bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Shoreline Dynamics under Macro to Meso-tidal Conditions through Integrative low-cost Remote Sensing Technique
Authors: riaz khurram , McAfee Marion , Gharbia Salem
Published: March 2024

Coastal erosion, a critical issue in shoreline management, arises from a combination of natural dynamics and anthropogenic influences. In macro to meso-tidal regions, this phenomenon is particularly pronounced due to the interplay of sea level fluctuations, erosive wave action, and sediment displacement. Significantly, this erosion poses a direct threat to the stability and integrity of coastal dunes, which are vital for protecting inland areas and maintaining ecological balance on these beaches. This study addresses this issue by analysing shoreline changes over the past decade at three unmanaged Northwest beaches of Ireland: Enniscrone, Streedagh, and Dunmoran. Utilising open-source satellite imagery, the research employed the CoastSat and DSAS tools to extract data on shoreline movement to tackle coastal erosion or accretion. Acknowledging the errors in satellite-derived shoreline data due to high tidal variations, the study further validates its findings with field data. This validation was performed using two contrasting technological approaches: a high-cost LiDAR-equipped drone (DJI Terra drone and DJI Zenmuse L2 Lidar) and a low-cost DJI Phantom 4 RTK drone with a standard camera. The comparison of data from these diverse sources reveals crucial insights. Firstly, the study validated shoreline changes detected by satellite imagery, ensuring the consistency and reliability of observed trends across different remote sensing platforms. Additionally, the comparison between high-cost and low-cost drone data was instrumental in assessing their respective efficacies in capturing coastal topography. The high-resolution LiDAR data offered detailed 3D models of the coastal landscape, allowing for precise measurements of dune morphology and erosion patterns. In contrast, the standard camera on the low-cost drone provided broader, less detailed views but was surprisingly effective in identifying larger-scale changes and erosion hotspots. The study highlights the potential of integrating various remote sensing techniques for coastal monitoring, which provides a cost-effective and accurate way of assessing the coastal erosion in Macro to Meso-tidal beaches.
Application of TDLAS analysers, challenges and implications for future monitoring of methane emission from the coal mine ventilation shafts. 
Authors: Nęcki Jarosław , Bartyzel Jakub , Jagoda Paweł , Swolkień Justyna , Field Robert
Published: March 2024

Tunable diode laser absorption spectrometers (TDLAS) are versatile devices with a wide range of applications. In particular, they can be used to detect methane using an analyzer that operates with an infrared band (1.6 – 1.7 μm) laser beam configured in an open path architecture. This setup is suitable for nonhomogeneous airflow coming from coal mine ventilation shafts. TDLAS devices are compact, robust, easy to install, and require minimal maintenance.Methane emissions from the coal mining sector in Poland account for approximately 0.5 million tons of methane per year and are significant contributors to the continental budget of this gas. Most of the emissions occur through the ventilation shafts, where the methane content can vary from 0.05% to 0.7%.During June 2023, a TDLAS analyzer (Unisearch, LasIR) was installed at a selected ventilation shaft air diffuser. The device operated for one month, recording the methane concentration in the ventilated air with a temporal resolution of 1 second. In addition to TDLAS, two other instruments were used to determine methane content: an ICOS analyzer (LGR/ABB, mGGA-918) and a pellistor sensor (EMAG, DCH). The ICOS analyzer was used to cross calibrate the TDLAS instrument across a wide range of methane concentrations. The pellistor sensor is a popular type of sensor used in coal mines for safety reasons. Typically, methane emissions are determined through gas chromatographic analyses conducted using periodically collected samples (e.g., once a month). However, methane content in ventilated air can vary on shorter timescales of hours, days, and weeks. Additionally, pellistor sensors are less precise, and the uncertainty of a single measurement cannot be better than 0.1%. In contrast, TDLAS analyzers can be commonly used by coal mine operators for methane reporting, as their precision is usually better than 0.01%.The presentation will address the challenges associated with using TDLAS for methane emission calculations and highlight its advantages over other commonly used techniques. It will also provide insights into interpreting pellistor sensor readings for quantifying methane emissions and assessing associated uncertainties. Finally, the presentation will discuss the benefits of deploying TDLAS techniques in the coal mining industry, both in the short term and as a potential long-term solution of the reporting of CH4 release. This research was funded by and performed in collaboration with UNEP's International Methane Emissions Observatory. The results presented here are part of the findings from a series of three measurement campaigns performed in Poland’s Upper Silesia coal basin.
Circulation of freshwater over the Labrador shelf and into the interior subpolar North Atlantic
Authors: Duyck Elodie , Frajka-Williams Eleanor
Published: March 2024

Increasing freshwater input from Greenland and the Arctic could potentially affect the stratification of the water column in the Labrador Sea, and weaken deep convection. While freshwater export from the West Greenland shelf to the interior Labrador Sea is well-documented, little to no exchange is believed to take place off the Labrador Shelf.In this study, we use drifters deployed on the Greenland and Labrador shelves since 2019 to deepen our understanding of the Labrador shelf surface circulation and cross-shelf exchanges. Trajectories confirm that fresh surface waters from Baffin Bay, Hudson Bay, and the West Greenland Current join to form the Labrador Current with two distinct velocity cores: one at the shelf break and a second inshore coastal core. The recent drifter observations provide further detail about the shelf circulation including topographically-steered exchanges between the main core and the coastal core of the Labrador Current, and confirm the absence of direct connection between Baffin and Hudson Bays, and the interior Labrador Sea. Instead, substantial export takes place between Flemish Cap and the tail of the Grand Banks, with the export location dependent on upstream circulation.Freshwater originating from the Baffin and Hudson Bays, and the west Greenland ice sheet, is unlikely to directly impact the Labrador Sea deep convection region. Their mixing and diluting along this longer pathway complicate their potential influence on deep convection in the Subpolar North Atlantic.
Importance of Pulse-Like Ground Motions and Directivity Effects in Moderate Earthquakes based on the 23 November 2022, Mw 6.1 Gölyaka-Düzce Earthquake (Turkey).
Authors: Türker Elif , Yen Ming-Hsuan , Pilz Marco , Cotton Fabrice
Published: March 2024

The North Anatolian Fault Zone in Turkey spans 1400 km, passing through densely populated areas, including Düzce, which experienced the destructive Mw 7.2 event in 1999 that caused more than 700 lives. On 23 November 2022, for the first time in over 20 years, a moderate Mw 6.1 earthquake struck the city and surrounding area. Despite its moderate magnitude, the event caused unexpectedly severe damage to numerous buildings, as reported by local institutions (Disaster and Emergency Management Presidency; AFAD). Recognizing the potential impact of near-field effects such as ground motion pulses and directivity effects, which are known to increase damage in the vicinity of the fault, we investigate these phenomena using the AFAD-Turkish Accelerometric Database. Our analysis delves into the spatial distribution of ground motion intensities, revealing higher peak ground velocities in certain azimuthal ranges than predicted by existing ground motion models. Surprisingly, our findings challenge outcomes derived from previous studies, suggesting that impulsive ground motions associated with directivity effects mainly occur on the fault-normal component of large-magnitude events. In contrast, our examination of near-fault recordings indicates a concentration of velocity pulses, primarily on the fault-parallel component, and thus questions the widely established understandings of earlier studies.
Estimating possible nonlinearities in the Human-Earth system with Earth system economics
Authors: Galbraith Eric
Published: March 2024

The capacity for tipping points in the climate system was elucidated decades ago by numerical climate models, which showed that nonlinearities could arise from physical interactions between the ocean, sea ice, and atmospheric components, leading to rapid shifts between qualitatively different states. However, there has been comparatively little work on physical interactions with the human component of the Earth system through numerical modeling due, in part, to the rarity of inclusion of the human system directly in Earth system models. Earth System economics provides a new approach for doing so, by proposing a particular set of physical variables that can be used as a basis for simulating such changes. These variables include spatially resolved population demography, time allocation to activities, a spatially resolved technosphere, and spatial networks that capture transportation fluxes. New global compilations of time use and technosphere data are helping to enable this approach, by quantifying the dependencies of material fluxes on time use and context. This opens the possibility of simulating long-term dynamics through motivated changes to time allocation, with outcomes dependent on the evolution of the technosphere and other coupled features of the Earth system. Examples will be discussed regarding how this approach can provide holistic, physically-grounded ways to identify possible nonlinearities and tipping points, by explicitly resolving aspects of human activities and technosphere changes, constrained by the conservation of mass, energy, and time.
Diurnal characteristics of the NO2 columns observed over Asia from Geostationary Environment Monitoring Spectrometer (GEMS)
Authors: Lee Hanlim , Park Junsung , Hong Hyunkee , Kim Jhoon , Lee Hyo-Jung , Jung Yeonjin , Roozendael Michel Van , Fayt Caroline , Park Rokjin , Kim Siwan , Ahn Myong-Hwan , Jacob Daniel J. , Kim Daewon , Choi Wonei , Lee Won-Jin , Lee Dong-Won , Wagner Thomas , Richter Andreas , Krotkov Nickolay A. , Lamsal Lok N.
Published: March 2024

Nitrogen oxides are key gas components of emissions from fossil-fuel combustion, are known to degrade air quality and have adverse health effects. Diurnal NO2 observations are crucial for enhancing our understanding of NOx emissions, lifetime, and chemistry. Geostationary Environment Monitoring Spectrometer (GEMS) has been providing hourly observations NO2 columns over Asia since November 2020. The latest NO2 version 3 products have significantly improved with updated air mass factors (AMFs) and the separation of stratospheric and tropospheric columns. To identify the dependency of the distribution on the time of the day, we investigated hourly tropospheric NO2 cycles of cities over Asia using GEMS measurements for the first time. The cities show similar diurnal concentration patterns with peaks in the morning and troughs in the afternoon, although the amplitude and specific times vary by city. The reduction rate of NO2 was influenced by the temporal dependence of the spatial distribution within and around cities. We also observed distinct NO2 diurnal patterns in certain industrial areas and cities where NOx emissions are thought to be controlled. To explain the location-dependent variations of the tropospheric NO2 columns, we compared the diurnal NO2 cycles obtained from the GEMS measurement with WRF-Chem models for some cities. In addition, estimated top-down NOx emissions from GEMS measurements are presented in comparison with bottom-up emission inventory, showing a smaller difference compared to the top-down emission from TROPOMI measurements. It is expected that hourly top-down NOx emissions using GEMS measurements can provide a useful information in improving the future performance of air quality modeling.
Bristlecone Pine Maximum Latewood Density as a Superior Proxy for Millennial Temperature Reconstructions 
Authors: Matskovsky Vladimir , de Mil Tom , Pearson Charlotte , Corluy Lode , Verschuren Louis , Salzer Matthew , Trouet Valerie , Van den Bulcke Jan , Van Hoorebeke Luc
Published: March 2024

Great Basin Bristlecone pine (Pinus longaeva) (PILO) trees are known for their old age. The longest tree-ring width (TRW) chronology covers a large part of the Holocene, and the temperature-sensitive upper treeline chronology extends back to 2575 BC. The TRW of upper treeline PILO trees is influenced by temperature variability, but the moderate strength and temporal instability of the signal is making it hard to use for reliable temperature reconstructions. Maximum Latewood Density (MXD) of conifers is known to be a good summer temperature proxy in the northern hemisphere. However, there are no PILO MXD records due to various reasons, including its location in semi-arid lower latitudes, as well as due to methodological difficulties such as narrow rings and a varying grain angle. Here, we used an X-ray Computed Tomography (X-ray CT) of 69 cross-dated cores to construct an MXD chronology of PILO from the upper treeline sites covering the last millennium, and to investigate its temperature signal. The chronology correlates significantly (r=0.63) with warm season (April to September) temperature for the period 1895-2005 and the signal is stable throughout the instrumental period. Our results demonstrate that MXD from the bristlecone pine archive can be used as a robust proxy for western North American warm season temperature variability at an unprecedented multi-millennial scale.
Hydrogen sulphide in a fattening pig barn operated with inhouse acidification
Authors: Kupper Thomas , Valach Alex C. , Juch Mathias , Bachmann Thomas
Published: March 2024

With in-house acidification treatments, the pH value of slurry is reduced to a target level of approximately 5.5. It is a promising option for ammonia emission abatement since an emission reduction can be achieved over the entire manure chain which includes housing, manure storage and application. Acidification is done through addition of sulfuric acid (H2SO4) to slurry in a reactor outside of the livestock housing. The acidified slurry is returned to the channels in the house. The excretions of the animals immediately end up in an acidified environment where the equilibrium between NH4+ and NH3,l is shifted towards NH4+. Through the addition of H2SO4, further sulphur is available which can be potentially converted to H2S. This induces concerns for enhanced formation of H2S that is highly toxic to humans and animals. Long-term workplace exposure limits given as 8-h time-weighted averages is 5 ppm with a 15 min exposure threshold of 10 ppm in the EU. The aim of this study is to present data from H2S concentration measurements in a fattening pig housing with 400 animal places in 16 pens littered with straw pellets with a partly slatted floor before and after installation of an in-house acidification method.In 2021, H2S concentrations were measured in the barn using portable gas detectors "PAC 6500 and Multiwarn II" from Dräger and with electrochemical sensors (range of 0.1 - 100 ppm). Four measurement campaigns were conducted. One of them was conducted before the acidification was operative and three campaigns with acidification in summer and winter with and without ventilation of the slurry channels. The number of measurement periods was 5 for the reference measurement and 6 to 14 for the measurement with acidification. The duration of a measurement period was 10 to 104 min, with less than 20 min occurring only in the summer campaign with 14 measurement periods.H2S was exclusively detected when channels were flushed. Outside of periods with flushing, H2S concentrations were below the detection limit of 0.1 ppm. The maximum average over 15 minutes value was 20.2 ppm which was obtained without acidification. With slurry acidification, no exceedance of the 15 Min threshold of 10 ppm occurred, as the maximum H2S concentration was 4.8 ppm. Overall, the mean H2S concentrations with slurry acidification (0.14 ppm) were lower than without acidification (1.44 ppm). The mean values of measured H2S concentrations in winter (0.16 ppm) were higher than in summer (0.06 ppm) due to higher barn ventilation rate in summer. The use of the ventilation system in slurry channels reduced H2S concentrations to 0.16 ppm compared to 0.30 ppm without ventilation. This can be explained by the inhibition of sulfate reduction by microorganisms at a pH of 5.5.Overall, in-house slurry acidification did not enhance H2S concentrations in the investigated pig barn which agrees with previous studies.
A zinc-finger transcription factor LGA1 negatively regulates lateral growth in Arabidopsis and trees
Authors: Fatz Wiktoria , Woodward George Malcolm , Kucukoglu Topcu Melis
Published: March 2024

Lateral growth in plants originates from the vascular cambium, where stem cells are located. Cambium provides thickness to plant organs by generating the conductive tissues - xylem (wood) toward the centre and phloem toward the organ periphery. Vascular development continues as long as the plant grows, and proliferation and differentiation of these tissues from the cambium is under strict control. Besides its fascinating theoretical significance, understanding cambial regulation has also a significant applied value because this knowledge brings us powerful tools to manipulate growth and enhance biomass production in trees in an ever-changing environment.
Through a functional genomics approach, we have recently identified that a novel zinc-finger transcription factor LATERAL GROWTH-ASSOCIATED 1 (LGA1) is expressed preferentially in the vascular tissues and activated by the plant hormone cytokinin, an enhancer of cambial cell division rate and lateral growth in plants. Unexpectedly, instead of priming radial growth, overexpression of LGA1 in Arabidopsis thaliana roots or hybrid aspen stems suppresses cell divisions and resulting xylem production. In comparison, loss-of-function lga1 plants often had increased number of cells in root vasculature and results in increased lateral growth.
To study the molecular mechanisms behind LGA1 action, we performed RNA-seq analysis in the mutant roots that are going through secondary growth. Our results showed that LGA1 induction activates the expression of genes associated with stress signalling pathways, while repressing the expression of genes associated with cytokinin responses. Altogether, these results culminate to the fact that LGA1 is a negative regulator of secondary growth and represses cell division activity in plants, while balancing the plant responses to various stress factors.
Spectral Modelling the Induction Effect of a Strong CME Hitting Planet Mercury
Authors: Heyner Daniel , Langermann Luis , Pump Kristin , Zomerdijk-Russell Sophia
Published: March 2024

Planet Mercury, with its weak internal magnetic field, is continuously exposed to an intense solar wind. This interaction becomes particularly dynamic during coronal mass ejections, resulting in a strong compression of the magnetosphere. Such events drive electrical currents within the planet, which, depending on the planetary conductivity structure, lead to secondary magnetic fields detectable outside. Analysis of these induced fields provides insights into Mercury’s interior structure.Here, we utilized data from the Helios-1 probe, recorded during a CME at 0.31 AU, to evaluate changes in solar wind conditions and their impact on Mercury's magnetosphere. We applied a semi-empirical model to estimate the external field variations and employed endmembers of radial symmetric conductivity models to calculate the range of induced magnetic fields. Our analysis highlights the influence of these variations on Mercury's upper mantle layers, taking into account both dipolar and quadrupolar components of the magnetic field. Eventually, we predict the potential induced magnetic fields at the future location of the BepiColombo spacecraft, currently en route to Mercury.
A daily ensemble of Past and Future Weather for rapid attribution and future perspectives
Authors: de Vries Hylke , Lenderink Geert , van Meijgaard Erik , van Ulft Bert , de Rooy Wim
Published: March 2024

Europe faced many extreme events in the year 2023; storms, heatwaves, intense precipitation, widespread flooding, to mention a few. Long-standing records were broken, and re-broken again. The events invariably received a lot of attention by the media and triggered many questions from journalists, eager to report about them. These questions are typically about the frequency or ‘extremeness’ of the event, whether or how already occurred climate change has impacted this frequency, and what the future perspectives are: Would a similar event in future or past climate have (had) a larger or smaller impact? It is a challenge for scientists to answer such (attribution) questions rapidly, i.e., before or on the day of the event, or in the immediate aftermath. Weather attribution teams like WWA (World Weather Attribution) now apply standardised procedures based on combining observations and climate modelling, to produce such analyses within weeks.Here we discuss an approach that may augment the set of already existing tools and frameworks for rapid attribution analysis. The approach is based on regional downscaling in combination with pseudo global warming (PGW). Each day a small downscaled ensemble is created using as initial and boundary conditions the ECMWF analysis and forecasts. In addition to this ‘present-day’ ensemble, also a ‘past’ and ‘future’ ensemble are created using PGW. Due to the synchronicity of the time-evolution of the past, current and future ensembles, the signal-to-noise ratio is high, allowing an immediate estimate of how (thermodynamic) changes could have contributed to the event, and how a similar event in a future climate could look. Inherent limitation of PGW is that it cannot, or only in a limited way, address the frequency-change aspect. We illustrate the PGW-ensemble with a number of events that occurred during 2023 such as storm Hans (August), the December snowfall, and the unprecedented yearly rainfall amount in the Netherlands.
GNSS low-cost prototype on ship for caching tsunami wave propagation 
Authors: Jarrin Paul , Rolland Lucie , Vidal Maurin , Sakic Pierre , Leclerc Frédérique , Dessa Jean-Xavier , Palagonia Sylvain
Published: March 2024

Ship navigation data records are proposed to be complementary information for monitoring offshore tsunami currents following great earthquakes. Offshore GPS measurements on the research vessel Kilo Moana of the University of Hawaii following the 2010 Mw 8.8 Maule earthquake have illustrated the potential of GPS kinematic positioning solutions, together with a filtering approach, for detecting the ship's vertical displacement promoted by the tsunami travel velocity. However, kinematic positioning of GPS observations on ships is challenging due to the load, ship speed, and wavefield changes on the open ocean that might produce fast changes in the ship's drift and vertical motion. Wavefield could also introduce additional noise frequencies to the GPS positioning, thus decreasing its precision. Herein, we present a dual-frequency Global Satellite Navigation System (GNSS) low-cost prototype based on the Septentrio Mosaic-X5 card and a low-cost AS-ANT2BCAL antenna. Such a low-cost GNSS station has been installed on a non-commercial ship fleet in order to assess the precision and noise content of offshore GNSS positioning and ionosphere Total Electron Content measurements. We discuss our preliminary results by comparing the precision of the multi-GNSS solution (GPS, GLONASS, Galileo) relative to the one from only the GPS solution using both long-baselines and Precise Point Positioning approaches in post-processing mode. In the second step, we simulate a real-time multi-GNSS positioning solution to evaluate their ability to catch wavefield changes. We finally discuss the detectability of tsunamis with the newly developed GNSS low-cost prototype under various conditions.
Glaciological characterization of Little Dome C: Influence of ice flow on the future Beyond Epica – Oldest Ice Core drilling project
Authors: Mulvaney Robert , Martín Carlos , Ritz Catherine , Vittuari Luca , Frezzotti Massimo , Eisen Olaf
Published: March 2024

An ice core is being drilled near Little Dome C, a small promontory about 30km downstream from the summit of Dome C, to extract a continuous record of climate over the last 1.5 million years. Present and past ice flow conditions are important to interpret the ice core because the surface velocity at the drilling site is about 40 mm/yr and the oldest ice in the record was deposited in the surface about 10km upstream of the drilling site. Here we explore newly acquired and existing geophysical data to describe present ice flow and investigate signs of past changes. We present new GNSS data that describes the subtle but complex local surface velocity, and ApRES radar data that provides englacial strain-rates along the flow path from the summit of Dome C and bulk englacial crystal orientation fabric. Ice currently flows from Dome C summit along the ridge to Little Dome C, even though a subtle uphill slope, but basal conditions are variable along the path due to the strong basal topography. Of special interest is an ice unit in contact with the bedrock with variable thickness up to about 300m that is vertically stagnant and produce a strong radar reflection.  This basal unit is not present in an area of strong melting about 5km upstream from the drilling site. The crystal orientation fabric reflects the ice flow horizontal extension along the path and changes with depth on ice flow properties following climatic transitions and, more intriguing, indicate a possible change in ice flow extension at the beginning of the Holocene. We aim to facilitate detailed ice flow models to better interpret the ice core data.  
Changes in growth and longevity of the exploited bivalve Arca noae in the northern Adriatic Sea: a conservation paleobiology perspective
Authors: Nawrot Rafał , Peharda Melita , Macharia Saskia , Uvanović Hana , Tomašových Adam , Zuschin Martin
Published: March 2024

Changes in life history of marine species in response to harvesting and human-induced environmental changes are frequently observed in modern ecosystems, but the true magnitude of these shifts is difficult to evaluate without robust information on the pre-impact state of the affected populations. The edible bivalve Noah’s Ark shell (Arca noae L.) is commercially exploited in the eastern Adriatic Sea, where its fishery rapidly expanded during the first half of the 20th century until a mass mortality in the late 1940s caused a population collapse. In spite of partial recovery, the lack of data on growth parameters of this species prior to that event complicates establishing sustainable levels of harvesting. To provide a baseline for assessment of the current state of populations of A. noae we compared modern and fossil (middle to late Holocene) specimens from the northern Adriatic Sea using samples from benthic surveys and sediment cores. Estimates of growth and longevity were based on annual shell growth lines visible in acetate peel replicas of the umbo and outer prismatic shell layer. The maximum lifespan observed in our modern samples was 35 years – a full decade longer than previously documented for this species. However, this estimate was still much shorter than the lifespan of multiple fossil specimens, among which the ontogenetically oldest one reached the age at least 85 years. Our results indicate that modern individuals of A. noae grow faster and have shorter lifespan compared to their Holocene counterparts, suggesting that harvesting pressure combined with increasing water temperatures and eutrophication of the northern Adriatic Sea had a significant impact on the population dynamics of this species.
Unveiled the Black Sea Spring dynamics using Underwater Glider Observations
Authors: Zarokanellos Nikolaos , Rubio Manuel , Balan Sorin , Ungureanu Viorel Gh. , Miralles Albert , Rotaru Sabin , Rivera Rodríguez Patricia , Papathanassiou Vangelis , Tyler Andrew , Casas Benjamin , Stanica Adrian , Tintore Joaquin
Published: March 2024

The Black Sea is a semi-enclosed basin with substantial river discharges. These inflows are crucial for the Black Sea's hydrography, nutrient supply, and ecological dynamics. The interplay of atmospheric forcing, river inflows, and mesoscale dynamics contribute to the formation of distinct water masses in the Black Sea. In the northern part, the extended shelf is prone to seasonal hypoxia and eutrophication, while the southern part is deep and stratified, marked by anoxic waters below 100m, rendering the Black Sea an immense meromictic sea. In the framework of the DOORS project (Developing Optimal and Open Research Support), during the DOORS field campaign, a first glider mission was performed in the Romanian Exclusive Economic Zone from May 6 to June 17, 2023, covering 288 nautical miles and conducting 863 physical and biogeochemical profiles at 1000m. The glider performed ten repeated transects perpendicular to the shelf parallel to the Danube Cone. Each transect has been completed approximately within four days, revealing the spatial and temporal characteristics of the region. At the shelf break, the isopycnals notably steepen and relax. In addition, intense surface heat gain of up to 3 oC induced strong stratification in two weeks, decreasing the density and MLD. The glider observations also captured small-scale eddies that contribute to the re-stratification process. These re-stratification events are essential to be monitored as they provide insights into the dynamic processes that affect the thermohaline characteristics of the water column and impact the nutrient availability in the euphotic layer. Understanding these events is essential for predicting and managing changes in the stratification, which plays a fundamental role in the upper layer circulation. By integrating glider-based observations with the broader regional Earth system dynamics context, our research supports a comprehensive understanding of the Black Sea's role in the global ocean climate system.
(Multi)annual variations in the microseism of the Northern Atlantic
Authors: Wiesenberg Lars , Schmidtko Sunke , Meier Thomas
Published: March 2024

Microseism is one of the biggest parts of ambient seismic noise and has a huge effect on seismic measurements on almost every regular broad band seismometer, but especially in coastal areas. Generally, microseism describes the interaction of water waves and the seafloor. Its variation over time is from huge interest. It is often used on short-period scales to investigate local weather effects, like storm events or seasonal variations. In this work, we are investigating variations in the microseism of the Northern Atlantic on multiannual scales. For that reason, we utilize up to 50 years of seismic data from several onshore stations across Central and Northern Europe. The focus is on secondary microseism of the Northern Atlantic which is normally sensitive at periods of ≈10 to 5 s. It is estimated over two-hour segments of seismic data, separately. Secondary microseism is post processed to eliminate effects of data gaps or outliers before lowpass filtering for the periods of interest. Besides of a dominant peak at one year period, secondary microseism shows also distinct variations at several year of periods. These variations clearly correlate with the North-Atlantic-Oscillation Index (NAO), not only visually, but also quantitatively and might therefore be relatable to climate variations affecting the North Atlantic.
Seismic Deformations due to 2023 Nepal Earthquake Sequence using Satellite Remote Sensing Techniques
Authors: Mondal Sandeep Kumar , Bharti Rishikesh , Tiampo Kristy
Published: March 2024

The seismic activity in the Himalayan region results from the ongoing collision between the Indian and Eurasian tectonic plates. The Himalayan thrust zone, comprising critical fault zones like the Main Central Thrust (MCT), Main Boundary Thrust (MBT), and Main Frontal Fault (MFF), is highly seismically active, leading to numerous moderate-to-high magnitude earthquakes annually. Nepal, situated in one of the world's most seismically active continental collision orogenic belts, has experience numerous devastating earthquakes in its history. Earthquakes can result in wide-ranging devastation that includes other, cascading natural disasters, including avalanches, landslides and glacial lake outburst floods (GLOFs). The present study aims to identify ground surface deformations associated with the 2023 Nepal earthquake sequence using C-band radar interferometry from the ESA Sentinel-1A/B synthetic aperture radar (SAR) datasets. The earthquake sequence includes a mainshock (Mw 5.7 triggered at a hypocentre depth of 32.6 km) on November 3, 2023, followed by an aftershock (Mw 5.3 triggered at a hypocentre depth of 10 km) on November 6, 2023. The mainshock's influence radius, determined using shake maps from the USGS earthquake catalog, is 57 km. Because the aftershock's influence radius of 51 km which is smaller than that of the mainshock, we use that as the study radius. Differential interferometric SAR (DInSAR) is employed for this region, utilizing co-seismic single-look complex (SLC) datasets acquired on October 25 and November 6, 2023, respectively. The DInSAR analysis reveals a maximum reliable (regions with coherence ≥ 0.4) and atmospherically-corrected ground deformation of -79 mm. The most significant ground deformations are observed around the Sisne Himal glacial region and the mountain slopes of the Ragda region. Other areas with ground deformations are identified over the mountain slopes of the Guthi Chaur region. The topographic slope of these regions is ≥35° except for Sisne Himal glacial region as observed through ALOS PALSAR high-resolution terrain corrected digital elevation model (DEM) at 12.5m ground resolution. Analysis of pre- and co-seismic coherence images revealed decreased co-seismic coherence in certain locations within the influence radius. These areas are further investigated for soil liquefaction/cyclic mobility using the Temporal Difference Liquefaction Index (TDLI) using Landsat-8 and -9 datasets of October 27 and November 4, 2023 respectively. TDLI detects changes in soil moisture content after an earthquake event. The observed ground deformations indicate potential earthquake-induced slope failures including some of the locations with liquefaction/cyclic mobility susceptibility. This emphasises the importance of monitoring such vulnerable areas for enhanced seismic risk assessment and disaster preparedness.
Quantifying Glacier Melt Contribution to Streamflow in Switzerland with CAMELS-CH using Deep Learning
Authors: Frank Corinna , Höge Marvin
Published: March 2024

Meltwater from glaciers is an essential resource of water in Alpine catchments that is however subject to large inter-annual fluctuations due to varying meteorological conditions. To optimize energy production and support water resource management, it is crucial to understand the expected range of arriving glacier melt volumes during the ablation season. Glacier contribution is generally estimated through dynamic glacier models, in-situ isotope measurements or a data-driven approach using hydrological modeling.
We present a simplified data-driven approach to indicate the potential of Deep Learning models for the determination of streamflow contributions. A regional LSTM was set up on the recently released CAMELS-CH dataset that includes over 20 catchments with substantial glacier cover (>10% catchment area coverage according to the Swiss glacier inventory GLAMOS). The LSTM was trained on all river catchments with dynamic meteorological forcings and static catchment attributes, including the glacier cover percentage, as inputs. Thereby reaching a median KGE of 0.83 over the test period. In a second test run, the glacier cover percentage was set to zero. Glacier melt time series were then interpreted as the difference in simulated streamflow with respect to the test simulation with the actual glacier cover percentage.
The resulting discharge time series exhibits the expected seasonal pattern for glacier-influenced catchments. Removing the glacier cover reduces the simulated streamflow during summer months, with the largest reduction observed around August/September. Simultaneously, an increase in streamflow is observed during spring months, which might be associated with the melt from excess snow that is not assimilated to the glacier during winter. We find relative glacier melt contributions to streamflow of 0% to 60% for the period of 2006-2020, with an average of 5% over all catchments, which are generally higher than contributions reported in literature determined using estimates from commonly used conceptual hydrologic models. This hints at the potential of DL models as an additional method to quantify glacier melt volumes and streamflow contributions. Further, this enables us to investigate glacier melt and to study  glacier dynamics in a data-driven way with a minimum set of assumptions in our modeling approach.
Exploring the wave storminess along the global coastlines
Authors: Lobeto Hector , Semedo Alvaro , Menendez Melisa , Lemos Gil , Ranasinghe Roshanka , Dastgheib Ali , Bidlot Jean-Raymond
Published: March 2024

Wave storms present a significant hazard to the coastal environment, particularly affecting the 10% of the population residing in low-lying coastal areas, as well as coastal zone infrastructure and developments. This study utilizes a ~40-year wave hindcast to conduct an analysis of wind-wave storminess along the worldwide coast (Lobeto et al., 2024). The main characteristics of wave storms, such as the associated wave height and direction, as well as the occurrence rate, duration and intensity, are analyzed. Additional climatic wave features including the relative importance of wind seas versus swells during wave storms are also explored. The combination of key storm features has led to a categorization of coastal regions based on their degree of wave storminess.Results indicate Northwestern Europe and Southwestern South America to be the coastal regions experiencing the most severe storms, while the Yellow Sea, along with the South African and Namibian coastlines, are noted for their high frequency of storms. A global holistic analysis of the wave storminess reveals that, for example, the exposed shores of northwestern Europe experience over 10 storms annually, with mean significant wave heights exceeding 6 meters. A general latitudinal pattern in degree of wave storminess is observed, with the main exception of those coasts affected by wave storms generated by tropical cyclones. Accordingly, regions such as Iceland, Ireland, Scotland, Chile, and Australia exhibit the highest storminess levels, contrasting with lower levels observed in Indonesia, Papua-New Guinea, Malaysia, Cambodia, and Myanmar. Lobeto, H, Semedo, A., Lemos, G., Dastgheib, A., Menendez, M., Ranasinghe, R., Bidlot, R. (2024). Global coastal wave storminess. Scientific Reports (in press).
Global distribution of methane in the mid-troposphere as seen by IASI onboard three successive Metop platforms
Authors: Meilhac Nicolas , Crevoisier Cyril , Orset Rémy , Armante Raymond , Kivi Rigel , Chen Huilin
Published: March 2024

Thanks to its continuous spectral coverage of the whole thermal infrared domain, the IASI sounder offers the possibility to monitor on the long term several essential climate variables, including mid-tropospheric columns of the 3 major greenhouse gases influenced by human activitie: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).To tackle the very small seasonal variability of these gases compared to their background values, combined to the strong dependence of IR radiances to atmospheric temperature and the simultaneous sensitivity of the channels to several gases, a non-linear inference scheme has been developed at LMD. Since 2007, mid-tropospheric columns of methane have been derived for both day and night conditions, over land and over sea. The retrieval scheme strongly relies on careful validation of level1c spectra, characterization of systematic radiative biases and severe cloud and aerosol screening. CH4 fields are delivered on ‘near real time’ (D-1) basis to the Copernicus Atmosphere Monitoring Service (CAMS) and are assimilated in ECMWF C-IFS system, along with total columns from GOSAT, to produce forecast of vertical profiles of atmospheric concentration. Owing to its 20 year-program, IASI also participates to the establishment of long time series in the Copernicus Climate Change Service (C3S). The retrievals are thus used for a variety of purpose: assimilation to produce CH4/CO2 profile forecasts; estimation of surface fluxes using “top-down” atmospheric inversions; characterization of specific emissions such as biomass burnings.In this talk we will present the latest development of the retrieval and application of methane. In particular, we will present the extension and validation of the retrieval to the high latitude regions achieved during the ESA MethaneCAMP project. By using AirCore 0-30 km profiles of methane concentration acquired at Sodankylä and Kiruna and several stations of the French AirCore network, we will also highlight the crucial need to better understand the variation of stratospheric methane in order to combine satellite-derived methane columns with simulations from atmospheric transport models. Finally, we will present long-term and interannual variability of methane as seen by IASI, with a focus of 2020-2021 methane anomaly and the characterization of specific emissions such as biomass burnings or NordStream leakage.
Evaluating Ordnance Survey sheets (1890s – 1957) for shoreline change analysis in the Maltese Islands 
Authors: Fenech Daniel , Tranchant Jeremie , Gauci Christopher , Ghirxi Daniela , Felix-Martins Ines , Colica Emanuele , Buhagiar George
Published: March 2024

 Jeremie' Tranchant1, Daniel Fenech1, Christopher Gauci1, Daniela Ghirxi1, Ines Felix Martins1, Emanuele Colica1, George Buhagiar11  Research and Planning Unit, Ministry for Transport, Infrastructure and Public Works, Project House, Triq Francesco    Buonamici, Floriana, FRN1700, MaltaThe assessment of coastal erosion through shoreline change analysis, is an exercise of national utility undertaken in many countries. The Maltese Islands are particularly vulnerable to coastal erosion given the economic value of coastal activities and their high ratio of coast-to-land surface. The integration of historical cartographic material is often used to hindcast shoreline change across long periods of time, as well as to model future erosion rates. The Public Works Department have produced detailed 1:2500 maps of Malta in collaboration with the British Ordnance Survey from the end of the 19th century to 1957, however these maps have never been scientifically assessed. The initial research carried out evaluated the usefulness of the two oldest 25-inches Maltese maps series (early 20th century and 1957) for shoreline change analysis.  The two series were digitised, georeferenced, and compared in a GIS environment to assess their differences. The inaccuracies of the original drawings, absent shoreline indicators, and the absence of a geographic coordinate system (datum and projection) were identified as limitations for their use in evaluating small gradual changes, but were ideal for the identification of stochastic, large-scale historic erosion events using difference maps. This assessment showed that the two series are highly congruous and any changes between the two series are largely attributed to changes in infrastructure. There were, however, minor exceptions and these need to be explored on a case-by-case basis. These methods and the insights garnered from their production will function as scientific steppingstones towards developing a holistic coastal erosion national monitoring program.  
The Atlantic sibling: a reconciling vision on the nature of El Niño’s “little brother” 
Authors: Carniel Cosimo Enrico , Borzelli Gian Luca , Russo Aniello , Carniel Sandro
Published: March 2024

The Atlantic Niño, also referred to as Atlantic zonal mode, equatorial Atlantic mode or, sometimes, El Niño’s little brother, is an important source of the year-to-year variability of the tropical Atlantic, consisting in an irregular oscillation of the Sea Surface Temperature (SST) in the eastern part of the basin. The physical mechanism underlying the activation of the oscillation is a matter of debate; some theories, termed dynamical, explain the Atlantic Niño as an ENSO-like phenomenon initiated by internal waves excited by the relaxation of easterly winds in the western tropical Atlantic and/or by the reflection of Rossby waves impinging the western Atlantic boundary. Some other theories, called thermodynamic, attribute the eastern tropical Atlantic SST variability to thermodynamic processes induced by off equatorial heat fluxes. Here, by using Sea Surface Height (SSH) data provided by orbiting altimeters and heat fluxes deduced from horizontal currents and Temperature-Salinity (TS) profiles provided by the Copernicus project, we show that, at least in the period Jan 1993-Dec 2021, both mechanisms were active and two sub-periods can be identified: the first, between Jan 1993 and Dec 2009, in which the eastern tropical Atlantic temperature variability can be explained reasonably well in terms of heat advected from the south by horizontal currents and, another period, between Jan 2010 and Dec 2021, in which the temperature variability of the eastern tropical Atlantic is explained by displacements of the thermocline induced by internal Kelvin waves propagating along the equatorial wave-guide. Finally, by using daily SST anomaly data over the period Jan 1940-Dec 2022, we show that the SST variability in the eastern tropical Atlantic and in the Angola-Benguela upwelling region are well correlated with each other with a lag slightly lower than a month and the SST in the Angola-Benguela region leading, suggesting a positive feedback between off equatorial heat availability and increasing SST in the eastern tropical Atlantic.