 ± 0.3 °C (2SEM) over Termination II. Similar to what has previously been found for Termination I (Løland et al., 2022), temperature over Termination II follows the timing of increasing atmospheric CO2 concentration and Southern Hemisphere warming. However, our record decouples from CO2 during glacial inception into MIS 5d, where the sea-level corrected temperature started to decrease to 21.0 ± 0.3 °C (2SEM) at around 122 ka whereas CO2 remained stable for another 7 kyr. The amplitude and timing of this cooling is confirmed with a second stalagmite from another nearby cave. Our observation shows that early cooling into MIS 5d is not limited to the high southern latitudes (Jouzel et al., 2007) but instead appears to be a more global phenomenon that will be important to understand in order to shed light on the sequence of events leading to glacial inception.ReferencesJouzel, Jean, et al. "Orbital and millennial Antarctic climate variability over the past 800,000 years." Science 317.5839 (2007): 793-796.Krüger, Yves, et al. "Liquid–vapour homogenisation of fluid inclusions in stalagmites: Evaluation of a new thermometer for palaeoclimate research." Chemical geology 289.1-2 (2011): 39-47.Løland, Marit Holten, et al. "Evolution of tropical land temperature across the last glacial termination." Nature Communications 13.1 (2022): 5158.
The Space Weather Research on Coronal Mass Ejections Required Before Operational Sub-L1 Monitors
Authors: Lugaz Noé , Regnault Florian , Banu Sahanaj , Al-Haddad Nada , Zhuang Bin , Lee Christina , Farrugia Charles J. , Möstl Christian , Winslow Reka M. , Davies Emma , Scolini Camilla , Yu Wenyuan , Galvin Toni
Published: March 2024

In-situ measurements from the Sun-Earth Lagrangian L1 point typically provide a 20-minute to 1-hour advanced warning of incoming interplanetary (IP) shocks, magnetic clouds before impact at the nose of Earth's magnetopause. Sub-L1 monitors may provide measurements sunward of the L1 point to improve the lead times for such transients to several hours, and various mission architecture have been proposed for more than 25 years. Because CMEs and shocks do not propagate exactly radially, the location of such a monitor with respect to the Sun-Earth line is a key parameter to take into account when designing such missions. Here, we highlight some recent results and measurements of CMEs that show that small angular separations may result in drastic differences in the CME properties measured by two spacecraft, and examples showing that CME evolution over a few hours may differ significantly from the average evolution as obtained from statistical studies over several decades. We highlight how a pathfinder mission is required to better understand the variation of properties within CMEs on moderate scales and the evolution of CMEs over a few hours. Such an improved knowledge will then allow for a dedicated fleet of operational monitors that will improve the lead time of space weather forecasting without a loss of accuracy
Mirror Mode Storms at the Magnetosheaths of Earth and Mars
Authors: Rojas Castillo Diana , Blanco-Cano Xochitl , Russell Christopher T. , Simon-Wedlund Cyril , Volwerk Martin
Published: March 2024

Wave-particle interactions are important in the momentum and energy transfer across a planetary magnetosheath, from the solar wind upstream of the bow shock to the magnetosphere. In the highly perturbed magnetosheath plasma of Earth and Mars, anisotropic ion distributions have enough free energy to drive low-frequency instabilities such as the mirror mode instability. The resulting mirror mode waves are therefore common structures inside those magnetosheaths. In the solar wind, long trains of holes and peaks in the magnetic field magnitude that can last for hours have been reported (Russell et al.,2009; Enriquez-Rivera et al., 2013). In this work, we explore the existence of mirror mode storms in the sheaths of the Earth and Mars like those observed in solar wind regions. We study the characteristics of a few observed storms and possible dependencies on factors such as the plasma beta and distance from the bow shock.  We also study the evolution of the ion distributions associated with mirror mode structures to investigate the waves' origin.
Reconstruction of bayhead delta in response to the Holocene sea-level changes in confined morphology, the Nakdong valley fill, southeastern Korea
Authors: Hong Seok-Hwi , Ryang Woo Hun , Yoo Dong-Geun , Kimg Jin Cheul
Published: March 2024

Bayhead delta is one of the links between fluvial and estuarine system where terrestrial sediments are prograding into the estuary. Despite the critical position of the bayhead delta, the Holocene reconstructions of coastal linkage area are poorly documented based on bayhead delta data from direct cores. This study provides sedimentary characteristics, stratigraphic interpretations, and also a new concept of a full-filled bayhead delta. Five cores are acquired in the Nakdong valley fills consisting of late Pleistocene to Holocene deposits. Sixteen facies are defined and grouped into eight facies association; alluvial plain, fluvial channel and floodplain, oxidized fluvial channel, tidal flat, tidal bar, central basin and bayhead prodelta, bayhead delta front, and bayhead delta plain. The associations are compiled up three depositional units in the Nakdong valley fills: Unit 1, 2, and 3. Unit I consists of alluvial plain and fluvial channel in the lowermost part of cores. Unit II contains tidal flats, tidal bars, and central basin in an estuarine environment adjacent to Unit I. The topmost Unit III is bayhead delta deposits consisting of bayhead delta plain, bayhead delta front, and bayhead prodelta after the depositions of Unit II. Age data for the Nakdong valley fills, suggest that these depositional environments developed in depositional stages (before about 12 ka, 12 and 9 ka, 9 and 7 ka, 7 and 5 ka, 5 and 3, and after 3 ka). The sequence stratigraphy of the Nakdong valley fills can be divided into three systems tract; a lowstand systems tract (LST), a transgressive systems tract (TST), and highstand systems tract (HST). The uppermost deposits of the Nakdong valley show a bayhead deltaic succession string imprint of fluvial processes in an embayed environment. Most bayhead deltas are limitedly developed within the head of the estuarine systems, whereas the Nakdong deltaic deposits fully filled in the estuary system. This full-filled type is interpreted to represent that the relative rate of fluvial sediment input exceeds the rate of local accommodation creation. 
Spatial variation in carbon storage within managed and unmanaged saltmarsh systems: A case study in the Rogerstown Estuary, Ireland
Authors: Rounce Juliet , Moeller Iris
Published: March 2024

Saltmarshes provide many vital benefits (ecosystem services), including carbon sequestration, flood protection and nutrient exchange. As “carbon sinks”, these ecosystems sequester carbon up to twice the rate of terrestrial forests. Recent national and international carbon emissions targets highlight the importance to both protect and increase the area of coastal saltmarshes. In addition, these intertidal wetlands are influenced by complex interacting bio-sedimentary and hydrological processes, thus restoration projects need to consider the various processes impacting such ecosystems. To address carbon emissions targets, upscaled estimates of carbon accumulation are required, for which modelling and time-consuming field surveys are employed. An understanding of within-marsh controls on soil organic carbon content (SOC) and the resulting feedbacks (sedimentary, hydrological, geomorphological, ecological) can improve field survey efficiency and provide training data for models.  Such data aids in constraining uncertainties around scaled-up carbon accumulation estimates per unit area saltmarsh for regional, national and international inventories. Quantitative data on the variation in SOC and the facilitating processes remains relatively scarce.This research investigates SOC distribution, alongside potential explanatory factors within unmanaged and managed saltmarshes. Through the collection of sediment samples (near-surface, core), alongside location-specific data on elevation, inundation, biomass and accretion rates in Turvey Nature Reserve (Co. Dublin), this project aims to quantify the impact of several key factors (e.g. drainage, topography, biomass and accretion) on carbon accumulation. SOC will be determined through Loss-on-Ignition laboratory analysis. An existing carbon accumulation model will then be improved upon, and the updated model will be utilised to inform an investigation of future carbon storage potential under various climate scenarios.Initial results from an on-going project are presented to provide quantitative field- and laboratory-derived data, enhancing knowledge of within- and between-marsh variation of SOC in saltmarshes.
Mutual impedance and quasi-thermal noise to measure electron properties at Mercury: merging simulations of the magnetosphere and of the instrumental apparatus
Authors: Dazzi Pietro , Lavorenti Federico , Henri Pierre , Issautier Karine
Published: March 2024

Mercury is the only telluric planet of the solar system, apart from Earth, possessing an intrinsic magnetic field. This magnetic field influences the dynamics of the solar wind plasma impinging on the planet, forming a magnetosphere. Mercury’s magnetosphere has been investigated by multiple space missions in the past, notably the NASA Mariner10 and MESSENGER missions, and is today the target of the joint ESA/JAXA BepiColombo mission, currently en route, with orbit insertion scheduled for December 2025. BepiColombo instruments will observe for the first time the electron kinetic physics at Mercury. In order to interpret and plan BepiColombo’s in-situ observations, an interplay is needed between numerical simulations of Mercury’s magnetosphere and instrumental modelling.In this work, we present a study of the expected instrumental response of the PWI/AM2P and PWI/SORBET experiments onboard BepiColombo, based on a two-step, fully-kinetic numerical approach.First, we run fully-kinetic, three-dimensional, global simulations of the interaction between Mercury’s magnetic field and the solar wind using the implicit particle-in-cell code iPIC3D. Non-maxwellian electron distribution functions are observed in the simulations.Second, we use the electron distribution function derived from the previous step as input for a numerical model of the electric antennas used by both the AM2P and SORBET experiments onboard the JAXA Mio craft (part of BepiColombo). The influence of the spacecraft and antennas geometries is included self-consistently in this second step.Our 3D full-PIC simulations show that magnetic reconnection in the tail accelerates and heats electrons up to energies of few keVs when the interplanetary magnetic field (IMF) is southward. Such high-energy electrons are ejected from the neutral line in the tail planetward in a substorm-like process, leading to strong particle precipitation in the nightside of Mercury, especially at local time 0-6 h. Double Maxwellian electron distribution functions are inferred from the simulations in the nightside of Mercury (with temperature and density ratio of order 10 and 0.1-1, respectively). We investigate the possibility of detecting these two Maxwellian populations using the AM2P and SORBET experiments, operating at Mercury after orbit insertion. We also explore regions where the AM2P experiment can be calibrated in-flight.
Second Year Progress of PREVENIR: Japan-Argentina Cooperation Project for Heavy Rain and Urban Flood Disaster Prevention
Authors: Miyoshi Takemasa , Skabar Yanina G. , Otsuka Shigenori , Amemiya Arata , Ruiz Juan , Ushio Tomoo , Tomita Hirofumi , Ushiyama Tomoki , Konishi Masaya
Published: March 2024

This presentation provides recent research highlights of the project PREVENIR, including radar quantitative precipitation estimates (QPE), ensemble nowcasting, data assimilation, numerical weather prediction (NWP), and hydrological model prediction. PREVENIR is an international cooperation project between Argentina and Japan since 2022 for five years under the Science and Technology Research Partnership for Sustainable Development (SATREPS) program jointly funded by the Japan International Cooperation Agency (JICA) and the Japan Science and Technology Agency (JST). The main goal is to develop an impact-based early warning system for heavy rains and urban floods in Argentina. PREVENIR takes advantage of leading research on Big Data Assimilation (BDA) with the Japan’s flagship supercomputer “Fugaku” and its predecessor “K” and develops a total package for disaster prevention, namely, monitoring, QPE, nowcasting, BDA and NWP, hydrological model prediction, warning communications, public education, and capacity building. The total package for disaster prevention will be the first of its kind in Argentina and will provide useful tools and recommendations for the implementation of similar systems in other parts of the world.
Investigating the stability and composition of LLSVP-like material in mantle convection models
Authors: Récalde Nicolas , Davies J. Huw , Panton James , Porcelli Donald , Andersen Morten
Published: March 2024

The Large Low Shear Velocity Provinces (LLSVPs) are basal mantle structures, located beneath the Pacific and Africa, which are defined by their negative anomaly in δVs. Since the first detection of LLSVPs, the reason for their seismic signature has been questioned, whether it is purely thermal, chemical or thermo-chemical in nature. The origin and age of LLSVPs have also been interrogated in the context of mantle dynamics as plumes seem to be associated with these structures and correlate with intraplate volcanism locations. The LLSVPs are often invoked as a potential reservoir to store primitive mantle in order to explain primitive He ratios observed in oceanic island basalts. Such a scenario would suggest that at least some part of the LLSVPs are long-lived, quasi-stable structures. Previous 3D geodynamic experiments suggest that LLSVP longevity is achieved through replenishment of the constituent material [1], potentially disqualifying them as a reservoir of primordial material. However, 2D experiments have shown that remnants of a primordial layer may become trapped within accumulations of recycled, dense oceanic crust for extended periods of time [2]. It remains to be seen if a similar process may occur in 3D simulations.
Using the 3D spherical mantle convection code TERRA [3] and seismic conversion tables [1], we investigate the ability of geodynamic models to generate such seismic structures and the preservation of primordial material within them. We explore various mantle viscosities, densities of material (buoyancy of primitive and enriched material) and concentrations of heat-producing elements. We track the core-mantle boundary coverage and volume of the detected structures to evaluate their stability as a function of time and geodynamical context. Results focus on the composition of these structures, the amount of primitive and early enriched material stored within them and how they evolve with time.

[1]  James Panton, J. Huw Davies, and Robert Myhill. “The Stability of Dense Oceanic Crust Near the Core-Mantle Boundary”. In: Journal of Geophysical Research: Solid Earth 128.2 (2023).
[2]  T. D Jones, N Sime, and P. E van Keken. “Burying Earth’s Primitive Mantle in the Slab Graveyard”. In: Geochemistry, geophysics, geosystems : G3 22.3 (2021).
[3]  John R. Baumgardner. “A Three-Dimensional Finite Element Model for Mantle Convection”. PhD thesis (1983).
Impact of summer-persistent ENSO events on the global climate and the occurrence of extreme weather events
Authors: Schultze Anna , Lu Zhengyao , Zhang Qiong , Zheng Minjie , Pugh Thomas
Published: March 2024

El Niño Southern Oscillation (ENSO), the most prominent climate variability in the tropical Pacific Ocean, significantly influences global climate and weather patterns, impacting ecosystems and societies worldwide. Our study focuses on the underexplored aspect of summer-persistent ENSO events, their global climatic impacts, and their role in triggering extreme weather occurrence.ENSO events follow a distinct cycle, with El Niños more tightly bound to this cycle, while some La Niñas tend to fall below the ENSO threshold during the summer and then re-intensify in the following winter, resulting in multi-year La Niña events. However, there have been cases of slower ENSO decay, where sea surface temperature anomalies (SSTA) exceeding the ENSO threshold values into the northern-hemisphere summer, have been observed. The 2018/2019 El Niño, persisting until July, is a recent example, linked to significant events like the severe Australian bushfires in 2020 and the longest heatwave in history in the North Pacific in 2019. The El Niño was followed by a triple-dip La Niña, linked to extreme weather events in Africa, Australia and the United States. This highlights the importance of understanding the summer-persistent ENSO events.Our study is structured based on three aims: identifying past summer-persistent ENSO events, assessing their impacts on global temperature and precipitation patterns, and examining their linkage to extreme weather events. Utilizing the Oceanic Niño Index calculated from the extended reconstructed sea surface temperature (ERSSTv5), we categorised ENSO events into conventional, summer-persistent, and multi-year summer-persistent types. The latter two were defined by events in which the Oceanic Niño Index exceeded the ENSO threshold until June for one or two consecutives summer seasons, respectively. We identified 12 summer-persistent ENSO events since 1940, separated into four summer-persistent El Niños, five summer-persistent La Niñas, and three multi-year summer-persistent La Niñas. Analyzing ERA5 reanalysis composites of 2-m temperature and precipitation, we compared the climatic impacts of these ENSO variants across winter and summer. This study advances our understanding of the climatic consequences of summer-persistent ENSO events, providing insights crucial for developing mitigation strategies for their impacts on global climate and extreme weather occurrences.
Himalayan deformation and its connection to geologic hazards: cross fault examples
Authors: Hubbard Mary , Mukul Malay , Gajurel Ananta
Published: March 2024

As a product of continental collision, the Himalaya developed major thrust and fold structures to accommodate convergence.  With the continental subduction of the Indian continent beneath Asia, the deformation front has migrated southward over time.  The result of these tectonic and structural processes is the world’s highest mountain belt that exposes rocks of a large span of ages and has had a dynamic geomorphological evolution for the past 50-60 million years.  The Himalaya is now home to more than 53 million people.  These people face the ongoing threat of earthquakes, landslides, and floods due the active landscape in which they live.  While most earthquake events are caused by thrust fault activity, it has been recognized that there are faults that cut across the range, cross faults, that also play a role in hazards.  In the central and eastern Himalaya, cross faults have been identified where the range front transitions from salients to recesses.  Examples of these structures in Sikkim and Nepal include the Gish and Kosi faults.  Similar structures have also been identified north of the range front in the Lesser and Greater Himalayan regions.  A map of aftershock data from the 2015 earthquake shows an abrupt termination of aftershocks in the region east of Kathmandu that aligns with a proposed cross fault known as the Gaurishankar lineament.  Geophysicists suggested that a cross fault could be responsible for blocking of the lateral propagation of the thrust rupture.  The Dudh Kosi valley that drains the Khumbu or Everest region has had historic and pre-historic large landslides that may have originated on the Benkar cross fault structure.  In 2021, the Melamchi valley east of Kathmandu experienced a devastating flood that was in part tied to the reactivation of a large landslide.  That landslide site is co-located with north-south striking shear zones or cross fault structures.  While cross faults are not the major structures accommodating convergence, our work suggests that there are implications for hazard occurrence due to the presence of these structures.
Nitrates Production by Volcanic lightning during Explosive Eruptions
Authors: Contamine Delphine , Martin Erwan , Aroskay Adeline , Bekki Slimane , Szopa Sophie , Savarino Joël
Published: March 2024

Volcanic lightning during explosive eruptions has been suggested has a key process in the abiotic nitrogen fixation in the early Earth. Although laboratory experiences and thermodynamic models convincingly suggest that volcanic lightning can fix atmospheric nitrogen (e.g. Navarro-Gonzalez et al., 1998, Martin et al., 2007). No geological archives of N-fixed by volcanic lightning have been found yet. Recently, high nitrate concentrations in volcanic deposits from large Neogene explosive eruptions (VEI>7; Aroskay et al. 2023) have been discovered. It is tempting to infer that these nitrates correspond to the end-product of N-fixation by volcanic lightning. However long-term atmospheric deposition of nitrate is suggested to be responsible of nitrate deposits in arid environment (e.g. Atacama Desert and Mojave Desert – Michalski et al. 2004, Lybrand et al. 2013). Therefore, the long-term atmospheric deposition could contribute to nitrates preserved in volcanic deposits.Our study aims to distinguish the origin of nitrates in volcanic deposits: end-product of volcanic lightning or long term atmospheric deposition? To answer this question, volcanic samples from super-eruptions as well as sediments have been collected in the Tecopa Basin – California, USA. The whole sedimentary column (sediments interspersed with volcanic deposits) has been preserved in the same arid conditions for the last 2Ma. The multi-isotopic composition of nitrate has been measured (δ18O, δ15N and Δ17O) and shows clear distinction between nitrate from volcanic deposits and those from sediments. It appears that while nitrate from sediments result from a mix between atmospheric nitrate and biogenic nitrate, in volcanic deposit the nitrate are most likely the end product of volcanic lightning.As a conclusion, we demonstrate that volcanic deposits can be an archive of N-fixation by volcanic lightning. This is an open window on the direct quantification of N-fixation by large explosive volcanic eruptions and their role on the development of life on the early Earth.
A New Realization of the Terrestrial Reference Frame: Combining GPS, SLR and VLBI at the Observation Level from 2010–2022
Authors: Haines Bruce , Bertiger Willy , Desai Shailen , Elmer Matthias , Heflin Michael , Kuang Da , Lanyi Gabor , Miller Mark , Naudet Chuck , Peidou Athina , Ries Paul , Tolstov Alex , Wu Xiaoping , Zivkov Nikki
Published: March 2024

We describe the development and assessment of a new terrestrial reference frame (TRF) based on combining GPS, SLR and VLBI at the observation level over the period 2010–2022. Included in the solution, in addition to station coordinates and precise orbit solutions for all participating satellites, are Earth orientation parameters (EOP) and low-degree zonal coefficients (J2 and J3) of the geopotential. The overall solution concept grew from earlier efforts to realize a TRF using GPS data alone, capitalizing on GPS receivers on the ground and in low-Earth orbit (LEO). Here we add observations from both the SLR and VLBI techniques, which provide the foundation for traditional realizations of the TRF.In linking the GPS and SLR techniques, our approach dispenses with traditional ground survey ties, relying exclusively on space ties from the GRACE and Jason LEO missions. In addition to SLR from these satellites, we include observations from the dedicated LAGEOS satellites, which prove particularly important for recovering low-degree gravity. A major evolution of our approach is the addition of VLBI at the observation level. Lacking a robust tie in Earth orbit for VLBI observations, we apply as constraints the published ground survey ties to nearby GPS stations, enforcing inclusion of the corresponding tracking data in the solutions. The VLBI effort is in the exploratory phase, and further tuning of the strategy is needed to better exploit collocations with both GPS and SLR. About 40% of the participating solution arcs (spanning 2010–2022) now include VLBI and support accurate recovery of UT1 as part of the EOP solution.Though the resulting TRF solution is based on only 12.6 years of data, it is competitive with ITRF2020 in terms of fundamental frame parameters (origin and scale) and their temporal evolution, both linear and seasonal. The relative rates of origin (3D) and scale (at Earth's surface) are 0.2 mm yr-1 and 0.1 mm yr-1 respectively. Absolute scale (at epoch 2015.0) and 3D origin both differ by 2 mm. One advantage of our technique is that precise orbit solutions for both GRACE and Jason missions, defined in the realized TRF, are byproducts of the overall solution. We use the Jason orbit solutions to characterize the impact of contemporary TRF errors on sea level variations (both global and regional) and discuss the implications of these results.
Glacier area changes on Baffin Island from 2000 to 2019 derived from Landsat and Sentinel-2 satellite images
Authors: Paul Frank , Rastner Philipp
Published: March 2024

Glaciers on Baffin Island present a mixture of abundant small to a few very large ice caps (Barnes, Penny) as well as thousands of valley glaciers, cirques and ice patches. Their large overall area (about 40,000 km2) combined with strong surface melting is responsible for their large contribution to sea-level rise over the past decades. However, area changes over the same time period are largely unknown, as a reliable glacier inventory for the year 2000 has only become available very recently. The previous version suffered from missing glaciers and missing debris cover on glaciers or outlines were outdated and had too large extents.Here we present the results of a new glacier inventory for the entire region as obtained from Sentinel-2 and Landsat 8/9 satellite images acquired within a few days of August 2019. Although glacier mapping conditions were excellent in regard to seasonal snow, glacier boundaries were often polluted by dark material that was excluded from the applied automated mapping with a band ratio. Hence, all glacier boundaries were checked and manually adjusted when required. To obtain glacier specific area change rates, we used the same revised drainage divides as for the recent year 2000 inventory in RGI 7.0.Overall, glacier area decreased by 10% from 2000 to 2019 i.e. at a rate of 0.54% per year. Thereby, glaciers 10 km2 contribute 70% to the total area and 40% to the loss. The area of Barnes Ice Cap decreased by 1.15%. As in other regions with glaciers, the shrinkage rate and scatter of values increases towards smaller glaciers and several glaciers melted away completely. Also some larger ice caps at low elevations suffered from substantial shrinkage and disintegration by down-wasting. The increasing extent of rock outcrops in the accumulation area of larger glaciers confirm the observed surface lowering over this period.
The impact of post-depositional processes on tsunami deposits - A quantitative analysis for tsunami hazard assessments
Authors: Weiss Robert , Dura Tina
Published: March 2024

Sandy tsunami deposits are essential stratigraphic markers to document the impact of tsunamis in the geologic record. Tsunami sands are also the only record of past tsunamis that can be interrogated to retrieve quantitative information about the causative tsunami event. Inversion of flow speed and flow depth from tsunami deposits is often employed to understand a tsunami event better and evaluate the impact of different tsunami events in the same stratigraphic sequence or geographic area. After deposition, like any other deposit, sandy tsunami deposits are exposed to a series of processes that alter the deposits, collectively called post-depositional processes. These post-depositional processes can change the characteristics significantly. If tsunami deposits are employed to gain quantitative insights into a past event, these post-depositional processes can potentially alter respective inversion results. The influence of post-depositional processes on the inversion of flow depths and speeds has been considered but remains understudied.To gain more insight into the influence of flow speed and flow depth inversions, we present a new model to simulate different post-depositional processes, such as erosion, bioturbation, winnowing, compaction, and dissolution of minerals. We employ stochastic processes for all these sediment alteration possibilities on a grain-size distribution level. In this context, we use a large number of reference grains for each grain-size class in a given deposit and calculate an individual grain's fate depending on the post-depositional process. This new model allows us to consider different combinations of processes to simulate different sedimentary environments and to quantify the influence of different post-depositional processes with time. We employ the established TSUFLIND model to invert flow speed and depth from the altered grain-size distribution. Our results indicate how individual post-depositional processes have a more significant influence on inverted flow speeds and depths than others, but they also show how they can influence each other to have a more substantial impact on the sum than individually. Furthermore, our results shed light on potential uncertainties any inversion of the flow characteristics might have depending on the sedimentary environment in which the tsunami deposit was created. In turn, this contributes to a better understanding of uncertainties in tsunami hazard assessments that include tsunami deposits.
A serious game approach to promote non-traditional solutions and ecosystem services for water adaptive management
Authors: Silva Gabriel , Benso Marcos , Silva Pedro , Mendiondo Eduardo
Published: March 2024

Water problems related to floods, droughts, water quality, and supply demand require methods focused on harnessing the inherent capabilities of ecosystems to cope with water related problems and the ecosystems natural capability to address water-related challenges by leveraging this advantage on maintaining ecological balance. Although it demands more investments than traditional approaches, Nature-based Solutions (NbS) has a significant impact on promoting sustainability and its success relies on careful planning, collaboration with local communities, and adaptive management strategies. This study aims to develop an engaging and educational serious game to demonstrate how NbS can serve as a strategic approach for fostering the development of smart and resilient cities in response to the challenges posed by climate change, water-related risks, and disasters. By engaging individuals in a virtual environment, serious games can effectively communicate the consequences of various water-related decisions and encourage sustainable practices among the public. Thus, designed for a diverse audience, including students, urban planners, decision-makers, and the general public, the game utilizes realistic mathematical models to simulate climate change scenarios and extreme weather events. Yet, players can make challenging decisions in implementing NbS, like creating urban green zones, watershed management, and aquatic ecosystem restoration. The game can also incorporate real-world data for specific geographic areas, emphasizing the effectiveness of NbS in regional contexts. Finally, the game incorporates water modeling techniques, leveraging the robust capabilities of HydroPol2D and/or HyMAP models. These models enable the simulation of water runoff in two dimensions by utilizing Digital Elevation Models (DEMs), land use and rainfall data. Furthermore, collaboration with local communities and adaptive management strategies are crucial components, showcasing the importance of stakeholder engagement.
Aircraft measurements of PAN (CH3C(O)OONO2) and PAA (CH3C(O)OOH) in the tropical atmosphere
Authors: Nelson Carolina , Andersen Simone T. , Crowley John N.
Published: March 2024

The two trace gases peroxyacetyl nitrate (PAN, CH3C(O)OONO2) and peracetic acid (PAA, CH3C(O)OOH) are products of reactions of the acetylperoxy radical with NO2 and HO2, respectively. They are formed during the oxidation of anthropogenic and biogenic VOCs and in biomass burning. PAN represents an important source of NOx in remote regions, while PAA is an indicator of the fate of peroxy radicals. To date, there have been very few simultaneous measurements of PAN and PAA. In this study, we present airborne measurements of PAN and PAA using a chemical ionization mass spectrometer (CIMS) in the clean troposphere above the Amazon rainforest in the framework of the CAFE Brazil measurement campaign. The absolute and relative abundances of PAN and PAA are analysed using data obtained during 20 flights performed during December 2022 until the end of January 2023.
Research on nearshore subaqueous geomorphology stability detection based on few-shot learning
Authors: Ren Zhongda , Zhang Peng , Cheng Heqin , Teng Lizhi , Chen Jinfeng , Jin Yang , Liu Ruiqing , Jia Zhengyang , Zhang Hong
Published: March 2024

Detecting the stability of nearshore subaqueous geomorphology is a crucial challenge for ensuring early warning and controlling the stability of riverbank slopes. Acquiring nearshore subaqueous geomorphology data using unmanned ship-mounted acoustic multibeam systems is difficult, costly, and time-consuming. Moreover, it is often influenced by weather conditions. The limited availability of nearshore subaqueous geomorphology samples suitable for model training, combined with the high similarity between targets of nearshore unstable geomorphology and the background, poses significant challenges for traditional detection methods. In response to issues such as high similarity in subaqueous geomorphology images, large-scale variations in target size, and a scarcity of samples, this study proposes a nearshore subaqueous geomorphology instability detection framework based on Few-shot learning. Firstly, a feature extraction network is designed, replacing the backbone network with a Swin Transformer network. This network employs a feature pyramid network to extract multi-scale geomorphology features containing global information from the query set, facilitating the fusion of features across deep and shallow layers. Secondly, a weight adjustment module is devised to transform the support set into weight coefficients with class attributes. This adjustment helps in adapting the distribution of geomorphology features for detecting new class objects. Experimental results demonstrate that the proposed detection framework achieves desirable performance in terms of average precision and average recall indicators.Keywords: Subaqueous Geomorphology; Stability Detection; Few-shot learning
Clustering of GNSS Velocities Using Unsupervised Machine Learning in the Southeastern Tibetan Plateau: Block Identification and the Dominance of Sinistral-slip Faults
Authors: Xu Rui , Liu Xuemei
Published: March 2024

Previous studies have constrained the fault slip rates and block geometries of the SoutheasternTibetan Plateau (SETP) with contradictory results due to complex deformation patterns, limited datasets, and subjective choices of block boundaries. In this work, we address the issue of uncertain block geometries by employing an unsupervised machine learning (Euler pole clustering) algorithm that automatically resolves regions that behave as rigid blocks (clusters) using ~1000 GNSS velocity vectors. The optimal clustering results, determined by F-test and Euler-vector overlap analyses, indicate 4 elongated blocks exist in the SETP that are approximately parallel and delineated by a set of arcuate sinistral-slip faults. Our clustering results redefine the kinematicsof the SETP region with new block definitions which elucidate the dominance of sinistral-slipfaults.
Application of DAS to reservoir microseismic monitoring: A case study of Xinfengjiang Reservoir in Guangdong, China
Authors: Jiang Xingda , Yang Huayong
Published: March 2024

     The stratigraphic activities of the reservoir pose a serious threat to the safety of life and property of the people around the dam. The Xinfengjiang Reservoir in China is one of the four reservoirs in the world that induce above M6.0 earthquakes, which has an important impact on drinking water and safety in the Greater Bay Area. For earthquakes in reservoirs, terrestrial seismometers are far away from the seismic center, while submarine seismometers (OBS) are difficult to be deployed with data transmission off-real time. Distributed optical fiber Acoustic Sensing (DAS) enables real-time detection of formation activity and is suitable for a variety of extreme environments on land and underwater. With wide spectrum and high stratigraphic resolution, DAS has potential broad application prospects in reservoirs .
   In this study, we will show our first (July 2022) and second (May 2023) experiments in Xinfengjiang Reservoir for microseismic monitoring and ambient noise imaging results. Different optical cables (security cables, ordinary submarine cables and high-sensitivity submarine cables) and external environment (land and underwater) are adopted to analyze the seismic signals and noise in Xinfengjiang reservoir. Through the monitoring of seismic events and ambient noise, we will conduct the following studies: (1) the similarities and differences of monitoring signals of different optical cables in DAS equipment; (2) DAS monitoring of seismic and other stratigraphic activities; (3) DAS ambient noise imaging. Through comparative analysis, we will quantitatively analyze the advantages and disadvantages of DAS monitoring reservoir formation activities. Besides, some suggestions are given for the safety of Xinfengjiang reservoir.
UAV-RFID landslide monitoring : centimetric precision with flying antennas
Authors: Charléty Arthur , Le Breton Mathieu , Larose Eric , Baillet Laurent
Published: March 2024

Radio-Frequency Identification (RFID) shows great potential for earth-sciences applications [1], notably for landslide surface monitoring at a high spatio-temporal resolution with long-term robustness to meteorological events (rain, fog, snow) [1,2]. The ability to localize RFID tags using Unmanned Aerial Vehicles (UAV) in a Synthetic Aperture Radar (SAR) approach, would offer new possibilites for monitoring inaccessible terrain, even under vegetation and snow [3].To that end, an onboard measurement system was built that allows Global Positionning (GPS) tracking of an RFID reader antenna, in order to perform real-time SAR measurement acquisition. Three antenna tracking methods were compared.In addition, Markov-Chain Monte-Carlo (MCMC) optimization was used to estimate tag position and characterize the solution, even in non-convex cost function scenarios. Two cost functions were compared, based on different RFID-phase processing approaches.Real-time SAR-RFID localization yielded a centimeter accuracy in the horizontal plane, with lower resolution in the vertical direction. The Post-Processed Kinematics algorithm proved to best fit antenna tracking. The unwrapped-phase cost function provided more convex solutions, at the cost of a lower accuracy compared to the complex-phase cost function. MCMC is computationally efficient in SAR-RFID optimization, with enhanced results concerning the shape and orientation of the main localization errors.    [1] Le Breton, Mathieu, et al. "Passive radio-frequency identification ranging, a dense and weather-robust technique for landslide displacement monitoring." Engineering geology 250 (2019): 1-10.    [2] Charléty, Arthur, et al. "2D Phase-based RFID localization for on-site landslide monitoring." Remote Sensing 14.15 (2022): 3577.    [3] Charléty, Arthur, et al. Towards centimeter precision UAV-RFID localization, in preparation.
Pleistocene-Recent deformation regime of the Eastern Hellenic forearc inferred from multiscale fault-kinematic analysis, Island of Rhodes, Greece
Authors: Ferreira Malu M. M. , Riller Ulrich
Published: March 2024

The Island of Rhodes constitutes an exhumed portion of the Eastern Hellenic forearc and, thus, lends itself to investigating upper plate deformation kinematics of oblique subduction. Much of the east coast of the island features prominent marine terraces carved into Cretaceous carbonate rocks and decorated by Pleistocene marine deposits. The terraces are displaced by kilometer-scale faults, which are part of an island-wide pattern of linear morphological discontinuities, the kinematics of which are unknown. The generation of a UAV-based high-resolution digital surface model of a coastal hill slope near the town of Archangelos allowed us to quantify the horizontal and vertical components of fault displacements. The hill slope counts 17 marine terraces, serving as ideal kinematic marker surfaces, that are displaced by a set of three NNE-striking continental margin-parallel faults. Slip vectors inferred from the displacement components indicate oblique normal sense-of-displacement on the faults on the order of tens of meters. Interestingly, displacement magnitudes increase with elevation and age of the terraces, thus, the results point to normal faulting during rock uplift (exhumation) and approximately 400m of rock uplift. Kinematic analysis of nearby small-scale brittle shear faults (slickensides) in Plio-Pleistocene marine deposits indicate an overall NE-SW extension, in agreement with the kinematics of the kilometer-scale faults cutting the marine terraces. Therefore, we conclude that tectonics of the Eastern Hellenic forearc throughout Plio-Pleistocene around the island of Rhodes is characterized by rock uplift during distributed margin-parallel left-lateral shear.
Contrasting effects of intensity and organisation on the structure and lifecycle of deep convective clouds
Authors: Jones William , Stier Philip
Published: March 2024

The anvils of deep convective clouds (DCCs) have an important impact on global radiation balance. While the anvil cloud area feedback to warming temperatures is expected to have a cooling effect, it has the largest uncertainty of any cloud-climate feedback. Differences in anvil structure contribute to this uncertainty due to changes in the proportions of thicker, cooling anvil and thinner, warming anvil cirrus. A lack of long-term observational datasets of both convective and anvil properties of DCCs has limited our understanding of the connections between these processes.Using a novel cloud tracking algorithm we detect and track the developing cores, thick and thin anvils of DCCs seen in 5 years of GOES-16 imagery, allowing investigations of their properties throughout the DCC lifecycle. Using this dataset, we compare how the amount of thin anvil cirrus changes with the intensity and organisation of observed DCCs. Previous studies of anvil structure have found that the proportion of thin cirrus increases with convective intensity across a range of regimes. We find that the thin anvil proportion increases with convective intensity both in area and lifetime. To the contrary, for more organised DCCs – those with more cores – we find, however, that the thin anvil area and lifetime both decrease as a proportion of the total anvil. While more intense DCCs have shorter growing phases and longer dissipating phases, the opposite is true for more organised DCCs. These differences in lifecycle have an important impact on thin anvil proportion. The contrast in structure and lifecycle between DCCs with increasing intensity and increasing organisation occurs despite both convective processes having positive impacts on the total anvil area, lifetime and temperature. As both the intensity and organisation of DCCs are expected to increase with warming, we may expect differences in anvil cloud area feedback between different regimes depending on the occurrence of isolated or organised DCCs.
Multi-task predictions of the Arctic sea ice by a transformer-based deep learning model
Authors: Ren Yibin , Li Xiaofeng
Published: March 2024

The Arctic sea ice has been retreating dramatically in recent years in summer and fall. The navigation season for open water vessels along the Northeast Passage has lengthened to sub-seasonal scales. Accurate perditions of Arctic sea ice in sub-seasonal scales are essential for planning shipping activities. The numerical model cannot achieve a high accuracy of daily sea ice predictions on a sub-seasonal scale. The advanced deep learning brings new solutions for the data-driven-based sea ice prediction.This study proposed a transformer-based deep learning model to predict multiple sea ice parameters, including sea ice concentration (SIC), sea ice thickness (SIT), and sea ice drift (SID), in the Pan-Arctic in a sub-seasonal scale, 90 days’ lead. An encoder and decoder are constructed based on transformer modules to extract spatio-temporal dependencies from daily SIC, SIT, and SID sequences. The spatio-temporal dependencies at different scales are fused to form the final feature maps. Three SIC, SIT, and SID output modules are designed based on the final feature maps to output different parameters for the next 90 days. The satellite-observed sea ice data from the National Sea Ice Data Center (NSIDC) are employed to train the proposed model. We compared our model with anomaly persistence and the European Centre for Medium-Range Weather Forecasts (ECMWF) ensemble predictions to demonstrate the model’s prediction skill.Further, based on the proposed model, we discuss the effects of typical thermal and dynamic factors on sub-seasonal scale daily sea ice prediction. The selected factors include surface air temperature (SAT), sea surface temperature (SST), surface solar radiation downwards (SSRD), and geopotential height. Finally, we conclude with some scientific guidelines for the sub-seasonal sea ice predictability of the Arctic. 