bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing early ENSO prediction: how the South American Monsoon onset connects the South Atlantic Subtropical Dipole and the South Pacific Oscillation
Authors: Bellacanzone Fabio , Bordoni Simona
Published: March 2024

In recent decades, a growing body of research has highlighted the intricate interplay between the El Niño-Southern Oscillation (ENSO) and various climatic patterns across multiple ocean basins. Several studies have highlighted the significance of the South Atlantic Subtropical Dipole (SASD) and its association with ENSO.This investigation examines the interaction between SASD and ENSO, focusing on the critical role of the South Pacific High in these dynamics. Our study proposes that the onset of the South American Monsoon (SAM) plays a crucial role in this connection, challenging the traditional perception of land's passive role in tropical interbasin interactions.We identified two eastern Pacific and two central Pacific ENSO precursors from SAM onset period using ERA5 reanalysis data along with 1200-year CESM2 PI run. Applying partial linear regressions revealed the following patterns: initially, warm Southwestern Tropical Atlantic (SWTA) and basin-wide low pressure in the equatorial and subequatorial Atlantic, evolving into cold Southeastern Tropical Pacific (boreal spring); then, negative South Pacific Oscillation (SPO) during the following boreal summer, culminating in La Niña conditions between 12 and 15 months later (SON and DJF of the following year).We hypothesize that anomalous upper-level divergent monsoonal circulation acts as a bridge connecting the two ocean basins. Ekman dynamics arguably transfers and amplify atmospheric signals from the SAM and SPO to the equatorial Pacific Ocean.Random Forest and Support Vector Machines for regression analysis yielded results consistent with those from the linear model; superior skill was noted in La Niña prediction compared to under-predicted El Niño events.Moving forward, we intend to construct causal networks to disentangle the complex interplays described herein while ensuring independence from other known teleconnections; alternatively, we plan to design appropriate numerical experiments using coupled GCMs.This study's preliminary results present exciting opportunities to enhance early ENSO prediction by considering the impact of the South American Monsoon on aligning the variability of the tropical South Atlantic and South Pacific oceans.
Assessing Surface Water and Groundwater Interactions Using Long-Term Hydrological and Time-Lapse Seismic Data in the Orgeval Critical Zone Observatory
Authors: Rivière Agnès , Dangeard Marine , Bodet Ludovic , Sanchez Gonzalez Ramon , Gesret Alexandrine
Published: March 2024

Quantifying the water and heat fluxes at the interface between surface water (SW) and groundwater (GW) is a key issue for hydrogeologists to consider for safe yield and good water quality. However, such quantification with field measurements is not straightforward because the SW-GW changes depend on the boundary conditions and the spatial description of the hydrofacies, which aren't well known and are usually guessed by calibrating models using standard data like hydraulic heads and river discharge. We provide a methodology to build stronger constraints to the numerical simulation and the hydrodynamic and thermal parameter calibration, both in space and time, by using a multi-method approach. Our method, applied to the Orgeval Critical Zone Observatory (France), estimates both water flow and heat fluxes through the SW-GW interface using long-term hydrological data, time-lapse seismic data, and modeling tools. We show how a thorough interpretation of high-resolution geophysical images, combined with geotechnical data, provides a detailed distribution of hydrofacies, valuable prior information about the associated hydrodynamic property distribution. The temporal dynamic of the WT table can be captured with high-resolution time-lapse seismic acquisitions. Each seismic snapshot is then thoroughly inverted to image spatial WT variations. The long-term hydrogeological data (such as hydraulic head and temperature) and this prior geophysical information are then used to set the parameters for the hydrogeological modeling domain. The use of the WT geometry and temperature data improves the estimation of transient stream-aquifer exchanges.
Assessing rock glacier activity in the Austrian Alps using radar interferometry and image correlation techniques
Authors: Otto Jan-Christoph , Schroeckh Timon Ruben , Keuschnig Markus
Published: March 2024

Rock glaciers serve as crucial indicators of climate change impacts, offering valuable insights into environmental consequences. Assessing the activity rate of these landforms is essential for understanding their vitality, yet recent activity remains largely undocumented, particularly across extensive regions. In this study, we present an innovative methodology for categorizing rock glacier activity, leveraging state-of-the-art remote sensing technologies and adhering to the latest guidelines established by the IPA Action Group on rock glaciers.In this work, we use SqueeSAR© processed Sentinel-1 data over two years (2020-2022) and digital image correlation (DIC) of repeated airborne imagery and digital elevation models using SAGA IMCORR tool to classify rock glaciers in Austria. DIC techniques were used in several local test sites to calibrate a model of SqueeSAR classification for rock glacier activity based on a threshold approach. The approach was verified using existing local rock glacier kinematic data from across the country.Our results show that around 10% of the almost 5800 rock glaciers in Austria can be considered active, showing motion rates above a 10 cm/yr threshold within more than 40% of their total area.  Another 350 rock glaciers (6%) have been categorised a transient status characterised by low movement rates at limited parts of the landforms. Furthermore, we identified about 1100 rock glaciers relict that have been classified intact in the original inventory. This increases the number of relict rock glaciers in Austria from 60% to 77%.  Active rock glaciers are located mainly in the Ötztal, Zillertal and Hohe Tauern ranges.This new categorisation enables to identify rock glaciers in motion that may react sensitive to increasing ground temperatures and may contribute to a local hazard potential.
Late Pliocene onset of millennial climate variability during the intensification of Northern Hemisphere Glaciation
Authors: Du Mengyao , Crowhurst Simon , Mleneck-Vautravers Maryline , Hodell David , Abrantes Fatima , Alvarez Zarikian Carlos , 397 Scientific Party Expedition
Published: March 2024

The retrieval of sediment cores from Site U1385 during Expedition IODP 397 off the Iberian Margin has yielded a high-fidelity record extending back to the base of Pliocene. This record provides an unprecedented opportunity to investigate the onset of millennial climate variability associated with the intensification of Northern Hemisphere Glaciation (iNHG) during the late Pliocene. Elemental ratios, specifically Ca/Ti and Zr/Sr, measured by core scanning X-ray fluorescence (XRF) have uncovered four distinct millennial climate events in Marine Isotope Stages (MIS) G6, G4, G2 and 104. These single ‘precursor events’ precede the onset of pronounced millennial climate variability marked by multiple events beginning with MIS 100 (2.54 Ma).The planktic δ18O record of Globigerina bulloides exhibits an increase associated with the peak in Zr/Sr and minimum in Ca/Ti, indicating colder temperatures during the stadial event in MIS G4 (2.69 Ma). A comparison with the δ18O record of mixed benthic foraminifera (Cibicidoides wuellerstorfi and Uvigerina peregrina) indicates that the identified cold stadial in MIS G4 coincided with the end of MIS G4 just before the deglaciation to MIS G3. We therefore suggest it represents a terminal stadial event, which is common during the latest part of glacial stages during the Quaternary. Moreover, the precursor stadial events of MIS G6, G4, G2 and 104 at Site U1385 can be correlated 1:1 to peaks in ice-rafted debris (IRD) in the high-latitude North Atlantic, indicating a connection to iceberg calving and freshwater forcing. Our results indicate that ice sheets had grown large enough during the glacial stages of the latest Pliocene to induce a significant response to freshwater forcing upon deglaciation.
Integrated surface–subsurface hydrological modeling for the assessment of groundwater recharge in the Venetian high plain, Italy
Authors: Camporese Matteo , Gatto Beatrice , Furlanetto Davide , Trentin Tommaso , Salandin Paolo
Published: March 2024

Groundwater accounts for almost 99% of the available liquid freshwater present on Earth and it is the main source of drinking water. It is recharged not only by rainwater (including losing streams) and snowmelt, but also by infiltration of water used for irrigation. In this study, CATHY (CATchment Hydrology), an integrated surface–subsurface hydrological model (ISSHM), is used to quantify current and future recharge fluxes in the Venetian high plain between the Brenta and Piave Rivers. This area, with a size of around 900 km2, represents an important source of drinking water supply for the Veneto region, Northeast Italy. In compliance with European directive indications, to decrease water withdrawals from the Piave River and preserve its ecological flow, the irrigation management must be reviewed. First, we calibrated CATHY through a combination of FePEST and the Shuffled Complex Evolution algorithm, whereby both the bottom of the unconfined aquifer and the hydraulic conductivity field were estimated. After validation, the model was used to simulate a scenario in which the flood irrigation method, currently the most widespread in the study area, is fully replaced by sprinkler irrigation. The results show that in response to a 50% decrease in water abstraction from the Piave River, the total recharge decreases by about 10%, with a local decrease in the groundwater level, mainly limited to wells located in areas directly affected by the change in irrigation technique and where hydraulic conductivity is higher. Overall, this work demonstrates that ISSHMs are capable of reproducing groundwater dynamics and its drivers at high resolution and regional scales, representing useful tools to investigate possible responses of hydrosystems to future land use and climate change.
Anomalous subsurface phosphorus transport from field to stream in a tile drained landscape: Tracer experiment and models
Authors: Sawyer Audrey , Decker Lauren , Welch Susan , Zhu Junfeng , Binley Andrew , Field Hannah , Hanrahan Brittany , King Kevin
Published: March 2024

In agricultural areas with poorly drained soils, subsurface tile drains are commonly installed to improve drainage but also serve as conduits that deliver excess nutrients to adjacent streams. Our goal was to understand the transport of phosphorus (P) along these flow paths by applying a novel mixture of tracers (including 866 g of conservative chloride (Cl), 3.4 g of potassium phosphate, and approximately 3.6x1011 fluorescent micrometer-sized particles, or 49.5 g) to a farm field and sampling their breakthrough curves at the outlet to a stream, approximately 30 meters away. Simultaneously, we performed a 26-hour time-lapse electrical resistivity tomography (ERT) survey to monitor the saline tracer migration in three dimensions every 0.5 to 1 hour. The initial pulse of tracers had a mean arrival time of 21 minutes and transported 262 g of added Cl (28%), 0.65 g of dissolved P (17%), and 1.4x1010 particles (4%) to the tile drain outlet. A stochastic mobile-immobile model fit the anomalous (non-Fickian) solute breakthrough curves, where the mobile zone represents the macropore and tile drain network, and the immobile zone represents the soil matrix. Residence times in the immobile zone exhibited a heavy (power-law) tail. ERT images confirmed the retention of tracer mixture in soils after concentrations were no longer measurable at the tile drain outlet. Core samples suggest that 96% of particles and 21% of dissolved P were retained within 10.5 cm of the application location. Solutes and particles were remobilized over longer timescales during three successive storms. Exported masses of Cl and dissolved P at the tile drain outlet ranged from 1,490-12,300 g and 25.7-65.2 g, respectively, indicating flushing of older Cl and P stored in soils before the tracer experiment. Less than 0.01% of the added fluorescent particles were flushed during these storm events. This study indicates the wide range of P travel times through the subsurface in tile drained landscapes and the need to incorporate non-Fickian transport behavior in models.
A Warming Climate's Wandering Jet: Investigating Jet Stream Waviness with Hemispheric and Regional Lenses
Authors: Gözlet Mehmet Sedat , Kjellsson Joakim , Latif Mojib
Published: March 2024

In the context of a warming Arctic, the behavior of jet streams, as they increasingly meander, is becoming more intricate and variable. In this study, we analyzed approximately 50 models, in total, from the CMIP6 project and ERA5 reanalysis to quantify jet stream waviness and its response to climate change. We found varying trends and spatiotemporally dependent significance levels in jet stream meandering, particularly in the Northern Hemisphere, linked to rising CO2 levels and natural climatic variability.Building on this foundation, our research delved into the complex patterns of jet stream meandering. We analyzed The Diagnostic Evaluation and Characterization of Klima (DECK) experiments within the CMIP6 framework—AMIP, piControl, and a scenario with a 1% per year CO2 concentration increase—including 21, 18, and 13 models, respectively. These specific datasets and models provided a robust foundation for unraveling the climatic factors affecting the jet stream's trajectory and variations. Spanning from 1979 to 2014, our analysis uses daily geopotential height readings to quantify jet stream waviness and assess the impact of climate change.The analysis centers on normalizing arc lengths to measure jet stream waviness using the meandering index (M-Index). Additionally, the study investigates median and minimum waviness in Eurasia, the North Atlantic, North America, and the North Pacific to explore regional effects. These insights reveal significant seasonal variations and trends in jet stream behavior, crucial for understanding the impact of climate change on atmospheric dynamics.In conclusion, this study aligns with the IPCC AR6, thoroughly investigating the complex nature of jet stream meandering and illuminating the roles of CO2 and natural variability. By adhering to the diverse metrics outlined by the IPCC, our research methodically quantifies jet stream trends with the help of M-Index calculations. This thorough exploration dissects the complex interplay between global warming and atmospheric behavior, demonstrating the depth and analytical rigor that is characteristic of climate research aligned with IPCC standards.
Route to chaos and resonant triads interaction in a truncated Rotating Nonlinear shallow-water model
Authors: Carbone francesco , Dutykh Denys
Published: March 2024

The route to chaos in a truncated rotating shallow-water model has been investigated by constructing an autonomous five-mode Galerkin truncated system with complex variables. Two distinct transitions to chaos were observed as the energy injected into the system increased. The first transition is characterized by forming a continuous sequence of bifurcations that follow the usual Feigenbaum path. The second transition, occurring for high values of injected energy, exhibits a sharp transition between quasi-periodic states and chaotic regimes. The first chaotic regime arises since nonlinear interactions are principally dominated by inertial terms, while the second one is related to the increasing importance of free surface elevation in the overall process. By rewriting the system in terms of phase and amplitude, for each variable truncated system, it has been found that phases are locked at the initial value for a certain period of time, followed by a sudden transition due to a simple rotation of $\pm \pi$, even when amplitudes show a chaotic dynamic. The time duration of phase locking decreases as the injected energy increases, and, for high values of injected energy, even phases reach a chaotic regime. This behaviour is observed since, in the nonlinear term of the equations, phases appear through linear combinations of triads of different modes. When the duration of locking periods is different for each mode, the superposition of multiple $\pi$ phases jumps, making the dynamics of the coupled phase triads stochastic, even for small values of the injected energy.
Geochemical monitoring of Cumbre Vieja volcano (La Palma, Canary Islands) by soil CO2 degassing surveys from 2001 to 2023 
Authors: Padrón Eleazar , Hussain Fiazah , Mansfield Igraine , Melián Gladys V. , Gironés Ana , Asensio-Ramos María , Barrancos José , Rodríguez Fátima , Padilla Germán D. , Hernández Pedro A. , Pérez Nemesio M. , Álvarez Antonio J.
Published: March 2024

La Palma Island is located in the northwest of the Canary Islands. Volcanic activity at La Palma in the last 123 ka has taken place exclusively at Cumbre Vieja volcano located at the southern part, which is characterized by a main north–south rift zone 20 km long and up to 1950 m in elevation. Cumbre Vieja covers an area of 220 km2 with vents located also at the northwest and northeast. On 19 September 2021, a new eruption began at the west flank of Cumbre Vieja volcano: the 2021 Tajogaite eruption. It resulted in a fissure and powerful strombolian eruption with a magnitude VEI = 3 (Bonadonna et al., 2022), the longest volcanic event on the island during the last 600 years and the most important eruption of Europe during the last 75 years in terms of the significant amount of SO2 released (Burton et al., 2023). Since no visible degassing (fumaroles, etc.) at Cumbre Vieja occurred before the eruption, the geochemical program for the volcanic surveillance has been mainly focused on diffuse degassing monitoring. Diffuse CO2 emission surveys have been yearly performed in summer to minimize the influence of meteorological variations with continuous surveillance diffuse CO2 surveys during periods with anomalous seismic activity and during the eruptive and post-eruptive periods. Diffuse CO2 emission is measured following the accumulation chamber method in about 600 sites and later spatial distribution maps are constructed following the sequential Gaussian simulation (sGs). Important increases in the diffuse CO2 emission rate were observed after the occurrence of several seismic swarms registered in 2017 and 2020, caused by an upward magma migration from an ephemeral magmatic reservoir. During the eruptive period (18 September – 13 December 2021), the diffuse CO2 emission rate showed a sustained increase up to the maximum value of the series: 4,573 ± 284 t/d in 15 December 2021. After the eruption, the time series showed a rapid decline until background values were recovered in March 2022. Diffuse CO2 emission surveys has demonstrated to be an important monitoring tool that contributes to detect early warning signals in the volcanic activity of Cumbre Vieja and to track the depressurization of magma batches beneath the volcanic system during seismo-volcanic unrest and eruptive episodes.Bonadonna et al. (2022). J.  Geophys. Res: Solid Earth, 127, e2022JB025302.Burton et al. (2023). Communications Earth & Environment, 4:467.
Circum-Antarctic seasonality in grounded ice flow
Authors: Boxall Karla , Willis Ian , Wuite Jan , Nagler Thomas , Scheiblauer Stefan , Christie Frazer
Published: March 2024

Recent advances in high-temporal-resolution satellite imaging has revealed the occurrence of seasonal ice-flow variability in the Antarctic Peninsula for the first time. This newly documented phenomenon provides motivation for identifying the as-yet-unknown ice, ocean and climate interactions responsible for driving the seasonal signals observed across the Antarctic Peninsula, and raises important questions about the possible presence and drivers of seasonality elsewhere in Antarctica. Knowledge of such mechanisms and the extent of seasonality around Antarctica will be important for refining discharge-based ice-sheet mass balance estimations, and for improving predictions of Antarctica’s future response to climate change.Here, we identify the likely drivers of the recently observed ice-flow seasonality in the western Antarctic Peninsula by carrying out statistical time series analysis using our published Sentinel-1-derived velocity observations (Boxall et al., 2022; doi:10.5194/tc-16-3907-2022) and an array of environmental variables. Our results reveal that both surface and oceanic forcing are statistically significant controls upon ice-flow seasonality in the western Antarctic Peninsula, although each mechanism elicits a unique lag between forcing and the ice-velocity response.By upscaling our Sentinel-1-derived velocity observations, we also report upon the nature of ice-flow seasonality along Antarctica’s entire coastal margin for the first time and, through additional time series analysis, assess the glacier- to regional-scale importance of surface and ocean forcing upon circum-Antarctic rates of flow.
Unveiling the Interplay: Flood Impacts on Transportation, Vulnerable Communities, and Early Warning Systems
Authors: Naghedi Seyedeh Negar , Piadeh Farzad , Behzadian Kourosh , Hemmati Moein
Published: March 2024

Flooding's impact on transportation infrastructure is crucial, influencing urban mobility, economic activities, and societal resilience [1]. Disruptions in transportation networks during flood events significantly impede access to essential services, intensifying the vulnerability of communities and hindering recovery efforts. Understanding the multifaceted consequences of flooding on transportation is fundamental for fortifying these critical systems against the escalating risks posed by changing climate patterns and extreme weather events [2].Floods, stemming from various sources like heavy rainfall, storm surges, or river overflow, profoundly affect transportation infrastructure. Bridges, roads, and rail networks face damage or complete destruction, impeding travel and access to crucial services. Moreover, inundated areas and compromised roadways exacerbate accessibility challenges for specific demographic groups [3]. Vulnerable communities, including low-income populations or geographically isolated areas, bear a disproportionate burden, experiencing limited access to jobs, healthcare, and emergency services during and after flood events.Research exploring the nexus between early warning systems and transportation resilience remains sparse but holds significant promise. Early warnings tailored to transportation vulnerabilities could mitigate disruptions, enhancing evacuation plans and rerouting strategies. Enabling timely and targeted information dissemination to affected areas or populations, especially those with limited mobility or access, can substantially reduce the adverse impacts on their daily lives and crucial infrastructure. Understanding the gaps in the interconnection of early warning systems and transportation resilience is crucial for bolstering the adaptive capacity of transportation networks, ensuring equitable access, and minimizing the disproportionate impacts of floods on vulnerable communities.[1] Naghedi, S., Huang, X., Gheibi, M., (2023). A smart dashboard for forecasting disaster casualties: An investigation from sustainable development dimensions EGU General Assembly 2023, Vienna, Austria. https://doi.org/10.5194/egusphere-egu23-17237[2] Piadeh, F., Behzadian, K., Chen, A.S., Campos, L.C., Rizzuto, J., Kapelan, Z. (2023). Event-based decision support algorithm for real-time flood forecasting in urban drainage systems using machine learning modelling. Environmental Modelling & Software, 167, p.105772.[3] Yan, J., Naghedi, R., Huang, X., Wang, S., Lu, J. and Xu, Y., 2023. Evaluating simulated visible greenness in urban landscapes: An examination of a midsize US city. Urban Forestry & Urban Greening, 87, p.128060.
Identifying urban subsurface thermal and hydraulic processes from time-series groundwater temperature data
Authors: Patton Ashley , Cleall Peter , Cuthbert Mark
Published: March 2024

The subsurface Urban Heat Island effect has been proposed as a shallow geothermal energy resource, however, annual near-subsurface temperature variation may result in unexpected system performance. Understanding heat transport processes in the urban subsurface is key to managing and modelling city-scale thermal regimes for geothermal energy resource development. Existing studies have focussed on analysis of repeat temperature-depth profiles rather than long-term groundwater temperature time-series. We show here how time-series analysis can complement temperature-depth profiles and offer additional insights into the controls on subsurface thermal transport processes.Annual variations in temperature time-series from 49 boreholes in the Cardiff Geo-observatory (UK), recorded between 2014-2018, fall into several distinct shape categories. We hypothesise these shapes are indicative of the dominance of particular flow and heat transport mechanisms such that sinusoidal profiles are associated with conduction-only settings, while ‘right-skewed’ profiles denote the influence of advection. Short-lived temperature events are observed on the cooling limbs of such profiles and are correlated with groundwater level rises, indicative of recharge events. These winter temperature drops have the effect of cooling groundwater faster in winter than it is warmed in summer. The short timescales of these events suggest recharge is localised and may be controlled by preferential flow paths within the superficial deposits overlying the aquifer. While these events do have an overall cooling effect on the seasonal temperature profile, groundwater temperatures following these events recover quickly to levels near what they were before the recharge event, suggestive of the presence of local thermal non-equilibrium with the gravel aquifer. More complex behaviours observed in boreholes located close to the city’s rivers indicate recharge responses coupled with the influence of stream-aquifer interactions. Thus, temperature time-series data have potential as a tool to identify subsurface hydraulic and thermal processes, with implications for geothermal exploration and the wider field of hydrogeology.
New insight into the ocean mesoscale field at the Nordic high latitudes
Authors: Bonaduce Antonio , Raj Roshin , Mangini Fabio , Moiseev Artem , Johannesen Johnny
Published: March 2024

The Norwegian Atlantic Current contributes fundamentally to the temperate climate of northwestern Europe and maintains an ice-free ocean well into the Barents Sea even in winter. The interaction between the two branches of the Norwegian Atlantic Current is not known in detail but is generally understood to be mediated by mesoscale eddies. In particular, the Lofoten Basin appears as a hot-spot of mesoscale activity in several studies in the literature, based on conventional altimetry. While satellite altimetry has made a fundamental contribution to our understanding of ocean circulation, the current constellation of nadir altimeters does not allow for resolving the spatial and temporal scales characterizing the intensification and dissipation of the mesoscale features. The Surface Water and Ocean Topography (SWOT) mission, based on Ka-band Radar Interferometry (KaRIn), extends the capability of existing nadir altimeters to two-dimensional mapping of the ocean surface at an unprecedented spatial resolution. The fast-sampling phase (1-day repeat) of the mission also allowed for resolving the temporal evolution of mesoscale eddies. The Lofoten Basin is located in an area where the SWOT tracks cross, which was sampled twice a day over 90 days in 2023. Building on this unique opportunity, the results presented in this work rely on both the fast-sampling and science (21-day repeat) phases of the SWOT mission to show a comparison of KaRIn retrievals with conventional altimeters and characterize the representation of the mesoscale field emerging from the different altimetry concepts.
The importance of magmatic degassing at a mineralized, submarine volcano: The case of Conical Seamount, Papua New Guinea
Authors: Gautreau Louis-Maxime , Hansteen Thor , Portnyagin Maxim , Brandl Philipp
Published: March 2024

Conical Seamount is an active submarine volcano of the Tabar-Lihir-Tanga-Feni island chain (TLTF) in north-eastern Papua New Guinea. This island chain is located within the New Ireland Basin and the related alkaline to shoshonitic magmas are ascending through a thick sedimentary sequence. The TLTF hosts several Cu-Au mineralized volcanic centers. Conical Seamount is a rare example of a submarine epithermal-style mineralization and is considered to be a juvenile analogue of the Ladolam world-class gold deposit located on the nearby island of Lihir.Recent research assessed important crustal magmatic processes as precursors for the mineralization at Conical Seamount. More specifically, the presence of a degassing crustal magma chamber has been found to be critical for the metal concentration and transfer into the epithermal system. This may explain why other seamounts in the TLTF island chain remain barren (unmineralized).Here we present new volatile (H2O, CO2, F, Cl, S) as well as major and trace element data of clinopyroxene-hosted melt inclusions. These data along with fluid inclusion data allow us to further constrain the volcanic plumbing system, more specifically the pressure (i.e., depth) of the crustal magma chamber, the degassing stage and sulfide saturation processes. Chalcophile elements and Au in particular are scavenged within sulfides concomitant with the magmatic fluid exsolution, leading to ideal conditions for the transfer of metals into the ore-forming system. 
Unprecedented changes in the Southern Ocean detected by satellites
Authors: Silvano Alessandro , Catany Rafael , Olmedo Estrella , González-Gambau Veronica , Turiel Antonio , Gabarró Carolina , García-Espriu Aina , González-Haro Cristina , Haumann F. Alexander , Narayanan Aditya , Naveira Garabato Alberto , Sabia Roberto
Published: March 2024

The Southern Ocean has experienced unprecedented changes since 2016. Most notably are 1) a reduction in sea ice cover and 2) the appearance of offshore polynyas not seen since the 1970s. Several hypotheses have been put forward to explain both these events, including atmospheric (e.g. winds, atmospheric rivers) and oceanic (e.g. upwelling) drivers. To help explain what has occurred over the past decade we use the first regional product of sea surface salinity (SSS) in the Southern Ocean derived by satellites as part of the SO-FRESH project. We combine this new dataset with sea ice observations from satellites as well as with in situ observations and models to show that both atmospheric and oceanic processes are involved in the observed changes, highlighting the complexity of the ice-ocean-atmosphere system in the Southern Ocean. 
Tree planting attenuates storm runoff response on the Chinese Loess Plateau
Authors: Liu Shaozhen , Seybold Hansjörg , van Meerveld Ilja , Wang Yunqiang , W. Kirchner James
Published: March 2024

Tree planting to mitigate climate change has become a popular topic in recent years. While it has been widely reported that tree planting reduces annual water yield, it is not clear how tree planting affects a catchment’s storm runoff response for events of different magnitudes. China’s “Grain for Green Program” almost doubled the vegetation cover on the Loess Plateau two decades ago, and thus represents a large-scale experiment revealing the impact of tree planting on hydrological processes. Here we show how the storm runoff response to rainfall has changed as a result of tree planting using five sub-catchments in a 26,000 km2 large basin that received different degrees of afforestation. Our dataset covers over 40 years of daily streamflows, allowing us to use new nonlinear Ensemble Rainfall-Runoff Analysis techniques to quantify the runoff response to rainfall events of different intensities. We find that after tree planting, the runoff response peak decreased up to 86%, proportional to the percentage increase in the Leaf Area Index (LAI). This attenuation of peak runoff is much larger than that of the decrease in average growing season runoff (59%). Surprisingly, the largest attenuation in peak runoff response occurs during high-intensity rainfall events rather than low-intensity rainfall events. This observation implies that the main mechanisms reducing runoff response cannot be increased canopy interception or soil moisture depletion, because these would be expected to have a larger effect on low-intensity events. Instead, we hypothesize that the main mechanisms are likely to be reductions in runoff-generating areas and increases in infiltration rates. Consistent with this hypothesis, low flows (i.e., Q95) do not decrease, but instead increase up to 25%, with the largest increases in low flows occurring in sub-catchments with the largest percentage increases in LAI. These findings highlight the positive effect of tree planting on reducing storm runoff peaks and increasing low flows, coincident with the reduction in annual water yield that has been widely reported in other studies. These substantial and persistent hydrological consequences of tree planting can inform future efforts at climate change mitigation through vegetation management.
Quantifying the generation of cold air during boreal winter and its relevance for cold weather extremes
Authors: Riboldi Jacopo
Published: March 2024

The presence of anomalously cold air close to the surface is a prerequisite for the occurrence of cold weather extremes, such as cold spells. However, the process of cold air generation features a substantial variability in space and time, modulated by the rate of energy loss to space by infrared radiation.Such a variability is investigated using a Lagrangian approach, identifying trajectories that experience rapid non-adiabatic cooling over Eurasia. This approach allows to identify source regions of cold air, and the meteorological conditions that particularly favor its generation and accumulation – which often precedes the most extreme cold spells.The unraveling of this connection allows to interpret the intra-seasonal and the inter-annual variability in the occurrence of cold extremes, and to gain a mechanistic understanding of how anthropogenic global warming will modify them.
Decoding major Climate Mysteries over the last 1.5 million years: Sea Surface Temperature Reconstruction at IODP Site U1385, Iberian Margin.
Authors: Rodrigues Teresa , O. Grimalt Joan , Casado Marta , Gonzalez Yolanda , J. Crowhurst Simon , Abrantes Fátima , Hodell David
Published: March 2024

The Iberian Margin provides a remarkably accurate record of millennial-scale climate variability, making it an invaluable site for deciphering historical changes in climate and oceanography. This region’s exceptional sensitivity to high latitude processes, such as meltwater discharges into the Northeast Atlantic, significantly influence ocean dynamics, nutrient supply, and climate change impacts. These processes play a pivotal role in understanding the complex interplay between the ocean, ice, and climate systems. IODP 339 Site U1385, also known as the “Shackleton site”, drilled at a water depth of 2582 mbsl, reaching a total depth of 155.9 m below the seafloor. The oxygen isotope and carbon isotope records confirm that Site U1385 contains a continuous hemipelagic sedimentation from the Holocene to 1.45 million years (MIS 47), providing a reference record of millennial-scale climate variability. Here, we present a high-resolution Sea Surface Temperature (SST) record that unveils the climate variability over the last 1.45 million years.  This record provides a comprehensive interpretation of the millennial climate variability of major climatic disruptions, namely the Mid Brunhes Event and Mid Pleistocene Transition (MPT). SST data reveals a clear change on the orbital-driven forcing on the MPT time interval 1200 to 800 ka, thereby contributing to our understanding the underlying mechanisms on glacial/interglacial and centennial to millennial scales. Furthermore the SST record shows extreme cold events occurred not only after the MPT but also during and after this enigmatic period. The highest temperatures were recorded during Interglacial periods, overall the record and coincident with maximum insolation (precession minimum), suggesting an orbital dependence of the Sea Surface Temperature (SST) over the past 1.45 million years. This SST record significantly contribute to documenting the major climate shifts and their relation to global climate change. This becomes particularly crucial as the IODP Expedition 397 enables the extension of this exceptional sediment record into the Pliocene.
British archaeology verifies 5th-Century rapid multi-metre sea-level rise and portends another before 2
Authors: Higgs Roger
Published: March 2024

Worldwide geological markers of former sea-level (SL), such as wave-cut benches (raised, drowned), reveal a ~3-metre(m) SL rise, loosely carbon-dated post-50AD/pre-600. This "Rottnest Transgression" is the youngest of several m-scale rises, interspersed with m-scale falls, on Fairbridge's (1961) global-compilation Holocene-interglacial SL curve.Copious British archaeological evidence (email me for sources), far better-dated (pottery-sherds/dendrochronology/Roman coins), confirms the Rottnest ("Romano-British marine transgression" of Godwin 1955), verifies its amplitude (~3m), and shows it spanned only ~70 years(y), ~430-500AD (early Dark Ages; Romans abandoned Britain 410AD). (An equally fast global SL rise, ~3m in decades, is proven by last-interglacial reef-facies relationships in tectonically stable Yucatan.) The Rottnest explains 5th-Century(C) mass-migration, underway by 450AD (dendro/artefacts/skeletal-DNA), of Saxon- and Angle civilians to SE Britain ('pre-subjugated' by rebellious Saxon mercenaries by 441AD), their North-Sea-coastal-plain homelands intolerably 'squeezed' between west-advancing Huns and rapid eastward shore-retreat. Among other British evidence: (1) Pevensey sea-fort (Roman-built ~290AD) straddles a promontory pointing NE into Pevensey Levels (reclaimed former tidal-flat embayment, beside English Channel). Indicating that high-spring-tide-level (HSTL) rose >2m in the 5thC, a defensive-ditch fronting the fort's SW gate contains "tidal" mud, dated early-5thC (sherds), whose top is ~1m higher than the NW-wall foundation and 1km-deep grounding-line). Regarding causation, the Rottnest rise began (~430AD) only ~25y after the ~405AD warmest Arctic temperature-spike of the period 1-2000AD. This spike followed ~100y after the Sun's 310AD strongest magnetic-grand-maximum (MGM) peak of the interval 1-1885AD. The ~100y lag is attributable to ocean-thermal-inertia. The additional ~25y lag in SL response (Rottnest start) may reflect AMOC 'conveyor-belt' oceanic-circulation, specifically the time needed for ocean-surface-water, 'overwarmed' by the MGM (Svensmark effect, reduced cloudiness), to down-well in the north-Atlantic (Arctic fringe), then travel south, then up-well and encircle Antarctica, unleashing ice-collapse. The resulting iceberg-armada would cool the ocean, hence the atmosphere, causing increased global snowfall (ice build-up), intrinsically lowering SL.Due to anthropogenic warming, the Arctic's average-surface-air-temperature exceeds, since 2005, the 405AD peak. This portends another rapid, metre-scale SL rise, beginning ~2030 (25y lag, above). Before 2100 the time-lagged effect of the Sun's even-stronger 1991 MGM peak will exacerbate warming.
Super-cooled glacial deep waters
Authors: Ishizu Miho , Timmermann Axel , Yun Kyung-Sook
Published: March 2024

Sea-ice formation in the Southern Ocean can generate supercooled waters, which can even remain below the in-situ freezing point at depths below 1,000 m. These water masses can play an important role in carbon transport to the abyssal ocean and may have therefore also played an important role in glacial-interglacial CO2 cycles.To address this question, we examined model outputs from the transient 3 Ma simulation conducted with the CESM1.2 model (Community Earth System Model version 1.2, ~3.75 horizontal resolution. This simulation was driven by time-varying orbital forcing and estimates of atmospheric greenhouse gas concentrations and northern hemispheric ice-sheet orography and albedo. Our analysis shows the presence of large swaths of supercooled glacial deep waters mainly in the northern Pacific. This water is originally formed in the seasonal sea-ice formation regions in the subarctic North Pacific during periods of brine release and rapid mixed layer deepening. During interglacial periods, the volume of supercooled water decreases, which may hint towards a possible positive climate-carbon cycle feedback.In climate models the freezing condition is usually only applied at the surface. Hence, they are incapable of simulating brinicles – vertical sea-ice structures that can extend from the surface to shallower depths, sometimes even reaching the ocean floor. In my presentation, I will address whether such structures may have played a more prominent role during glacial periods, and whether localized deep ocean freezing may have been a possibility.
Improving template matching detections using a Convolutional Neural Network
Authors: Jozinović Dario , Toledo Tania , Simon Verena , Kraft Toni
Published: March 2024

The use of template matching to detect previously missed small earthquakes is widespread in seismology, due to its power in searching for similar signals. The newly detected earthquakes improve understanding of the geology, seismo-tectonics and seismogenesis of the area explored. The usefulness of template matching has sparked the development of many software tools (e.g. QuakeMatch; Toledo et al., 2024) that allow seismologists to easily apply them to their area of interest. Like every detection technique, the performance of template matching shows a tradeoff between sensitivity and false detection rate that is dependent on the choice of the detection threshold. The value of the correlation coefficient between two earthquake signals is highly dependent on several properties such as the distance of the earthquake from the station, the noise level at the station, the magnitude of the earthquake, the focal mechanism of the earthquake, etc, making the selection of a specific correlation coefficient threshold hard. To detect a larger number of earthquakes, researchers often use a lower correlation coefficient detection threshold and manually inspect the detected events to classify them as true events (Toledo et al., 2024). This is, however, a tedious task, especially when using a large number of templates. To reduce the human workload, which can be especially important during evolving earthquake sequences, we employ a Convolutional Neural Network (CNN) to discriminate between earthquakes and noise using the template matching detections as input. We use the data from several microearthquake natural and induced Swiss sequences (Simon et al., 2024, in prep.), to train and test the developed CNN model. Our CNN model uses single-station 3-component waveforms of any length and outputs an earthquake detection score. We demonstrate that the developed CNN can be used to significantly reduce the human workload with high accuracy, allowing the use of low correlation coefficient value thresholds for template matching detections. Furthermore, we show the implementation of the method inside the QuakeMatch software (Toledo et al., 2024).
 
The role of fire radiative power to estimate fire-related smoke pollution.
Authors: Durao Rita , Alonso Catarina , Russo Ana , Gouveia Célia
Published: March 2024

The intensity of a wildfire can be assessed based on its released energy, obtained through remote measurements of the fire's radiative power. Since the Fire Radiative Power (FRP) is proportional to the amount of burned biomass and therefore to smoke production. Higher FRP values are associated with more severe fires, suggesting higher levels of smoke production and, consequently, higher emissions of particulate matter and other pollutants. The specific composition of smoke emissions can vary depending on factors such as the type of vegetation burned, the temperature of the fire, and the combustion conditions. In general, fire smoke is composed of a variety of air pollutants, including gases (NOx, CO, VOCs, O3, PAHs, etc) and particulate matter (PM). The objective of this work is to evaluate the ability of FRP, to be used as an indicator of fire smoke pollution. Particulate matter (PMx) and carbon monoxide (CO) concentrations emitted during recent wildfires in Portugal are analyzed to assess the link between pollution concentration levels and fire intensity over the affected areas, taking into account the spatial and temporal characteristics of each event. For this purpose, two particularly severe fires with significant impacts on air quality in central and southern Portugal were analyzed namely the ones taking place in October 2017 and August 2018. Concentrations of PMx and CO were evaluated through CAMS data, and the radiative power through the FRP product of the SEVIRI/MSG disseminated by LSA-SAFThe results show that the emitted pollutant concentrations significantly exceeded the established daily target limit values (air quality and public health guidelines). The fire intensity, based on the emitted Radiative Energy (FRE) derived from FRP, aligns with the known severity of these events, consistent with the observed concentrations of air pollutants, being demonstrated that the FRP can be associated with smoke production, especially PMx emissions during a fire. Thus, the proposed methodology using FRP can be a valuable tool for assessing the impact of wildfires on air quality and understanding the potential for smoke dispersion over fire-affected regions. The role of FRP as an indicator of air pollution highlights the potential use of FRP in assisting in management activities, operational planning, and emergency intervention during ongoing fires. Acknowledgments: This study is partially supported by the European Union’s Horizon 2020 research project FirEUrisk (Grant Agreement no. 101003890); and by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES on behalf of DHEFEUS -2022.09185.PTDC and the project FAIR- 2022.01660.PTDC).