bluuebunny/crossref_metadata_2025 huggingface dataset:
Tailoring climate change information to assess the vulnerability of Greek airports, in support of prioritising adaptation measures
Authors: van der Schriek Tim , Giannakopoulos Christos , Roukounakis Nikolaos , Karali Anna , Kitsara Gianna , Lemesios Giannis , Gratsea Myrto
Published: February 2023

This study assesses the vulnerability of Greek airports to the impacts of future climate change. Its key aim is to increase the understanding and usability of climate information for airport operators and airlines. The extraction of relevant climate change information from published, and in-house produced, scientific data is therefore informed by a dialogue with the end-users and thus tailored by the needs of the airport operators. The vulnerability assessment methodology uses risk categories and, specifically, critical climate change threshold values concerning airport infrastructure. The approach is aligned with the current airport industry standard as outlined in “ACI Policy Brief – Airport’s Resilience and Adaptation to a Changing Climate (2018)”. The vulnerability matrix has been adapted to the Greek situation and may be used in future regional infrastructure reviews.
This study used projected climate change data from: (i) the Greek “Regional Adaptation Action Plans” (RAAPS), (ii) the national climate change adaptation strategy, developed in the framework of the EU integrated project “LIFE-IP AdaptInGR” (https://www.adaptivegreece.gr), and (iii) the assessment of the impacts of climate change and extremes in Greece derived from the nationally funded CLIMPACT project (www.climpact.gr). Extreme weather trends were assessed using up-to-date climate change projections on a regional scale. Specific reference is made to considerations of whether design inputs/standards for infrastructure works are likely to change in the future.
This vulnerability study addresses the need for the early identification of climate change risks associated with Greek airports and their effective management through implementing adaptation measures. Recommendations may feed into individual Master Plans of airports. We show how climate services can successfully facilitate airport adaptation to climate change by providing information that is tailored to the real user need.
Opposite Impacts of Interannual and Decadal Pacific Variability in the Extratropics
Authors: Seabrook Melissa , Smith Doug , Dunstone Nick , Eade Rosie , Hermanson Leon , Scaife Adam , Hardiman Steven
Published: February 2023

It is well established that the positive phase of El Niño Southern Oscillation (ENSO) tends to weaken the Northern Hemisphere stratospheric polar vortex (SPV), promoting a negative North Atlantic Oscillation (NAO). Pacific Decadal Variability (PDV) is characterised by a pattern of sea surface temperatures similar to ENSO, but its impacts are more uncertain: some studies suggest similar impacts of ENSO and PDV on the SPV and NAO, while others find the opposite. We use climate model experiments and reanalysis to find further evidence supporting opposite interannual and decadal impacts of Pacific variability on the extratropics. We propose that the decadal strengthening of the SPV in response to positive PDV is caused by a build-up of stratospheric water vapour leading to enhanced cooling at the poles, an increased meridional temperature gradient and a strengthened extratropical jet. Our results are important for understanding decadal variability, seasonal to decadal forecasts and climate projections.
Forecasting solar wind speed by machine learning based on coronal hole characteristics
Authors: Collin Daniel , Bianco Stefano , Gallego Guillermo , Shprits Yuri
Published: February 2023

One of the main sources of solar wind disturbances are coronal holes which can be identified in extreme ultra-violet (EUV) images of the Sun. Previous research has shown the connection between coronal holes and an increase of the solar wind speed at Earth. The time lag between the appearance of coronal holes on the visible side of the Sun and its effects on Earth is 2-5 days. In this study, a machine learning model predicting the solar wind speed originating from coronal holes is proposed. It is based on the analysis of solar EUV images. A segmentation algorithm is applied to the images in order to identify coronal holes and derive their characteristics (e.g. area, location). We also present a new method to calculate the geoeffective coronal hole area: Instead of specifying in advance a sector of the solar surface in which the area is measured and a lag time between area measurement and the arrival of the solar wind, the specification of this sector and the corresponding delay are formulated as a mathematical optimization problem and included in the machine learning model. This approach facilitates an improvement of the prediction accuracy and also prolongs the prediction horizon, as the solar wind speed can be predicted up to approximately 5 days in advance of the disturbance. Several machine learning model architectures are explored. We also study how the time evolution can be included in the model.
How do magnetic holes cross a bow shock? Results from the kinetic hybrid plasma model Menura
Authors: Henri Pierre , Simon Wedlund Cyril , Pucci Francesco , Behar Etienne , Ballerini Giulio
Published: February 2023

Linear magnetic holes (LMH) are magnetic field depressions in the solar wind found everywhere in the heliosphere and sometimes downstream of planetary bow shocks. LMH, with only very little rotation of the magnetic field B across the structure, are often considered as the evolutionary endpoint of mirror modes, thus retaining certain characteristics of their parent structure: embedded in a plasma with large temperature anisotropy, large plasma beta, anticorrelation between B and the plasma density. One question is how and under which conditions these large depressions may survive a shock crossing, as observations have recently shown that such a crossing is possible. In other words: what is the interaction between two nonlinear space plasma structures that both scale as the ion gyroradius? To answer this question, we present here the first hybrid simulations of the evolution of a LMH crossing the bow shock boundary of a medium-activity comet using the hybrid Particle-In-Cell (PIC) model Menura. We first create a LMH with mirror mode characteristics in the pristine solar wind and, then, convect it down toward a comet, through the shock, into the cometary magnetosheath. We study its morphology along its path, and how the magnetosheath is impacted locally and as a whole. This work also aims at preparing fundamental space plasma physics aspects of the upcoming multi-spacecraft Comet Interceptor mission.
Hydrogeophysical characterization of a limestone vadose zone and determination of the Archie and CRIM petrophysical parameters by integrating geophysical and hydrogeological data in a grid search algorithm
Authors: Abbas Mohamad , Deparis Jacques , Isch Arnaud , Mallet Céline
Published: February 2023

The hydrological characterization of the vadose zone remains a major challenge considering the spatiotemporal variability of its properties and the limitations associated with hydrological measurements techniques. Geophysical methods, in particular the DC-resistivity and ground penetrating radar, can provide large scale images of hydrogeological structures and a non-invasive assessment of the subsurface dynamic processes. However, these approaches rely on the accuracy of the petrophysical relationships connecting the geophysical parameters to hydrogeological ones, where the site-specific determination of the associated petrophysical parameters is considered crucial. The first objective of this study was to investigate the relationship between the water content, geological properties, and geophysical attributes at the vadose zone of a vulnerable limestone aquifer. The second objective aimed to obtain the Archie’s and Complex Refractive Index Model (CRIM) petrophysical parameters by using borehole electrical resistivity and cross-hole ground penetrating radar data. For this purpose, we adopted a grid search inversion algorithm where the field geophysical data were integrated with water content profiles simulated by using HYDRUS-1D. The vadose zone profile was divided into three layers, and the inversion was carried out for the petrophysical parameters in each of the model layers. The electrical resistivity and relative dielectric permittivity data showed a very good correspondence with the simulated and experimental water content distributions along the vadose zone profile. The petrophysical parameters estimated by the inversion showed values that fall in the ranges reported in the literature. Similar values have been observed in the different model layers, with slight differences that were attributed to the vertical heterogeneities associated with the alteration and fracturation features of the limestone vadose zone. This study showed a very good correlation between geophysical, hydrogeological and geological data, and highlighted the presence of heterogeneities that can have profound effects on the vadose zone water dynamics.
The residence time and overturning circulation of the Gulf of Gabès in the Eastern Mediterranean Sea
Authors: Döös Kristofer , Abdennadher Jihene , Boukthir Moncef
Published: February 2023

The water mass transformation in the Gulf of Gabès and its associated overturning circulation is investigated. The strong all year evaporation in the Gulf leads to a salinification of the entering water masses, which hence return with a strong salinity increase.  The heat transports in and out have a strong seasonal cycle, with approximately as much entering as exiting the Gulf in the yearly mean.The overturning circulation is calculated from Lagrangian trajectories, which makes it possible to follow in detail the water mass transformation from where the water enters in the north, following an anticlockwise circuit along the coast in the Gulf until it exits in the southeast. The densest and most saline water exits, however, in the deepest middle part of the Gulf, where it tends to mix with the slightly fresher Mediterranean Waters. The trajectories are computed with the velocity and mass transport fields from a high-resolution (1/96°) hydrodynamic model, which includes the strong tides in this part of the Mediterranean. Figure: Examples of trajectories entering and exiting the Gulf of Gabès. Colour for individual trajectories as a function of salinity. 
Weathering of airless body surfaces by the heavy minor ions of the solar wind: inputs from Wind ion observations
Authors: Nenon Quentin , Raines Jim , Poppe Andrew
Published: February 2023

The role and importance of solar wind ions heavier than helium for the weathering of airless body surfaces across the solar system remain debated. In addition, the contribution to surface weathering of suprathermal and energetic heavy ions, which have extremely low densities compared to thermal ions but high energy, is an open question.In this presentation, we will take advantage of the advanced ion instrumentation and long duration of the Wind mission to finely characterize the spectrum and anisotropy of the heavy minor ions that bombard airless body surfaces. Specifically, we will combine heavy ion measurements from the Wind-SWICS (thermal ions), Wind-STICS (suprathermal), and Wind-STEP (energetic) experiments.We will constrain the long-term averaged properties of the heavy ion populations, which are relevant for the development of long-term surface weathering effects. We will also study the heavy ion populations during solar wind events, relevant for short-term alteration effects. Finally, we will detail the impact of our ion-data-based results on the global field of space weathering.
High-resolution simulations of tropical island thunderstorms: Does an increase in resolution improve the representation of extreme rainfall?
Authors: Bergemann Martin , Lane Todd , Wales Scott , Narsey Sugata , Louf Valentin
Published: February 2023

Recent increases in computational resources have led to the application of kilometre- and sub-kilometre-scale simulations in research, numerical weather prediction, and climate modelling alike. Despite anticipated improvements with resolution, there is still considerable work needed to evaluate how well such models improve the representation of intense convection. In this study we conduct ensemble simulations with kilometre- and sub-kilometre-scale horizontal grids to investigate intense convective events in the tropical island thunderstorm system Hector, which frequently occurs over the Tiwi Islands in North Australia. To avoid losing information through spatio-temporal averaging we apply a tracking algorithm to simulated and observed storms. When compared with observations, the model storms exhibit a lack of propagation across the study domain. In general, simulated storms are too intense but too small and too short-lived. This is especially true for the sub-kilometre simulations, where storms are more intense, smaller, and more numerous than in the kilometre-scale counterparts. We argue that size and duration errors compensate for storm number and intensity errors, which could lead to misleading interpretations when only comparing time and space averages of rainfall fields. Investigating some properties of the simulated storms suggests that storms with high rainfall intensities have stronger updrafts in the sub-kilometre model and are accompanied by an increase in cold pool intensity. The results and their resolution sensitivities highlight that the remaining parametrisations and their many tuning parameters in high-resolution set-ups influence the representation of convective storms in such models.
Morphological plasticity and environmental heterogeneity drove resilience of high latitude marine calcifying taxa across the Cretaceous-Paleogene mass extinction
Authors: Witts James , Birch Heather , Flower Amy , MacFie Calum , Schmidt Daniela
Published: February 2023

The Cretaceous-Paleogene (K-Pg) boundary 66 Ma coincides with the most recent of the ‘Big Five’ Phanerozoic mass extinctions. The extinction was driven by rapid and extreme environmental changes, which included global cooling, surface ocean acidification, and productivity decline, following an extra-terrestrial impact at Chicxulub in the Gulf of Mexico. The excellent global fossil record of the K-Pg extinction and recovery allows examination into how severe environmental perturbations affect calcifying organisms across different oceanographic settings. Combining samples from the expanded shelf section on Seymour Island, Antarctica, and IODP sites 690 and 1135 (paleolatitude 65°S), we present new quantitative morphometric and μ-computed tomography data from large collections of well-preserved macro- and microfossil taxa (benthic molluscs, planktonic and benthic foraminifera) across the K-Pg boundary in the southern high latitudes. Planktonic foraminifera show large extinctions and a size decrease in survivors at the K-Pg boundary itself, but the magnitude of size change is smaller than at lower latitude localities. Surviving shallow marine bivalves from Seymour Island show increased variability of body size and volume at the K-Pg boundary persisting for ~300 kyrs into the Paleogene. Surviving deep-sea benthic foraminifera from Site 690 in the same ocean basin and at the same paleolatitude, respond to both events at the boundary itself and the initial re-stabilisation of the global carbon cycle some 300 kyrs after the K-Pg, with shifts in size, growth rate, and surface:volume ratio. These data reveal the importance of morphological plasticity for promoting resilience and survival in calcifiers across this mass extinction event. They also suggest that trait changes across the K-Pg event occur at different times in different environmental settings and groups, supporting the hypothesis that environmental heterogeneity plays an important role in modulating resilience.
Modeling the partitioning of assimilated C along the soil-plant-atmosphere continuum based on a 13C labeling experiment
Authors: Adamczewski Ruth , Liu Qiong , Pausch Johanna , Zarebanadkouki Mohsen
Published: February 2023

Modeling and quantification of carbon (C) allocation through the soil-plant-atmosphere continuum (SPAC) has received increasing attention in recent years. Although advanced imaging and numerical methods have boosted our knowledge, we still lack an experimental and mechanistic understanding of C flux and its partitioning across the SPAC. Here we combined a 13C pulse labeling technique with modeling of C transport across the SPAC to describe the flow of newly assimilated C from shoots to roots, to soils and then respired back to the atmosphere. To do so, different plants - maize (Zea mays L.), soybean (Glycine max (L.) merr. cv. sohae), and wheat (Triticum aestivum L.) - were exposed to a 13CO2 pulse for 2 hoursduring daytime. A CO2 Isotope Analyzer (CCIA-38d-EP, Los Gatos Research) was used to continuously monitor 13CO2 flux from the soils. Subsequently, after harvest the respective 13C contents of shoot and root biomass and of the soil was quantified.To model the C fluxes, we developed a simple multi-compartment domain, representing the SPAC. The SPAC was envisioned as four interconnected horizontal compartments namely atmosphere, shoots, roots, and soil compartment. The shoots and roots compartment were further simplified in three vertical compartments (phloem, storage, and structural pool). The C transport between these pools was represented by constant rates. These rates were inversely estimated by adjusting the model parameters to best reproduce the measured C flux and C contents in the various compartments.   Our model described the allocation and transport of 13C within the shoots, roots, and soil well. The best-fitted coefficients of the model were reproducible among different replications of the same plant species. We also checked the sensitivity of our model to its parameters and observed a good sensitivity to most of the model parameters. In particular, our model was very sensitive to C loading and unloading in the phloem and also root exudation rates. The results of our study show that the combination of tracing 13C and modeling of 13C transport across SPAC is a promising tool to study C flux and its partitioning across SPAC.
On the elaboration of a robust calibration strategy for the large-scale GEM-Hydro model
Authors: Gaborit Etienne , Princz Daniel , Mai Juliane , Shen Hongren , Tolson Bryan , Fortin Vincent
Published: February 2023

As part of the Great-Lakes Runoff Inter-comparison Project (GRIP-GL; Mai et al., 2022), which aims at comparing the performances of different hydrologic models over the Great-Lakes when calibrating them using the same meteorological inputs and geophysical databases, the GEM-Hydro hydrologic model used at Environment and Climate Change Canada (ECCC) to perform operational hydrologic forecasts was calibrated using different strategies. Following the calibration work related to GRIP-GL, progress has been achieved with regard to improving the calibration of the GEM-Hydro model.The work presented here focuses on improvements achieved with regard to calibrating the GEM-Hydro model, compared to the default version of the model and to the performances obtained during the GRIP-GL project. For various reasons explained, the GEM-Hydro calibration performed as part of GRIP-GL was suboptimal. The general calibration framework remains the same as in GRIP-GL, for example by using the MESH-SVS-Raven model to speed-up simulation times and transferring the calibrated parameters into GEM-Hydro afterwards, by relying on global calibrations for each of the 6 Great-Lakes subdomains, etc. However, several important changes have been made compared to the work performed in GRIP-GL, like a new approach to represent the effect of Tile Drains, changing the set of flow stations used for calibration, revising the objective function, etc.The proposed calibration methodology updates significantly improve GEM-Hydro streamflow performance across the Great-Lakes domain and in addition also improve or maintain similar performance levels as the default version of the model, with respect to auxiliary variables and surface fluxes: snow, soil moisture, evapotranspiration, 2m air temperature and dew point. Indeed, the model relies on 40m atmospheric forcings for wind speed, temperature and humidity, and simulates its own 2m atmospheric variables. To achieve this, it was necessary to constrain some parameter interval values during calibration, in order to prevent the calibration algorithm to choose physically-irrelevant parameter values that could allow to improve streamflow performances while degrading other hydrologic variables, due to equifinality.Reference:Mai, J., Shen, H., Tolson, B. A., Gaborit, E., Arsenault, R., Craig, J. R., Fortin, V., Fry, L. M., Gauch, M., Klotz, D., Kratzert, F., O'Brien, N., Princz, D. G., Rasiya Koya, S., Roy, T., Seglenieks, F., Shrestha, N. K., Temgoua, A. G. T., Vionnet, V., and Waddell, J. W. (2022). The Great Lakes Runoff Intercomparison Project Phase 4: The Great Lakes (GRIP-GL). Hydrol. Earth Syst. Sci., 26, 3537–3572. Highlight paper. Accepted Jun 10, 2022.  https://doi.org/10.5194/hess-26-3537-2022
Removing Internal Variability as a Means of Improving Regional Emulation of Ocean Dynamic Sea-Level Change
Authors: Malagón-Santos Víctor , Slangen Aimée B.A. , Hermans Tim H.J. , Dangendorf Sönke , Marcos Marta , Maher Nicola
Published: February 2023

Regional emulation tools based on statistical relationships, such as pattern scaling, provide a computationally inexpensive way of projecting ocean dynamic sea-level change for a broad range of climate change scenarios. Such approaches usually require a careful selection of one or more predictor variables of climate change so that the statistical model is properly optimized. Even when appropriate predictors have been selected, spatiotemporal oscillations driven by internal climate variability can be a large source of model disagreement. Using pattern recognition techniques that exploit spatial covariance information can effectively reduce internal variability in simulations of ocean dynamic sea level, significantly reducing random errors in regional emulation tools. Here, we test two pattern recognition methods based on Empirical Orthogonal Functions (EOF), namely signal-to-noise maximising EOF pattern filtering and low-frequency component analysis, for their ability to reduce errors in pattern scaling of ocean dynamic sea-level change. These two methods are applied to an initial-condition large ensemble (MPI-GE), so that its externally forced signal is optimally characterized. We show that pattern filtering provides an efficient way of reducing errors compared to other conventional approaches such as a simple ensemble average. For instance, filtering only two realizations by characterising their common response to external forcing reduces the random error by almost 60%, a reduction level that is only achieved by averaging at least 12 realizations. We further investigate the applicability of both methods to single realization modelling experiments, including four CMIP5 simulations for comparison with previous regional emulation analyses. Pattern scaling leads to a varying degree of error reduction depending on the model and scenario, ranging from more than 20% to about 70% reduction in global-mean mean-squared error compared with unfiltered simulations. Our results highlight the relevance of pattern recognition methods as a means of reducing errors in regional emulation tools of ocean dynamic sea-level change, especially when one or a few realizations are available.
Using infrasound from explosions for probing internal gravity waves in the middle atmosphere
Authors: Vorobeva Ekaterina , Assink Jelle , Chunchuzov Igor , Renkwitz Toralf , Espy Patrick , Näsholm Sven Peter
Published: February 2023

This study uses ground-based recordings of low-frequency, inaudible acoustic waves (infrasound) to probe the wind and temperature fluctuations associated with internal gravity waves breaking in the middle atmosphere. Building on the approach introduced by Chunchuzov et al., the recorded waveforms are used to retrieve the effective sound speed fluctuations in an inhomogeneous atmospheric layer of infrasound backscattering. The retrieval procedure was applied to infrasound from controlled blasts related to the disposal of military explosives in Hukkakero, Finland and recorded at the IS37 station in Norway over a four-year period from 2014 to 2017. Our findings indicate that infrasound scattering occurs in the lower mesosphere between 50 and 75 km in altitude in a region where gravity waves interact due to strong nonlinear effects and form thin layers with strong wind shears. The retrieved effective sound speed fluctuations were then analysed in terms of the vertical wave number spectra. The analysis revealed that the spectra follow a kz–3 power law that corresponds to the "universal" saturated spectrum of atmospheric gravity waves within kz ∈ [2.1·10–3; 2.7·10–2] cycles/m. Based on this wavenumber range, we estimate the outer and inner vertical scale of atmospheric inhomogeneities that infrasound is sensitive to as Linner= 33 – 37 m, Louter = 382 – 625 m.  
Furthermore, the spectra of the retrieved effective sound speed fluctuations were compared to theoretical linear and nonlinear gravity wave saturation theories as well as to independent wind measurements made by the Saura MF radar near the Andøya Space Center in Norway. The comparison showed a good agreement in terms of the amplitude and slopes of the vertical wavenumber spectra in both cases. The overall agreement allows us to suggest that the Saura radar and infrasound-based effective sound speed profiles represent the low- and high-wavenumber regimes of the same "universal" gravity wave spectrum. These results illustrate that the use of infrasound makes it possible to probe fine-scale motions that are not well captured by other techniques. The latter suggests that infrasound observations can be used as a complementary technique to probe internal gravity waves in the middle- and upper atmosphere. 
Grid spacing effects on convection initiation and aerosol-cloud interactions: A case study of a supercell storm from the Swabian MOSES 2021 field campaign
Authors: Barthlott Christian , Czajka Beata , Kohler Martin , Hoose Corinna , Kunz Michael , Saathoff Harald , Zhang Hengheng
Published: February 2023

The predictability of deep moist convection is subject to large uncertainties, mainly due to inaccurate initial and boundary data, incomplete description of physical processes, or uncertainties in microphysical parameterizations. In this study, we present hindcasts of a supercell storm that occurred during the Swabian MOSES field campaign in southwestern Germany in summer 2021. The supercell storm of 23 June 2021 passed directly over the main observation site equipped with various instruments, allowing a detailed comparison of simulations and observations. The preconvective radiosonde observations revealed suitable conditions for supercell development, i.e., low convective inhibition, moderate convective available potential energy, sufficient deep-layer shear, and a Bulk Richardson number of 22. Numerical simulations were performed with the ICOsahedral Non-hydrostatic (ICON) model using two horizontal grid spacings (i.e., 2 km/1 km) with a single-moment and a double-moment microphysics scheme. The double-moment scheme allows us to study aerosol effects on clouds and precipitation with cloud condensation nuclei (CCN) concentrations ranging from low to very high. Numerical results show that all 2-km model realizations do not simulate convective precipitation at the correct location and time. For the 1-km grid spacing, changes in aerosol concentration resulted in large changes in convective precipitation, causing the supercell to disappear completely in some simulations. Only the 1-km model run, which assumes a clean environment, is able to realistically capture the supercell storm. During the Swabian MOSES field campaign, aerosol particle concentrations and size distributions were continuously measured with an optical particle counter from June to August 2021. The day of the supercell storm was characterized by the lowest potential CCN values of the month, suggesting that the low aerosol concentration in the successful model run is a reasonable assumption for this case study. Possible reasons for the discrepant model results, i.e., effects of grid spacing on convection initiation and detailed analyses of microphysical process rates, are discussed. These results demonstrate the benefits of using an aerosol-aware double-moment microphysics scheme at high model resolution for convection initiation and cloud evolution, and that the use of different CCN concentrations can determine whether a supercell is successfully simulated or not.
Flood indirect impacts assessment: A systematic review of models and empirical literature
Authors: Nobile Elisa , Arosio Marcello , Martina Mario , Caiani Alessandro
Published: February 2023

Floods are among the most frequent and costliest natural hazards worldwide and the associated human and economic losses are expected to increase due to climate change, urbanization and population growth. Therefore, it is crucial to develop a comprehensive understanding of the economic impacts of these disasters on our interconnected society. This should include the indirect impacts (e.g. business interruption, service disruption, cascading effects), which have been very often overlooked, especially in engineering works.For this reason, this study reviews the recent scientific literature in the fields of economy and engineering on the socio-economic impacts of floods to derive the current state-of-the-art of the indirect impacts estimation. Given the complexity of the problem, it is necessary to integrate economic theory studies, which in general tend to focus on flow losses, and civil engineering studies, which, on the other hand, have centred their attention mainly on stock losses.The different frameworks, methodologies and empirical studies are analysed through a systematic qualitative and quantitative review. The published articles are derived from well-known scientific database by setting indicators and keywords.The results highlight the different sectors (e.g. economic sectors, firms, transportation system) and the different metrics (e.g. monetary values, time, space), adopted to quantify the indirect impacts, as well as the different purposes (e.g. risk assessment, risk management) of each study.This work derives the current knowledge on the estimation of indirect impacts of flooding to provide clarity on the different perspectives of indirect impacts. Moreover, the findings can help to underline key gaps in the existing scientific literature and to indicate future research work.
Space-time landslide size modelling in Taiwan
Authors: Lombardo Luigi , Fang Zhice , Wang Yi , van Westen Cees
Published: February 2023

Landslide susceptibility assessment using data-driven models has predominantly focused on predicting where landslides may occur and not on how large they might be. The spatio-temporal evaluation of landslide susceptibility has only recently been addressed, as a basis for predicting where and when landslides might occur.The present study combines these new developments by proposing a data-driven model capable of estimating how large landslides may be, for the Taiwanese territory in a fourteen year time window. To solve this task, our model assumes that landslide sizes follow a Log-Gaussian probability distribution in space and time. Spatially the area is subdivided into 46074 slope units, with 14 annual timesteps from 2004 to 2018. Based on this subdivision, the model we implemented regressed landslide sizes against a covariate set that includes temporally static and dynamic properties. In the validation of our model, we nested a wide range of cross-validation (CV) procedures, such as a randomized 10fold-CV, a spatially constrained CV, a temporal leave-one-year-out CV, and a spatio-temporal CV. The final performance was described both numerically as well as in map form.Overall, our space-time model achieves interpretable and satisfying results. With the availability of more complete landslide inventories, both temporally and spatially, we envision that spatio-temporal landslide size prediction will become the next challenge for geomorphologists to finally address a fundamental component of the landslide hazard definition. And, because of it’s spatio-temporal nature, we also envision that it may lead to landslide simulation studies for varying climate scenarios.
Areal reduction factor assessment for extreme rainfalls through a new empirical fixed-area formulation
Authors: Flammini Alessia , Dari Jacopo , Saltalippi Carla , Morbidelli Renato
Published: February 2023

In the hydraulic structures design against extreme events a proper estimate of the areal reduction factor (ARF) is required. Specifically, rainfall-runoff models widely used need to be fed with information on areal-average rainfall over a watershed surface, while rainfall data is typically available at a point scale. The ARF allows to convert rainfall data from point to areal scale.In this work, a new fixed-area and deterministic approach for estimating the ARF is proposed; it involves ratios between observed annual maxima with specific duration of average rainfall occurring in a specific area and those referring to all the available point rainfalls in the same area. The approach was applied to the Umbria region in Central Italy where, using high-quality and validated rainfall data (with a temporal resolution of 1 minute), a parametric relation expressing ARFs as function of duration and area was found. The outcomes were then compared with those of the most widespread empirical approaches available in literature, often applied when rainfall data are lacking, obtaining substantial over- or underestimation of empirical ARFs. This confirms that the transposition of ARF relations from a geographic area to another could have not-negligible impacts on the design of hydraulic structures. In addition, indications aimed at selecting the most suitable method to be applied for ARF estimation are provided. Specifically, the proposed approach is suitable when a limited number of years of rainfall observations is available. In this regard, the robustness of the methodology was tested by varying the length of the rainfall observation period; a minimum number of about 6 years was found to make the derived empirical formulation sufficiently accurate in a specific area.
Array beamforming on ambient seismic noise correlations reveals repeating direct waves in the coda
Authors: Safarkhani Mahsa , Schippkus Sven , Hadziioannou Céline
Published: February 2023

Over the past two decades, the ambient seismic noise correlation method has revolutionized our ability to investigate the Earth's subsurface structure. Perfect reconstruction of the cross correlation wavefields towards Green's function demands some strong hypotheses about uncorrelated and spatially uniform seismic source distributions. In reality, violation of this assumption impacts the accuracy of the Green’s function estimate, which may bias applications in further studies. As this technique has become a standard method for subsurface imaging and monitoring, a methodology that identifies the effect of seismic source distributions plays an essential role in removing their contribution to achieve less-biased signals. Seismic array beamforming is commonly applied in estimating the direction of seismic waves crossing the array.In this study, we use a new strategy based on beamforming of noise correlation signals. We consider several seismic stations surrounding the Gräfenberg array throughout Europe as virtual sources. We process two years of vertical component continuous noise recording from the Gräfenberg array in Germany and virtual sources in Poland, Italy, Portugal, France and Finland. Using the noise correlation-based beamforming method, we detect source directions for direct and coda waves for the primary (0.05-0.1 Hz) and secondary (0.1-0.4 Hz) microseism frequency bands. The source directions for the direct waves correspond to the converging and diverging part of the correlation wavefield. Throughout the coda, however, we detect the dominant noise source directions, i.e., surface waves generated by ocean microseisms in the Northern Atlantic during winter months and body waves from the Southern Pacific during summer months. This suggests that the coda of the correlation functions contains repeating direct waves from the dominant source regions, which may lead to incorrect estimates and interpretation of velocity variations if not accounted for. Knowledge of the ambient noise source origins and their spatiotemporal distribution is required to correctly interpret velocity variations.
A global synthesis of speleothem radiocarbon data – is it a sensitive proxy for past ecosystem processes?
Authors: Lechleitner Franziska A. , Day Christopher , Fohlmeister Jens , Warken Sophie , Frank Norbert , Stoll Heather , Welte Caroline
Published: February 2023

Speleothems, secondary cave carbonate precipitates, can serve as tools to reconstruct past terrestrial ecosystem processes, particularly related to soil and vegetation. Radiocarbon, often in conjunction with other geochemical proxies, has been increasingly used for this purpose, as the speleothem reservoir effect retains useful information on local ecosystem conditions. On the other hand, speleothems are also of interest to the radiocarbon community as they can be dated very precisely with the U-Th method, which may allow the reconstruction of atmospheric radiocarbon levels in time if the reservoir effect remained constant.Over the past decades, a growing number of speleothem radiocarbon records have been generated from vastly different climate zones and ecosystem types. While much progress has been made in the interpretation of these records, a unified and global view of the factors driving variability in speleothem radiocarbon is still lacking. We compiled a global dataset of averaged speleothem radiocarbon measurements, and provide a critical evaluation of the applicability of the radiocarbon reservoir effect as a proxy for past ecosystem conditions. We compare our dataset to geographic (latitude, elevation), climatic (temperature and precipitation), and ecosystem and geological parameters (soil and bedrock thickness, soil age, vegetation type, and land cover). Our preliminary results show that it is difficult to extract a strong globally relevant driving factor for the mean absolute value in the reservoir effect at the investigated cave sites, and highlights the importance of detailed reporting of local conditions.To provide insight into the amplitude range of processes affecting published speleothem radiocarbon records we perform a series of numerical forward modeling experiments. We test how the effects of changing soil age, soil pCO2, carbonate dissolution regime, and pyrite oxidation affect carbon isotopes in stalagmites.Together, the global synthesis and modeling experiments provide us with the first global overview of how cave site parameters and climate and ecosystem processes affect speleothem radiocarbon records, and allow us to assess the sensitivity of this proxy as a tool for past ecosystem conditions.
Statistical validation of the Magnetospheric–Ionospheric–Lithospheric Coupling model on occasion of the Marche Earthquake (Mw 4.2) main shock occurred on November 20th 2022
Authors: Piersanti Mirko , D'Angelo Giulia , Battiston Roberto , Bertello Igor , Cicone Antonio , Diego Piero , Papini Emanuele , Parmentier Alexandra , Recchiuti Dario , Ubertini Pietro
Published: February 2023

In the last few decades, the efforts of the scientific community to search earthquake signatures in the Earth atmosphere, ionosphere and magnetosphere have grown rapidly. The increasing amount of good quality data from ground stations and satellites allowed the detection of specific signatures with high statistical significance such as ionospheric plasma density perturbations and/or atmospheric temperature and pressure changes. In addition, the recent development of a magnetospheric–ionospheric–lithospheric coupling (M.I.L.C.) analytical model has provided promising results in the identification of causal links between the observed anomalies and their possible seismic origin. With the aim of statistical validating such a model, we have performed a multi-instrument analysis of a mid-latitude seismic event, including also the investigation of atmospheric activity, in order to validate the identification of confounders and possibly explain any observed anomalous signal. Specifically, we have investigated the earthquake (Mw 4.2) occurred in Italy (Marche) on November 20th 2022 by using high-quality data from both ground-based detectors and satellites, preserving their statistical significance, that we have compared with the predictions of the M.I.L.C. model.
Could land management modify water resources in Mediterranean mountain areas?
Authors: Zabalza-Martínez Javier , Nadal-Romero Estela , Llena Manel , Cortijos-López Melani , Lasanta-Martínez Teodoro , López-Moreno Juan Ignacio , Vicente-Serrano Sergio M. , Pascual Diana , Pla Eduard
Published: February 2023

Water resources availability is one of the main concerns for policy makers around the World. In the Mediterranean basin, this problem has been increased given the extreme variability in climate and the land use changes that have occurred during the last century (i.e. land abandonment). Streamflow and other environmental variables related to vegetation have been analysed in three Mediterranean mid-mountain basins under conditions of Climate Change (CC), under conditions of Land Use Change (LUC) and under its Combined Action (CA). The Land Use changes have been defined in the framework of the Life MIDMACC project and are related to land management through shrubland cleaning activities in abandoned fields and forest management that is determined by a 50% decrease in tree density in a forest community.Three basins (Leza, Estarrún and L'Anyet) have been simulated using the Regional Hydro-Ecologic Simulation System (RHESSys) for the periods 2035-2064 and 2070-2099. The aim of the study is to determine the impacts of climate change and land management on both streamflow and other variables such as Net Primary Production or Potential Evapotranspiration in these basins (representative of Mediterranean mid-mountains) in order to analyse how the management proposed can be used to adapt these basins to climate and whether it is capable of mitigating the forecast reduction in streamflow associated with climate trends.The results with LUC reveal a clear positive trend, increasing the streamflow in the basins of Leza and L'Anyet rivers (+9.76% and +4.70%) and slightly decrease (-0.13%) in Estarrún river due to the limited area to be managed. The combined action (CA) shows, in general, an attenuation in the clear negative trend of streamflow under climate change (CC) conditions. This suggests that the land management proposed in the LIFE MIDMACC project could help the adaptation of Mediterranean mid-mountain basins to climate change and the mitigation of its effects.Acknowledgements: This research project was supported by the Life MIDMACC project ((LIFE18 CCA/ES/001099)) project funded by the European Commission. Melani Cortijos-López is working with an FPI contract (PRE2020-094509) from the Spanish Ministry of Economy and Competitiveness associated to the MANMOUNT project. Manel Llena has a “Juan de la Cierva Formación” postdoctoral contract (FJC2020-043890-I/AEI/ 10.13039/501100011033) from the Spanish Ministry of Science and Innovation.  
Evaluation of five reanalysis products over France: implications for agro-climatic studies
Authors: Er-rondi Mariam , Troin Magali , Coly Sylvain , Buisson Emmanuel , Serlet Laurent , Azzaoui Nourddine
Published: February 2023

Agriculture is extremely vulnerable to climate change. Increase in air temperature alongside the more frequent extreme climate events are the main climate change’s negative impacts influencing the yields, safety, and quality of crops. One approach to assess the impacts of climate change on agriculture is the use of agro-climatic indicators (AgcIs). Agcls characterize plant-climate interactions and are practical and understandable for both farmers and decision makers.Climate and climate change impact studies on crop require long samples of reliable past and future datasets describing both spatial and temporal variability. The lack of observed historical data with an appropriate temporal resolution (i.e., 30 years of continuous daily data) and a sufficient local precision (i.e., 1km) is a major concern. To overcome that, the reanalysis products (RPs) are often used as a potential reference data of observed climate in impact studies. However, RPs have some limitations as they contain some biases and uncertainties. In addition, the RPs’ evaluation is often conducted on climate indicators which raises questions about their suitability for agro-climatic indicators.This work aims to evaluate the ability of five of the most used RPs to reproduce observed AgcIs for three specific crops (i.e., apple, corn, and vine) over France. The five RPs selected for this study are the SCOPE Climate, FYRE Climate, ERA5, ERA5 Land and the gridded dataset RFHR. They are compared to the SYNOP meteorological data provided by Météo-France, considered as a reference dataset from 1996 to 2021.Our findings show a higher agreement between the five RPs and SYNOP for the temperature-based Agcls than the precipitation-based Agcls. RPs tend to overestimate the precipitation-based Agcls. We also note that, for each RP, the discrepancies between the AgcIs and the reference SYNOP dataset do not depend on the geographical location or the crop. This study emphasizes the need to quantify uncertainty in climate data in climate variability and climate change impact studies on agriculture.