bluuebunny/crossref_metadata_2025 huggingface dataset:
The need to adopt process-based or impact-based definitions for marine heatwaves
Authors: Liguori Giovanni
Published: March 2024

The oceanographic and climate communities are putting significant effort into reaching a consensus on a common definition for Marine Heatwaves (MHW). The absence of such a unified definition poses a substantial obstacle when it comes to making retrospective comparisons between various MHW studies. This hindrance is critical for achieving a mechanistic understanding of the role of MHWs in marine ecosystems.However, why is it so challenging to characterize and define MHWs? The answer is straightforward: there isn't a single, distinct dynamical mechanism responsible for the persistence of heat anomalies in the ocean, which we refer to as MHWs. Unlike variability associated with phenomena such as large oceanic eddies, oceanic fronts, upwelling systems, tropical cyclones, or climate modes, prolonged heat anomalies do not exhibit characteristic time or spatial scales. As a result, common MHW definitions group together prolonged temperature anomalies lasting from days to years and spanning from a few kilometers to thousands of kilometers in scale.Analyzing sea surface temperature anomalies through power spectra reveals a "red" power spectrum with no discernible time scales. A similar analysis in spatial dimensions similarly shows a lack of any specific scale. Given this absence of emergent scales, we suggest adopting a process-based definition for MHWs. Such an approach would classify all events into a smaller number of categories, each linked to a specific driver or dynamical process operating on certain spatiotemporal scales. This shift could significantly reduce the subjectivity involved in selecting the temporal and spatial scales required for current MHW definitions, ultimately advancing our understanding of these events.
Applicability of CSD-based resilience analyses to remotely sensed Vegetation Indices in the Tropics
Authors: Blaschke Lana , Morr Andreas , Bathiany Sebastian , Telschow Fabian , Smith Taylor , Boers Niklas
Published: March 2024

Tropical forests are vital for climate change mitigation as carbon sinks. Yet, research suggests that climate change, deforestation and other human influences threaten these systems, potentially pushing them across a tipping point where the tropical vegetation might collapse into a low-treecover state. Signs for this trend are reductions of resilience defined as the system's capability to recover from perturbations. When resilience decreases, according to dynamic system theory, a critical slowing down (CSD) induces changes in statistical measures such as the variance and the autocorrelation. This allows to indirectly examine resilience changes in the absence of observations of strong perturbations. Yet, deriving estimates of the statistical measures indicating resilience changes based on CSD impose several assumptions on the system under observation. For tropical vegetation, it is not obvious that these assumptions are fulfilled.Additionally, the conditions of tropical rainforests pose difficulties on the observation of the vegetation. Among other factors, cloud cover, aerosols, and the dense vegetation hinder the reliable retrieval of Vegetation Indices (Vis), especially from data gathered in the optical spectrum. Thus, such data might not be suitable for resilience analyses based on CSD, even if the theory is applicable in principle.We investigate the different assumptions of CSD and test them on a diverse set of remotely sensed VIs. Hereby, we establish a framework that allows to decide whether a specific dataset is appropriate for resilience analyses based on CSD.
Change characteristics and influencing factors of extreme precipitation events in Hanjiang River Basin, China
Authors: Jing Yuanyuan , Shi Peijun
Published: March 2024

The Hanjiang River basin (HJB), a representative monsoon-influenced basin in China, is alternately influenced by the southwest monsoon and southeast monsoon throughout the year. However, the variation characteristics of extreme precipitation in the basin, the specific relationship between extreme precipitation and monsoons, and the relative contribution of different monsoons, remains unclear in the HJB. Using multiple datasets, this study analysed the variability of various extreme precipitation types in the HJB during 1985–2020, investigated their relationships with different monsoon indicators and assessed the contribution of natural factors on the extreme precipitation variance. The results reveal a nonsignificant increasing trend in rainstorms within the basin, the severe convective rainstorm days accounted for a high proportion of the total rainstorm days, and the spatiotemporal characteristics of different rainstorm types are different. The rainstorm indicators are significantly correlated with the monsoon within the HJB and are positively correlated with the SWM, particularly its intensity. The SEM exhibits a weak correlation with rainstorms and has limited explanation for the variance in rainstorms. The intensity of SWM within the HJB shows a significant positive correlation with all rainstorm indicators. It is also detected as the most important indicator for explaining the interannual variation in rainstorms, explaining 41.97% and 39.45% of the variance in daily rainstorm frequency and totals, which comprises more than half of the total explanatory portion. The explanation of circulation factors for the variance in daily rainstorms is higher than that for severe convective rainstorms. In addition to monsoons, the Pacific Decadal Oscillation and the Southern Oscillation Index also have a great contribution to the rainstorm variability in the HJB.
Multifractal analysis of aerosol particle concentration during rain and dry conditions in nm and µm range
Authors: Jose Jerry , Roustan Yelva , Gires Auguste , Tchiguirinskaia Ioulia , Schertzer Daniel
Published: March 2024

Below cloud scavenging by rain is known to be a very efficient sinking mechanism for aerosols in atmosphere. Since this scavenging depends on interaction between aerosol particles as well as the scavening raindrops, and notably their respective size ranges, it is interesting to examine both fields together across various size ranges and across temporal scales. Towards this, a 4 month long data was used from Cherbourg-Octeville, France from 01/11/2010 to 12/03/2011 from the experimental station managed by Institut de Radioprotection et de Sûreté Nucléaire (IRSN). Here, simultaneous and continuous measurement of size resolved particle concentration (14.6 to 478.3 nm and 0.523 to 19.81 µm) range has been done using Scanning Mobility Particle Sizer (SMPS) and Aerodynamic Particle Sizer (APS), and rain measurement using a disdrometer.Variation of total aerosol concentration in nm and µm range, as well as individual number concentration in small size bins were analyzed according to rain and dry events, using the framework of Universal Multifractals (UM). UM is widely used, as a physically based scale invariant framework, for characterizing and simulating extreme variability and intermittency in geophysical fields. From initial analysis, the total concentration showed scaling properties (1 min to 1 hr), in both rain and dry events, regardless the scavenging efficiency of event. This was further explored in individual concentration ranges and they showed similar scaling properties in different rain types. However, while considering the different stages of rain, say start and end, the values of UM parameters showed some variation. To understand the behavior more clearly, few sizes were selected from nm and µm range, and efforts were made to extract the field which is devoid of scavenging by rain. Understanding the correct transformation required to extract accurate UM values and comparing the scavenging and non scavenging fields will improve understanding of particle concentration variation, and eventually understanding of scavenging coefficient.
Complex emergencies: drivers of the humanitarian impacts of climate-related disasters
Authors: Berntell Ellen , von Uexkull Nina , Rao Tanushree , Bender Frida , Dellmuth Lisa
Published: March 2024

Climate-related disasters such as floods, droughts and storms often pose significant threats to human livelihoods, especially in developing countries. The extreme weather events often lead to destroying of shelter, harming of crops and livestock as well as fueling of conflicts, and the threat to human livelihoods are likely to increase due to climate change. While we know that climate change and conflict interact and reinforce each other, less is known in the context of natural disasters and disaster aid. In this paper we address this gap by studying how hazard severity, disaster exposure and drivers of vulnerability interact to produce humanitarian impacts, and if the delivery of emergency disaster aid alleviates these impacts. We do this by generating meteorological hazard severity measurements based on the reanalysis dataset ERA5, comparable across different climate-related disaster types, allowing us to study drivers of vulnerability to climate-related hazards. Secondarily, we study the role of aid allocation on limiting disaster mortality and displacement, with the results having broad implications for the understanding of disaster impacts and aid effectiveness.
Central European lapse rate based on speleothem fluid inclusions
Authors: Kipfer Timon , Fleitmann Dominik , Affolter Stéphane , Hofmeister Elisa , Häuselmann Anamaria , Lütscher Marc , Cheng Hai
Published: March 2024

While the modern stable isotope lapse rate for precipitation shows a gradient of -0.19 ‰ per 100 meters elevation for Switzerland (Schotterer, 2010), there is only scarce information about the isotope lapse rate in the past and it is usually assumed that they remained constant through time. To investigate the lapse rate in the past, we use speleothems from caves along an altitudinal transect, which contain past drip water preserved in micrometric sized fluid inclusions (0.01 to 0.1 weight %). This drip water corresponds to precipitation water falling above the cave and thus constitutes an excellent archive of past precipitation, allowing us to determine lapse rates in the past. To extract and analyze this water, we used an improved speleothem fluid inclusion water extraction line available at the Quaternary Geology group of the University of Basel. The new design allows us to measure up to ten samples a day.For this study, we measured more than 100 fluid inclusion samples from various stalagmites in a transect from the Jura mountains to the swiss alps with elevations ranging between 373 and 2’000 meters. These measurements enable us to obtain direct information on past precipitation as well as determine absolute paleotemperatures (Affolter et al., 2019). They allow us to determine the stable isotope and temperature lapse rates for different time intervals, such as Marine isotope stage 5a, the Younger Dryas and the Holocene.Furthermore, to better understand the water isotopes in cave environments, we have launched (in 2023) the Citizen Science project “Cave Drip Water” in collaboration with various caving clubs in Switzerland and France (https://duw.unibas.ch/de/quartaergeologie/citizen-science/). The purpose of this program is to collect drip water samples and consequently monitor stable isotopes from numerous caves distributed at different elevations across Switzerland and in neighbouring regions. From this data, we will reconstruct a modern cave drip water lapse rate for Switzerland. In addition, it will allow us to investigate the spatial distribution of water isotopes in karst systems and compare it with the most recent water isotope patterns in precipitation from Switzerland. Moreover, these observations will set a baseline for the use of water isotopes analyzed in speleothem fluid inclusion measurements.Here we present preliminary isotope and temperature lapse rates based on speleothem fluid inclusion water for the Holocene, Younger Dryas and the MIS 5a intervals as well as the first results from the Citizen science project “Cave Drip Water”.REFERENCESSchotterer U., Schürch M., Rickli R., Stichler W. (2010). “Wasserisotope in der Schweiz: Neue Ergebnisse und Erfahrungen aus dem nationalen Messnetz ISOT“ Gas, Wasser, Abwasser 2010Affolter et al. (2019), Sci. Adv. 5 eaav3809, doi.org/10.1126/sciadv.aav3809
Assessment of nutrient export in agroforestry catchments dominated by tea farms in subtropical small mountainous rivers, Taiwan
Authors: Chen Pei-Hao , Naqvi Hasan Raja , Lin Guan-Zhou , Lee Tsung-Yu , Lee Li-Chin , Huang Jr-Chuan
Published: March 2024

Human-induced land-use change has profound effects on both societies and ecosystem services. For example, transitioning from forests to conventional farms using fertilizers can escalate soil nitrogen, degrade groundwater, and impair downstream ecosystems. This study explores the intricate dynamics of human-induced land-use change, focusing on the shift from forests to tea farm-dominated catchments in Taiwan, where conventional farming practices with fertilizers impact soil quality, groundwater, and downstream ecosystems. Utilizing the Soil and Water Assessment Tool (SWAT) for nutrient export analysis, our research reveals that when agricultural land use exceeds 2%, exports of nitrate, phosphate, and potassium spike significantly, ranging from 25% to 150%. Notably, agricultural land use induces a higher impact on nitrate, with concentrations surpassing those by 120% and 233% during the dry season and wet season, respectively. Tea farms, constituting a substantial portion, exhibit a nearly tenfold increase in NO3-N yield compared to forests. Implementing a modified fertilization strategy, involving application during small rainfall events, enhances nitrogen uptake and tea tree harvest yield while reducing nitrogen input by 10%. This research offers actionable recommendations for sustainable agroforestry practices by integrating river and rainwater data with SWAT modeling. By doing so, it advances our understanding of hydrological and biogeochemical processes in subtropical tea farm-dominated catchments, providing valuable insights into hydrology and biogeochemistry.
Modelling of C stock development for assessing the feasibility and implications of humus build-up in humus-oriented farming 
Authors: Stadler Susanne , Bahlmann Lisa , Noell Ursula , Stange Florian , Mollenhauer Silke , Woelk Alice , Rode Andrea , Aue Christina
Published: March 2024

Soil and groundwater resources in the North Sea region are under increasing pressure due to climate change and human activities, calling for the need of sound strategies for their sustainable protection. The EU Interreg North Sea Project "Blue Transition" targets at a systemic change that balances activities in urban, agricultural or natural areas. It considers a transition in land-use and fosters political structures and governance, investigating 16 pilot sites in Denmark, The Netherlands, Sweden, Belgium, France and Germany to exchange and develop transnational solutions for water boards, farmers, authorities and society.Within the project, we conduct scenario-based simulations (some based on strip experiments) regarding humus build-up under climate-induced rising temperatures and leaching from humus decomposition in arable soils in Lower Saxony, comparing conventional and organic farming. The aim of our study is an improvement of soil management in conventional and organic farming – especially regarding humus build-up and N loss reduction from soil. The results will serve as a base for elaborating best practices in management strategies for humus-oriented farming, and for investigating implications on soil water. We show first approaches of the numerical simulations.
Assessment of convection-permitting sub-daily extreme precipitation simulations over Italy
Authors: Borga Marco , Mazzoglio Paola , Lompi Marco , Marra Francesco , Dallan Eleonora , Deidda Roberto , Claps Pieluigi , Manfreda Salvatore , Noto Leonardo , Viglione Alberto , Raffa Mario , Caporali Enrica
Published: March 2024

Convection-permitting climate models have the potential to capture crucial processes in the climate system, presenting an opportunity to significantly enhance climate projections by providing more accurate representations of precipitation extremes. In this work, we conduct an evaluation of the accuracy of sub-daily precipitation extremes obtained from VHR-PRO_IT (Very High-Resolution PROjections for Italy, Raffa et al., 2023) over the Italian peninsula,. VHR-PRO_IT is generated through dynamic downscaling of the Italy 8km-CM climate projection at approximately 2.2 km resolution under the IPCC RCP4.5 and RCP8.5 scenarios, employing the Regional Climate Model COSMO-CLM.Gauged locations are used to assess the accuracy of VHR-PRO_IT in reproducing observed extremes. More specifically, the observed dataset used as ground truth for the comparison is I2-RED (Improved Italian – Rainfall Extreme Dataset; Mazzoglio et al., 2020). For this work, 742 rain gauges covering the entire country with a minimum of 30 years of short-duration (1, 3, 6, 12, 24 h) annual maximum rainfall depths recorded from 1980 to 2022 are used. Conversely, the dataset derived from the VHR-PRO_IT climate projections includes annual maxima from a 30-year time series, connecting the historical period (1981-2005) with 5 years of the RCP8.5 scenario (2006-2010) of the CPM. Return levels are obtained for both dataset by means of a GEV distribution and inform the assessment of the CPM simulations. Preliminary results outline the quality of the CPM simulations, especially at 24 hours duration, and show the impacts of return period, seasonality, elevation, latitude and proximity to the sea on the CPM model deviations. The results from this work are expected to have implications for both water resources management and adaptation measures.ReferencesMazzoglio P., Butera I., Claps P. (2020). I2-RED: a massive update and quality control of the Italian annual extreme rainfall dataset. Water, 12, 3308.Raffa M., Adinolfi M., Reder A., Marras G.F., Mancini M., Scipione G., Santini M., Mercogliano P.  (2023). Very High Resolution Projections over Italy under different CMIP5 IPCC scenarios. Scientific Data, 10, 238.
Comprehensive assessment of hazard, exposure, and vulnerability using a new database of climate impact indicators to identify hotspots for adaptation needs
Authors: Werning Michaela , Byers Edward , Hooke Daniel , Andrijevic Marina , Krey Volker , Riahi Keywan
Published: March 2024

In the 21st century, an increasing global population will be exposed to various risks caused by climate change. The impact depends not only on the geophysical climate change hazards, but also on the population’s vulnerability, its spatial distribution, and its capacity to adapt. Here we present a new database of climate impact indicators at various global warming levels (1.2 - 3.5°C) using global climate and hydrological model data from the latest Coupled Model Intercomparison Project (CMIP6) and Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3b) simulation rounds.Indicators include a variety of temperature and precipitation extremes, heatwaves, drought intensity, hydrological variability, and water stress. Building on previous work (Byers et al. 2018),  the first novel aspect of this work is the development of a bi-variate hazard index that includes statistics on the absolute hazard level (e.g. low or high precipitation) and the relative change under global warming compared to the historical baseline (e.g. a large change from low to high precipitation).We combine this new index with gridded projections of population from the Shared Socioeconomic Pathways (SSPs) and land area to calculate temporal and spatial exposure.  Finally, to allow for risk assessment, we introduce the layer of vulnerability measured through various socio-economic indicators, such as income, inequality, or the Notre-Dame Global Adaptation Index (ND-GAIN).In aggregate, we find that impacts manifest substantially even in the near-term at lower global warming levels. For example, even at 1.5°C 93% of the population of South Asia will face a medium exposure to heatwave events. Countries predominantly in the low latitudes and global south are comparatively more severely affected by multiple climate impacts. The window for reducing the risk burden is rapidly closing while there is substantial unavoidable risk even at 1.5C, thus adaptation actions will be key. By analysing impact and vulnerability hotspots, our work can help identify these adaptation needs, i.e. for financial assessments or loss and damage, down to high spatial resolution but also at the country level. With further categorisation, we can assess populations at the highest risk, such as those with high impacts, high vulnerability and lowest institutional governance capacities.
Identifying the Transition Zone between Peat and Mineral Soils Using Airborne Radiometric Data: a national scale case study from Ireland
Authors: O Leary David , Connolly John , Gilet Louis , Tuohy Patrick , Hodgson Jim , Daly Eve
Published: March 2024

National and international climate change mitigation plans require a knowledge of peat soil extent across large geographic areas. Peat soils, which play a vital role in carbon storage and climate regulation, have a physical margin where soils change from high to low organic content. Accurate delineation of both national extent of peat soils and peat to mineral soil transition is required for assessing land use and planning effective conservation and carbon loss mitigation strategies. This abstract presents a novel approach for defining both peat soil extent nationally and transition zones between peat and mineral soils at field scale.At a national scale, peat soil maps are created using optical satellite remote sensing or legacy soil/quaternary maps or a combination of both. However, optical remote sensing cannot detect peatlands under landcover such as forest or grassland and legacy maps are often created from sparse in-situ auger data making the accurate delineation of the boundary between peat and mineral soils difficult and cost prohibitive.Airborne radiometric data, which measures natural environmental radiation, has been shown to differentiate between peat and mineral soils due to high attenuation of gamma rays in organic soils. Radiometric data is considered a direct measurement of the subsurface and so is minimally affected by landcover. Additionally, as airborne radiometric data can be acquired in a spatially consistent manner, it has the potential to identify areas of peat soil across the landscape and highlight areas of transition between high and low organic soils.In Ireland, the Tellus survey, acquired by Geological Survey Ireland (GSI) aims to acquire airborne data (including radiometric data), consistently across the country (flight line spacing of 200m) at a resolution of 50 x 50 m. Utilising this national radiometric dataset, a machine learning classification methodology is presented. Data are classified as peat (> 30 % organic material) or non-peat, with 85 % accuracy, is validated using a national soils sampling survey. A confidence value is extracted, once data are classified, which results in the identification peat soils. Several field sites across the midlands of Ireland, which are located at verified transition zones, are then used to show the effectiveness of the classification at identifying transition zones at the field scale.The methodology is robust and can be applied in all areas where these data exist. The results highlight that inclusion of an airborne radiometric dataset in a national climate plan can be used to update national and international carbon inventories of peatlands areas and inform European policy. Understanding the location of these peat to mineral soil transitions is paramount when considering the impact on climate change mitigation strategies such as potential impact of rewetting of peat soils.
Soils and surface waters are secondary sources of polycyclic aromatic compounds
Authors: Lammel Gerhard , Bandowe Benjamin A. Musa , Bohlin-Nizzetto Pernilla , Degrendele Céline , Halse Anne Karine , Iakovides Minas , Kukučka Petr , Kyprianou Marios , Martiník Jakub , Mwangi John , Palátová Nežiková Barbora , Přibylová Petra , Prokeš Roman , Sáňka Milan , Sobotka Jaromir , Vinkler Jakub , Wietzoreck Marco , Pöschl Ulrich , Stephanou Euripides G. , Tsapakis Manolis ,   PAC air-surface exchange
Published: March 2024

Polycyclic aromatic hydrocarbons (PAHs) in the atmospheric environment are almost exclusively formed in combustion processes. Oxygenated and nitrated PAHs are co-emitted with parent PAHs from fossil fuel and biomass combustion processes, and many are formed in photochemical and microbiological reactions of PAHs in air and soil. As semivolatiles resisting biodegradation in soils and surface waters to some extent, polycyclic aromatic compounds (PACs) i.e., PAHs and their derivatives, can be subject to re-volatilisation., which may turn soils and surface waters from sinks into secondary sources and enhances the long-range transport potential of PACs by multihopping (grasshopper effect). The significance of these secondary sources for PAC abundances in ambient air is unknown and is not accounted for in emission inventories. Gaps in PAH emission inventories have been indicated by field studies in various countries.We determined the concentrations of 15 parent, 10 oxygenated and 17 nitrated PAHs in air and soils at a rural and near-coastal northern European site and a central European rural background site, and in air and surface seawater at two off-shore sites in the eastern Mediterranean and along NW-SE transects in the Mediterranean. Directions of air-soil and air-sea exchanges were derived from the substances’ fugacities.At the central European site, a number of 2-4 ring PACs were found to volatilise from grassland and more from forest soils in summer, and much less in winter. Conversely, at the receptor site in northern Europe, net deposition of PACs prevails and re-volatilisation occurs only sporadically. In the Mediterranean, 3-4 ring PAHs and dibenzofuran are found to volatilise in most seasons.Existing data on air-surface exchange of PACs is notably scarce, and methodological uncertainties persist in quantifying air-soil exchange. As very little is known about the spatial and seasonal distributions of PACs soil burdens and net mass fluxes, an assessment of the significance of soils and surface waters as secondary sources of PACs in the air of source and receptor areas is not possible. 
The connection between the "Zero Net Artificialisation 2050" objective and the "Urban Digital Twin" tool, a methodology for assessing strategies to reduce the risk of urban heat islands using data.
Authors: Josse Fanny
Published: March 2024

Soil artificialisation due to urban sprawl, infrastructure development and concreting is one of the causes of the loss of urban biodiversity. In addition, the rise in global temperatures as a direct consequence of climate change has become a major challenge for urban planning. The urban heat island, which is mainly the result of the waterproofing of soils to encourage surface reflection (Aldebo), contributes to global warming. The Urban Digital Twin, a design tool that can simulate, predict and monitor through the implementation of data, enables urban resilience strategies to be put in place.This proposal aims to discuss the relationship between the "Zero Net Artificialization (ZNA) by 2050" objective (the ban on artificialization over a " defined period ") of the 2021 French "Climate and Resilience" legislation and the "Urban Digital Twin" in view of building models for planning cities that are more resilient to heat islands.The first part of this presentation is devoted to the development of a methodology for selecting data (type of land use, topography, albedo of materials, etc.) and implementing them in numerical models in order to obtain "urban and climate Digital Twins".The second part of this document is devoted to the methodology for evaluating the various strategic models developed in the first part of the document at different scales, from the block to the territory, but also over different temporalities in line with the ZNA objective (currently conditional on the renaturation of an equal proportion of artificialised spaces over a specific timeframe) and further research into the fight against heat islands.By using the Urban Digital Twin to meet the ZNA objective, this proposal focuses on developing predictive models for controlling heat islands in an attempt to guide urban planning towards sustainable and resilient environments.
Planktic foraminifera reflects surface productivity and hydrographic changes in the tropical Indian Ocean during the last 24,000 years
Authors: Rai Soni , Singh Dharmendra Pratap
Published: March 2024

The tropical Indian Ocean presents a distinctive opportunity to investigate monsoon-induced changes in primary productivity and ocean hydrography. Planktic foraminifera, with their unique ecological preferences, are well-suited for reconstructing past environmental conditions. Different species of planktic foraminifera exhibit varied responses to changes in the physico-chemical parameters of the ambient water. This study presents a high-resolution planktic foraminiferal assemblage from the marine sediment core SSD004 GC03 for the last 24,000 years from the tropical Indian Ocean. The record includes 24 planktic foraminifera species with G. bulloides, G. glutinata, G. ruber, G. sacculifer, N. dutertrei and G. menardii  being the most abundant. The species are categorized into eutrophic, oligotrophic, mixed layer, and thermocline assemblages. Notably, during the last glacial maximum (LGM; 19.0-23.0 ka), a significant abundance of mixed layer assemblage is observed between 21.0-19.0 kyr. Heinrich stadial 1 (~15.0-18.0 ka) and the Younger Dryas (~11.-12.9 ka) periods exhibit a lower mixed layer assemblage and a higher thermocline assemblage. The Bølling-Allerød (~12.9-15.0 ka) period is characterized by a sudden increase in mixed-layer assemblages. The abundance of eutrophic species G. bulloides and G. glutinata during the LGM and Holocene indicates increased surface productivity influenced by the Northeast Monsoon and the strong Southwest Monsoon, respectively. The results underscore the unique and intricate dynamics of the studied region, primarily influenced by both the southwest and northeast monsoons.
Where and when will the next precipitation record be broken? 
Authors: de Vries Iris , Fischer Erich , Sippel Sebastian , Knutti Reto
Published: March 2024

Not only will climate change lead to more intense extreme precipitation, it will also lead to more frequent record-breaking daily rainfall. Given the tendency of society to design critical infrastructure and emergency plans based on (statistics derived from) historical observations, an increasing occurrence of record-breaking events – events that are more intense than ever recorded – poses a high risk for loss and damage. A major challenge in the projection of very extreme events is their inherent rarity. This problem is even more prominent for record events: by definition these events are not present in sample data because they have not yet occurred. An additional difficulty, which is particularly challenging for precipitation, is the high internal variability in and local character of very rare extremes. This implies that, by chance, an observed data sample of finite size might contain few extremes, whereas the true probability and intensity of extremes given by the (unknown) underlying distribution is much higher. In practice, this can lead to “surprise extremes”. With the help of extreme value theory, we approach this problem from two angles, using multi-model CMIP6 data and two different ground-station based observational datasets. Firstly we assess, for all observed land grid cells, where the last observed precipitation record is “extraordinarily long ago” given the theoretical record breaking rate prescribed by historical and future climate according to the CMIP6 models. Secondly, we assess where the last observed record value is “extraordinarily low in intensity” given the historical and future modelled distribution of extreme precipitation. Combining these two approaches, we highlight regions on earth where the probability of record precipitation events in the near future is high.We find that grid points where the last observed precipitation record is extraordinarily long ago are ubiquitous and scattered globally. When combining this with the observed record intensity, the number of grid points that stand out for their high near-term record probability decreases drastically. We find a somewhat higher density of high-probability grid points in Australia and southern South America, but the pattern is not very clear. Nonetheless, every world region contains a number of grid points where the current observed record is both extraordinarily long ago and low in intensity, and where the near-term probability of a new precipitation record is thus high.
Insights into fault behaviour and seismic hazard from studying active and inactive faults over a range of timescales
Authors: Mildon Zoe , Andrews Billy , Rodriguez Piceda Constanza , Diercks Manuel
Published: March 2024

Tectonics and active faults are studied using a broad range of techniques and observations, and each of these datasets have both strengths and limitations. Ideally, a multidisciplinary approach should be used when studying active faults, to mitigate against gaps in data and knowledge, and to span the spatial scales of deformation. Furthermore different approaches can provide insights into how faults and fault networks behave over a wide range of timescales, from annual behaviour (e.g. geodesy, seismology) to millennia (e.g. paleoseismology) and millions of years (e.g. seismic reflection). By using a range of techniques to study fault behaviour over a range of timescales, we gain insights into how faults behave and interact, which ultimately can improve our understanding of the resultant seismic hazard.For seismic hazard studies, it is important to quantify fault geometry, dimensions and connectivity as these factors influence the magnitude and propagation of earthquakes. However these are typically difficult to constrain from onshore continental faults where  sub-surface information is often limited. Another important aspect to consider for seismic hazard studies is the slip rate of faults, but an aspect that is rarely considered is how slip rates vary spatially and temporally. Using seismic reflection datasets of inactive normal faults, we can study how slip rates vary over far longer timescales than can be considered from field studies alone. While it is challenging to study onshore faults using the same approach, what our findings indicate is that slip rates can vary by more than an order of magnitude over the lifetime of a single fault. Additionally, faults are almost never a single isolated structure, and instead form fault networks, with variable spacing, orientation and lengths. Understanding how a fault network behaves and interacts over time is also important to gain insights into seismic hazard.Ultimately to gain a comprehensive understanding of fault behaviour in time and space, a range of complementary studies, including observations and modelling, are needed to span the broad range spatial and temporal scales that need to be considered when assessing active faults. 
The pivotal roles of the scientists in the initiative lead by the French government to train all civil servants on climate, biodiversity and natural resources issues
Authors: Cassou Christophe , Abbadie Luc , Tubiana Laurence , Dorioz Ulysse , Lecomte Jane , Gouny Claire ,   GAES (Groupe d'Appui et d'Expertise Scientifique)
Published: March 2024

As anticipated by scientists for decades, impacts of climate change, biodiversity losses and natural resources scarcity, are increasingly challenging human societies in these early 2020s. To respond to this challenge, a large number of countries are undertaking profound societal shifts towards low-carbon and biodiversity-friendly lifestyles. So far, these efforts have been clearly insufficient to achieve sustainable development goals and more ambitious action will be needed at all decision levels.In France, the government has taken the decisive step to train all civil servants on the three above-cited environmental issues. The aim of this unique and ambitious initiative is to engage as many state stakeholders and practioners as possible, by raising their awareness and knowledge about both environmental risks and challenges to be faced, in order to initiate an effective, societal-scale transition that has to be collective, collaborative and systemic by essence. This initiative is partly related to a "foot in the door" media operation carried out in June 2022, just after the presidential and legislative elections, and initiated by the scientific community to offer free training courses on climate and biodiversity issues to newly-elected members of parliament.The ongoing inter-ministerial initiative is steered at national level by an interdisciplinary group of scientists who are responsible for framing training content and methods. Its operational implementation is ensured by regional committees of scientists to address local issues grounded in actionable reality, and to facilitate effective scaling-up. The ambition is to train 25,000 top managers civil servants by the end of 2024, and 5,7 million civil servants by 2027. Scientific knowledge is at the heart of the training program and the entire cursus runs over 28 hours in face-to-face to ensure cooperative dynamics during workshops, masterclasses, debates and field trips. More than 1,200 academics have volunteered to disseminate scientific facts as aid to decision-making, and to present the scientific methods that supports them. Training courses in scientific mediation will be offered to scientists engaged in the project, especially to early career researchers. The evaluation of the full initiative will be independently carried out through 3 PhD theses.The ultimate aim of this initiative is to create shared and long-lasting spaces for dialogue and trust between public decision-makers and the scientific community. In this talk, we will describe and discuss the pivotal role played by the scientific community in this initiative. We will report the lessons learnt from the first training courses, as well as the successes and various obstacles that have been encountered.
Statistical and geospatial approaches to evaluate the quality of earthquake-triggered landslide inventories
Authors: Pokharel Badal , Alvioli Massimiliano , Lim Samsung
Published: March 2024

Evaluating landslide inventories is crucial and the first step in assessing the extent of landslide event damage. Despite the several studies in landslide inventory preparation and assessment, there is a lack of standardised criteria for measuring their quality and completeness. This study aims to introduce an integrated approach for analysing different event inventories prepared by different geomorphologists. We considered five landslide inventories prepared by various authors following the 2015 Gorkha earthquake in Nepal [1-5]. We prepared susceptibility maps using multiple realisations of logistic regression, with slope units of the areas as a spatial basic unit for the analysis [6]. The goal was to analyse their differences or similarities and comprehend the influence of using them to prepare landslide susceptibility maps [7].The key questions we explored were: How can the quality and reliability of landslide inventories be evaluated? And what are the similarities or differences in the landslide susceptibility maps generated using inventories from different research teams for the same event? To this end, we utilised three evaluation criteria: (i) an error index to check the discrepancies between inventories, (ii) statistical analysis to examine the inconsistencies in predisposing factors and susceptibility map performance, (iii) geospatial analysis to evaluate differences among inventories and their corresponding.The study highlighted differences in landslide inventories and attributed them to differences in data collection methods and subjective judgments. It emphasised the need to address subjectivity for more accurate and consistent landslide mapping. The results from statistical analysis showed substantial differences in the areal extent and overlapping degree between inventories. The geospatial analysis, such as hot spots and cluster/outlier analysis, highlighted the distinctive differences in spatial patterns of landslide susceptibility maps corresponding to different inventories. The suggested geospatial methods offer investigators a viewpoint for quantitatively analysing earthquake-triggered landslide inventories and related susceptibility maps.References[1] Zhang et al., Journal of Mountain Science (2016). https://doi.org/10.1007/s11629-016-4017-0[2] Gnyawali et al., Springer International Publishing (2017). https://doi.org/10.1007/978-3-319-53485-5_10[3] Roback et al., US Geological Survey Data Release (2017). https://doi.org/10.5066/F7DZ06F9,   [4] Kargel et al., Science (2016). https://doi.org/10.1126/science.aac8353[5] Pokharel and Thapa, Journal of Nepal Geological Society (2019). https://doi.org/10.3126/jngs.v59i0.24992[6] Alvioli et al., Journal of Maps (2022). https://doi.org/10.1080/17445647.2022.2052768[7] Pokharel et al., Scientific Reports (2021). https://doi.org/10.1038/s41598-021-00780-y 
Storm-surge barriers induce loss of geomorphic diversity in shallow tidal embayments
Authors: Carniello Luca , Tognin Davide , Finotello Alvise , Viero Daniele Pietro , Pivato Mattia , Mel Riccardo Alvise , Defina Andrea , Bertuzzo Enrico , Marani Marco , D'Alpaos Andrea
Published: March 2024

Flood regulation systems and storm-surge barriers are increasingly being employed to safeguard coastal cities worldwide from the threats of flooding linked to rising sea levels. Prominent examples include London, the Netherlands, New Orleans, St. Petersburg, and Venice. While these barriers effectively control the propagation of surges and tides, they also induce changes in sediment transport, consequently altering the morphological evolution of estuarine systems near the protected urban areas. However, the precise impact of flood regulation on the morphodynamic evolution of tidal environments remains an unanswered question.Our study delves into the effects of recently activated storm-surge barriers, designed to protect Venice (Italy) from flooding, on the morphological evolution of the Venice Lagoon. This investigation combines numerical modeling with field data.The artificial reduction of water levels influences the interaction between tides and waves, leading to increased sediment resuspension on tidal flats. However, the deposition of resuspended sediments on salt marshes is importantly reduced by the diminished flooding intensity and duration resulting from artificially-lowered water levels. This situation could potentially compromise the marsh's ability to adapt to rising sea levels via mineral sediment deposition. At the same time, eroded sediments tend to accumulate within channels, thereby impeding water exchange and escalating dredging costs.Over longer (i.e., seasonal) timescales, we propose that while barrier closures decrease net sediment export to the open sea, they do not necessarily preserve the characteristic lagoonal morphology. Instead, this may hinder salt marsh vertical accretion, promote tidal flat deepening, and lead to channel infilling. Consequently, the operation of flood barriers could trigger a significant loss of tidal landforms, adversely impacting the preservation of shallow tidal environments and the valuable ecosystem services they provide.
A new model of plate kinematics describing the early development of the Indian Ocean
Authors: Eagles Graeme
Published: March 2024

Models depicting the plate kinematic development of the Indian Ocean have a range of applications including in paleogeographic studies and in formulating and testing ideas about plume/plate interactions. Until now, these applications have been forced to tolerate egregious model/observation inconsistencies concerning the relative motion history of India and Madagascar. Whilst the Phanerozoic record of these motions begins with ∼90 Ma basalts that erupted along a narrow rift basin, all modern plate kinematic models for the Indian Ocean predict hundreds of kilometres of relative motions, in diverse and conflicting senses, over several tens of millions of years prior to the eruptions. The diversity of these predicted motions suggests they are artefacts that arise from differing approaches taken to modelling the development of the eastern and western parts of the ocean, rather than a reflection of insufficient or absent geological observations. In this contribution, I present a new model for the early plate kinematic development of the Indian Ocean that is constrained by observational evidence for relative plate motion azimuths in the Enderby and western Bay of Bengal basins and by explicitly maintaining a rigid mid- and early Cretaceous Indo-Malagasy body. This approach requires the model to feature two small tectonic plates between the continental margins of eastern India and East Antarctica. The older of the two, Mandara, is an intraoceanic plate in the Enderby Basin that may have formed in relation to delivery of excess melt from the Kerguelen plume to the basin's mid-ocean ridge. The younger plate, Vasuki, in the western Bay of Bengal Basin, also accommodated plume-related melt at its boundaries, in its case from the Marion and possibly also the Crozet plume. The model shows this plate transporting Sri Lanka ∼800 km southwards along the eastern Indian continental margin to its present location. The model also requires the presence of around half a million square kilometres of continental crust beneath the Kerguelen Plateau, which lies within the range of published observation-led estimates of its extent. Neither the absence of evidence for relative motions between India and Madagascar prior to ∼90 Ma, nor the modelled Euler rotation pole's location afterwards, are consistent with suggestions that traction forces related to the ascent of the Marion plume drove the mid-Cretaceous onset of subduction in the western Neotethys.
Molecular characterization of PM2.5 in Xi'an, Northwest China to reveal seasonal variation in sources of the organic fraction
Authors: Li Linjie , Shang Yijun , Sun Tingting , Kong Xiangrui , Wang Sen , Hallquist Mattias
Published: March 2024

Organic aerosols (OA) are an important component of fine particulate matter (PM2.5), constituting a substantial portion of its total mass. Seasonal ambient PM2.5 samples were collected in Xi’an from April 2018 to March 2019. In order to achieve a molecular-level understanding of the OA fraction, the samples were analyzed using an iodide chemical ionization mass spectrometer combined with a Filter Inlet for Gases and AEROsols (FIGAERO-CIMS). The sum of compounds identified by FIGAERO-CIMS represented 29% organic matter in PM2.5 on an annual average, including compounds containing CHO, CHON, CHOS, and CHONS. In the winter, the concentration of identified compounds notably surpasses levels observed in the other seasons. It was especially evident during a severe pollution episode in January 2019. The relative contribution of compounds containing only CHO, i.e., no sulfur or nitrogen, increases during summer which is likely due to enhanced photochemical oxidation. It was also indicated by a slightly elevated oxidation state being observed in summer compared to other seasons. The CHON compounds are most likely mainly consisting of nitro-aromatics, e.g., phenols-like compounds, where biomass burning and secondary formation are the dominant sources. Both biogenic and anthropogenic volatile organic compounds are contributing to sulfate-containing organic compounds in urban Xi’an.