bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of isolated noise sources on correlation wavefields
Authors: Schippkus Sven , Snieder Roel , Safarkhani Mahsa , Hadziioannou Céline
Published: February 2023

Seismic interferometry gives rise to a correlation wavefield that is closely related to the Green’s function under the condition of uniformly distributed noise sources. Asymmetric correlation wavefields result from the violation of this condition and are commonly observed in field data. In the presence of an additional isolated noise source a second contribution to the correlation wavefield is introduced that emerges from the isolated source location at negative lapse time. The two wavefield contributions interfere, resulting in biased surface wave dispersion measurements. Isolated noise sources that act continuously, such as machinery or ocean microseisms, further have significant impact on the coda of the correlation wavefield. The coda can be dominated by direct waves propagating from the isolated noise source, not by multiply scattered waves originating from the master station. This fundamentally challenges the current understanding of how velocity changes detected in the coda can be measured and interpreted.
Does net-zero CO2 stabilize the climate? - On the contributions of the remaining climate forcing
Authors: Monteiro Estela , Mengis Nadine
Published: February 2023

The Paris Agreement long-term temperature goal (Paris Agreement LTTG) aims to limit global warming to well below 2ºC, if possible to a maximum of 1.5ºC. To understand how this goal could be accomplished, idealized scenarios have been explored in the past years, with a special focus on pathways for reaching net-zero CO2 emissions. Non-CO2 forcing is, however, known to contribute to a decrease in the remaining carbon budgets related to the Paris Agreement LTTG (e.g., Mengis & Matthews, 2020). A full picture regarding this benchmark can therefore only be painted when including the effects of aerosols, non-CO2 greenhouse gases and land use changes. These forcings along with the zero emissions commitment to CO2 will define whether temperature is able to stabilize once CO2 emissions decrease.  To explore individual effects from anthropogenic non-CO2 forcing agents, their respective contributions to the Paris Agreement LTTG scenarios (Rogelj, et al., 2019) is estimated and put into relation. We will present results primarily on the impacts of aerosols and land use change representation as well as their effects on the carbon cycle and climate by simulating LTTG scenarios using an Earth system model of intermediate complexity (UVic ESCM, version 2.10, Mengis et al., 2020). The climate response in these all forcing net-zero CO2 emission scenarios will provide us with relevant insights concerning allowable emissions for temperature stabilization.References: Mengis, N., Matthews, H.D. Non-CO2 forcing changes will likely decrease the remaining carbon budget for 1.5 °C. npj Clim Atmos Sci 3, 19 (2020). https://doi.org/10.1038/s41612-020-0123-3Mengis, N., Keller, D. P., MacDougall, A. H. et al. Evaluation of the University of Victoria Earth System Climate Model version 2.10 (UVic ESCM 2.10). Geosci. Model Dev. 13, 4183–4204 (2020). https://doi.org/10.5194/gmd-13-4183-2020  Rogelj, J., Huppmann, D., Krey, V. et al. A new scenario logic for the Paris Agreement long-term temperature goal. Nature 573, 357–363 (2019). https://doi.org/10.1038/s41586-019-1541-4
Downward counterfactual analysis of historical rainfall events in Germany
Authors: Voit Paul , Heistermann Maik
Published: February 2023

In the last 20 years a variety of heavy precipitation events (HPEs) have caused severe floods and large damages in Germany. However, the impact of an HPE is not solely determined by the event itself, but also by the geomorphologic characteristics of the location where it occurs.Previous studies have shown that HPEs can happen anywhere in Germany. To find out where in Germany historical HPEs could have caused a potential hazard, we extracted the 10 most extreme HPEs by using the cross-scale weather extremity index (xWEI) from the last 20 years of radar data (RADKLIM) and shifted these events to every mesoscale subbasin in Germany.We use the geomorphological instantaneous unit hydrograph as a simple screening tool to investigate the runoff concentration at the mesoscale and the following flood wave propagation in these subbasins as response to historical HPEs. While this method might not be sufficient to model precise discharge, it can be used to spot rapid increase in direct runoff and shed light on the peak development further downstream, depending on the spatiotemporal characteristics of the HPE. By using historical HPEs as benchmarks, our method can help to identify areas in Germany which are prone to flood hazard and assist to adjust mitigation measures accordingly.
An ozone mini-hole associated with the record-breaking Australian bushfires 2019-2020: satellite observations and the modelled impact on surface ultraviolet radiation
Authors: Belhadji Redha , Sellitto Pasquale , Eremenko Maxim , Bucci Silvia , Minh Nguyet , Dufour Gaëlle , Legras Bernard
Published: February 2023

The Australian record-breaking bushfires around the turn of the year 2020 generated an unprecedented perturbation of thestratospheric composition through the injection of biomass burning material at relatively high altitudes in the upper-troposphere—lower-stratosphere. Associated with this event, a highly-stable smoke-charged anticyclonic vortex, with horizontal extent as large as about 1000 km, was observed. Due to the solar radiation absorption in this vortex, this structure was observed to rise from the initial ~15 km altitude to altitudes higher than ~35 km [Khaykin et al 2020]. This structure persisted in the stratosphere for about 3 months.Here we present a detailed analysis of the vertically-resolved ozone fields based on the Infrared Atmospheric Sounding Interferometer (IASI) observations, supported by total column observations at relatively high horizontal resolution with Sentinel 5p TROPOMI (TROPospheric Ozone Monitoring Instrument), associated with the smoke-charged vortex due to the Australian bushfires. A marked ozone mini-hole is found, horizontally and vertically co-located with this smoke structure. The dynamical and/or chemical origin of this ozone mini-hole is briefly discussed. Then, ozone profile information is fed to the LibRadtran/UVSPEC radiative transfer model to estimate the impact of this ozone reduction on surface ultraviolet radiation and the results are critically discussed in terms of the possible impacts on the biosphereRef : Khaykin, S., Legras, B., Bucci, S., Sellitto P., Isaksen, L., Tencé, F., Bekki, S., Bourassa, A., Rieger, L., Zawada, D., Jumelet, J., and Godin-Beekmann, S.: The 2019/20 Aus- tralian wildfires generated a persistent smoke-charged vortex rising up to 35km altitude, Commun. Earth Environ. 1, 22, https://doi.org/10.1038/s43247-020-00022-5, 2020.
Active segments along the North Anatolian Fault system in the Sea of Marmara
Authors: Gasperini Luca , Polonia Alina
Published: February 2023

High-resolution multibeam and seismic reflection data collected during several oceanographic expeditions allowed us to compile an updated morphotectonic map of the North Anatolian Fault below the Sea of Marmara. We reconstructed kinematics and geometries of active fault segments at 10 ka time-scale, an interval that includes several earthquake cycles, taking the base of the latest marine transgression as a stratigraphic marker. Given the high deformation rates relative to sediment supply, most active tectonic structures have a morphological expression at the seafloor, even in the presence of composite fault geometries and/or overprinting due to mass-wasting or turbidite deposits. In the frame of the right-lateral strike-slip domain characterizing the North Anatolian fault system, three types of deformation are observed: almost pure strike-slip faults, mainly oriented E-W; NE/SW-aligned axes of transpressive structures; NW/SE-oriented trans-tensional depressions. Fault segmentation occurs at different scales, but main segments develop along three major right-lateral oversteps, which delimit main fault branches, from east to west: i) the transtensive Cinarcik segment; ii) the Central (East and West) segments; iii) the westernmost Tekirdag segment. We performed a quantitative morphometric analysis of the shallow deformation patterns observed by seafloor morphology maps and high-resolution seismic reflection profiles along the entire basin, to determine the nature and cumulative lengths of individual fault segments. These data were used as inputs for empirical relationships, to estimate maximum expected Moment Magnitudes, obtaining values in the range of 6.8 to 7.4 for the Central, and 6.8 to 7.1 for the Cinarcik and Tekirdag segments, respectively. We discuss such findings considering analyses of inherited geological structures, historical catalogs, and available paleoseismological studies for the Sea of ​​Marmara region, to formulate reliable seismic hazard scenarios. 
Controls on benthic alkalinity fluxes from natural and enhanced silicate weathering in coastal and shelf sediments: new diagenetic model insights
Authors: Freitas Felipe S. , van de Velde Sebastiaan , Hendry Katharine R. , Meysman Filip , Arndt Sandra
Published: February 2023

On geological timescales, continental silicate weathering plays a crucial role regulating Earth’s climate. Accelerating this slow thermostat might be the key to help mitigate present-day global warming and ocean acidification through increased alkalinity generation produced by enhanced marine silicate weathering. Laboratory studies show that benthic dissolution of olivine minerals can stimulate oceanic CO2 uptake by increasing seafloor alkalinity release. Although enhanced benthic silicate weathering is an attractive solution to both CO2 problems, until now its efficiency remains unclear. This is because the intrinsic dissolution rate of silicates in the seafloor remains poorly constrained, while also the impact of secondary reactions such as carbonate precipitation and reverse silicate weathering (authigenic clay formation) remains poorly quantified. Thus, we first need to develop a detailed understanding of natural benthic silicate dissolution and the feedbacks on carbon and silicon cycles.Here, we couple two well-tested diagenetic model set-ups that resolve benthic carbon, redox and pH dynamics (organic matter degradation, re-oxidation of reduced species, equilibria reactions, carbonate dissolution and precipitation) and benthic silicon dynamics (biogenic silica dissolution, and authigenic silica precipitation) in the uppermost sediments. We use this new framework to resolve natural basalt and/or olivine weathering by explicitly accounting for the dissolution of key basalt constituents (basaltic glass, plagioclase, pyroxene, and olivine). We also account for reverse weathering through illite authigenic formation. The newly coupled model captures the observed shifts in porewater pH and carbonate system, and the dynamics of benthic alkalinity production and consumption associated with marine silicate weathering. We assess the impact of benthic redox state and basalt compositions on benthic alkalinity fluxes by performing an extensive sensitive study over the entire plausible parameter and bottom water forcing space. We find complex links between rates of benthic silicate weathering and net alkalinity production. Ultimately, we will apply the new model framework to explore the geological context of Iceland. As such, we will fully constrain natural rates of benthic silicate weathering associated to the substantial inputs of natural basalts to coastal and shelf sediments.
Earthquake Early Warning: observe, analyse, deduce and act in seconds
Authors: Pirenne Benoît
Published: February 2023

Over the past 7 years, Ocean Networks Canada has established an earthquake early warning system to alert key urban areas in southwestern British Columbia of the onset of a (potentially major) earthquake developing in the Cascadia subduction zone, a mere 200-300 km away. With a new dedicated observing network comprised of about 35 new sites covering a detection area of about 200,000 km2, this digital twin is observing a critical section of the earth system with underwater and land-based accelerometers, and GNSS receivers. The novel architecture and software system allow for a rapid analysis of minimal latency data, for sending notifications and for allowing recipients such as critical infrastructure operators to react in mere seconds to minimize the impact on life and property. This contribution will describe the system, its architecture, the results of its commissioning and use cases from its subscribers. 
Wave field prediction for denoising of seismic measurements using an autoencoder network
Authors: Klinge Jana , Gajewski Dirk , Hadziioannou Celine , Walda Jan
Published: February 2023

The adoption of machine learning in different sectors demonstrates a huge potential of multiple techniques applicable to learn specific features of a dataset. We aim to make use of machine learning methods to predict the development of seismic wave fields between two seismic stations and use this information to remove random noise post-measurement, considering the phase and time information of the signal. Thereby, the initial approach follows the use of an autoencoder network in a self-supervised fashion. Aiming to reconstruct its input, the form of the autoencoder corresponds to the traditional U-Net structure but expands with residual blocks for increased network capacity. To refine results, we modify the interrelated training process of encoding and reconstruction and separate it into sequential phases. To make sure that the dataset includes multiple sources and thus provides various features, we use field data gathered at a seismic exploration site in an area containing several roads, wind turbines, oil pump jacks and railway traffic. Using the well-known autoencoder network structure and applying it in the context of transfer learning enables us to automatically learn a representation of the wave field and, more importantly, predict its spatial development based on different frequency bands. The gained knowledge can be used in future directions to exclude non-relevant parts of the data in the context of denoising and to compare results to currently used methods such as the Wiener optimum filters.
Circular approach for industrial water management via water balance and LCA: A poultry slaughterhouse case study
Authors: Teo Chuan Jiet , Wintgens Thomas , Poinapen Johann
Published: February 2023

Ensuring the availability and sustainable water management not only is one of the UN SDGs, but sustainable water production is also one of the main accelerating global challenges within the upcoming decades. Unless the efficiency of water use rises, this imbalance of available freshwater resources and the increasing consumption will reduce freshwater ecosystem services. Industries are one of the largest freshwater consumers. Despite the huge potential to tackle water scarcity, industrial (waste)water management is often underlooked and has become a barrier to overcome to complete the transition towards a circular economy. This means designing for resource (water) minimisation and reduced hazards (such as phosphorus and heavy metals). A decentralised wastewater treatment, in association with local organisation and governance, is increasingly recognised as one of the options to contribute towards increasing the efficiency of wastewater treatment and closing the industrial water loop by the recovery and reuse of the treated wastewater. However, the design of an industrial water treatment system is a complex problem that involves different trade-offs (i.e. use of energy vs use of chemicals). In this context, life cycle assessment (LCA) offers an opportunity to evaluate the environmental sustainability of these technologies and processes, identifying the environmental impacts of the processes in the value chain by capturing trade-offs across various categories of environmental concern.Circular water management for a slaughterhouse is especially relevant for the sustainable transition towards a circular economy. Throughout the value chain of livestock processing, the slaughterhouse is the second largest user of water, and also a potentially significant point source of pollution to local ecosystems and communities.The objective of this study is to apply LCA and water footprint analysis to evaluate the environmental impact and missed opportunity of treating industrial wastewater streams generated from a poultry slaughterhouse located in Romania. LCA will be carried out at the planning and design levels of the wastewater system to allow analysis to be done regarding alternative wastewater management strategies, considering different treatment schemes including retrofitting physical-chemical treatment and biological treatment as separate scenarios. The foreground data is based on field data collection that considers effluent qualities. The background inventories are based on the Ecoinvent database v.3. The life cycle impact assessment is applied on both the characterised and normalised levels using the Environmental Footprint (EF) method.
Geomorphica, the new diamond open access journal in the field of geomorphology
Authors: Stammler Melanie A. , Lefebvre Alice , Bosch Rachel , Fernández Roberto , Giaime Matthieu , Goodwin Guillaume
Published: February 2023

Today we introduce you to Geomorphica, the new diamond open access journal in geomorphology. Next to Volcanica, Tektonika, Seismica and Sedimentologika, it adds to the growing family of Diamond Open Access Journals in the Geosciences. What exactly is diamond open access publishing? It describes a bottom-up publishing structure that reduces barriers in accessing scientific literature because there are no journal subscription fees and no article processing charges. As such, it allows the reader to access and the author to publish the article for free. Diamond open access publishing promotes inclusivity, equal access to information and provides the newest findings to a large and diverse audience.Geomorphica has been community-built over the last year. Our structure comprises six commissions – format, website, communications, inclusivity, ethics, and editorial – and a steering committee formed of the chairs of each commission. We determined our name by poll in January and our logo by friendly competition in April. We started cooperating with the International Association of Geomorphology (IAG) in July and signed our hosting agreement with Penn State University in December 2022. At EGU 2023 we are excited to celebrate the achievements of the previous year as well as to exchange ideas on our future together. We welcome feedback, comments, ideas and a stimulating discussion from all sectors of the geoscientific community to help us continually improve the initiative. We are always looking for volunteers and we encourage everyone to start brainstorming on potential submissions to Geomorphica, as we plan to open a call for manuscript submissions in spring 2023.
A data integration system for ocean climate change research in the Northwest Pacific
Authors: Kim Sung Dae , Park Hyuk Min , Kwon Young Shin , Han Hyeon Gyeong
Published: February 2023

A data integration and processing system was established to provide long-time data and real-time data to the researcher who are interested in long-term variation of ocean data in the Northwest Pacific area. All available ocean data of 6 variables (ocean temperature, salinity, dissolved oxygen, ocean CO2, nutrients) in the NWP area (0°N - 65°N, 95°E - 175°E) are collected from the Korean domestic organizations (KIOST, NFIS, KHOA, KOEM), the international data systems (WOD, GTSPP, SeaDataNet, etc.), and the international observation networks (Argo, GOSHIP, GLODAP, etc.). Total number of data collected is over 5 millions and observation dates are from 1938 to 2022. After referring to several QC manuals and related papers, QC procedures and test criteria for 6 data items were determined and documented. Several Matlab programs complying with QC procedures were developed and used to check quality of all collected data. We excluded duplicated data from the data set and saved them in 0.25° grid data files. Long-term average over 40 years and standard deviation of data at each standard depths and grid point were calculated. All quality controlled data, qc flag, average, standard deviation of each ocean variables are saved in format of netCDF and provided to ocean climate researchers and numerical modelers. We also have 2 plans using the collected data from 2023 to 2025. The one is production of long-term grid data set focused on the NWP area, the other is developing a data service system providing observation data and reanalysis data together.Acknowledgement : This research was supported by Korea Institute of Marine Science & Technology Promotion(KIMST) funded by the Ministry of Oceans and Fisheries(KIMST-20220033)
Long-term crustal modification of large terrestrial meteorite impact structures: insights from scaled analogue experiments
Authors: Eisermann Jan Oliver , Riller Ulrich
Published: February 2023

Meteorite impact is recognized as a fundamental geological process of the solar system. Although mechanisms of large impact cratering have been studied intensely, mostly by numerical modelling, an outstanding problem concerns long-term crater modification, which operates on time scales of tens of thousands of years after impact. Localized deformation in the form of radial and concentric floor fractures (FFCs) are known from large craters on all terrestrial planets. On Earth, we can observe the occurrence of radial and concentric impact melt rock dikes in the eroded basement of large impact structures, such as Sudbury (Canada) and Vredefort (South Africa). Two mechanisms were proposed in the past to explain the formation of FFCs: the intrusion and inflation of igneous bodies below the crater floor and long-term isostatic re-equilibration of impacted target rocks. Using two-layer analogue experiments scaled to physical conditions on Earth, we explore to what extent isostatic re-equilibration of crust may account for the observed dike and fracture patterns of FFCs.The structural evolution of model upper crust was examined for a variety of initial depths and diameters of crater floors. The crater diameter-to-depth ratio was scaled according to numerical models for average continental crust. Specifically, a tank, 80cm by 80cm in size, was filled with PDMS, representing the viscous middle and lower crust and granular material, simulating the brittle upper crust. Moreover, we introduce a method, which allowed us to generate any shapes of model impact crater floors.The experiment surfaces were monitored with a 3D digital image correlation system allowing us to quantify key parameters, such as surface motion as well as the distribution and evolution of surface strain. The results of our scale models enabled us to quantify the duration, geometry and distribution of brittle deformation of upper crust. Most importantly, the analogue experiments provided, for the first time, a quantitative relationship between diameter, depth and fracture geometry of crater floors.Our results indicate that FFCs are caused by long-term uplift of the crater floor, compensated by crustal flow toward the crater center. Such radial convergent flow generated radial and concentric dilation fractures. Crater floor uplift is accompanied by long-wavelength subsidence of the crater periphery on the order of 50 minutes, amounting to some 3000 years in nature. The formation of radial versus concentric fractures depends on the ratio between crater diameter and crater depth and, hence, is controlled by isostacy and crustal strength. The geometry and distribution of fractures in analogue experiments are strikingly similar to the geometry of impact melt rock dikes at Sudbury and Vredefort.
Can Statistical Downscaling based on Machine Learning compete with Regional Climate Models? A comparison for temperature, precipitation, wind, humidity and radiation over Europe under present conditions
Authors: Hernanz Alfonso , Correa Carlos , Domínguez Marta , Rodríguez-Guisado Esteban , Rodríguez-Camino Ernesto
Published: February 2023

Two main approaches to downscale global climate projections are possible: dynamical and statistical downscaling. Both families have been widely evaluated, but intercomparison studies between the two families are scarce, and usually limited to temperature and precipitation. In this work, we present a comparison between a Statistical Downscaling Model (SDM) based on Machine Learning and six Regional Climate Models (RCMs) from EURO-CORDEX, for five variables of interest: temperature, precipitation, wind, humidity and solar radiation. The study expands at a continental scale over Europe, with a spatial resolution of 0.11o and daily data. Both the SDM and the RCMs are driven by the ERA-Interim reanalysis, and observations are taken from the gridded dataset E-OBS. Several aspects have been evaluated: daily series, mean values and extremes, spatial patterns and also temporal aspects. Additionally, in order to analyze the intervariable consistency, a multivariable index (Fire Weather Index) derived from the fundamental variables has been included. The SDM has reached better scores than the RCMs for all the evaluated aspects with only a few exceptions, mainly related to an underestimation of the variance. After bias correction, both the SDM and the six RCMs present similar results, with no significant differences among them. Results presented here, combined with the low computational expense of SDMs and the limited availability of RCMs over some CORDEX domains, should motivate the consideration of statistical downscaling at the same level as RCMs by official providers of regional information, and its inclusion in reference sites. Nonetheless, further analysis on crucial aspects such as the impact on long-term trends or the sensitivity of different methods to being driven by Global Climate Models instead of by a reanalysis, is needed.
An Integrated Coupling Framework for Atmospheric Dynamics and Physics
Authors: Zhou Linjiong , Harris Lucas
Published: February 2023

Atmospheric resolved-scale air flow (dynamics) and sub-grid parameterizations (physics) are two essential components of a weather or climate model. These two independent components are coupled and advanced using the same time step, either parallel or sequentially split. However, traditionally dynamics and physics are engineered in isolation and developed independently in models. As a result, many parts of the physics run at a physically-inappropriate time frequency or with heat transfers that are inconsistent with the dynamics, leading to errors. In addition, physical parameterizations should contain dynamical and non-dynamical processes. We believe there are compelling reasons that dynamical processes, if resolved, should be taken care of by the dynamical core.Our study proposes a novel integrated dynamics-physics coupling framework (Zhou and Harris, 2022) within the GFDL (Geophysical Fluid Dynamics Laboratory) weather-to-seasonal prediction system SHiELD (System for High-resolution prediction on Earth-to-Local Domains; Harris et al., 2020) that promises to resolve the above issues. We will present our integrated coupling framework and the development of integrated physical parameterization for this framework in detail. The performance of forecast experiments using the modeling system SHiELD with this integrated coupling framework will be highlighted, focusing on large-scale circulation, cloud and precipitation, hurricane, and convective-storm predictions.
The evidence and global extent of alternative stable states in forest leaf phenology
Authors: Zou Yibiao , Zohner Constantin , Averill Colin , Ma Haozhi , Merder Julian , Berdugo Miguel , Bialic-Murphy Lalasia , Mo Lidong , Crowther Thomas
Published: February 2023

Whether forests are composed of evergreen or deciduous species largely affects biogeochemical cycles and the functioning, structure and biodiversity of ecosystems. These leaf phenology types may be self-promoted through positive plant-soil feedbacks, which may shift the distribution of forest types towards alternative stable states. However, we still lack empirical evidence of phenological alternative stable states and a spatial understanding of where they might be present. Here, we test the presence of alternative stable states using forest inventory data at the continental (North America and Europe) and global scale. We show that the distribution of forest leaf phenology types is bimodal, and demonstrate the presence of positive feedbacks in recruitment, growth and mortality. Data-driven simulations show that the observed positive feedbacks are sufficient and necessary to produce the alternative stable states, which also lead to hysteresis during ecosystem transition. Spatial random forest models further reveal hotspots of alternative stable states in evergreen-deciduous ecotones and the poleward range limit of forests, which appear largely driven by soil feedbacks. Given the close connection between forest leaf phenology and ecosystem biogeochemical processes, our insights on evergreen vs. deciduous alternative stable states inform our understanding of the distribution of forest biomes, allowing more accurate quantification of carbon turnover and terrestrial climate feedbacks.
RESCUE a new physically-based large scale flood model
Authors: Pavesi Luciano , Volpi Elena , Fiori Aldo
Published: February 2023

Flood mapping is an essential step in flood risk assessment to reduce losses. Through flood mapping, we can detect vulnerable areas, assess flood impacts and create mitigation plans.From the literature, we have two consolidated approaches to delineating flood maps. The first one is the hydrologic-hydraulic approach. Its strength relies on the possibility of simulating scenarios for different probabilities of occurrence (return period scenarios), considering the physics of the phenomenon. At the same time, the weaknesses of this approach regard the required amount of input data and high computational costs. The second approach is the geomorphological one, which allows to delineate flood-prone areas directly from some topographic features derived from a Digital Terrain Model (DTM), i.e. elevation, distance to the channel, etc.. Thanks to the limited request of input data and its rapidity in terms of computational efficiency, this approach is particularly appealing for large scale analyses. However, the geomorphological approach does not allow for the delineation of flood maps for different return period scenarios; further, the output is strongly linked to the quality of the input DTM.Here we propose a model that combines the two approaches to enable preliminary mapping of flood areas for different scenarios at the regional scale; the model is named RESCUE, laRgE SCale inUndation model. RESCUE takes advantage from coupling geomorphological analysis and simplified hydrologic-hydraulic modeling, providing simple and reliable large scales inundation estimates. Like geomorphological models, it requires few data in input and has a high computational efficiency; while like hydrological-hydraulic models, it is physically-based and linked to a return period scenario.Noteworthy, RESCUE allows for parameter uncertainty estimation through Monte-Carlo analysis, leading to a probabilistic assessment of flooded areas. Here, we show the potentialities and limitations through two examples: The Paglia-Chiani River system, and Central Apennines District (Central Italy).
Modeling the interactions between slab dynamics and continental overriding plate deformation during flat subduction
Authors: Grima Antoniette Greta , Becker Thorsten
Published: February 2023

Shallowing of slabs during their descend into the upper ~200 km of the mantle, i.e. flat subduction, can be associated with extensive geochemical, structural, and dynamic modification of the continental lithosphere. Anomalously buoyant oceanic lithosphere, overthrusting, and interactions with cratonic keels have been suggested to explain flat slabs, but the dynamics of flat slab subduction remain to be fully understood. Here, we explore self-consistent flat-slab subduction using the finite element code ASPECT with adaptive mesh refinement and a free surface boundary condition. We focus on the role of the structure of the overriding continental plate including the role of keels. Results show that flat slabs arise when the subduction interface is weak and the overriding continental lithosphere is positively buoyant, leading to trench rollback. Substantiating previous work, we also observe that a strong continental keel further enhances flat slab formation. Our results also indicate that as the slab flattens, regions of pronounced subsidence and extension develop within the foreland region, on top of more typical, larges-scale subsidence recorded within the continental interior. Regional uplift and subsidence of the overriding plate are not only linked to flat slab emplacement and removal, but also affected by slab dynamics of the shallow upper mantle. Our work can contribute to a better understanding of continental deformation including sediment transport on continent-wide scales.
Non-target screening of organic aerosol tracers applied to a high-alpine firn core
Authors: Huber Carla , Salionov Daniil , Burgay François , Eichler Anja , Jenk Theo , Bjelic Sasa , Schwikowski Margit
Published: February 2023

Ice cores are unique natural archives that provide important information about the past evolution of the Earth’s atmosphere. Whereas the inorganic atmospheric aerosol fraction is well characterized, the organic composition is less understood. The organic aerosol burden is consistently underestimated in the current state-of-the-art models, thus highlighting major gaps in our understanding of the pathways by which organic aerosols accumulate and evolve in the atmosphere. So far, organic aerosols in ice cores have been primarily reported as either bulk (e.g., water insoluble or dissolved organic carbon) or specific parameters (e.g., biomass burning tracers).To provide a more comprehensive characterization of the organic fraction, we applied a non-target screening approach optimised for determining oxidation products of volatile organic compounds to a firn core collected on the Corbassière glacier (Grand Combin, Swiss Alps), in 2020, covering the period 2008-2020. In comparison with a firn core drilled two years earlier (2018), we observe a drastic disturbance of seasonal trends for certain species, such as major ions at depths corresponding to the annual layers from 2008 to 2016, induced by meltwater percolation.As organic tracers are present in low concentrations in the firn core, we performed solid phase extraction. The organic tracers were analysed with high-resolution mass spectrometry based on Orbitrap technology coupled with liquid chromatography. This technique makes it possible to study a wide range of individual compounds at low concentration and to identify them with MS/MS fragmentation. We can attribute molecular formulas to detected compounds by comparing the MS/MS spectra with spectral libraries (e.g., mzCloud) or reference standards. With this approach we will present a unique record of molecular composition of organic aerosol in the Corbassière firn core.Furthermore, this firn core presents a unique opportunity to examine the effect of melting on the organic tracers. We found that specific burning tracers (e.g., vanillic acid, vanillin and syringaldehyde) are less affected than other biomass tracers (e.g., pinic acid) by meltwater percolation. In general, we observe a decrease in concentration of the organic tracers in the same firn core section where we also observe a decrease in major ion concentrations.
A Deep Learning-Based Bias Correction Method for Predicting Ocean Surface Waves in the Northwest Pacific Ocean
Authors: Sun Danyi , Huang Wenyu , Luo Yong , Luo Jingjia , Wright Jonathon S. , Fu Haohuan , Wang Bin
Published: February 2023

Ocean waves, especially extreme waves, are vital for air-sea interaction and shipping. However, current wave models still have significant biases, especially under extreme wind conditions. Based on a numerical wave model and a deep learning model, we accurately predict the significant wave height (SWH) of the Northwest Pacific Ocean. For each day in 2017-2021, we conducted a 3-day hindcast experiment using WAVEWATCH3 (WW3) to obtain the SWH forecasts at lead times of 24, 48, and 72hr, forced by GFS real-time forecast surface winds. The deep learning-based bias correction method is BU-Net by adding batch normalization layers to a U-Net, which could improve the accuracy. Due to the use of BU-Net, the mean Root Mean Squared Errors (RMSEs) of the SWH forecast from WW3 at lead times of 24, 48, and 72hr are reduced from 0.35m to 0.21m, 0.39m to 0.24m, and 0.43m to 0.30m, corresponding to drop percentages of 40%, 38%, and 30%, respectively. During typhoon passages, the drop percentages of RMSEs reach 45%, 42%, and 35% for three lead times. Therefore, combining numerical models and deep learning algorithms is very promising in ocean wave forecasting.
Lesser Antilles slab reconstruction suggests significant northwestwards lateral slab transportation underneath the Caribbean
Authors: Chen Yi-Wei , Wu Jonny
Published: February 2023

How the surface plates link to mantle slabs is fundamental for paleo-tectonic reconstructions and has implications on mantle dynamics. Assuming a simplified, vertical sinking slab, many tomography-based studies have vertically projected the surface features into the mantle, arguing for the tectonic explanations of mantle structures or vice versa. In contrast, geodynamic models continue to suggest that slabs can be laterally transported by a few hundred kilometers up to ~6000 km near the core-mantle boundary. The dynamics of mantle slabs remain controversial.The Caribbean mantle has recently been suggested for vertical slab sinking. However, a vertically sinking slab at a near-stationary eastern Caribbean trench would require slab buckling in the mantle, because at least 1,200 km subduction needs to be accommodated within the upper 660 km mantle. Yet, mantle tomographies show expected (~100 km) slab thickness with limited slab thickening or buckling. With no need for a priori assumption on mantle dynamics, here, we used a slab-unfolding approach to restore and re-interpret the slab structures of the Lesser Antilles slab underneath the Caribbean. Our results show that the slab structure can be alternatively explained with limited intra-plate deformation if the slab was transported northwestward by ~900 km after subduction. Such lateral transportation in the mantle is possibly due to the physical connection with the North American plate, whose northwestward motion since the Eocene has been dragging the slab toward the same direction. We also provided our tectonic explanations on the edges and gaps of the slabs, supporting previous work that pre-existing weak zones and plate boundaries determine the fragmentation of the Lesser Antilles slab. The slab unfolding approach used in this study has the potential to be applied to other subduction zones, with no need for a priori assumption on mantle dynamics (i.e., vertical slab sinking) for future tomography-based analysis.
A Lagrangian study on the structure and pathways of the Irminger Current
Authors: Fried Nora , Katsman Caroline A. , de Jong M. Femke
Published: February 2023

The Irminger Current (IC), located over the western flank of the Reykjanes Ridge, is a contributor to the northward volume transport related to the Atlantic Meridional Overturning Circulation.Previous studies showed that the IC is associated with a region of enhanced eddy kinetic energy. Using high-resolution mooring data from 2014 – 2020 combined with satellite altimetry, a strong intensification in volume transport of the IC in August 2019 could be attributed to the presence of mesoscale eddies in the vicinity of the moorings. At this time, altimetry showed an anticyclone lingering next to a cyclone in the mooring array, which intensified northward velocities within the IC. This example shows that mesoscale variability can directly impact the transport variability of the IC.Further research presented here uses the high-resolution model POP (Parallel Ocean Program, 1/10°) to investigate the pathways of the IC up- and downstream of the mooring array. Here, the focus lies on determining the origin of waters feeding the IC and the role of mesoscale eddies in shaping the current and its pathways using Lagrangian particle tracking with the Ocean Parcels software. First results from a backtracking experiment reveal different origins for the water masses feeding the respective cores of the IC. Waters of the eastern core mostly originate from the eastern side of the Reykjanes Ridge. The western core appears to contain a substantial amount of waters from the interior Irminger Sea that partly recirculate from the Labrador Sea.Additionally, we explore the mesoscale variability within the whole eastern Irminger Sea to investigate the potential impact of mesoscale eddies on restratification in the central Irminger Sea.  We focus on identifying the characteristics of variability along the ridge using the output of the Lagrangian particle tracking in POP. First results from a forward experiment show stronger mesoscale activity in the western core than the eastern core, which is in line with available mooring observations.
A snow reanalysis for Italy: IT-SNOW
Authors: Avanzi Francesco ,   IT-SNOW team
Published: February 2023

Quantifying the amount of snow deposited across the landscape at any given time is the main goal of snow hydrology. Yet, answering this apparently simple question is still elusive -- particularly in complex and high-elevation terrains where data are sparse. To contribute to the advancement of snow hydrology in Mediterranean regions, we present the first serially complete and multi-year snow reanalysis for Italy (IT-SNOW). IT-SNOW covers the period from September 2010 to August 2021, with future updates envisaged on a regular basis. This reanalysis is the output of a real-time snow and glacier monitoring chain – S3M Italy -- developed for the Italian Civil Protection Department by CIMA Research Foundation. Spatial resolution is 500 m, with input data coming from thousands of weather stations across the Italian territory. By assimilating blended snow-covered area maps from Sentinel-2, MODIS, and the Eumetsat H-SAF products, as well as interpolated snow-depth maps from in-situ data, IT-SNOW optimally combines dynamic modeling and data towards reconciled estimates of snow amount and water equivalent at various scales. IT-SNOW was validated using Sentinel-1-based maps of snow depth and in-situ snow data in the Alps and the Apennines, with little bias compared to the former and typical Root Mean Square Errors of 30 to 60 cm and 90 to 300 mm for snow depth and Snow Water Equivalent, respectively. A comparison at 102 gauge stations showed a strong (0.87) correlation between peak SWE in IT-SNOW and measured annual streamflow, with snow being 22% of annual streamflow on average. IT-SNOW is freely available at the following DOI: https://doi.org/10.5281/zenodo.7034956 and we encourage users to validate and provide critical feedback for future releases.  
Improving post-processing of East African precipitation forecasts using a generative machine learning model
Authors: Antonio Bobby , McRae Andrew , MacLeod Dave , Cooper Fenwick , Marsham John , Aitchison Laurence , Palmer Tim , Watson Peter
Published: February 2023

Existing weather models are known to have poor skill over Africa, where there are regular threats of drought and floods that present significant risks to people's lives and livelihoods. Improved precipitation forecasts could help mitigate the negative effects of these extreme weather events, as well as providing significant financial benefits to the region. Building on work that successfully applied a state-of-the-art machine learning method (a conditional Generative Adversarial Network, cGAN) to postprocess precipitation forecasts in the UK, we present a novel way to improve precipitation forecasts in East Africa. We address the challenge of realistically representing tropical convective rainfall in this region, which is poorly simulated in conventional forecast models. We use a cGAN to postprocess ECMWF high resolution forecasts at 0.1 degree resolution and 6-18h lead times, using the iMERG dataset as ground truth, and investigate how well this model can correct bias, produce reliable probability distributions and create samples of rainfall with realistic spatial structure. We will also present performance in extreme rainfall events. This has the potential to enable cost effective improvements to early warning systems in the affected areas.
Integrating Green and Grey Infrastructure for Resilience Enhancement of Conventional Urban Drainage System and its Evaluation through Modeling
Authors: Mehta Osheen , Kansal Mitthan Lal , Bisht Deepak Singh
Published: February 2023

High urbanization rate and climate change are the main drivers of urban floods in developing countries. The increase in urban flooding incidents has become a significant threat to cities, which also result into considerable losses of life and the economy. Adapting to the risks of a changing climate and ill-effects of urbanization is imperative for national and local governments. This calls for a functionally and structurally resilient urban drainage infrastructure. Functional resilience is the coping capacity of system against external threats such as urbanization and climate change, whereas structural resilience is the resilience against internal failures such as blockage of inlets or sewers, structural damage of a pipe, bed load sediment deposition, asset aging/decay, and sewer collapse. This work aims to understand the impact of nature-based solutions on urban drainage resilience. Various researchers have identified Low Impact development (LID) practices as a potential solution to enhance drainage systems' resilience. LID can be defined as a land development and retrofit strategy that emphasizes the protection and use of distributed interventions to reduce the volume and rate of stormwater runoff from a developed landscape. In the present study, the green roofs and rain gardens are simulated in a part of Gurugram city of India using the Storm Water Management Model (SWMM) 5.2. Sensitivity analysis is conducted to overcome the problem of a lack of in-depth data to perform model calibration and validation. The simulations were carried out by developing various scenarios for functional and structural resilience assessment. The results indicate that if 25% of potential subcatchments are deployed with LIDs, functional resiliency of the system enhances by 25%, and structural resilience of vulnerable nodes decreases by 17%.  The study reveals that introduction of LIDs aids into enhancing the functional resilience of the system rather than structural resilience. This research provides evidence of LIDs' positive influence on the resilience performance of drainage systems. Overall, the study can help urban planners and drainage management engineers to develop understanding on LIDs role vis-à-vis city's resilience to urban flood problems.