bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequency Distribution of Solar Oscillation Inside The Coronal Hole
Authors: Wisniewska Aneta
Published: February 2023

Coronal holes are characterized by open magnetic field lines morphology. The strongest solar wind originates exactly from the area of solar coronal holes. From the other hand the solar oscillation is present at every point of the solar surface. Currently the mechanism which is responsible for formation of open coronal regions is still unidentified. We present a novel study of waves propagation and frequency distribution in coronal holes, which can bring a new insights in its origin. We investigate the discrepancies in the in waves propagation inside the coronal hole are and in its surrounding, using multi-channel intensity observations data from Atmospheric Imaging Assembly (AIA) and Dopplergrams from Helioseismic and Magnetic Imager (HMI) on board Solar Dynamics Observatory (SDO) at the level of photosphere, chromosphere and corona. We study power distribution of p-modes (5-minute oscillation) and wave frequencies above the acoustic cut-off frequency ѵ=5.3 mHz, for very fast waves, in the various levels of solar atmosphere, through helioseismic approach of wavelet 2D-spatial maps of the power spectral density estimated for the coronal hole area.
Discerning relationships between urban ecosystem connectivity and social vulnerability in a major US city
Authors: Havens Zane , Macko Stephen , Mogensen Laura
Published: February 2023

As the body of research surrounding the benefits of Urban Green Infrastructure (UGI) grows, questions regarding how and where UGI is implemented in regards to vulnerable populations require more investigation. Although US cities and municipalities have begun to examine the environmental justice implications of UGI placement, the spatial aggregation and connectivity characteristics of urban ecosystems in vulnerable areas aren’t always considered when making these decisions.  Evidence suggests that connectivity of UGI can influence the ecosystem services UGI provides, but currently research into the differences in UGI connectivity between vulnerable and non-vulnerable populations is sparse. Understanding this relationship can help to better inform decisionmakers on how to effectively address discrepancies in UGI implementation while minimizing the expenditure of municipal resources.In this case study of Washington, DC, we explore relationships between metrics of ecosystem connectivity derived from high spatial resolution (1m) land cover maps and components of the US Center for Disease Control’s Social Vulnerability Index.  These relationships are analyzed using PCA to uncover correlations between commonly used indicators of social vulnerability and the spatial patterns of land cover in a major US city.
Can machine learning help us to create improved and trustworthy satellite-based precipitation products?
Authors: Tsoukalas Ioannis , Kossieris Panagiotis , Brocca Luca , Barbetta Silvia , Mosaffa Hamidreza , Makropoulos Christos
Published: February 2023

Key variable of earth observation (EO) systems is precipitation, as indicated by the wide spectrum of applications that is involved (e.g., water resources and early warning systems for flood/drought events). During the last decade, the EO community has put significant research efforts towards the development of satellite-based precipitation products (SPPs), however, their deployment in real-world applications has not yet reached the full potential, despite their ever-growing availability, spatiotemporal coverage and resolution. This may be associated with the reluctancy of end-users to employ SPPs, either worrying about uncertainty and biases inherited in SPPs or even due to the existence of multiple SPPs, whose performance fluctuates across the globe, and thus making it difficult to select the most appropriate SPP (some sort of a choice paradox). To address this issue, this work targets the development of an explainable machine learning approach capable of integrating multiple satellite-based precipitation (P) and soil moisture (SM) products into a single precipitation product. Hence, in principle, to create a new dataset that optimally combines the properties of each individual satellite dataset (used as predictors), better matching the ground-based observations (used as predictand, i.e., reference dataset). The proposed approach is showcased via a benchmark dataset consisted of 1009 cells/locations around the world (Europe, USA, Australia and India), highlighting its robustness as well as its application capability which are independent of specific climatic regimes and local peculiarities.
Scattering cross sections for O(3P), C(3P), and H colliding with a CO2 molecule for planetary aeronomy
Authors: Gacesa Marko , Krishnan Balasubramoniam Murali , Chaluvalappil Saheer Velluvakandi , Alraie Mariam
Published: February 2023

We present scattering cross sections for O(3P), C(3P), and H colliding with a CO2 molecule at collision energies between 0.1 and 5 eV. The kinetics, transport, and energy relaxation associated with collisions between fast atoms and thermal background atomic and molecular species are of fundamental interest for escape processes in the Martian atmosphere. Two of three primary objectives of the Emirates Mars Mission are related to hydrogen and oxygen escape processes and the collision cross sections are used in the models needed to interpret the observations by the EMUS and EMIRS instruments.In this work, the collision cross sections have been computed using first principles electronic potential energy surfaces constructed in reduced dimensionality for the lowest-energy asymptotes corresponding to the ground states of the interacting pairs. For the three systems, namely C(3P)-CO2, O(3P)-CO2, and H-CO2, velocity-dependent elastic, rotationally inelastic, and corresponding differential cross sections and derived quantities, including the momentum-transfer cross sections, were constructed. In all cases, the CO2 molecule was modeled using the rigid-rotor approximation, and the collisions were treated as non-reactive. The cross sections were calculated from the first principles (no external parameters) by solving quantum-mechanical coupled channel equations following the approach of Arthurs-Dalgarno, with the coupled-state approximation1,2.We estimate the impact of the collision cross sections impact on the O, C, and H escape rates at Mars using simple 1D transport models and find significant differences compared to the values in the literature. In the transport model, we used the altitude density profiles taken from NASA’s MAVEN mission. In case of all three energetic atoms, the inelastic cross sections are found to be a significant part of the total cross sections. In case of O escape, we obtain a larger escape flux closer to the estimates based on the MAVEN measurements. We find that that O+CO flux affects the O escape more significantly than expected3, due to its effects on the available energetic O flux. We expect a similar effect to be present not only at Mars but at all CO2-rich planets due to the O-CO-CO2 photochemistry. The impact on C escape is inconclusive, suggesting that the accounted mechanisms of photochemical escape of C are not sufficient to explain the missing carbon at Mars4,5. Please insert your abstract HTML here.
yams: Yet another modeling software (Julia) for the simulation of coupled reactive transport processes (THC) in geothermal systems.
Authors: Wuttke Manfred W.
Published: February 2023

Geothermal systems (energy production or storage in geological environments) are characterised and controlled by coupled THC-processes occurring simultaneously on different spatial and time scales. The chemical reactions may take place between mobile and immobile phases. The hydraulic transport is either controlling the chemical reactions or is driven by them. For the understanding, the assessment or the prediction of the performance of such systems simulation experiments with numerical implementations of mathematical models are necessary. For this purpose at LIAG a simulation toolkit is under development (yams). This work was begun in C++ (oops!) but recently migrated to Julia for better performance and maintenance reasons. We discuss the aspects of the numerical approach, in particular the capabilities and limits of the time-scale ordered operator splitting method, by simulation examples of such systems, in particular the permeability changes induced by dissolution and precipitation processes under realistic conditions.
High-resolution geomorphological studies of a Red Sea Rift segment in Hadarba Deep
Authors: Augustin Nico , Le Saout Morgane , Schiebener Cora K. , van der Zwan Froukje M.
Published: February 2023

The mid-ocean rift in the Red Sea is recently regaining attention in the geosciences due to the possibility of investigating this young ocean in more detail than ever by state-of-the-art methods and modern deep-sea instrumentation. During the first AUV surveys of the Red Sea rift in Spring 2022, we collected multibeam bathymetry, backscatter, sub-bottom, and water column data over a 9 km long ridge segment in the Hadarba Deep between 22.49°N and 22.56°N to investigate the volcano-tectonic processes of this mid-ocean ridge. This area's total spreading rate of about 12 mm per year is defined as ultra-slow spreading. The high-resolution hydroacoustic data of the used Kongsberg Hugin Superior AUV (operated by Fugro) revealed more than 100 individual lava flows with different stages of sedimentation. The oldest lava flows are buried under 3-4 m of sediment, indicating ages of up to 28 ka. A dome volcano with a 2.5 km diameter and an average height of 300 m dominates the mapped area but has been inactive for at least ~8.4 ka. Several younger lava flows show recent episodes of volcanism along the rift axis. However, their sediment cover is below the vertical sub-bottom-profiler resolution of about 10 cm and thus might be only a few hundred years old or younger. We will present our geomorphological maps, analyses, and statistics that reveal a moderately faulted, ultra-slow spreading MOR segment in the Red Sea with a surprisingly large amount of magmatic extension and show implications for the formation history of this ridge segment.
Towards quality-assured measurements of microplastics in soils using fluorescence microscopy
Authors: Phan Le Quynh Nhu , Halsall Crispin , Peneva Stoyana , Wridley Olivia , Amelung Wulf , Braun Melanie , Quinton John , Surridge Ben
Published: February 2023

Fluorescence microscopy utilising Nile Red staining was applied and tested to analyse microplastic particles in soil. Given a large number of analytical methods for measuring plastic particles in environmental and biological matrices, often utilising microscopy/spectroscopy approaches, efforts were made to validate this method for a range of soils and different microplastic (MP) particle types (varying size and morphology).  Eight MP types (including both non-biodegradable and biodegradable plastics) within three size categories (dia. 500-1000 µm, 100-250 µm and 10-150 µm) were spiked into three different agricultural soils (loam-reference soil, clay, and sandy soils) for a comprehensive assessment of the fluorescence microscopy methodology. Each soil (with replicates) was subject to digestion, density separation and filtration (with Nile Red staining) prior to analysis using fluorescence microscopy (GFP filter set, excitation/emission 470/525 nm) and bright filed microscopy for black microplastics. As a tool to shorten the analysis time, a digital image analysis pipeline using Image J was developed, allowing fully automated particle recognition and quantification of MPs in the samples. The main steps for image analysis, including background correction, fluorescent intensity thresholding, watershed segmentation and particle analysis, were optimised, the validation of which showed high accuracy (88% match to true observation) for MP particles on a filter without a soil matrix. To avoid false positive results due to the presence of natural organic particles from the soil matrix, the numbers of microplastics recovered from spiked samples were corrected with those found in the non-spiked soils. Recoveries ranged from 80-90% for MP with sizes from 500-1000 µm regardless of the soil types, whereas those for smaller MP (10-250 µm) varied between different soils and plastic types (e.g., recovery for low-density polyethylene, LDPE, from sand and loam-reference soil were 85% and 90% respectively whereas those for polybutylene adipate terephthalate/polylactic acid, PBAT/PLA, were 60% and 10% respectively). The lowest recovery rates were observed in clayey soil (20% for LDPE and 5% for biodegradable plastics PBAT/PLA). A relationship between the microplastic mass (LDPE and PBAT/PLA fragments) and the corresponding particle number was established in this study, which enabled the conversion between mass and particle number data. Fluorescence microscopy with Nile Red staining and automatic particle recognition software provides a relatively reproducible and accurate technique for plastic particle counts in heterogeneous matrices like soil. Still, selectivity for different polymer types is clearly limited. 
Energy and mass balance of Mera glacier (Everest region, Central Himalaya) and its sensitivity to climate
Authors: Khadka Arbindra , Wagnon Patrick , Brun Fanny
Published: February 2023

Recent glacier mass changes are very heterogeneous in High Mountain Asia, owing to climatic variability and the mass balance sensitivity to climate, which may differ from one region to another. Mera glacier in the Everest region is one of the longest field-based monitored and well-studied glaciers of the Central Himalaya. In this study, we examine the sensitivity of Mera glacier mass balance to climate variables using the COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY), using 4 years (2016-2020) of in-situ meteorological data recorded at different elevations in the ablation and accumulation zones of the glacier. This shows that the net short-wave radiation is the main energy input at the surface, and in turn albedo is a key parameter controlling the glacier mass balance. As a result, at 5360 m asl, in the ablation zone, surface melt accounts for 90% of mass loss whereas sublimation and subsurface melt account for less than 10%. This analysis is performed at point scale at 5360 and 5770 m asl, in the ablation and accumulation zones respectively, as well as in a distributed way. We produce and analyze 88 distinct climatic scenarios, varying from dry and warm to wet and cold conditions. Dry conditions, primary during the pre-monsoon and secondary during the monsoon, strongly decrease the glacier mass balance, revealing that the annual amount and the seasonal distribution of snowfalls primary drives the glacier-wide mass balance of Mera Glacier.   
Linking detailed canopy structure and snow process model representations to explore the dynamics of snowpack properties and ground conditions
Authors: Mazzotti Giulia , Nousu Jari-Pekka , Jonas Tobias , Lafaysse Matthieu
Published: February 2023

A large portion of boreal and alpine forests of the Northern Hemisphere hosts seasonal snowpacks over multiple months of the year. Rising temperatures and forest disturbances are causing rapid change to these environments; therefore, accurate prediction of forest snow is relevant for a variety of disciplines such as biogeochemistry, ecohydrology, cryospheric, and climate sciences. Research in each of these fields relies on process-based models that are usually discipline-specific, e.g., snow hydrology and land surface models. These models are intended for a broad range of spatiotemporal scales and consequently include canopy and snowpack process representations of varying complexity. Detailed snow physics models that resolve the microstructure of individual snow layers, motivated by avalanche forecasting and snow remote sensing, have existed for years. More recent advances in forest snow process representation and increasing availability of high-resolution canopy structure datasets have led to the development of snow-hydrology models capable of resolving tree-scale processes.Here, we introduce a new model system that combines concepts from two such sophisticated models: the snowpack representation from Crocus, and the canopy representation from the Flexible Snow Model. We present multi-year simulations at 2-m resolution across sub-alpine and boreal forest landscapes. Spatially explicit simulations allow us to assess the spatio-temporal dynamics of snow properties, ground conditions and land surface states, and to unravel their distinct dependencies on canopy structure heterogeneities at a previously unfeasible level of detail. This work aims to inform and further promote the use of process-based modelling tools in interdisciplinary ecosystem research at the interface between snow and ecosystem science, and in support of environmental change impact studies, management practices and mitigation/adaptation strategies.
Montreal Protocol's impact on the ozone layer and climate
Authors: Sedlacek Jan , Egorova Tania , Sukhodolov Timofei , Karagodin-Doyennel Arseniy , Zilker Franziska , Rozanov Eugene
Published: February 2023

It is now recognized and confirmed that the ozone layer shields the biosphere from dangerous solar UV radiation and is also important for the global atmosphere and climate. The observed massive ozone depletion forced the introduction of limitations on the production of halogen-containing ozone-depleting substances (hODS) by the Montreal Protocol and its Amendments and adjustments (MPA). Further research was aimed at analyzing the role played by the Montreal Protocol to increase public awareness of its necessity. In this study, we evaluate the benefits of the Montreal Protocol on climate and ozone evolution using the Earth system model (ESM) SOCOLv4.0 which includes dynamic ocean, sea ice, interactive ozone, and stratospheric aerosol modules. Here, we analyze the results of the numerical experiments performed with and without limitations on the ozone-depleting substances emissions. In the experiments, we have used CMIP6 SSP2-4.5 and SSP5-8.5 scenarios for future forcing behavior. We confirm previous results regarding catastrophic ozone layer depletion in the case without MPA limitations. The climate effects of MPA consist of additional global mean warming by up to 2.5 K in 2100 caused by the direct radiative effect of the hODS. We also obtained dramatic changes in several essential climate variables such as regional surface air temperature, sea-ice cover, and precipitation fields. The warming rate without the MPA under the SSP2-4.5 scenario is comparable to the warming rate of the SSP5-8.5 scenario with MPA. Our research updates and complements previous modeling studies on the quantifying of MPA benefits for the terrestrial atmosphere and climate.
Hydrological and thermal signatures to characterize groundwater influence and improve a spatialized regional hydrological model
Authors: Rouchy Léo , Branger Flora , Hévin Guillaume , Moatar Florentina
Published: February 2023

Groundwater flow and stream-aquifer interactions are the most fundamental processes that control the physical and biological characteristics of entire hydrographic networks during low-flow periods. Our study focuses on these complex flows represented in a physically based, regional, and fully distributed hydrological model. We use the J2000 hydrological model, applied to the case study of the Saône river in France. This 30,000 km² watershed has a contrasted lithology, with karstic sectors, which makes it possible to study the performance of the model according to the karstification of its sub-watersheds. It is also a heavily monitored watershed with daily flow measures at 227 hydrological stations evenly distributed over the study area and 587 hourly temperature measurement stations.J2000 model performance is estimated by calculating widely used hydrological signatures such as BFI (Base Flow Index), IGF (Interbasin Groundwater Flow), or FDC (Flow Duration Curve) characteristics. This set of signatures evaluates the performance of the model with respect to the representation of groundwater flows. In addition, we calculate thermal signatures derived from the relationship between air and water temperature (damping factor, time lag, slope). They are not used as a performance criterion but they give some more information about the spatial distribution of thermal regime and the type of groundwater contribution. The analysis of observed and simulated hydrological signatures, and observed thermal signatures, revealed various hydrological and thermal responses (e.g. shallow and deep groundwater signature), depending of the lithology of the sub-basin. In our future work, we will couple the J2000 model with the process-based thermal model T-NET (Thermal NETwork). The work presented aims to increase the performance of the thermal regime determination, which has shown significant sensitivity to groundwater contributions.
Detection of suspended macroplastics in the field using acoustic backscatter
Authors: Boon Anouk , van Emmerik Tim , Vermeulen Bart
Published: February 2023

Suspended plastic transport is one of the big unknowns in present plastic research. It is either neglected or measured using expensive and labour-intensive underwater net-measurements. In search for additional measurement methods, the Acoustic Doppler Current Profiler (ADCP) has recently been explored as a tool for detecting plastic debris. ADCPs emit a high-frequency acoustic signal, which is scattered back to the transducer by particles in the water column. The frequency shift and the strength of the returned signal (backscatter) are used for respectively flow velocity and suspended sediment concentration estimates. Large objects like fish and organic material can be recognised in the acoustic signal by a strong local increase in backscatter. It has been shown that ADCPs can also detect plastic debris during controlled tests. The characteristics of the acoustic signal of plastics in an uncontrolled setup under varying conditions is still understudied.To develop knowledge on in situ plastic detection, we first deployed an ADCP in a small flowing system into which we introduced plastic litter varying in size, composition and shape. Secondly, a test was undertaken with a simultaneous ADCP and net measurement in a large Dutch river. The uncontrolled plastic transport of the river is estimated based on ADCP data, and calibrated and validated using the net measurement. The tests gave novel insight into the signature of flowing plastics in the backscatter signal, and the present possibilities and challenges of in situ plastic detection using ADCPs. Overall, plastic detection using ADCPs has the potential to provide valuable information about the spatial and temporal variability of suspended macroplastic transport in rivers, aiding efforts to mitigate the negative impacts of plastic pollution. More research is needed to create a complete overview of backscatter characteristics of litter and to develop effective automated algorithms and methods for accurately distinguishing plastic.
UAV-based monitoring of sedimentary processes at a large-scale revitalisation of an alpine river – concept and outlook
Authors: Zöschg Hannes , Bacher Tobias , Boschi Max , Fey Christine , Schöber Johannes , Reindl Robert , Schletterer Martin , Aufleger Markus
Published: February 2023

In the 19th and 20th centuries, numerous alpine rivers were modified into straightened and monotonous channels by river regulations, which had significant negative effects on the ecology of the river systems and their floodplains. River revitalisations aim to restore river sections in order to create stepping stones in anthropogenic altered rivers. A large-scale example are the measures along the alpine Inn River between Stams and Rietz in Tyrol (Austria) over a length of about 3 river kilometres, which are implemented within the extension project of the hydropower plant Sellrain-Silz. During two low-water periods (October - April), starting in 2021, the existing bank protections were removed to a large extent, the river bed was widened up to 75 meters and a back water zone as well as a branch were created. As a result, the river stretch can develop by its own dynamics and ecologically valuable areas such as shallow water zones as well as gravel and sand banks are supposed to be formed.In order to assess the morphodynamics and ecological functionality of these measures, while also maintaining flood protection, a comprehensive monitoring program is being conducted. This includes nine photogrammetric surveys using an unmanned aerial vehicle (UAV) between March and October 2022. The UAV data were used to generate ortho-images and digital elevation models. The accuracy was assessed by comparison with airborne LiDAR data from one flight in March 2022. The objective is to quantify the erosion and deposition processes in the area of the measures and to determine the sedimentological processes that occurred during the survey period using the UAV results and hydro-morphological data (e.g., hydrograph, suspended sediment concentration) from nearby gauging stations on the Inn River. In addition, the suitability of high-resolution data from UAV surveys for monitoring sediment and bedload dynamics in alpine rivers will be evaluated. First results show that deposition processes dominated in the area of the measures, while relatively low discharge values were recorded throughout the study period. Based on the data analysis, we elaborate a suggestion for further monitoring in addition to the cross-section surveys already conducted since 1980, i.e., one UAV flight per year at low-flow conditions in order to establish a long term monitoring of morphodynamics.
Lend Me Your Ears: Space Weather Citizen Science Through Harnessing Sonification
Authors: Archer Martin , Hartinger Michael , Cottingham Marek , Shi Xueling , Vidugiris Evaldas , Holland Anne , Harold James , Masongsong Emmanuel , Hill Duke , Fox Michael , Coyle Shane , Alexander Robert , Pacini Alessandra , Candey Robert
Published: February 2023

The changing conditions in near-Earth space cause space weather. This poses a risk to our everyday lives through the technology we rely upon through impacts on crucial power, communications, navigation, and transport systems. Analogues of sound in the space plasmas around our planet, known as Ultra Low Frequency (ULF) waves, are one means by which energy is circulated from the solar wind to the radiation belt, auroral, and ionospheric regions. Time-series data of ULF waves is often analysed visually, however, such data lends itself more naturally to our sense of sound. Guided by experts in audio, citizen science, and public engagement, we have developed sonification tools that render ULF waves audible. Alongside this, a graphical user interface has been developed, enabling citizen scientists to highlight signals within this audible data that standard methods can struggle to identify. These efforts are part of a NASA-funded pilot project called HARP (Heliophysics Audified Resonances in Plasmas), where high-school students and members of the public contribute to space weather science through listening. We provide an overview of how we carefully developed and tested this citizen science project before launching it publicly.
Volcano hazard monitoring at Mount Etna: the 2022 case study
Authors: Cappello Annalisa , Bilotta Giuseppe , Ganci Gaetana , Zuccarello Francesco
Published: February 2023

Combining field measurements, satellite estimates and numerical modeling provide great advantages for the continuous monitoring of effusive eruptions. Here we demonstrate the potential of a new integrated monitoring system called HOTFLOW developed for Etna volcano, which is based on the CL-HOTSAT thermal monitoring system for the processing of satellite imagery and GPUFLOW model for the simulation of lava flows. The potential of HOTFLOW is demonstrated here using the ongoing eruption of Mount Etna started on November 27, 2022. We provide insights into lava flow field evolution by supplying detailed views of flow field construction (e.g., the opening of ephemeral vents) that are useful for more accurate and reliable forecasts of the eruptive activity. Moreover, we give a detailed chronology of the lava flow activity based on field observations and satellite images (i.e. SEVIRI, MODIS, Landsat 8/9, Sentinel-2, Planetscope, Skysat), assess the potential extent of impacted areas, map the evolution of lava flow field, and provide lava flow hazard projections. 
Wave Power in Lanzarote: Spatiotemporal Variability, Wind Co-location and Non-Physics based Modelling
Authors: Christie David , Neill Simon , Arnold Peter
Published: February 2023

The Canary Islands in the eastern North Atlantic has an abundant and diverse renewable energy resource but currently generates much of its electricity from imported diesel, at significant financial and environmental cost.  To address this, the government and electricity supplier are investing heavily in infrastructure to transform the islands’ energy mix to incorporate offshore wind and wave power. 
Economically and technically feasible offshore wave energy projects rely on understanding the regional distribution of wave properties (e.g. to optimize site selection), and how the wave power varies at inter- and intra-annual timescales.  We have constructed an 11-year wave hindcast model for a potential wave energy site at an energetic location in the north-west coast of Lanzarote, one of the largest of the Canary Islands, to investigate the spatial and temporal distribution of wave power. 
Due to a lack of a continental shelf, wave power is homogeneous until a few km from the coastline, and then begins to vary rapidly in space.  Temporal variation is relatively low due to the latitude.  The wave resource is heavily dominated by swell, with uninterrupted fetch across the Atlantic, and largely uncorrelated with local wind.  This makes co-location of wind and wave energy arrays particularly attractive from the perspective of reducing resource variability, as well as the other practical and financial benefits of sharing a grid location with more established offshore wind technology.
Finally, we demonstrate and validate a simple non-physics based process for extending the output timeseries beyond the hindcast duration, by correlating with parameters from global datasets.  This method also allows the possibility of power forecasting based on global operational models.
First results of RACMO2.4: A new model version with updated surface and atmospheric processes
Authors: van Dalum Christiaan , van de Berg Willem Jan
Published: February 2023

In recent years, considerable progress in surface and atmospheric physics parameterizations has been made by the scientific community that could benefit regional climate modelling of polar regions. Therefore, we developed a major update to the Regional Atmospheric Climate Model, referred to as RACMO2.4, that includes several new and updated parameterizations. Most importantly, the surface and atmospheric processes from the European Center for Medium-Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS), which are embedded in RACMO, are updated to cycle 47r1. This includes, among other changes, updates in the cloud, aerosol and radiation scheme, a new lake model, and a new multilayer snow module for non-glaciated regions. Furthermore, a new spectral albedo and radiative transfer scheme in snow scheme, which has been introduced and evaluated in a previous, yet inoperative version, is now operational. Here, we shortly introduce the aforementioned changes and present the first results of RACMO2.4 for several domains, particularly of the Greenland ice sheet.
Social production of ignorance – the role for geoscientists in addressing “undone science”
Authors: Johnson Fiona , Higgins Philippa , Andersen Martin , Howey Kirsty , Kearnes Matthew , Khan Stuart , Leslie Greg
Published: February 2023

In this presentation we discuss the role of geoscientists and engineers in advocating for improved civic science that can minimise the impacts of industrial and mining activities on the environment and downstream communities, with a particular focus on water-related impacts. We argue that, if not carefully designed, data collection, analyses and communication by geoscientists does not always contribute to the wider public good because the issues that communities care about are not addressed – so called “undone science”. A case study, focusing on the environmental impacts of the McArthur River mine (MRM) in a remote part of the Northern Territory, Australia, is used to highlight key issues that should inform civic science and lead to better outcomes for communities and the environment.Despite thousands of pages of “data” about the MRM project and its impacts, we argue that this project is an example of the social production of ignorance – because the knowledge of the communities most impacted by the mine’s activities is not improved by the reporting and impact assessments associated with the project. Based on a temporal synthesis of independent monitoring reports of the McArthur River Mine which covered the period from 2007 to 2018, we identify three main lessons for improving civic science. Firstly, without adequate baseline monitoring prior to development, data collection during a project cannot satisfactorily assess impacts of a development. Baseline data is particularly important when seasonal and interannual variability is high. Baseline and ongoing monitoring programs should be co-designed with the community, so that what matters to the community is monitored (e.g. culturally important sites, contamination in animal species relevant to the community). Secondly, geoscientists and engineers need to partner with social scientists and local community organisations to ensure that communities are effectively informed about the impacts of development, focusing on the impacts that matter to communities, not just the impacts that are conveniently measured. Finally regulatory processes need to be improved to ensure that problems identified by geoscientists and engineers are addressed.
Estimation of the spectral diffuse attenuation coefficient Kd(λ) from UV to NIR using ocean color images: Application from SeaWiFS to PACE
Authors: jamet Cedric , Jorge Schaeffer Daniel , Loisel Hubert
Published: February 2023

The fine-scale study of the diffuse attenuation coefficient, Kd(l), of the spectral solar downward irradiance  is only feasible by ocean color remote sensing. Several empirical and semi-analytical methods exist. However, most of these models are generally applicable for clear open ocean waters. They show limitations when applied to coastal waters. A new empirical method based on neural networks has been developed using a relationship between the remote-sensing reflectances between 443 and 670 nm and Kd(λ). The architecture of the neural network has been defined using synthetical and in situ dataset. The model has been developed for SeaWiFS, MODIS-AQUA, MERIS, VIIRS, OLCI and PACE space-borne sensors. Validation using in-situ measurements from a wide range of type of waters (from oligotrophic to very turbid waters) shows similar retrievals accuracies for low values of Kd(490)  (i.e. <0.20 m-1) and better estimates for greater values of and Kd(490). The new model is compared to empirical and semi-empirical methods and is suitable for open water but also for turbid waters.
Incorporating nonstructural carbohydrate dynamics in the ISBA biomass allocation scheme
Authors: De Pue Jan , Barrios José Miguel , Arboleda Alirio , Hamdi Rafiq , Balzarolo Manuela , Maignan Fabienne , Delire Christine , Janssens Ivan , Gellens-Meulenberghs Françoise
Published: February 2023

Within land surface models (LSM), the biomass allocation scheme (BAS) allows to simulate the dynamics of vegetation growth in response to climatic variation and other drivers. It distributes the assimilated carbon across different biomass pools, and consequently determines the spatio-temporal variability of the leaf area index (LAI).In many LSM, large uncertainties are associated with the BAS, which propagate via the prognostic LAI to the surface fluxes. Here, we propose a revision to the BAS of the ISBA land surface model, by incorporating the dynamics of non-structural carbohydrates (NSC) explicitly. The target of the proposed BAS is the reproduction of LAI as observed with remote sensing, coupled to the modelled surface fluxes. Using in situ eddy covariance observations of the carbon fluxes, and remote sensing observations of the leaf biomass, estimates can be made of the biomass allocation and NSC dynamics. By combining this dataset with other (climatological) variables, a machine-learning based BAS is developed.The simulated evolution of the biomass pools is evaluated using in situ observations of leaf turnover and remote sensing observations of leaf biomass. The proposed model is compared to the standard photosynthesis-driven BAS of ISBA and the more advanced BAS in ORCHIDEE.
Challenging our knowledge on flood frequency
Authors: Kauzlaric Martina , Martius Olivia , Simon Schick , Andreas Paul Zischg
Published: February 2023

In recent times water-related hazards have captured public attention and led to an increased interest in developing hydrologic forecasting systems, and quantifying their reliability. Despite major investments in flood forecasting and flood protection measures undertaken after recurring widespread inundations (e.g. 2002 and 2013 in Eastern Europe), heavy rainfall events led to severe flooding in Western Europe during July of the past summer, resulting in severe impacts and massive losses, including over two hundred deaths. Extreme precipitation, breaking observed records, is expected to have an increased likelihood under global warming, all the more we should question and scrutinize our knowledge about the frequency and severity of floods. Reliable estimates of these, and a better quantification of their uncertainty are key information for improving our preparedness and developing adaption measures in the future.For this purpose we explore the potential of running pooled weather reforecasts through the flexible hydrological model framework DECIPHeR (Coxon et al.2019) in Switzerland, modified to include snow, glaciers and the effect of lakes and reservoirs on the river network. For three case studies of different climatic regions (one including regulated lakes), we compare floods generated by the 10 largest precipitation events and precipitation events of low frequency (return period >= 100 years), both extracted from the pooled data, for three accumulation periods (1, 3, 5 days) with the official flood frequency curves and flood frequency curves generated with long continuous simulation using the pooled data (> 1000 years). This analysis will show us possible deficiencies of record-based flood frequency curves, if running selected precipitation events according to a return period already gives us a representative “flood sample”, and what is the gain of running long continuous simulations (e.g. are there overlooked events, summoning hydrological extremes through particular spatio-temporal patterns? What is the effect of different initial conditions?).Coxon G., Freer J., Lane R., Dunne T., Knoben W.J.M., Howden N.J.K., Quinn N., Wagener T. and Woods R. : DECIPHeR v1: Dynamic fluxEs and ConnectIvity for Predictions of HydRology. Geosci Model Dev.,12,2285-2306, https://doi.org/10.5194/gmd-12-2285-2019, 2019.
A modular Pan-European Flood Catastrophe model
Authors: Sampson Christopher , Winsemius Hessel , Wing Oliver , Meynadier Remi , Rakotoarimanga Hugo , Hegnauer Mark , Boisgontier Hélène , Smith Andy
Published: February 2023

The flood event “Berndt” in North-Western Europe in July 2021 demonstrated to stakeholders the critical importance of understanding present-day events, their spatial-temporal coherence and magnitude, and the probability of their occurrence. The shear size of multi-country events such as “Berndt” necessitate a large scale and highly automated approach to the modelling of their characteristics.To this end, we (AXA, Fathom and Deltares) developed a modelling framework that can efficiently compute very large event sets and worked on improving its underlying skill by making the framework highly modular. The framework consists of the following modules: a synthetic weather generator, which may sample many thousands of years of continuous weather data at daily and sub-daily time scales; a gridded hydrological model forced by the synthetic weather that produces long-term hydrological timeseries and derived statistics, and a subcatchment-scale fluvial and pluvial flood model archive, produced from large amounts of simulations with the Fathom hydraulic flood model engine. Its modular character allows for exchanging components, improving existing components or modifying parameters to assess sensitivities or uncertainties.In last year’s contribution, we presented our first synthetic simulations of weather and hydrology. In this year’s contribution we have improved stochastic weather generation and have established a full 10,000-year event set and flood catalogue, both under the present climate and a future climate projection that encompasses several assumptions. We will show the statistics and spatial configuration of past events according to our catalogue, including “Berndt 2021”, and how the statistics of extreme events will change according to the defined climate scenario simulation.
Storylines of Southern Hemisphere climate change from CMIP6: Antarctica and the Southern Ocean
Authors: Williams Ryan , Marshall Gareth , Levine Xavier , Graff Lise , Mooney Priscilla
Published: February 2023

The manifestation of regional changes in climate at high latitudes is notoriously uncertain according to climate models, aside from the expected polar amplification of the global warming trend. This poses a particular issue for policymakers in designing targeted adaptation and mitigation strategies, in limiting the impact of human-induced climate change. The leading mode of uncertainty arises from the unknown response of the atmospheric circulation to global warming, resulting from inconsistencies in the model representation of key physical processes, which are typically parameterised as they operate on sub-grid spatial scales. Using the latest suite of state-of-the-art climate models as part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6), a storyline approach is adopted to derive physically plausible scenarios of climate change over Antarctica and adjacent regions of the Southern Ocean for the end-of-the-century (2070-2099), according to both emission scenarios SSP3-7.0 and SSP5-8.5. We identify two robust features of climate change simulated across all models known to lead to a strengthening and poleward displacement of the eddy-driven mid-latitude jet: (1) the decline in Southern Hemisphere sea ice extent and (2) the strengthening of the wintertime stratospheric polar vortex and delayed summertime breakdown. Whilst the response of these two aspects is consistent in sign, a large intermodel spread exists in terms of magnitude. Using a multi-linear regression framework, we generate storylines of climate change conditional upon the magnitude of change in each driver centred around the multi-model mean response. We examine the response of both the near-surface climate (Southern Annular Mode, air temperature, precipitation) and Southern Ocean (SSTs, salinity and mixed layer depth) for both an extended austral summer (DJFM) and winter season (JJA). Through ancillary evaluations of model historical performance with respect to ERA-5 reanalysis over the 1985-2014 period, including investigation of both prognostic and diagnostic variables, the presented storylines are refined to help minimise the impact of model deficiencies in affecting the realism of the generated storylines. Our results highlight the merit of using the storyline approach to identify future potential scenarios of regional climate response and constrain uncertainty in Antarctic climate predictions. Storyline impact assessments for the Southern Ocean marine ecosystem, particularly the ecologically sensitive South Scotia Sea region, will later be investigated within the EU Horizon 2020 ‘PolarRES’ project through storyline-guided downscaling experiments using regional climate models.  
Freezing-Thawing Cycles of Saturated Sand Sample
Authors: Sobotkova Martina , Zak Alexandr , Snehota Michal , Benes Michal
Published: February 2023

Freezing and thawing cycles in laboratory were studied. Freezing-thawing cycles were carried out in the laboratory on fully saturated packed sand sample (15 cm in diameter and 20 cm in height). Series of freezing-thawing cycles were conducted with newly designed experimental setup. The setup consisted of inner plastic tube covered on its sides and outer plastic tube. The column sample was placed into the precisely controlled freezer chamber. The top of the sample was covered by an aluminum lid. Initially the sample was equilibrated at +10 °C then the temperature inside the chamber was changed to -10 °C. The inner temperature of the sample was monitored in three depths by thin temperature sensors (109 SS, Campbell Scientific, USA) horizontally inserted into the sample. The experiment aims to provide information on freezing dynamics and thermo-mechanical changes during the freezing and thawing cycles. Horizontal gradient within freezing cycle was monitored. The data were compared with simulations obtained by a numerical model (Žák et al., 2013). The model is based on the heat balance within the sample assembly and a modified heat equation for the porous medium temperature allowing for the phase transition below the freezing point depression. 
Breaking down the overturning circulation to local mixing
Authors: Klingbeil Knut , Henell Erika , Gräwe Ulf , Burchard Hans
Published: February 2023

I will present an analytical relation that directly shows how mixing locally drives the overturning circulation. The theory is based on the application of the well-known Water Mass Transformation framework to each local water column. The budgets for volume and tracer content mapped to tracer space are supplemented by a budget for the squared tracer. Mixing is defined by the destruction term of squared tracer, which is equivalent to the decay of tracer variance. I will present maps of the simulated diahaline mixing and the associated diahaline exchange velocity in the Baltic Sea. In addition, our numerical model offers to separately diagnose the mixing due to turbulence parameterizations and the spurious mixing due to discrete transport schemes. This enables us to also quantify the amount of spuriously induced overturning circulation. The planned application to diapycnal exchange and the global overturing circulation will be outlined.
Pavements Layered Media Characterizations using deep learning-based GPR full-wave inversion
Authors: Zeng Li , Zhou Biao , Xie Xiongyao , Lambot Sébastien
Published: February 2023

The possibility to estimate accurately the subsurface electric properties of the pavements from ground-penetrating radar (GPR) signals using inverse modeling is obstructed by the appropriateness of the forward model describing the GPR subsurface system. In this presentation, we improved the recently developed approach of Lambot et al. whose success relies on a stepped-frequency continuous-wave (SFCW) radar combined with an off-ground monostatic transverse electromagnetic horn antenna. The deep-learning based method were adopted to train an intelligent model including the waveform of the Green’s functions. The method was applied and validated in laboratory conditions on a tank filled with a two-layered sand subject to different water contents. Results showed agreement between the predictions of measured Green’s functions deep-learning model and the measured ones. Model inversions for the dielectric permittivity and heights of antenna further demonstrated for a comparison of presented method.