bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulating the evolution and impact of Fimbulisen basal channels in a coupled ice shelf -ocean model
Authors: Gladstone Rupert , Zhou Qin , Zhao Chen , Hattermann Tore , Morris Ashley
Published: February 2023

Small-scale basal features, such as channels and crevasses, are abundant on many ice shelves and play a role in determining spatial basal melt patterns, impacting on freshwater released to the Southern Ocean.  These features may also, either directly or via basal melt patterns, impact on ice shelf stability and therefore also global sea level. However, simulating the effect of these features on basal melting at a hundred-meter scale or smaller is still challenging even for dedicated regional simulations, which typically ignore the small-scale features and instead smooth the ice draft.  In this study, we simulate the effect of small-scale basal features on the Fimbulisen Ice Shelf (FIS) with the unstructured grid Finite-Volume Community Ocean Model (FVCOM), which allows refinement of model resolution in selected regions to resolve the small-scale features. Fine-resolution (8 m) basal topography of the FIS, retrieved from the Reference Elevation Model of Antarctica (REMA) data, reveals that the ice thickness of the Jutulstraum ice stream changes rapidly northwards from ~1500 m to ~ 600 m within 60 km of the grounding line. It also reveals that channelized basal features of several tens of kilometers traverse the ice base both along and across the ice stream, providing an intricate ice base topography. We set up a fine-scale FVCOM model of the FIS ice cavity to resolve the complicated basal topography, with grid resolution varying from 50 m in the focused region along the Jutulstraum ice stream to 1500 m in the open ocean. Sensitivity studies are performed, using the high-resolution ice draft from REMA as well as smoothed versions of it, to assess the effect of small-scale basal features on the cavity circulation and melt rates of the FIS. Ice shelf simulations, using Elmer/Ice, are carried out on the same refined mesh, to investigate the ice dynamic response to finely resolved ocean-induced melting.  Finally, coupled Elmer/Ice - FVCOM simulations are carried out to investigate the coupled evolution of the channelised system.  We aim to quantify the net basal mass balance contributions from small-scale basal features and finally to parameterize their effects in coarser ocean models.
Application of deep convolutional neural networks for precipitation estimation through both top-down and bottom-up approaches
Authors: Mosaffa Hamidreza , Filippucci Paolo , Ciabatta Luca , Massari Christian , Brocca Luca
Published: February 2023

Reliable and accurate precipitation estimations are a crucial hydrological parameter for various applications, including managing water resources, drought monitoring and natural hazard prediction. The two main approaches for estimating precipitation from satellite data are the top-down and bottom-up. The top-down approach uses data from Geostationary and Low Earth Orbiting satellites to infer precipitation from atmosphere and cloud information, while the bottom-up approach estimates precipitation using soil moisture observations, e.g.  the SM2RAIN algorithm. The main difference between these approaches is that the top-down approach is a more direct method of measuring precipitation that estimates it instantaneously, which may lead to underestimation, while the bottom-up approach measures accumulated rainfall with more reliable precipitation estimation between two consecutive SM measurements. In this study, we develop the deep convolutional neural networks (CNN) algorithm to combine the top-down and bottom-up approaches for estimating precipitation using the satellite level 1 products including the satellite backscatter information from the Advanced SCATterometer (ASCAT), infrared (IR) and water vapor (WV) channels from geostationary satellites. This algorithm is assessed at 0.1° spatial and daily temporal resolution over Italy for the period of 2019-2021. The results show that the developed model improves the accuracy of precipitation estimation. Additionally, it indicates that there is a significant potential for global precipitation estimation using this model.
Linking Aftershock-free significant earthquakes to the dynamics of volcanic arcs; and linking aftershock-rich significant earthquakes to devolitization.
Authors: Gunatilake Thanushika , Miller Stephen A.
Published: February 2023

Earthquakes are typically followed by a series of aftershocks. Deeply trapped and internally generated high-pressure fluid diffuses along permeable paths and subsequently reactivates faults that drive thousands of seismic events. The thermal decomposition of CO2 in the carbonate regime in the central Apennines contributes significantly to seismogenesis and provides substantial quantities of internally derived high-pressure fluids. We develop a 3-dimensional model of non-linear diffusion with a source term that diffuses along faults and to the surroundings, triggering seismicity along the flow paths, and compare model results with the spatial and temporal observations from the 2009 L'Aquila (Mw 6.3) and the 2016 Amatrice-Visso-Norcia (Mw 6.5) earthquake sequences. The model mimics the generation of additional fluid by thermal decomposition and shows solid correlations in space by comparing the calculated fluid pressure field and the locations of over 50,000 well-constrained hypocenters.In contrast, other earthquakes result in only a small number or even no aftershocks. These include the Peru earthquake (Sep. 25, 2013 -Mw 7.1), the Mexiko earthquake (Sep. 19, 2017 - Mw 7.1), and the Crete earthquake (Oct. 12, 2021). Additionally, great earthquakes in Pakistan (Jan. 18, 2011 - Mw 7.2) and Iran ( Apr. 16, 2013 -Mw 7.7) also spawned no aftershocks despite the high magnitudes. These phenomena can be linked to the dynamics of volcanic arcs.
Constraints for Mercury’s Inner Core Size by Dynamo Modelling
Authors: Kolhey Patrick , Heyner Daniel , Wicht Johannes , Gastine Thomas , Plaschke Ferdinand
Published: February 2023

Mercury possesses an internally generated global magnetic field which significantly differs from Earth’s magnetic field in geometry and strength. While being much weaker (1% of Earth’s surface field strength), Mercury’s magnetic field is strongly aligned to the rotation axis and the magnetic equator is offset towards north. These characteristics of the field have been a challenging task for dynamo modelling. Current dynamo models for Mercury suggest that a stably stratified layer below the core-mantle boundary is necessary to explain the the weak, axisymmetric and offset dipole magnetic field. Although, having different geophysical measurements by NASA’s MESSENGER mission the inner core size of the planet is barely constrained. While interior models from geodetic measurements suggests an inner core sizes which can occupy half of the total core, dynamo models which generate a Mercury-like magnetic field have mostly a rather small inner core of around 400 km. In this study we performed dynamo simulations with a stably stratified layer below the core-mantle boundary which are able to reproduce Mercury’s magnetic field characteristics and we vary the inner core size in these models systematically. First results of the study reveal, that only dynamo models with a small inner core well below 750 km radius are capable of reproducing a Mercury-like magnetic field, while models with a larger inner cores cannot reproduce the offset magnetic equator.
Variations of the system properties of a high-rise building over 1 year using a single station 6C approach.
Authors: Rossi Yara , Tatsis Konstantinos , Reuland Yves , Clinton John , Chatzi Eleni , Rothacher Markus
Published: February 2023

We demonstrate that the dynamic response of an engineered structure, including modeshape identification, can be obtained from just a single measurement at one position - if rotation is recorded in combination with translation. Such a single-station approach can save significant time, effort and cost when compared with traditional structural characterization using horizontal arrays. In our contribution we will focus on the monitoring of a high-rise building by tracking its dynamic properties and their variations due to environmental (e.g. temperature) and operational (e.g. wind) conditions (EOCs) over a 1-year period. We present a real-case structural identification procedure on the Prime Tower in Zurich. This is a 36-story tower of 126 m height, with a poured-in-place-concrete core and floors and precast-concrete columns; this concrete core structure, surrounded by a triple-glazed facade, is the third highest building in Switzerland. The building has been continuously monitored, over a 1-year period, by an accelerometer (EpiSensor), a co-located rotational sensor (BlueSeis) and a weather station located near the building center on the roof. Roof and vertical seismic arrays were deployed for short periods. The motion on the tower roof includes significant rotation as well as translation, which can be precisely captured by the monitoring station. More than 20 structural modes, including the first 6 fundamental modes, where translations are coupled with rotations, are tracked between 0.3 – 14 Hz. We will also show the variation of natural frequencies due to seasonal but also more short-term effects, in an effort to understand the effect of environmental and operational variability on structural deformation and response. Additionally, an amplification of the modes, not only during strong winds, but also during a couple of Mw 4.0 - 4.4 earthquakes at regional distance has been observed and analysed. The frequency band between 0.3 and 10 Hz is of key interest for earthquake excitation, making an investigation thereof essential. The work closes with a summary of the main benefits and potential in adopting collocated rotation and acceleration sensing for geo-infrastructure monitoring purposes.
Time to recognize the geoscience disclosure as the tool to face climate change impacts: can we care about something that we do not know?
Authors: Mancini Alan Maria , Negri Alessandra , Tonon Marco , Lozar Francesca
Published: February 2023

Human-induced climate alteration is impacting ecosystem functioning and services. Ocean acidification and deoxygenation, mass extinction, rising sea level and extreme meteorological events are related to the rise of atmospheric CO2 and the consequent increase in temperature. The rate of environmental change is extremely fast, hampering the biota to adapt to the ongoing new conditions, therefore increasing the potential impact on the ecosystem. The geological record is a powerful tool to investigate past trends in order to better understand the current climate change. The ability of geosciences to reconstruct the whole “evolutionary history” of past extreme events, from their onset to their conclusion and the consequent recovery of the ecosystem is something that must be exploited to increase awareness. As an example, the environmental reconstruction of the main events related to abrupt (natural) emissions of CO2 during Earth history underlines that the current climate change is outstanding in terms of rate of environmental change and impact on ecosystems. Understanding and disclosing these findings is crucial in order to increase the population’s awareness of the current ecosystem threat and therefore, contributing to mitigate the impact. This because, trivially, “people cannot care about something that they do not know”. Anthropogenic pressure mostly derives from governance regime; this can be changed if population consciousness boosts governance actions for climate change mitigation. In this perspective, the geoscience, with its potential to explore and constrain past environmental changes, necessitate to be more considered in the educational career both at school and in the mass media worldwide. Clear examples of how, and how much, the awareness of the population regarding the current climate change plays a fundamental role in stimulating sustainable governance actions derive from the “Youth for climate” movement. Here we propose easily performable, inclusive and proactive educational tools for mitigation strategies to face possible future impacts deriving from the climate evolution, as pointed out in the United Nations 2030 Agenda (Sustainable Development Goal 13: Climate Action). We mainly focus our activities on marine sediments, in order to draw the attention to this widely unknown environment and to show how climate change affects the oceans; this also supports the UN Ocean Decade. In order to assess the knowledge and perception on climate change and ocean life evolution, we will present some data collected among the secondary school students reached by a public engagement project devoted to the dissemination of these subjects.
Influence of resolution and parameterization of the WRF model on the verifiability of weather forecast
Authors: Kendzierski Sebastian
Published: February 2023

Numerical weather prediction (NWP) models are frequently used tools in operational weather forecasting. The NWP bases on current weather observations and processing of this data using computational models to forecast possible weather conditions. The aim of the study was to determine the optimal configuration of the Weather Research and Forecasting (WRF) model , version 4.2 (Skamarock et al. 2008), for more effective weather forecasting for the area of Poland. For model evaluation, we used observations from the IMWM-NRI network (above 50 meteorological stations). Numerical simulations were run using GFS model data was obtained from NOAA's NCEP servers. The WRF model was configured for a 3 km horizontal resolution grid, using unique parameterization settings for this model. Validation of forecast data was performed using statistical measures recommended by the WMO, e.g. mean error, mean absolute error, mean squared error, showing the values of forecast error. In this study, the model settings were configured based of other papers for Europe (Stergiou et al. 2017, Mooney et al. 2013, Kioutsioukis et al. 2016, Garcia-Diez et al. 2015, Carvalho et al. 2014, Santos Alamillos 2013), especially from its central part (Wałaszek et al. 2014, Kryza et al. 2017). The results of the work present statistical summaries of optimal model parameterization schemes, depending on their verifiability. Model configuration characterized by the best performance will be further examined over a longer time period (in the study, the average MAE for air temperature was 0.8°C). The research was funded by National Science Center (project number: 2017/27/N/ST10/00565)
Density oscillations in the solar corona seen in radio occultation measurements and a MHD simulation
Authors: Chiba Shota , Imamura Takeshi , Shoda Munehito
Published: February 2023

The solar wind is a supersonic plasma flow streamed from the solar corona. The acceleration of the solar wind mainly occurs in the outer corona at heliocentric distances of about 2­–10 RS (= solar radii), where the coronal heating by magnetohydrodynamic waves and the wave-induced magnetic pressure are thought to play major roles in the acceleration. The mechanisms have not been fully confirmed because the acceleration region is where no spacecrafts have ever reached to date. Recently, however, an inner heliosphere observation network is getting ready, by such as NASA’s Parker Solar Probe and ESA's Solar orbiter and BepiColombo.Radio occultation observations cover the acceleration region fully and can obtain information complementary to in-situ observations. The radio occultation observations are conducted during the passage of a spacecraft on the opposite side of the sun as seen from the Earth. Inhomogeneity of coronal plasma density structure traversing the ray path disturbs radio waves' frequency, so we can interpret the received frequency fluctuations as density fluctuations in the coronal plasma. Previous observations detected quasi-periodic components thought to represent magnetoacoustic waves (e.g, Efimov et al., 2012; Miyamoto et al., 2014). The details of the detected waves still have not been investigated.A recent MHD simulation have reproduced the formation of the solar wind based on the wave/turbulence-driven scenario, in which ubiquitous presence of density fluctuation is found. We applied the spectral analysis to the density fluctuations to compare them with the wave components observed by radio occultation observations conducted by JAXA’s Akatsuki spacecraft in 2016. The time-spatial spectrum of density fluctuations has two components whose phase speeds correspond to the Alfvén speed and sound speed, and these two components are considered to be fast and slow modes. The dominant periods of the slow modes in the model are longer than 100 s, which is consistent with the density fluctuations observed by the radio occultation. The periods of the fast modes in the model are about 20–100 s; such short-period components are also seen in the radio occultation observations. These different modes might have been observed by radio occultation simultaneously.
A Computational Fluid Dynamics based framework to assess the wind energy potential of an urban landscape: A case study in Brussels
Authors: Raghunathan Srikumar Sampath Kumar , Mosca Gabriele , Tsionas Ioannis , Llaguno-Munitxa Maider , Stephan André , Gambale Alessandro
Published: February 2023

Wind is a clean and renewable energy source that has the potential to significantly contribute to the electricity supply in urban areas. Electricity generation through Micro Wind Turbines (MWTs) in an urban setting is not often implemented given their expected low performance due to low wind speed. Wind speed is indeed generally lower in urban areas than in open, rural, and coastal areas: buildings and structures represent obstacles to the wind flow and reduce its velocity. But those same obstacles also locally accelerate the flow at some locations, so that accurate positioning of wind turbines can often result in a satisfactory performance. In the present work, a framework is detailed to assess the wind energy potential of an urban neighborhood using Computational Fluid Dynamics (CFD) and applied to the Northern District of Brussels, Belgium, a neighborhood that has the ambition to become a Positive Energy District. Assessing the wind energy potential of an urban area requires knowledge of local wind properties (speed, direction, turbulence) to a high spatial resolution, as conditions even on a single roof are not uniform. CFD is a powerful tool that can be used to discern wind patterns and aid in an accurate assessment of the wind energy potential. By using CFD, it is possible to accurately predict the wind speed, direction and turbulence within an urban landscape, taking into account the effects of buildings, terrain and other structures. Statistical wind data from the last 30 years collected by the nearest meteorological station is used to define the conditions for a large enough number (typically 5-10) of CFD simulations for each wind direction. Based on the obtained results, the potential energy output of a specific MWT can be predicted and sites with suitable conditions can be identified. Simulations are performed using the opensource finite-volume solver OpenFOAM v7. A modified RANS turbulence model (k-ω SST)  with the improved Atmospheric Boundary Layer (ABL) approach from Bellegoni et al  is used to solve the flow equations in order to improve the accuracy of results. The numerical analysis allowed to identify the most suitable locations for MWTs in Brussels Northern District, demonstrating how the described approach can be effectively used in assessing the wind energy potential in an urban environment. 
Attribution of Tropospheric Ozone to Sources of NOx and VOC Precursor Emissions in a Global Chemistry-Climate Model (CESM1.2.2-CAM4-Chem) for the 2000-2018 Period
Authors: Nalam Aditya , Lupascu Aura , Butler Tim
Published: February 2023

Tropospheric ozone (trop-O3) is a regional air pollutant and an important greenhouse gas. Major sources of trop-O3 are: transport from the stratosphere; and photochemical production within the troposphere involving reactions of ozone precursors: oxides of nitrogen (NO and NO2, collectively NOx) and volatile organic compounds (VOC), including methane.Trop-O3 has an atmospheric lifetime of about a few weeks making it transportable over inter-continental distances. This makes ozone precursor emissions from one “source” region affect the ozone concentration at local and remote “receptor” regions, making it important for us to understand source-receptor relationships. These source-receptor relationships can be modelled using the source-attribution technique (also known as Tagging) where ozone molecules are tagged/labelled with their source identities allowing a direct attribution of sources in receptor regions, thereby, the relative contribution of various sources can be obtained.Simulations using CESM 1.2.2- CAM4-Chem are performed for a global study of trop-O3 source attribution for the 2000-2018 period. Here, we modify the default chemical mechanism to output the ozone and its tags attributed to the source region/sector of its emitted precursors. For example, an NO molecule originating from biogenic source would be called NO_BIO, and all the other chemical species emanating from NO_BIO (NO2, NO3, O3 etc.) will hold the tag “BIO”.Separate simulations are performed for tagging trop-O3 with its NOx and VOC precursor emission sources. We specify separate tag identities for emissions from anthropogenic, biogenic, biomass burning, and aircraft sources. Additional tags are specified for lightning NOx in the NOx-tagged simulation, and for methane in the VOC-tagged simulation. Here, all surface-based anthropogenic emissions hold tags representing the geographical location at which the emissions occur. Further, the ship-NOx emissions hold tags representing the ocean basin from which they are emitted.The design of these simulations and several prominent results will be presented.
Interoperable digital twins of the ocean through aligned architectures
Authors: Bye Bente Lilja , Berre Arne-Jørgen , Brönner Ute
Published: February 2023

Digital twins are designed to support decision-making and to make well-timed interventions that provide better outcomes. Thus, it is not only the digital twin itself that is important, but also the ease of creating actionable information or decisions, through policy, management or operational decisions. This implies the need for a well-formulated interface between the digital twin and a machine or human. Digital twins of the ocean comprise multiple geoscientific disciplines in itself and the thematic twins rely on both data and models based on science and technology that are interoperable. The EU Horizon2020 project ILIAD Digital Twin of the Ocean capitalizes on the explosion of new data provided by different Earth observation sources, advanced computing infrastructures (cloud computing, HPC, Internet of Things, Big Data, citizen science) in an inclusive, virtual/augmented, and engaging fashion to address all Earth data challenges. In addition, the EU is also building a broad foundational ecosystem for the European Digital Twin of the Ocean (EDITO) led by Mercator Ocean International, VLIZ et al.  There are many other initiatives that work toward or in support of a Digital Twin of the Ocean, e.g. NOAA’s National Centre for Environmental Information, the IOC Ocean Data and Information System ODIS, the IOC Ocean Best Practice System OBPS, the Ocean Data Action Coalition and the UN Data Coordination Group. DITTO, a Global Program of the UN Decade of Ocean Science for Sustainable Development (2021-2030) aims to develop and share a common understanding of digital twins of the ocean (DTO); to establish best practice in the development of DTOs; and advance a digital framework for DTOs to empower ocean professionals from all sectors around the world including scientific users, to effectively create their own digital twins. One of the activities to implement this is the Interoperability ArchitecTURes for a DigiTaL OcEan (TURTLE). This presentation gives an overview of the initiatives and introduces the strategy and some of the tools for making these systems interoperable.
Bivariate modeling of flood peak and volume for assessing the hydrological safety of dams
Authors: Patro Epari Ritesh , Cazzaniga Greta , De Michele Carlo
Published: February 2023

The dam failure can be caused by multiple factors such as slope instability, presence of structural faults, or overflow. The latter is one of the most frequent causes and accounts for more than 40 % of them worldwide. Checking the hydrological safety of dams means assessing the ability of the dam, and thus of its outlets, to dispose of intense flood events without overflow. In Italy, the assessment of the hydrological safety of dams is a key and urgent issue in Italy. About the 8% of the large dams were built more than one century ago, and such a percentage is expected to increase up to 23% in a decade. Traditionally, such assessment is performed by means of the millennial quantile of flood peak. However, in literature, it has been shown that the determination of critical flood events should consider the statistical dependence between flood peak and flood volume. In the present work, we assess the hydrological safety of three Italian dams (namely, Ceppo Morelli, Mignano, and Molato) exploiting a bivariate approach, which stems from the method presented by De Michele et al., 2005. The statistical dependence between flood peak and volume is firstly estimated and modelled using copula models. Massive synthetic simulations are afterward performed to estimate the rate of overtopping of each dam, and consequently the return period. Results show that all the three dams result as hydrologically safe, even if Ceppo Morelli dam needs to be regularly monitored. Furthermore, for each dam, we also define a critical region, where the couples flood peak-flood volume may lead to overtopping. It is observed that the shape of such regions strictly depends both on flood peak and volume. Eventually, the routing effects of the three dams are compared, with respect to the return period and assuming three different dependence behaviors. It is proved that an overestimate of the dependence degree would result in an underestimate of the dam routing effect, and viceversa, leading to improper assessment of the risk.
Developing policy recommendations to support innovation in soilless agriculture within the Nile River Basin: A participatory approach using Multi-Actor Working Groups
Authors: Stergiopoulou Lydia , Akinsete Ebun , El-Said Nouran , Koundouri Phoebe
Published: February 2023

Increasing demand for energy, food and water in the Mediterranean along with the decline of freshwater availability due to climate change necessitate the exploration of options for producing more food with less water, land and energy. Innovations in soilless agriculture aim to address this challenge by exploring novel approaches towards food production including aquaponics and hydroponics. However, inadequate and inefficient legislation and policy frameworks are ill equipped to provide the support necessary for the successful uptake and scale out of these new technologies.  This paper examines the implementation of soilless technologies in the water-stressed Nile River Basin. By applying a stakeholder-centered participatory approach developed by the project which takes into consideration the Water-Energy-Food- Ecosystem (WEFE) Nexus, we present targeted policy recommendations for the development of soilless agriculture in the region which inherently embed the views of key local stakeholders. 
Glaciological monitoring at A. P. Olsen Ice Cap in NE Greenland
Authors: Hillerup Larsen Signe , Rutishauser Anja , Binder Daniel , Korsgaard Niels , Hynek Bernhard , Citterio Michele
Published: February 2023

In situ glaciological monitoring of A. P. Olsen Ice Cap in NE Greenland has been ongoing since 2008. The monitoring effort is part of the Greenland Ecosystem Monitoring (GEM) programme at Zackenberg research station. The monitoring includes: Three automatic weather and ablation stations along a transect, manual stake observations upon every visit in April, ground based radar profiles of last year snow accumulation and geodetic mass balance from satellite based observations. Here we present an overview of all glaciological monitoring data, and use the dataset to estimate the mass balance of A. P. Olsen over the past 13 years.
Cd isotopes in carbonates deposited during ‘OAE 2’: Assessment of a novel palaeo-productivity tracer
Authors: Gangl Sophie , Stirling Claudine , Druce Matthew , Clarkson Matthew , Jenkyns Hugh
Published: February 2023

Cadmium (Cd) displays nutrient-type patterns in the modern ocean and has potential as a tracer of the efficiency of the ‘biological pump’ and its ability to transport CO2 from the atmosphere to the deep ocean during intervals of extreme environmental change. This potential arises because phytoplankton preferentially incorporate lighter Cd isotopes under many oceanic conditions, leaving surface waters relatively enriched in heavier isotopes. As a consequence of this fractionation, Cd-isotope ratios have been shown to reflect nutrient availability and the intensity of primary productivity in the modern ocean. However, the ability of the Cd stable-isotope system to serve as a robust palaeo-productivity tracer is not yet well established.Oceanic Anoxic Event 2 (OAE 2; ~94 Ma) represents a period of widespread environmental degradation and oceanic de-oxygenation, likely the result of increased volcanic activity, intensified marine and continental silicate weathering, augmented nutrient input to the ocean and elevated primary productivity. However, direct evidence for the availability of bio-limiting nutrients in the oceans and the role of primary productivity as a feedback mechanism to eventually re-stabilise climate is limited. Here we present the first Cd-isotope record for OAE 2, from the well-preserved and biostratigraphically well-constrained organic-lean pelagic carbonate section through the English Chalk at Eastbourne (UK). Contrary to expectations, Cd isotopes at Eastbourne do not seem to be controlled by surface ocean productivity, but likely reflect global sub-surface signatures. The isotopic record suggests an active biological pump during OAE 2 coupled with changes in ocean circulation on a global scale. Our new record proposes that the Cd-isotope proxy is powerful and potentially very important for unravelling environmental changes during deep time events.
Towards Physically Consistent Sea Level Rise Storylines for the United Kingdom
Authors: Harrison Benjamin , Palmer Matthew , Allison Lesley , Gregory Jonathan , Howard Tom , Pardaens Anne , Tinker Jonathan
Published: February 2023

There is increasing awareness of the need for comprehensive information on potential future sea-level rise to inform adaptation planning and coastal decision-making. The IPCC Sixth Assessment Report (AR6) states that global mean sea level rise approaching 5 m by 2150, and more than 15 m by 2300, cannot be ruled out under high greenhouse gas emissions due to uncertainty in ice sheet processes. Moreover, local sea level rise may be further exacerbated through systematic changes in the climate system, such as a rapid weakening of the Atlantic Meridional Overturning Circulation (AMOC).We combine the latest United Kingdom national sea-level projections (UKCP18) with recently published projections of Antarctic ice mass loss to develop a small set of physically consistent storylines of local sea-level change that extend to 2300. The storylines span the range of uncertainty assessed by AR6 and deliver continuous sea level rise information around the UK coastline. While we focus on the UK, the methods are generic and can be readily applied to other geographic locations. Further, we consider potential changes in coastal flood hazard associated with a weakening of the AMOC using dynamical downscaling and storm surge modelling of climate model projections.
A study of the mantle flow field and lithospheric deformation beneath the Kuril-Kamchatka subduction zone using seismic anisotropy
Authors: Kaviani Ayoub , Rümpker Georg , Sens‐Schönfelder Christoph , Abolfazl Komeazi Abolfazl Komeazi , Shapiro Nikolai
Published: February 2023

We investigate the flow field and deformation in the mantle wedge and subslab mantle beneath the Kuril-Kamchatka subduction zone using seismological data from a recently deployed seismic network around the Klyuchevskoy Volcanic Group (KVG) complemented by data from previous temporary deployments and permanent stations to reach a total number of 145 seismic stations covering a region defined in the geographic coordinates 150°-167°E and 50°-61°N.We perform splitting analysis of both local and core-refracted (SKS) shear waves to study mantle seismic anisotropy as a proxy for the pattern of the mantle flow field and deformation. Anisotropy in the mantle wedge is studied by shear splitting analysis (SWS) of waveform data from local mantle events that occurred along the subducting slab (Wadati-Benioff-Zone) and in the mantle wedge. Crustal anisotropy is also studied by SWS analysis of crustal events. The combined data set (SKS and local) allows us to discriminate the source of mantle anisotropy (sub-slab, mantle wedge, or crust). Shear-wave splitting measurements from the local shear waves give small delay times independent of the depth of the events suggesting that the mantle wedge is characterized by a weak anisotropic fabric. The fast directions of mantle wedge anisotropy are predominantly parallel to the strike of the slab indicating either a trench-parallel flow or B-type seismic anisotropy in the mantle wedge. The relatively small delay times from local shear waves suggest that SKS waves are less affected by potential anisotropy in the mantle wedge and that the results of the SKS-splitting analysis are mainly representative of the sub-slab anisotropy. Our SKS-splitting measurements indicate a trench-normal mantle flow beneath the eastern edge of the Kamchatka peninsula that converts to a more complex pattern beneath the KVG region. We argue that this pattern of fast polarization direction suggests the rotational mantle flow beneath the slab that may be related to the change in slab geometry at the junction between the Kuril-Kamchatka and Aleutian arcs. The observation of relatively strong sub-slab anisotropy against weak mantle-wedge anisotropy suggests that slab termination causes some disturbance in mantle flow; however, no significant component of an around-slab flow occurs in the mantle wedge.
Spatio-temporal variations of phosphorus (P) fractions in surface sediments of the southern Caspian Sea
Authors: Ebrahimi Pooria , Nematollahi Mohammad Javad , Nasrollahzadeh Saravi Hassan , Vogt Rolf David , Vahedi Fariba , Baloei Mahdie
Published: February 2023

Sediments act as a sink and a secondary source of contaminants, accounting for a central part of coastal and marine biogeochemical cycles. Phosphorus (P) is a macronutrient that governs primary productivity and phytoplankton growth, but excess P influx results in algae bloom and deteriorates aquatic ecosystems. This study assesses seasonal fluctuations, spatial distribution and fractions of P in the sediments of the southern Caspian Sea. In this study, at eight sampling points, composite samples of the surface (from 0 to 10 cm) seabed sediments were collected at 10 and 30 m water depths. The sampling campaigns were carried out in the four seasons and a total of 64 sediment samples were obtained. Total organic matter (TOM), total P (TP) concentration and particle size distribution were determined. Then, P was fractionated using a four-step sequential procedure to quantify the loosely bound P (LP), the reductant soluble P (FeP), the metallic oxide-bound P (AlP) and the calcium carbonate (CaCO3) bound P (CaP). The inorganic P (IP) pool refers to the sum of LP, FeP, AlP and CaP, while the organic P (OP) was calculated by subtracting IP from TP.The results show that seasonal fluctuations of mean TP were statistically insignificant (p-value > 0.05). Still, the highest levels were recorded in autumn (1555 mg kg-1), followed by winter (1405 mg kg-1), spring (1378 mg kg-1) and summer (1130 mg kg-1). These minor temporal variations in P levels are associated with the seasonal differences in the amount of runoff and the intensity of rivers discharging into the Caspian Sea, and thereby their sediment load and the physicochemical characteristics. The large riverine influx resulted in TP contamination hotspots in the river deltas of Anzali wetland, Babolrood and Sefidrud (northern Iran), where high loadings of suspended particles are discharged into the sea. The spatial TP distribution is thus site-specific and uneven. The main P fraction was CaP, reflecting the phosphate (PO43-) strong affinity for, and association with, calcium-bearing minerals. Only a minor fraction of P was determined as LP. The fraction of the mud-size particles was the main explanatory factor for the spatial distribution of overall low levels of non-residual (or bioavailable) P forms (i.e., LP, FeP and AlP) during spring and summer, while the sand fraction had the greatest explanatory value for the distribution of residual (non-bioavailable) P form (CaP) during autumn and winter. This study demonstrates that P bioavailability in sediments is mostly controlled by the physicochemical characteristics of the sediment material, which again is steered by seawater chemistry. A low content of bioavailable P fractions could therefore be related to the relatively low content of fine-grained (i.e. below 63 µm) particles in sediments of the southern Caspian Sea.
Direct observations of coupled interactions between near-ice ocean stratification and ice slope and morphology in basal terraces beneath Thwaites Glacier
Authors: Washam Peter ,   ITGC MELT Team
Published: February 2023

Here, we present detailed ice and ocean data from beneath Thwaites Eastern Ice Shelf, Antarctica, collected with the underwater vehicle Icefin as part of the ITGC MELT project. The observations are a subset of the full data set that focus on the ice-ocean interactions within several well-sampled terrace formations occupying the ice base. These terraces range from 0.50 to 6 m in height and up to 100 m in width. We present measurements of ocean conditions to within centimeters of the ice surface along flat terrace roofs and their steeply sloping sidewalls. The ocean observations are combined with ice base elevations and scaled morphological melt patterns in the ice to understand the dominant mechanisms driving ice-ocean interactions within these features. We then input these data into the three-equation melt parameterization to estimate spatial variability in melt rates within these topographic features. We test various parameterizations for ocean heat flux into the flat and sloped ice surfaces, and compare the results to melt rates sampled along a nearby terrace sidewall and roof with a phase sensitive radar. This work in progress aims to better understand how ocean conditions interact with ice slope on small scales to drive variable melting in warm, highly stratified environments. We expect regions beneath much of the ice shelves occupying West Antarctica to interact similarly with the underlying ocean to what we observe beneath Thwaites Glacier. Hence, our observations hold relevance for how ice sheet models parameterize ocean-driven melting in this type of melt-driven regime.
Monitoring and Interpreting Shanghai Maglev Deformation Using Deep Clustering on MT-InSAR Analyses
Authors: Wang Ru , Hooper Andy , Gaddes Matthew , Liao Mingsheng
Published: February 2023

Multi-temporal InSAR (MT-InSAR) technique has been widely used in the earth observation field. However, there are still challenges in the high-resolution monitoring and interpreting of urban infrastructures, especially for long-term time series analysis. We develop a data-driven post-processing method to provide a new solution to using MT-InSAR analyses in urban infrastructure health monitoring. We use a deep learning-based clustering method to classify different displacement temporal evolution patterns along Shanghai maglev from 7 years of TerraSAR-X observations (2013 to 2020). Our study region is observed by the satellite with alternating viewing angles between consecutive passes. We jointly estimate the orbital error per epoch to combine the two interweaving time series with different viewing geometries. We include spatial information of observation points for more reliable clustering. We then interpret the cluster results with maglev structural knowledge and surrounding groundwater level change. Different from previous classification methods, the deep learning-based clustering method is independent of predefined deformation models, allowing the identification of previously unknown types of deformation signals. Our preliminary results highlight the potential of applying deep clustering for MT-InSAR time series analyses for future automated structural health monitoring.
Role of brittle off-fault damage on fault step-over dynamics
Authors: Flores-Cuba Joseph , Thomas Marion Y. , Bhat Harsha S. , Jolivet Laurent
Published: February 2023

Strike-slip fault systems consist of a variety of geometrical complexities like branches, kinks and step-overs. Especially, the presence of a step-over structure can strongly determine the final size of the earthquake rupture. Thus understanding the dynamics of a rupture through such a complexity is crucial for seismic hazard assessment. A few studies have looked at this within the context of a linear elastic medium. However, during an earthquake off-fault damage is generated, especially at the ends of a fault, that significantly changes the overall dynamics of a rupture. Using a micromechanical model, that accounts for crack growth and opening and its impact on the dynamic evolution of elastic moduli, we evaluate how dynamic off-fault damage can affect the capability of a rupture to navigate through step-over fault structures. We show that sometimes, accounting for this energy sink, off-damage suppress the ability of the rupture to jump from one fault to another. Whereas, in some specific cases, the dynamically created low-velocity zone may aid the rupture to jump on the secondary fault. Combing this numerical study with an analytical analysis we set the contours for a systematic approach useful for earthquake hazard assessments.
Tridimensional vulnerability assessment of wells supplying drinking water in agricultural areas
Authors: Costa Leonardo , Salandin Paolo
Published: February 2023

In the Treviso province (Veneto, Italy) most of the drinking water (nearly 60 %) is supplied from wells located in the northern piedmont area, where agricultural activities are developed using chemical plant protection products (chemical PPPs). In this area the aquifer interested by the groundwater extraction is unconfined, making the subsurface water resource intrinsically vulnerable to any PPP or PPP residue (metabolite) leaching from the agricultural soil to the groundwater table, and raising concerns about the consequences of a possible groundwater contamination on the health of the local inhabitants.To protect the drinking water resource, in 2019 the Veneto Region provided a technical framework for the definition of the wellhead protection areas (WHPAs, Resolution 1621) in accordance with the EU directives 2000/60 and 2006/118, related to the establishment of safeguard zones for the water bodies used for drinking water supply.  In the WHPAs the use of PPPs is only allowed when accounting for the vulnerability of the groundwater and the well extracting water for human consumption. To define the vulnerability of wells supplying drinking water, a procedure that considers the tridimensional behavior of a possible contaminant is suggested, taking into account the mobility of the chemical species across the vadose zone, the total amount of PPPs applied on the soil, and combining the probability of contaminant infiltration with the groundwater pathlines reaching the well.An application has been developed in the piedmont area of the Treviso province where a geospatial analysis of the vine-specific PPPs sales data identified over 30 WHPAs potentially affected by the PPPs use. The 3D vulnerability assessment couples the position of the vulnerable WHPAs retrieved from the geospatial analysis with 1) the data related to the infiltration capacity of agricultural and not-agricultural unsaturated soils in the piedmont area of the Treviso province, 2) the mobility of the vine-specific PPPs, and 3) the groundwater pathlines in the superficial phreatic aquifer obtained by physically-based numerical modeling.This research has been funded by the contribution from the UNI-IMPRESA 2021 joint research project (Centre of Hydrology ‘Dino Tonini’ - University of Padua, Alto Trevigiano Servizi Spa, Piave Servizi Spa): Subsurface Water quality and Agricultural pracTices monitoring 2 (SWAT-2).
Time-normalized plasma flow mapping during the quadrature of SolO and SDO
Authors: Muro Gabriel , Morgan Huw
Published: February 2023

Observations of plasma motions in the low corona are often limited to magnetic field lines originating in active regions, which are ideal for spatial domain enhancements across individual extreme ultraviolet (EUV) images to see loops, flares, and other bright activity contrasted against dim background features.The quiet Sun is essentially all dim background features, which requires advanced image processing and ideal observation parameters to emphasize the temporal domain in order to visualize faint, fine-scale plasma flows. We utilize time-normalized optical flow (TNOF) on large sets of high cadence EUV data by reducing instrumental noise to a high degree and then emphasizing the minor brightness variations indicative of plasma motion. Maps of plasma flow paths are produced via optical flow tracking algorithms by the computer vision method of Lucas-Kanade and the underlying velocity field is estimated with line integral convolution.To test the effectiveness of the TNOF approach, we have applied this method to an EUV case study of data from EUI 174 and AIA 171 on 29 March 2022. This date marked a near-perpendicular line of sight orientation between the two spacecraft, had similarly short observation intervals, and provided the opportunity to compare contrast enhanced plasma features off-limb with temporally enhanced on-disk plasma motion. In this case study, we generated movies and flow paths that show TNOF succeeds at qualitatively outlining plasma flow along magnetic field lines from both Solar Orbiter’s and SDO’s point of view which are in general agreement with potential field models. Additionally, detailed velocities of plasma motion within coronal loops, overall velocity trends, and a new quasi-magnetic flow trend within the quiet Sun are presented.