bluuebunny/crossref_metadata_2025 huggingface dataset:
Intercomparison of long-term ground-based tropospheric ozone measurements
Authors: Björklund Robin , Vigouroux Corinne , Langerock Bavo , Smale Dan , Petropavlovskikh Irina , Effertz Peter , Hannigan James , Querel Richard , Ortega Ivan , Koji Miyagawa , Robinson John , Smale Penny , Kotkamp Michael , Nedoluha Gerald , Poyraz Deniz , Van Malderen Roeland
Published: February 2023

Ground-based observations are indispensable for the long-term monitoring of atmospheric constituents. In this work, we take advantage of multiple collocated instruments to analyze potential biases and drifts in ground-based ozone observations, within the context of the HEGIFTOM (Harmonization and Evaluation of Ground-based Instruments for Free Tropospheric Ozone Measurements) working group in the Tropospheric Ozone Assessment Report, Phase II (TOAR-II). This work is performed at Lauder (New Zealand), Boulder (Colorado), and Mauna Loa (Hawaii) where comparisons are made between Fourier Transform Infrared (FTIR) spectroscopy, Dobson Umkehr, and ozonesonde observations. The validation is performed with respect to FTIR as arbitrary reference, while considering the differences between the a priori profile information for the techniques that employ these as well as accounting for the different vertical resolution of each measurement technique. Such intercomparison is done for a handful discrete altitude partial columns, defined to have independent pieces of information also in the case of the low vertical resolution techniques (FTIR and Umkehr). This leads to 4 independent vertical layers to be compared, including one in the troposphere where ozone plays an important role as a greenhouse gas and as a risk to human health. In this tropospheric layer we compare the FTIR, Dobson Umkehr and ozonesonde techniques and derive a consistent bias from the FTIR data of about 5%, which we attribute in part to the assumed spectroscopy. Fitting the time series of the relative measurement differences using multiple linear regression, we obtain a linear trend, which quantifies the drift between pairs of techniques. Within the uncertainties, we find no significant drift between FTIR and Umkehr or ozone sonde data in the troposphere.
Assessing the boundaries of seasonal forecast skill for European winter storms from different hindcast suites
Authors: Leckebusch Gregor C. , Degenhardt Lisa , Berrie Elleanor , Ng Kelvin S. , Spreitzer Elisa
Published: February 2023

European winter storms are a significant threat to communities, public infrastructure, and private and commercial properties. On seasonal timescales, potential predictability was evidenced in recent state-of-the-art seasonal hindcast suites e.g., the UK Met Office’s GloSea5. Related positive and potentially usable forecast skill for frequency and intensity measures were based on pre-season model initialisation around the beginning of November for the following core winter (DJF) season’s assessment.This study expands on these findings by analysing extended lead times of seasonal forecast into autumn and late summer before the winter season. Here, in a systematic way, a multi-model ensemble of hindcasts is analysed to evaluate current models’ capability to forecast the seasonal activity for initialisations from September to November. First results indicate potential predictability precursors already from the September initialisations for storm frequencies. These results vary from model to model though. The presentation will discuss differences between models as well as lead times for both, storm frequency and intensity.
Quantitative three-dimensional imaging of macropore flow in undisturbed soil under different irrigation intensities
Authors: Koestel John , Schwenk Anna , Jarvis Nick , Larsbo Mats
Published: February 2023

Macropores have important beneficial impacts on the hydrological cycle, since they reduce risks of waterlogging, surface runoff, soil erosion and flooding. On the other hand, macropore flow is also associated with significant ecosystem disservices, since it can dramatically accelerate the leaching of contaminants to surface water and groundwater. Several approaches to model preferential macropore flow have been developed. One approach is to use the kinematic wave equation, in which the kinematic exponent should depend on the exponent in a power law relationship between wetted macropore surface area and macropore saturation. Most model applications have relied on calibration of model parameters against measured data on water flow. This makes critical testing of the underlying model concepts difficult and raises the question of whether the model is matching the data for the right reasons or not. In this study, we used X-ray tomography to quantify water and air distributions in macropores at varying steady-state flow rates in two topsoil and two subsoil columns (diameter 9 cm) sampled from a clay soil. We collected sufficient data to derive the kinematic wave exponent from the image data for the two topsoil samples. We found that the wetted macropore surface area and macropore saturation were indeed related by a power law for the first three irrigation intensities, corresponding to kinematic exponents of 1.22 and 1.26, respectively. These promising results need to be verified in future experiments that should be conducted on soil samples with smaller diameters to achieve better image resolutions and signal-to-noise ratios.
Anisotropies of solar energetic electrons in the MeV range measured with SolO/EPD/HET
Authors: Fleth Sebastian , Kühl Patrick , Kollhoff Alexander , Wimmer-Schweingruber Robert F. , Heber Bernd , Rodríguez-Pacheco Javier , Dresing Nina
Published: February 2023

Solar Orbiter is an ESA-led mission of international collaboration with NASA to investigate how the Sun creates and controls the heliosphere, and why solar activity changes with time. One of its top-level science questions is how solar eruptions produce energetic particle radiation that fills the heliosphere. With its four viewing directions the High-Energy telescope (HET) provides critical information about the sources and transport of high-energy particles.This study analyses relativistic electron measurements obtained by HET in the energy range from 200 keV to above 10 MeV. The purpose of this study is to analyse anisotropies of relativistic solar energetic electrons utilizing the different viewing directions of HET. Time periods with enhanced fluxes of relativistic electrons, have been identified. A list of these time periods including additional observations such as maximum energy and flux as well as the first order anistropy will be presented. This is the first time since the Helios mission that anisotropies of high energy electrons have been measured.
Utilization of crowdsourced macroseismic observations to distinguish damaging from harmless earthquakes globally within minutes of an event
Authors: Lilienkamp Henning , Bossu Rémy , Cotton Fabrice , Finazzi Francesco , Landès Matthieu , Weatherill Graeme
Published: February 2023

Rapid assessment of an earthquake’s impact on the affected society is a crucial step in the early phase of disaster management, determining the further organization of civil protection measures. In this study, we demonstrate that felt-reports containing macroseismic observations, collected via the LastQuake service of the European Mediterranean Seismological Center, can be utilized to rapidly estimate the probability of a felt earthquake to be “damaging” rather than “harmless” on a global scale. In our fully data-driven, transparent, and reproducible approach, we first map the reported observations to macroseismic intensities according to the EMS-98 macroseismic scale. Subsequently, we compare the distribution of felt-reports to documented earthquake impact in terms of economic losses, number of fatalities, and number of damaged or destroyed buildings. Using the distribution of felt-reports as predictive parameters and an impact measure as the target parameter, we infer a probabilistic model utilizing Bayes’ theorem and Kernel Density Estimation, that provides the probability of an earthquake to be “damaging”. For 22% of felt events in 2021, a sufficient number of felt-reports to run the model is collected within 10 minutes after the earthquake. While a clean separation of “damaging” and “harmless” events remains a challenging task, correct and unambiguous assessment of a large portion of “harmless” events in our dataset is identified as a key strength of our approach. We consider our method an inexpensive addition to the pool of earthquake impact assessment tools, that can be utilized instantly in all populated areas on the planet. Being fully independent of seismic data, the suggested framework poses an affordable option to potentially improve disaster management in regions that lack expensive seismic instrumentation today and in the near future.
On the importance of atmosphere-snow humidity exchange for the climate signal stored in the snow isotopic composition
Authors: Steen-Larsen Hans Christian , Dietrich Laura , Wahl Sonja , Town Michael , Hughes Abigail , Hoerhold Maria , Zuhr Alexandra , Behrens Melanie , Fettweis Xavier , Werner Martin
Published: February 2023

Research over the last five years dedicated to identifying and quantifying the processes responsible for driving the climate signal in the isotopic composition of the snow have documented the role of the humidity exchange between the snow and atmosphere in changing the initial precipitation isotopic composition. Laboratory and field experiments combined with direct vapor isotope flux measurements have shown that not only does the depositional flux changes the surface snow isotopic composition, but sublimation from the snow surface induces isotopic fractionation leading to changes in the snow isotopic composition. Thus, it was shown that for the EastGRIP ice core location, including fractionation during sublimation, atmosphere-snow exchange processes explain between 35 and 50 % of the day-to-day variations in the snow surface signal when no precipitation occurs.Until recently, it was unknown on which time scales these surface exchange processes are important for the isotope signal.Here we combine direct accumulation and eddy-covariance humidity flux measurements with high resolution regional climate model simulations. Focusing on the EastGRIP ice core site, we find that during the summer season up to 40% of the accumulation is sublimated and about 10% is re-deposited. Such relative high fluxes compared to the amount of precipitated snow would naturally lead to an influence of the seasonal isotopic composition of the snow.By combining outputs from an isotope-enabled general circulation model (ECHAMwiso) and a regional polar climate model (MAR) with the SNOWISO exchange and snowpack model, we find that the influence on the snowpack isotopic composition is not only isolated to the summer isotope signal but influences the full seasonal cycle. In fact, we find that that the atmosphere-snow exchange influence on the annual mean isotopic composition results in a significant bias in the source region condition deduced from the isotopic composition of the ice core.
Late spring frost impacts on radial growth of European beech near its upper elevational limit
Authors: Vitasse Yann , Baumgarten Frederik , Reim Joann , Gessler Arthur , Martinez-Sancho Elisabet
Published: February 2023

Global warming has considerably advanced the start of the growing season of temperate trees. However, the rate of this phenological change does not necessarily track the changes in the date of the last spring frost, also induced by climate change, which may result in a higher risk of false spring. When a late spring frost (LSF) occurs during tree leaf emergence, it can lead to complete tree defoliation. Although the impacts of LSFs are rarely fatal for a tree, they may play a decisive role in combination with extreme droughts in determining species distribution limits in the near future.Here we aimed at assessing the impact of LSFs on tree growth of a frost-sensitive species, European beech (Fagus sylvatica L.), and retrospectively quantify the LSF regime in two sites of the Swiss Jura mountains. We collected increment cores of beech and a more freezing tolerant species, Norway spruce (Picea abies (L.) Karst) from a site where LSF damage was observed in May 2020 located at 1,365 m asl and in a second site where no frost damage was observed in 2020 at 1,065 m asl. Climate-growth relationships were established at both sites and for two different periods (1953–1986 and 1987–2020) to identify species-specific climatic drivers and potential temporal shifts. To further distinguish years with LSF impacts on beech radial growth, climatic signals not related to LSF recorded in the spruce series were removed from the beech chronologies.Our preliminary analyses indicated that tree growth was dominated by different climatic factors in the two study sites: tree growth was limited by cold temperatures during both study periods in the higher elevation site whereas drought signals were apparent in tree growth during the second study period in the lower elevation site. Interestingly, beech growth was initially negatively and then positively related to spring minimum temperature at the higher elevation site. At the lower elevation site, warm temperatures in spring promoted tree growth of both species only during the second period (1987–2020). By subtracting the climatic signals of spruce on beech chronologies, we identified five and two years potentially affected by LSF during the last 30 years at the upper and lower sites, respectively. We are currently calibrating phenological models to climatically identify the years with potential frost damage and verify if these years are consistent with the ones identified with the previous dendrochronological analyses.We further hypothesized that a damaging spring frost followed by a severe drought during summer may have a much larger impact than drought alone. Further investigations should be conducted on this aspect as the frequency and severity of extreme droughts are expected to increase while spring onset will continue to advance under a warmer climate, potentially increasing the risk of frost damage. 
A possible nitrogen limitation ahead? Low discharges fuel nitrogen retention in the Elbe estuary
Authors: Schulz Gesa , Sanders Tina , Ankele Markus , van Beusekom Justus , Dähnke Kirstin
Published: February 2023

Eutrophication of surface water bodies is an important factor that impairs the chemical quality of surface waters. In consequence, legislation and management efforts have been made over the past decades to reduce the agricultural nutrient input and meet the goals set by the EU Water Framework Directive and, more recently, by the UN Sustainability Goals.  In this study, we evaluate trends in nitrate concentration and isotope composition at the entrance of the Elbe Estuary, Northern Germany.  We find a distinct seasonality of nitrate isotope composition and nitrate concentration, with high isotope values in summer, pointing towards assimilation and denitrification in the Elbe River and catchment.Our data indicate that low discharge conditions intensify biological nitrate retention and nitrogen uptake during the growing season, leading to more intense nitrate isotope enrichments and low the water column concentrations. This suggests that recent reduction in Elbe River nutrient loads do not result from successful nutrient management but from a long-lasting drought in the catchment. In consideration of climate change predictions, we anticipate more frequent and extensive periods of low discharges, possibly even leading to a future nitrogen limitation in the lower Elbe River.    This study was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany‘s Excellence Strategy – EXC 2037 “CLICCS - Climate, Climatic Change, and Society” – Project Number: 390683824, contribution to the Center for Earth System Research and Sustainability (CEN) of Universität Hamburg.
High resolution Vp and Vs imaging for geothermal exploration in the Ilan Plain, northeastern Taiwan by joint inversion of body-wave and surface-wave data
Authors: Su Po-Li , Huang Hsin-Hua , Lin Cheng-Horng , Lee Jian-Cheng
Published: February 2023

The Ilan Plain in northeastern Taiwan located at the southern termination of the Okinawa Trough, which is formed by the back-arc extension of the Ryukyu subduction zone. Owing to this extensional tectonic setting, the Ilan Plain shows distributed hot springs with high geothermal gradient in several places, such as the Chingshui, Jiaoxi, Longde-Lize and Hongchailin areas. These are potential locations for geothermal exploration which require a thorough investigation to understand their geothermal system and to evaluate their potential in geothermal power generation. Seismic velocity provides key information to determine properties of a geothermal system including the distribution of fluids, fractures, and porosity. This study obtained seismic velocity images of the Ilan Plain and the surrounding area by joint inversion of body wave travel times of local earthquakes and Rayleigh wave phase velocities from ambient noise correlations recorded by a temporary dense geophone array in the Ilan Plain and the Formosa Array in northeastern Taiwan. The joint inversion takes advantage of the complementary sensitivities of both data types to better constrain both shallow and deep structures. In addition, we also lift the flat earth surface assumption commonly assumed in the surface wave tomography to avoid possible biased velocity structure due to topography by adapting the surface wave sensitivity kernel to the surface topography in the inversion. The obtained image at the 1-km depth shows low Vp and Vs corresponding to unconsolidated Quaternary sediments. The deeper images at 2- to 5-km depths show a low-velocity corridor extending from the Guishan volcanic island northeastern offshore to the southwest corner of the Ilan Plain, implying that the heat source of the geothermal systems in the Ilan Plain may be related to magmatic intrusions of backarc rifting. Locally, in the shallow region of the Chingshui and Jiaoxi area and the deeper region of the Hongchailin and Longde-Lize area, the high Vp/Vs ratio with little increase in Vp and significant decrease in Vs could indicate a saturated rock with high porosity, based on the rock physics principles in geothermal environment summarized in previous study. The low Vp, Vs, and Vp/Vs ratio in the shallow region of the Hongchailin area could indicate vapor-rich high temperature environment. Our results demonstrate the potential of new seismic imaging integrating body- and surface-wave data for geothermal exploration.
Analysis of Wind Energy production conditions in Catalonia (NE Spain) based on multiple data sources: station data, ERA-5 Reanalysis, WRF/CALMET, and EURO-CORDEX.
Authors: Aguilar Enric , Skrynyk Oleg , Olano Pozo Jon Xavier , Boqué Ciurana Anna , Domènech Antoni
Published: February 2023

Climate Change is largely affecting western societies and urgent decarbonization is a must to limit as much as possible global warming. Renewable energy is a critical component of this energy transition, as well as changes in human behavior. According to the Catalan Institute of Energy (ICAEN), Catalonia generated 2,706 GWh of wind energy in 2021, accounting for 6.4% of the total production.  

 

In this contribution, we explore the clear connection between wind energy capacity and weather and climate conditions. First, we use ERA-5 mean sea level pressure data (1959-2021) to identify the dominant circulation types and their evolution. Second, we combine these data with accurate local station data from the Catalan network of automatic weather stations (XEMA, from the acronym in Catalan) for the period 2009-2021 to identify the geographic patterns of wind energy production under the different circulation types. This analysis is refined using a coupled WRF/CALMET (on a 3km and 1km grid, respectively) hybrid dynamical/statistical downscaling of the GFS global data performed for the period 2016-2020. The investigation supports the assumption that, climatologically speaking, the southern areas in the mountains of Tarragona’s province and the northeastern area of Catalonia, bordering with France, are the most suitable for producing wind energy in most circumstances.  

 

Finally, using EURO-CORDEX climate model projections, we inspect future conditions.  

 
How does peatland restoration alter hydrological function and fluvial carbon exports?
Authors: Benaud Pia , Gatis Naomi , Goodger Louise , Anderson Karen , Brazier Richard E
Published: February 2023

Globally, significant resources are being targeted towards the restoration of degraded peatlands in an attempt to recover ecohydrological conditions and promote the delivery of ecosystem services, such as flood management, water storage and carbon sequestration. However, though crucial for net zero plans and climate change adaptation strategies, the ecohydrological response to restoration efforts are not yet fully understood.

Using a before-after-control-impact experimental design in an ecohydrologically degraded peatland on Dartmoor, southwest United Kingdom, we are quantifying restoration impacts on water table depth in an erosional pan/hagg complex and related alterations to flow regimes in a downslope erosional gully, within paired sub-catchments. Through monitoring water quality at the gully, with a particular focus on DOC and colour, we also seek to describe the impact of any changes in peatland function on fluvial carbon fluxes.

Preliminary results, collected 3 years post-restoration, indicate increased water table depths and water storage duration within peat pans and a significant reduction in peak discharge following restoration. In turn, we hypothesise that there will be a significant reduction in fluvial carbon exports and, as time since restoration increases and water tables stabilise, alterations to the relationship between water discolouration and carbon.
Evaluation of long-term changes of upper tropospheric and lower stratospheric water vapour and ice supersaturated regions in different altitudes and geographical regions derived from MOZAIC and IAGOS routine in-situ observations
Authors: Rohs Susanne , Smit Herman , Blomel Torben , Li Yun , Bundke Ulrich , Petzold Andreas
Published: February 2023

Water vapour is the most important greenhouse gas in the Earth’s atmosphere, both, due to radiative forcing and the formation of clouds. The upper troposphere and lowermost stratosphere (UTLS) region is an especially sensitive region for climate radiative forcing. In the UTLS the air is cold with a large spatial and temporal variability of water vapour.  With the MOZAIC (Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft) data it was recently shown that in the extratropical UT close to the tropopause the air is nearly saturated with respect to ice and contains a significant fraction of ice-supersaturated regions (ISSRs) (Petzold et al., ACP, 2020, doi.org/10.5194/acp-20-8157-2020).In the present study we investigate the long-term changes of water vapour in the tropopause region using the combined time series of MOZAIC and IAGOS (In-Service Aircraft for a Global Observing System; www.iagos.org). Their observation systems are deployed on a fleet of commercial aircraft and aim at the provision of long-term, regular, and spatially resolved in situ observations of the atmospheric composition on a global scale. The combined water vapour and relative humidity time series spans now more than 27 years and is comprised of nearly 65000 flights. This makes the data set well-suited for long-term characterization of the water vapour distribution in the extratropical UTLS, namely at mid-latitudes with highest flight densities. We will present analyses of the time series from 1996 to 2020 for long-term changes of absolute humidity, temperature, relative humidity with respect to ice (RHice) and occurrence of ISSRs. Our focus lies on different altitude levels in the UTLS at northern mid-latitudes over the regions Eastern North America, North Atlantic and Europe.
How to power an off-grid telescope? Comparative life cycle analysis of renewable-based energy systems
Authors: Viole Isabelle , Valenzuela Venegas Guillermo , Shen Li , Ramirez Camargo Luis , Sartori Sabrina
Published: February 2023

A new radio telescope in the Atacama desert, Chile, is currently under design and envisaged to be powered by an off-grid energy system of photovoltaic arrays during the day-time and a hybrid energy storage system for non-sunny hours. Similar isolated solar energy systems employ Lithium-ion or Lead-acid batteries as storage, which either increase the pressure on critical materials like lithium and cobalt or contain lead which mining brings a set of harmful environmental impacts. Hydrides based on intermetallic compounds are emerging as a viable solution for energy storage in stationary applications and are particularly appealing due to their abundance and non-toxicity. Here, by developing a multi-objective techno-environmental optimization, we size a power system that can fuel the telescope’s demand economically while also maintaining a low life cycle carbon footprint. The optimization includes life cycle inventory data of potential components next to costs, including monocrystalline photovoltaic arrays, lithium-ion batteries, hydrogen storage in metal hydrides and as compressed gas, alkaline electrolyzers, PEM fuel cells and diesel generators.Pure techno-economical optimization without life-cycle inventory optimizes towards power systems with up to 32% of curtailed photovoltaic power. Levelized costs of electricity resulted in $120/MWh with photovoltaics, hybrid storage systems and diesel generators as a backup, and $140/MWh for systems relying on solely batteries and photovoltaics. With our optimization, we propose a system resulting in a low life cycle carbon footprint and acceptable electricity prices, analyzing indirect carbon emissions of the stationary system as well as costs.The life-cycle carbon footprint optimization performed allows both the remote telescope in question and other off-grid energy systems to make informed decisions on sustainable solutions to fuel their power needs.
Assessing Resilience Components in Maritime Pine Provenances Grown in Common Gardens
Authors: Lisella Concetta , Antonucci Serena , Santopuoli Giovanni , Marchetti Marco , Tognetti Roberto
Published: February 2023

Knowledge acquisition on the response of tree species to drought in the Mediterranean hotspot is an important step to guide adaptation strategies to climate change impacts, e.g., assisted migration.We assessed the resilience components - i.e., resistance, recovery, and resilience - to droughtin 2003 in five provenances of maritime pine planted in four common gardens in Sardinia, and analysed the possible influence of climate variables on these indices. The provenances showed differences in growth rate but not in the components of resilience. Among the provenances, Corsicawas the most productive, while Tuscany was the least. One of the two provenances from Sardinia (Limbara) showed good performance in terms of tree growth in the comparatively drier site. The resilience components were influenced by prevailing environmental conditions at the common gardensites. In the relatively drier sites, trees showed the lowest resistance but the highest recovery values. However, two sites - which had the lowest stand density - showed the opposite trend during the drought year, probably due to moderate thinning. Predictive models showed different probability inthe response of resilience components to climate variables. Resistance and resilience had a similar pattern, both being positively related to temperature, while recovery showed an opposite trend. The models’ results indicate a noticeable adaptation of maritime pine to the drought conditions of Sardinia, though the age factor should be considered as well. Despite only minor differences among provenances being found, environmental conditions and management practices at the common gardens were important in determining tree growth patterns. This study suggests that the provenance of Corsica may provide appropriate material for forest plantations in Mediterranean conditions with mitigation purposes.
3D Crustal structure of the Basque-Cantabrian Zone (N Spain) through a nonlinear joint inversion of surface wave phase velocities, teleseismic receiver functions and Rayleigh wave ellipticity
Authors: Olivar-Castaño Andrés , Pedreira David , Pulgar Javier A. , Pilz Marco , Díaz-González Alba , González-Cortina Juan Manuel
Published: February 2023

The Basque-Cantabrian Zone (BCZ) is a large, inverted Mesozoic basin (the Basque-Cantabrian basin or BCB) forming part of the Pyrenean-Cantabrian mountain belt, in the north of Iberian Peninsula. The Mesozoic basin developed in one of the most subsident regions between the European plate and the Iberian sub-plate during the stage of crustal hyperextension linked to the rifting of the Central-North Atlantic and the opening of the Bay of Biscay. The high subsidence rate led to the accumulation of more than 15 km of sediments according to some estimates, and the significant crustal extension caused the exhumation of the mantle in the easternmost sector of the BCB. The Alpine orogeny caused the closure and inversion of the BCB and its incorporation to the Pyrenean-Cantabrian orogen. In this work, we studied the crustal structure of the BCZ resulting from this long and complex tectonic evolution using five years of continuous seismic recordings gathered by a local network of broadband stations, most of them deployed in the framework of projects SISCAN and MISTERIOS. A total of 66 locations were used (not all of them simultaneously), with an average spacing of ~30 km between stations. From this dataset, we extracted the multi-mode phase velocities of surface waves and the ellipticity of Rayleigh waves from cross-correlations of the seismic ambient noise. This allowed us to retrieve the shear-wave velocity structure of the crust, especially at shallow to intermediate depths. To better constrain the deeper crustal structure, we also extracted teleseismic P-wave receiver functions for all suitable events. Each dataset was carefully analyzed before performing a nonlinear, joint inversion using the simulated annealing technique. The result is a set of 1D shear-wave velocity models that represent a compromise between all three datasets. These 1D models were then used in a linear interpolation to build a 3D model of the BCZ. The main feature of the 3D model is a thickened crust of up to 50 km beneath the Cantabrian Mountains. A discontinuous, intracrustal level of high-velocities is identified in the northern part of the model, coherently with previous geological and geophysical observations, suggesting that the thick crustal root would be caused by the indentation of the Cantabrian Margin lower crust into the Iberian crust, as has been already proposed. This new 3D model fills a gap in the knowledge of the study area, whose seismic characterization was primarily based on active source studies, which often only provide estimates of the P-wave velocities along 2D profiles.
A network of water vapor Raman lidars for improving heavy precipitation forecasting in southern France: introducing the WaLiNeAs initiative and first highlights from the 2022 field campaign
Authors: Flamant Cyrille ,   WaLiNeAs Team
Published: February 2023

Extreme heavy precipitation events (HPEs) pose a threat to human life but, despite regular improvement, remain difficult to predict because of the lack of adequate high frequency and high-resolution water vapor (WV) observations in the low troposphere (below 3 km). To fill this observational gap, The Water vapor Lidar Network Assimilation (WaLiNeAs) initiative aims at implementing an integrated prediction tool (IPT), coupling network measurements of WV profiles, and a numerical weather prediction system to try to improve the  forecasts of  the amount, timing, and location of rainfall associated with HPEs in southern France (struck by ~ 7 HPEs per year on average during the fall).In the fall/winter of 2022-2023, a network of 6 mobile Raman WV lidars was specifically implemented in Southern France (Aude, Gard, Var and Bouche du Rhone) and in Corsica. The network was complemented by 2 fixed Raman WV lidars in Barcelona and Valencia with the aim to provide measurements with high vertical resolution and accuracy to be assimilated in the French Application of Research to Operations at Mesoscale (AROME-France) model, using a four-dimensional ensemble-variational approach with 15-min updates in addition to the observations operationally assimilated (radar, satellites, …). This innovative IPT is expected to enhance the model capability for kilometer-scale prediction of HPEs over southern France up to 48 h in advance.The field campaign was conducted from October of 2022 to January 2023, to cover the period most propitious to heavy precipitation events in southern France. A consortium of French, German, Italian, and Spanish research groups operated the Raman WV lidar networkIn this presentation, we will provide an overview of the precipitation events in southern France during the WaLiNeAs campaign, as well as an outline of the operations period of the different Raman WV lidars and the lidar data monitoring procedure implemented during the experiment. We will highlight the cases of interest and provide an outlook at next steps towards lidar data assimilation in AROME.
Towards ecosystem functionality: the case of sulphide mining tailings colonization.
Authors: Campos Juan Antonio , Villena Jaime , Moreno Marta Maria , Peco Jesús Daniel
Published: February 2023

The enormous diversity of variables that come together in the functioning of ecosystems makes it very difficult to establish reliable patterns of functionality, understood as the ability of ecosystems to progress in a balanced way with their own resources. The natural colonization of spaces degraded by mining offers us the opportunity to study the construction of an ecosystem from its beginnings. The scarcity of resources and the geochemical conditions that occur in these spaces carry out a screening of species and, consequently, the communities that establish in these soils are much simpler. In a mining area close to the city of Ciudad Real (Spain), large deposits of fine material, originating from mining processes, have remained untouched for more than 70 years and have become an exceptional place to study the rate of natural colonization and soil formation on a short scale of time and space. The transition between a bare regolithic substratum and a functional soil was monitored and analyzed to find out which are the key factors on which the functionality of the ecosystem is based. The special abilities of some pioneer plant species, the collaboration between them and the climatic factors of the study area, establish a unique path towards the achievement of a viable and functional ecosystem. In our work we have studied the natural colonization process that has occurred in a mining tailings dump (6 ha), analyzing the essential role of the reed (Phragmites australis) as a colonizing plant. Indeed, this species creates a dense network of rhizomes that favors the retention of edaphic resources such as organic matter, water and clay that will help other species to settle. In this way, a process of creating a new ecosystem begins, whose evolution will be conditioned only by the restrictions imposed by climatic patterns of rainfall and extreme temperatures. Plant species specific distribution, the standing biomass the microbial composition and enzymatic activity of the soil have been monitored, as well as the standardized soil parameters such as pH, texture, organic matter characterization, etc.
Machine learning for water detection in ephemeral streams
Authors: Peña-Haro Salvador , Hernandez Daniel , Cecilia José M.
Published: February 2023

Measuring the volumetric water flow in ephemeral streams, typical of semi-arid climates, in which water rarely flows, is challenging since water only flows some days per year and some times it is in the form of flash floods. In this type of conditions it is important to detect when there is water in the stream. For this, we have implemented a machine learning algorithm for water detection and for stream gauge measurement.Machine learning was used to differentiate pixels of the image that contains water from those those that do not via image segmentation. Different segmentation models have been proposed, but in our case we used an encoder-decoder DNN architecture based on DeepLabV3. To train the model, we used the ArtificiaL And Natural waTer-bodIes dataSet (ATLANTIS) data-set. However not all the images were used since these data-set includes classes that are not representative for our application, hence the total number of images used for training was 685. Additionally the original defined classes were merged to reduce the problem to a semantic binary segmentation problem, since our objective is to simply detect the presence of water on the stream. In addition to those images, we have used other images recorded by fix cameras looking at some ephemeral streams to improve the training.The trained network was used to analyze 50 images with different water levels or no water. To evaluate its performance and indicator was defined which considered the number of pixels classified as water inside the image area covered by the stream over the total number of potential pixels having water, and a 60% threshold was used to determine if there is water in the stream. From the 50 images analyzed, only 3 were wrongly classified giving promising results.This work has been supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101017861 and also by projects RTC2019-007159-5 and Ramon y Cajal Grant RYC2018-025580-I, funded by MCIN/AEI/10.13039/501100011033, “FSE invest in your future” and “ERDF A way of making Europe”
Modeling soil moisture variations for direct groundwater recharge estimation in the critical zone
Authors: Krüger Nina , Külls Christoph
Published: February 2023

It is becoming increasingly important to develop simple and efficient models for the assessment of groundwater recharge to improve sustainable groundwater management strategies. Reliable data on environmental fluxes can be collected on-site and for corresponding periods, providing information on groundwater recharge only after measurement campaigns covering several years. However, the large amount of hydrological data necessary for some methods to estimate recharge is not always available. To address these issues, a specific model for the evaluation of vertical water fluxes in the critical zone was developed. The model is directly based on soil moisture sensor data in the critical zone and does not require modeling of meteorological processes, nor time series of precipitation, temperature, relative humidity, global radiation, or sunshine hours. Based on the numerical solution of the Richards equation and using Van Genuchten relationships for soil parameterization, percolation rates and subsequent groundwater recharge are derived from potential gradients and variations of volumetric soil moistures at different depths in the critical zone. Model results are evaluated with a detailed performance analysis with several mathematical error indices and graphical methods. The resulting fluxes have been validated with an independent stable isotope profile approach confirming the applicability of the model. The model can be applied to a soil moisture monitoring station with three monitoring sensors in the critical zone to derive daily time series of water fluxes.
Multi-centennial modulation of Atlantic multi-decadal variability in a 2000-year climate integration
Authors: Kjellsson Joakim , Park Wonsun
Published: February 2023

We explore the amplitude and frequency of Atlantic Multi-decadal Variability (AMV) in a 2,000-year pre-industrial control simulation with the FOCI-OpenIFS coupled climate model. We find a statistically significant AMV-like mode on the 20-year and 80-year time scales. We also find a mode of multi-centennial variability where the North Atlantic Ocean shifts a regime of a warm period to/from a cold period of ~400 years. The warm period is characterised by mean states of a stronger and deeper Atlantic Meridional Overturning Circulation (AMOC), less Arctic sea ice, and more deep convection in the Labrador Sea than the cold period.  We find that the AMV has a much higher amplitude in the cold period compared to the warm period, and also that the lead-lag relationship between the AMOC and the AMV is different between the two periods. In the warm period, AMOC leads the AMV; a strong AMOC enhances the oceanic poleward heat transport which warms the North Atlantic Ocean both at the surface and deeper down, producing a positive AMV. In the cold period, however, AMV leads AMOC; a warm surface anomaly reduces the sea ice in the Labrador Sea which enhances local air-sea interactions and deep convection, and later a stronger AMOC. In the cold period, the warm anomaly associated with the AMV does not extend below the mixed layer, suggesting that it is driven by the atmosphere and not ocean dynamics.
A novel user-friendly Jupyter-based tool for analysing orbital subsurface sounding radar data.
Authors: Nodjoumi Giacomo , Lauro Sebastian Emanuel , Rossi Angelo Pio
Published: February 2023

Orbital radars, such as the SHAllow RADar (SHARAD) [1] or the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) [2] instruments on board Mars Reconnaissance Orbiter (MRO) and Mars Express (MEX) respectively, provide valuable data about the Martian subsurface [3,4].Common analysis methodologies comprise a direct comparison between the radargram (RDR) and the corresponding Surface Clutter Simulation (SCS) to visually spot any subsurface reflector. The surface time delays converted in the space domain are then compared with the corresponding topographic profile to check if any discrepancy occurred. and thus be mistaken for subsurface reflections. Once confirmed that the subsurface reflector is valid, the proper picking can be performed by looking at the radargram and both the radargram and the simulation power intensities. Finally, it is possible to estimate the real dielectric constant ε', which is the real component of the complex permittivity ε' - iε'' using Equation Eq1 [3]:where Δt is the two-way travel time between the surface and the subsurface reflector, c is the speed of light in a vacuum and h is the reflector’s depth. Assuming different values for ε' and inverting Eq1, is possible to estimate the depth, thus the thickness of the reflector’s unit. In this work, we present the first pre-release of a user-friendly interface, with which is possible to easily perform the above analysis while granting robustness and reproducibility. Besides, it is possible to implement further custom processing functions to increase the accuracy of the results and/or expand the tool capabilities. We started the development using SHARAD US RDR and SCS, while MARSIS compatibility is under implementation. We provided also additional Jupyter notebooks for data download. This tool is based on the Jupyter lab environment and open-source python packages served as a docker container.Open Research: The tool presented here is available on GitHub [5]Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No 101004214 and No 871149.References:[1] Seu, R., et al., SHARAD Sounding Radar on the Mars Reconnaissance Orbiter., doi:10.1029/2006JE002745.[2] Jordan, R., et al., The Mars Express MARSIS Sounder Instrument. doi:10.1016/j.pss.2009.09.016.[3] Shoemaker, E.S., et al., New Insights Into Subsurface Stratigraphy Northwest of Ascraeus Mons, Mars, Using the SHARAD and MARSIS Radar Sounders. doi:10.1029/2022JE007210.[4] Lauro, S.E., et al., Using MARSIS Signal Attenuation to Assess the Presence of South Polar Layered Deposit Subglacial Brines. doi:10.1038/s41467-022-33389-4.[5] Nodjoumi, G. MORDOR - Mars Orbital Radar Data Open-Reader 2023.
Sustainable Pathways under Climate Variability
Authors: Rehfeld Kira ,   SPACY research group members
Published: February 2023

External forcings and feedback processes of the Earth system lead to timescale and state-dependent climate variability, causing substantial surface climate fluctuations in the past. Particularly relevant for future livelihoods, changing variability patterns could also modify the occurrence of extreme events. However, spatiotemporal mechanisms of climate variability are poorly understood. Likewise, the societal implications are weakly constrained, particularly variability’s potential to drive sustainable transformation. The SPACY project investigates climate variability from past cold and warm periods to future scenarios. One research focus is how forcing mediates climate fluctuations. Bridging the gap between Earth system models and palaeoclimate proxies, we study vegetation and water isotope changes. A second focus is exploring sustainable pathways under climate variability, addressing potential interactions between artificial carbon dioxide removal and surface climate, among others. In particular, we validate the ability of climate models to represent potential climate variability changes. Here, we focus on isotope-enabled simulations with dynamic vegetation. We find that models exhibit less local temperature and water isotope variability than paleoclimate proxies on decadal and longer timescales. Simulations with natural forcing agree much better with proxy records than unforced ones. The mean local temperature variability decreases with warming. Furthermore, we analyze potentials and limitations of terrestrial hydroclimate proxies. This includes water isotopes in speleothems and ice cores and vegetation indicators derived from pollen assemblages.Transferring our understanding to the future, we contribute to mitigation and sustainable transitions. Weather and climate extremes determine losses and damages, but their impact on socioeconomic development is poorly examined. We scrutinize damage parametrization of economic models regarding the ability to consider variability. While large-scale sequestration of atmospheric carbon dioxide is paramount to mitigation targets, its representation in climate models is insufficient. Accounting for feedbacks of carbon dioxide removal (CDR) requires model experiments with modified land surfaces. We develop CDR representations of “artificial photosynthesis” in Earth system models. Pollen records benchmark the simulated climate–carbon dioxide–vegetation interactions. This supports modeling endogenous societal land use decisions in the future.Our work continues to improve the understanding of long-term climate predictability. The combined knowledge from past climate studies and comprehensive modeling for future scenarios underlines the relevance of changing boundary conditions for a future within planetary boundaries.  