bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving data, metadata and service quality within Résif-SI
Authors: Schaeffer Jonathan , Engels Fabien , Grunberg Marc , Maron Christophe , Pardo Constanza , Saurel Jean-Marie , Wolyniec David , Arnoul Patrick , Bollard Philippe , Touvier Jérôme , Chèze Jérôme , Peix Fabrice , Pequegnat Catherine
Published: March 2021

Résif, the French seismological and geodetic network, was launched in 2009 in an effort to develop, modernize, and centralize geophysical observation of the Earth’s interior. This French research infrastructure uses both permanent and mobile instrument networks for continuous seismological, geodetic and gravimetric measurements.

Résif-SI is the Information System that manages, validates and distributes seismological data from Résif.

The construction of Résif-SI has lead to a federated organisation gathering several data and metadata producers (Nodes) and a national Seismological Data Centre.

The Résif Seismological Data Centre is one of 19 global centres distributing data and metadata in formats and using protocols which comply with International Federation of Digital Seismograph Networks (FDSN) standards. It is also one of the eleven nodes in EIDA, the European virtual data centre and seismic data portal in the European Plate Observing System (EPOS) framework.

Inside Résif-SI, each Node has it's specificities and dedicated procedures in order to manage and validate the data and metadata workflow from the station instruments to the Résif Seismological Data Centre.

To meet the expectations and needs of the end user in terms of data quality, metadata consistency and service availability, Résif-SI operates a complex set of quality enhancement operations.

This contribution will present the quality expectations that are in the core of Résif-SI, and show the methods and tools that help us meeting the expectations, and that could be of interest for the rest of the community.

We will then list some of our quality improvement projets and the expected results.
Do PSHA maps overpredict or are there shaking deficits in the historic record?
Authors: Salditch Leah , Stein Seth
Published: March 2021

Probabilistic Seismic Hazard Assessment (PSHA) attempts to forecast the fraction of sites on a hazard map where ground shaking will exceed the mapped value within some time period. Because the maps are probabilistic forecasts, they explicitly assume that shaking will exceed the mapped value some of the time. At a point on a PSHA map, the probability p that during t years of observations shaking will exceed the value on a map with a T-year return period is assumed to be described by the exponential cumulative density function: p = 1 – exp(-t/T). The fraction of sites, f, where observed shaking exceeds the mapped value should behave the same way. To assess the 2018 USGS National Seismic Hazard Model maps for California, we created the California Historical Intensity Mapping Project (CHIMP), a 162-yr long dataset that combines and consistently reinterprets seismic intensity information that has been stored in disparate and sometimes hard-to-access locations (Salditch et al., 2020). We use two performance metrics; M0 based on the fraction of sites where modeled ground motion is exceeded, and M1 based on of the difference between the mapped and observed ground motion at all sites. M0 is implicit in PSHA because it measures the difference between the predicted and observed fraction of site exceedances and is therefore a key indicator of map performance.

We explore these metrics for CHIMP. Assuming the dataset to be correct, it appears that the hazard maps overpredicted shaking even correcting for the time period involved. Assuming the model is also correct, a shaking deficit exists between the model and observations. Possible reasons for this apparent overprediction/shaking deficit include: 1) the observations in CHIMP are biased low; 2) the observation period has been less seismically active than typical – either by chance or temporal variability due to stress shadow effects; 3) the model overpredicts due to either the earthquake rupture forecast or the ground motion models. Similar overpredictions appear for past shaking data in Italy, Japan, and Nepal, implying that seismic hazards are often overestimated. Whether this reflects too-high models and/or biased data remains an important question.
Chemical weathering response to extreme global warming during Paleocene-Eocene Hyperthermals, Southern Pyrenees, Spain
Authors: Jaimes-Gutierrez Rocio , Adatte Thierry , Puceat Emmanuelle , Braun Jean , Castelltort Sebastien
Published: March 2021

The Paleocene and early Eocene were periods yielding multiple hyperthermal events. The most pronounced of them was the Paleocene-Eocene Thermal Maximum (PETM), which was characterized by an abrupt increase in global temperature (5–8 °C) over a short time (20 ka). A negative carbon isotope excursion marks the onset of the PETM, which resulted in the fast injection of CO2 into the ocean-atmosphere system, triggering global climatic changes. Geochemical, mineralogical, and sedimentological markers record the resulting increase in continental weathering. This is important, as enhanced chemical erosion influences both the CO2 concentration in the atmosphere and ocean acidity, generating a feedback mechanism. Hence, constraining the rates and intensity of weathering response can further clarify the causes for the PETM and Eocene hyperthermals. This study focuses on the well-preserved Pyrenean foreland basin and intends to assess the continental chemical weathering response of the sediment routing system during the PETM. Clay mineralogy is a climate-sensitive proxy, which records changes in continental erosion. Therefore, clay mineral proportions will be analyzed using X-ray diffraction and major element chemistry on clay-rich samples from the entire source-to-sink system (continental to deep marine deposits). Kaolinite and smectite will be separated from the detrital clay fraction and further subjected to δ18O and δD isotopic analysis for paleoclimatic reconstruction. The combined Lu-Hf and Sm-Nd isotope systems in the clay fraction of the sediments will be used to track the evolution of chemical weathering intensity. The outcome of this project will serve to validate numerical models to understand erosion as a function of rapid climatic change. This topic is of keen interest, as the PETM and its sedimentological signal work as a natural analog for anthropogenically-induced climatic change. The project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No 860383.
Swissforages: the Free and Open-Source Borehole Data Management System
Authors: Antonovic Milan , Cannata Massimiliano , Oesterling Nils , Brodhag Sabine
Published: March 2021

Most of the time boreholes data, particularly those collected in the past, are in the form of static data reports that describe the stratigraphy and the related characteristics; these data types are generally available as paper documents, or static files like .pdf of images (.ai). While very informative, these documents are not searchable, not interoperable nor easily reusable, since they require a non negligible time for data integration. Sometime, data are archived into database. This certainly improve the find-ability of the data and its accessibility but still do not address the interoperability requirement and therefore, combining data from different sources remain a problematic task. To enable FAIR borehole data and facilitate the different entities (public or private) management Swisstopo (www.swisstopo.ch) has funded the development of a Web application named Borehole Data Management System (BDMS) [1] that adopt the borehole data model () [2] implemented by the Swiss Geological Survey. From the first beta release (2019) several improvements to the platform has been implemented leading to the last official release of the platform (v1.0.2) officially available on www.swissforages.ch. The latest released features includes:

Borehole document storage

Interface customization

Improved access & authorization managemnt

External WMS/WMTS background map support

User feedbacks form

Handling of personalized and versioned terms of service

Enhanced bulk data import

Minor enhancements and bug fixes

 
Electrical-elastic modelling of rocks using cross-property DEM
Authors: Cilli Phillip , Chapman Mark
Published: March 2021

The combination of electrical and elastic measurements can be useful in lowering subsurface characterisation uncertainty. The majority of rock physics relations which relate a rock’s electrical and elastic properties, however, rely on the estimation of porosity as an intermediate step. By combining differential effective medium schemes which relate a rock’s electrical and elastic properties to porosity and pore shape, we obtain cross-property expressions which are independent of porosity, depending only on pore aspect ratio. Analysing published joint electrical-elastic measurements shows the cross-property model works well for clean sandstones, and models Vp/Vs ratios as a function of resistivity without porosity. Although clay-bearing sandstones are more complex, our model can still identify the correct trends. On theoretical grounds, it seems our approach has the potential to produce additional cross-property relations; a topic upon which we speculate.
Rice water requirements: local assessment based on remote sensing data in the Lower Mondego (Portugal)
Authors: P. de Lima Isabel , G. Jorge Romeu , L.M.P. de Lima João
Published: March 2021

Irrigated rice agriculture, which is traditionally conducted applying continuous flooding, requires much more irrigation water than non-ponded crops. This can be a constraint in areas facing water scarcity issues, where the pursue for water resources optimization requires that water use efficiency is increased. Therefore, main local challenges for rice production are often to identify and apply more favorable and efficient irrigation and crop management practices, while guaranteeing high crop yields. For this purpose, the knowledge of rice crop water requirements is an important practical consideration. However, there are usually several limiting factors to obtain relevant data for the local conditions. Several recent approaches and methodologies based on remote sensing data, such as images obtained from satellites and Unmanned Aerial Systems (UAS), are offering attractive alternative routes to estimate crop evapotranspiration in a fast and easy way, including in rice fields.

For the rice producing area of the Lower Mondego region (Portugal), we report on exploring the usefulness of remote sensing tools for the local rice agriculture monitoring and management. Data include 25 land surface images of rice cultivated areas obtained from satellite Sentinel-2A during 2020, which together with weather data and crop parameters permits to calculate biophysical indicators and indices of vegetation water stress. Although remote sensing data available from satellite imagery presents some practical constraints (e.g. cloud cover, resolution), preliminary results from this study show that they allow to improve the characterization of the rice local cultivation conditions, therefore contributing to evaluate the impact of applying different irrigation and agriculture management practices, in particular those that have the potential to lead to significant savings of irrigation water.

This work was conducted under the umbrella of the international project MEDWATERICE (www.medwaterice.org) that focus on improving the sustainable use of water in the Mediterranean rice agro-ecosystem and aims to exploring the opportunity to apply water-saving, alternative, rice irrigation methods.
The effect of fluctuating light on canopy photosynthesis: a focus on a chlorophyll-deficient Soybean mutant
Authors: Salvatori Nicole
Published: March 2021

In natural environments plants are subjected to variable light conditions and therefore need an efficient regulatory system to regulate photosynthesis and the downstream metabolism. Most of the measurements available are taken at steady state and at leaf level but those may overestimate total carbon uptake in a more dynamic environment. Furthermore, some plants may be more adapted than others to deal with light fluctuations and therefore is difficult to draw general conclusions. We then grew a commercial soybean variety and a chlorophyll deficient mutant in a recently developed growth chamber system (DYNAMISM) which allowed to obtain instantaneous gas exchange data at canopy level for several weeks. By doing so we could investigate both short term responses and long term adaptations to light dynamic conditions of the two varieties. At steady state, chlorophyll deficient crops are thought to have a similar or even a higher photosynthetic rate compared to the green wildtypes, enhanced by a higher light transmittance throughout the canopy. But little is known about how they respond to fluctuations in light. The two varieties were grown either in fluctuating (F) or non-fluctuating (NF) light conditions to evaluate how variable light would affect biomass accumulation. Two different light treatments were applied, low light (LL) and high light (HL) with different light intensities and amplitude of fluctuations. The LL treatment did not entail any difference among F and NF in both varieties. The chlorophyll-deficient mutant was instead found to be susceptible to the fluctuations of light in the HL treatment, by accumulating less biomass. It is hypothesised that this might be due to its longer non‐photochemical quenching relaxation time  in light transitions, but other acclimatation mechanisms need to be investigated.
Agricultural decision-making under uncertainty: a loss function on the kriging variance from soil properties predicted by infrared and X-ray fluorescence spectroscopy
Authors: Breure Timo , Haefele Stephan M. , Webster Richard , Hannam Jacqueline A. , Corstanje Ronald , Milne Alice E.
Published: March 2021

Obtaining detailed soil information at a scale suitable for variable rate application (VRA) of fertilizer requires intense sampling. Within this context, traditional wet chemistry analysis of the soil is too costly to provide sufficient detail on the spatial variation of soils within fields. Infrared and X-ray fluorescence spectroscopy of soil is much cheaper and might provide sufficient data to map the concentrations affordably. Estimates of the concentrations from spectroscopy are subject to error, however, and these errors in turn carry with them costs if they lead to under- or over-applications of fertilizer and resultant loss of potential crop yields or environmental pollution. Given a loss function and an error distribution for the estimates of the concentrations, it is possible to minimize the expected loss from VRA fertilizer management.

Within this study, we have estimated the variation of available P and K within horticultural fields and the effect of errors on the expected loss. The topsoil (0-25 cm) of four fields was sampled at numerous points and analysed by infrared and X-ray spectroscopy to provide estimates of available P and K. . The spatial variation in the estimates were modelled as mixtures of fixed and random effects by residual maximum likelihood (REML), with the spectroscopic model error accounted for in the parameter estimates. These models where then used to map the P and K content by universal kriging together with their kriging variances. Loss functions were computed based on the error distribution and a dose response curve from the literature. We then computed the total loss (compared to perfect information) for each field under VRA of fertilizer and a blanket fertilizer scheme based on the wet chemistry data.

Underestimation of the error variance in four out of eight linear mixed models underlines the importance of error propagation to estimate the short-scale spatial variance of the soil property correctly. As expected, the optimum fertilizer rate when accounting for uncertainty tends towards over-application. The asymmetry of the loss function described that underestimation generally leads to a higher loss compared to overestimation of soil P and K. The effect of error variance on the expected loss was further found to be dependent on the range of the kriging predictions relative to the parameterization of the dose response curve. There was a financial incentive for VRA of P fertilizer but not for K. Additionally there is an environmental incentive for VRA of P because much less fertilizer would be applied compared to a blanket fertilizer rate based on wet chemistry data.
A people-centred approach for emergency communication: The case of site-specific warnings in Terrassa, Spain
Authors: Meléndez-Landaverde Erika , Sempere-Torres Daniel , Berenguer Marc
Published: March 2021

The resilience of communities depends on how their citizens react during emergencies and how authorities implement systems to support appropriate self-protection responses from the public. Past events such as the storm Gloria in Spain demonstrate that one of the main challenges in risk communication remains citizens' inappropriate understanding of the upcoming risk and its potential impact in their daily lives. The current official warnings to the population in Spain continue to be based on the exceedances of the event's physical parameters, such as rainfall intensities and accumulations, that can be difficult for citizens to understand, personalize and translate into the expected local risks. The above can create a communication gap between what authorities provide to citizens in terms of risk information and what they actually need from a flood warning to make better decisions and react appropriately during an emergency. 

Society is now demanding localized, people-centred risk communication for better social comprehension and acceptation, which provides understandable information about the expected local impacts and clear guidelines for ensuring citizens' safety during emergencies.

Thus, to support citizens' understanding and decision-making process at risk, we present a people-centred approach to design and implement new site-specific warnings (SSWs), i.e. warnings at problematic points based on local vulnerability and exposure information. The proposed methodology places people and communities at the core of the early warning system process. It blends meteorological information coming from radar-based rainfall nowcasting, numerical modelling and historical flood data to translate forecasts into relevant local impacts that the citizens may experience due to the coming weather-induced events and appropriate self-protection actions to help secure their lives. In this context, an active collaboration process with civil protection authorities, stakeholders and citizens is established from the start to incorporate their detailed local knowledge to the system and target their communication needs during emergencies. New technologies, such as smartphone applications, are used to disseminate the SSWs within the area of risk.

A first pilot based on the SSWs methodology is currently at the operational stage in Terrassa, Spain, for selected vulnerable points. Besides contributing to address the current gaps in risk communication, the implemented methodology in this study can help create a proactive, dynamic society by empowering its citizens to respond appropriately during the first instances of an emergency.
Verification and communication of the scientific quality of operational oceanography products of the Copernicus Marine Service
Authors: Garcia Hermosa Isabel , Régnier Charly , Drevillon Marie , Garcia sotillo Marcos , Sczcypta Camille
Published: March 2021

The Copernicus Marine Environment Monitoring Service (CMEMS) is delivering ocean satellite observations, in situ observations, together with ocean model reanalyzes, analyzes and forecasts from a unique web portal (Le Traon et al, 2019, https://doi.org/10.3389/fmars.2019.00234). Each one of these products is evaluated before its entry into service, and its quality is documented in a Quality Information Document (QUID). This information is complemented by regular quality metrics updates on the CMEMS website. Due to a relatively sparse observation network, in particular in subsurface, it is still a challenge to propose meaningful uncertainty estimates and forecast skills to the operational oceanography user’s community. In order to improve, and better target the scientific quality information provided to the various types of CMEMS users, several developments are ongoing which will be described in this presentation.
Atmospheric pressure compared to rainfall as landslide triggering factors along a hillslope
Authors: Pelascini Lucas , Steer Philippe , Longuevergne Laurent
Published: March 2021

Landslides are one of the sources of natural hazards that cause damages and losses but also shapes the landscape. A better understanding the factors triggering or pre-conditioning landslide occurrence is therefore critical for risk assessment, with implications for hillslope erosion and landscape dynamics Triggering of catastrophic landslides is generally associated with events such as earthquakes or intense rainfalls. In Taiwan, a minimum of 22,705 landslides were reported during the typhoon Morakot in 2009 (Lin et al., 2011). Landslides triggered during storms are generally associated to the intensity and cumulated amount of rainfall, as water infiltration destabilize slopes (Iverson, 2000). However, a correlation has also been reported between slope stability and the change in atmospheric pressure (Schulz, 2009). Indeed, a change in air-pressure can lead in a readjustment in pore pressure, and cause fluid movements normal to the surface. The aim of this study is to characterize the effect of atmospheric pressure changes and define its specific contribution on slope stability when combined with rainfall

A 2-dimensional analytical model has been developed based on diffusion equations to describe the destabilization induced by water infiltration and atmospheric pressure changes induced by typhoons. As both mechanisms are function of pore pressure, and especially groundwater pore pressure, the water table within a finite-length hillslope is modelled using Townley’s (1995) analytical expression of water flow in a unconfined aquifer. The hillslope itself is a simple tilted half-space with a water divide at the top and a river at the toe forcing the water table to the surface. Slope stability is inferred through a safety factor computed using the coulomb criterion. Both rainfall infiltration and air pressure modify pore pressure through a diffusion process. While rainfall increases water table height and induce large increases in pore pressure within days or hours, , we show that atmospheric-induced pore pressure change is instantaneous and can occur even if the hillslope is fully saturated.

The model allows to separate the hillslope response into two regimes, upslope or downslope, where the destabilization is mainly linked to rainfall or to atmospheric pressure change, respectively.  Our results suggest that landslide occurring during storms in the downstream part of the hillslope are likely candidate for being triggered by atmospheric pressure change, in particular if the storm occurs with a humid initial condition. We show that the effect of atmospheric pressure changes is not negligible. On contrary, it is crucial to define the amplitude, timing and geometry of the hillslope instability, especially when combined to rainfall.
Cloudburst catastrophe modelling: Case study – Jönköping municipality, Sweden 
Authors: Karagiorgos Konstantinos , Halldin Sven , Haas Jan , Knos Daniel , Blumenthal Barbara , Nyberg Lars
Published: March 2021

In Europe, flash floods are one of the most significant natural hazards, causing serious risk to life and destruction of buildings and infrastructure. The intense rain causing those floods has a few different names, however, with very similar meaning. The term chosen in this study, ‘cloudburst’, was introduced by Woolley (1946) as “…a torrential downpour of rain which by its spottiness and relatively high intensity suggests the bursting and discharge of the whole cloud at once”. While these events play an important role in the ongoing flood risk management discussion, they are under-represented among flood models.

The main aim of this study is to demonstrate an approach by showing how methods and techniques can be integrated together to construct a catastrophe model for flash flooding of Jönköping municipality in Sweden. The model is developed in the framework of the ‘Oasis Loss Modelling Framework’ platform, jointly with end-users from the public sector and the insurance industry. Calibration and validation of the model were conducted by comparisons against three historical cloudburst events and corresponding insurance-claim data.

The analysis has shown that it is possible to get acceptable results from a cloudburst catastrophe model using only rainfall data, and not surface-water level as driving variable. The approach presented opens up for such loss modelling in places where complex hydraulic modelling cannot be done because of lacking data or skill of responsible staff. The Swedish case study indicates that the framework presented can be considered as an important decision making tool, by establishing an area for collaboration between academia; insurance businesses; and local authorities, to reduce long-term disaster risk in Sweden.

 

Woolley, Ralf R., "Cloudburst Floods in Utah 1850-1938" (1946). Elusive Documents. Paper 55.
South Adriatic Recipes: Estimating the Vertical Mixing in the Deep Pit
Authors: Wirth Achim , Cardin Vanessa , Khosravi Maziar , Gačić Miroslav
Published: March 2021

The available historical oxygen data show that the deepest part of the South Adriatic Pit remains well-ventilated despite the winter convection reaching only the upper 700 m depth. Here, we show that the evolution of the vertical temperature structure in the deep South Adriatic Pit (dSAP) below the Otranto Strait sill depth (780 m) is described well by continuous diffusion, a continuous forcing by heat fluxes at the upper boundary (Otranto Strait sill depth) and an intermittent forcing by rare (several per decade) deep convective and gravity-current events. The analysis is based on two types of data: (i) 13-year observational data time series (2006–2019) at 750, 900, 1,000, and 1,200 m depths of the temperature from the E2M3A Observatory and (ii) 55 vertical profiles (1985–2019) in the dSAP. The analytical solution of the gravest mode of the heat equation compares well to the temperature profiles, and the numerical integration of the resulting forced heat equation compares favorably to the temporal evolution of the time-series data. The vertical mixing coefficient is obtained with three independent methods. The first is based on a best fit of the long-term evolution by the numerical diffusion-injection model to the 13-year temperature time series in the dSAP. The second is obtained by short-time (daily) turbulent fluctuations and a Prandtl mixing length approximation. The third is based on the zero and first modes of an Empirical Orthogonal Function (EOF) analysis of the time series between 2014 and 2019. All three methods are compared, and a diffusivity of approximately κ = 5 · 10−4m2s−1 is obtained. The eigenmodes of the homogeneous heat equation subject to the present boundary conditions are sine functions. It is shown that the gravest mode typically explains 99.5% of the vertical temperature variability (the first three modes typically explain 99.85%) of the vertical temperature profiles at 1 m resolution. The longest time scale of the dissipative dynamics in the dSAP, associated with the gravest mode, is found to be approximately 5 years. The first mode of the EOF analysis (85%) represents constant heating over the entire depth, and the zero mode is close to the parabolic profile predicted by the heat equation for such forcing. It is shown that the temperature structure is governed by continuous warming at the sill depth and deep convection and gravity current events play less important roles. The simple model presented here allows evaluation of the response of the temperature in the dSAP to different forcings derived from climate change scenarios, as well as feedback on the dynamics in the Adriatic and the Mediterranean Sea.
Large ensemble assessment of how the global surface warming response to cumulative carbon differs for negative and positive carbon emissions  
Authors: Vakilifard Negar , Turner Katherine , Williams Ric , Holden Philip , Edwards Neil , Beerling David
Published: March 2021

The controls of the effective transient climate response (TCRE), defined in terms of the dependence of surface warming since the pre-industrial to the cumulative carbon emission, is explained in terms of climate model experiments for a scenario including positive emissions and then negative emission over a period of 400 years. We employ a pre-calibrated ensemble of GENIE, grid-enabled integrated Earth system model, consisting of 86 members to determine the process of controlling TCRE in both CO2 emissions and drawdown phases. Our results are based on the GENIE simulations with historical forcing from AD 850 including land use change, and the future forcing defined by CO2 emissions and a non-CO2 radiative forcing timeseries. We present the results for the point-source carbon capture and storage (CCS) scenario as a negative emission scenario, following the medium representative concentration pathway (RCP4.5), assuming that the rate of emission drawdown is 2 PgC/yr CO2 for the duration of 100 years. The climate response differs between the periods of positive and negative carbon emissions with a greater ensemble spread during the negative carbon emissions. The controls of the spread in ensemble responses are explained in terms of a combination of thermal processes (involving ocean heat uptake and physical climate feedback), radiative processes (saturation in radiative forcing from CO2 and non-CO2 contributions) and carbon dependences (involving terrestrial and ocean carbon uptake).  
CO2 increase and ocean acidification in the Southern Indian Ocean over the last two decades
Authors: Leseurre Coraline , Lo Monaco Claire , Reverdin Gilles , Metzl Nicolas , Fin Jonathan , Mignon Claude
Published: March 2021

The Southern Ocean is recognized as a major player in the sequestration of anthropogenic carbon. As pH is naturally low at high latitudes, the increase in oceanic CO2 raises particular concerns in this region were surface waters could become rapidly under-saturated with respect to carbonate. We used repeated observations collected by the French monitoring program OISO (Ocean Indien Service d’Observation) in the surface ocean and the mixed layer over the last two decades (1998-2018), conducted on board the Marion Dufresne (IPEV/IFREMER). We used complementary data, available in SOCAT, to expand the study area, in order to investigate the evolution of CO2 and ocean acidification in the Southern Indian Ocean (45°S-57°S). South of the polar front in the High Nutrients Low Chlorophyll (HNLC) region, our results show an increase in the fugacity of CO2 (fCO2) in surface waters during summer, close to the increase in the atmosphere (on the order of +2 µatm yr-1) associated with a decrease in pH in the range of the mean global ocean trend (on the order of -0.0020 yr-1). However much larger changes are found in the phytoplankton blooms in the vicinity of Crozet and Kerguelen Islands for both fCO2 (between +3.0 µatm yr-1 and +5.0 µatm yr-1) and pH (ranging from -0.0033 yr-1 to -0.0059 yr-1). In all regions, the trends observed during summer are mainly driven by an increase in total carbon that is consistent with the accumulation of anthropogenic carbon evaluated below the summer mixed layer.
Estimating coal mine methane emissions using ground-based FTIR spectrometry, WRF driven Lagrangian dispersion modelling, and a regularized inversion approach
Authors: Luther Andreas , Kleinschek Ralph , Kostinek Julian , Stanisavljevic Mila , Dandocsi Alexandru , Forstmaier Andreas , Defratyka Sara , Scheidweiler Leon , Wildmann Norman , Dubravica Darko , Hase Frank , Frey Matthias , Chen Jia , Dietrich Florian , Knote Christoph , Nęcki Jarosław , Roiger Anke , Butz André
Published: March 2021

Methane (CH4) emissions from coal production are one of the main sources of anthropogenic CH4 in the atmosphere. Poland is the second largest hard coal producer in the European Union with the Polish area of the Upper Silesian Coal Basin (USCB) as a part of it. Emission estimates for CH4 from USCB for individual coal mine ventilation shafts range between 0.03kt CH4/yr and 25.9kt CH4/yr, amounting to a basin total of roughly 465kt CH4/yr (E-PRTR database, 2014). During CoMet (Carbon Dioxide and Methane Mission 2018) four ground-based, portable FTIR (Fourier transform infrared) spectrometers EM27/SUN were deployed in the USCB. We arranged these instruments in fixed locations in the North, East, South, and West of the USCB in approx. 50km distance to the center of the basin. This set-up ensures both, upwind and downwind measurements of CH4 for the prevailing wind directions. Subtracting upwind from downwind XCH4 observations gives the net methane enhancement of the region in between two selected instruments. These enhancements are also modeled with the Lagrangian particle dispersion model Flexpart. The model is driven by WRF wind simulations calculated in a nested domain using data assimilation of 3D wind-lidar data measured at three locations in the area of interest. The residuals between modeled and measured enhancements are minimized with a Phillips-Tikhonov regularized, non-negative least squares approach using the E-PRTR inventory data as a-priori information. The regularization parameters are graphically chosen via L-curve determination. Simulation uncertainty is expressed through an ensemble of different model runs, each with altered, basic meteorological parameters. The model generally matches the E-PRTR inventory data within it's error range for a small number (6 to 10) of coal mine ventilation shafts, whereas it suggests higher emission rates than the E-PRTR for more involved point sources (>30).
Enhanced volcanism associated to the emplacement of the North Atlantic Igneous Province during the PETM evidenced by mercury anomalies in Pyrenean foreland sections
Authors: Tremblin Maxime , Khozyem Hassan , Spangenberg Jorge E. , Fillon Charlotte , Calassou Sylvain , Grauls Arnaud , Lasseur Eric , Roig Jean-Yves , Serrano Olivier , Guillocheau François , Adatte Thierry , Castelltort Sébastien
Published: March 2021

The Paleocene-Eocene thermal maximum (PETM; ~55.6 Ma) is one of the most pronounced and the best known of the transient hyperthermal events of the Paleogene. The PETM is characterized by global warming, a significant perturbation of the carbon cycle, and a large perturbation of the biosphere. This extraordinary event is recorded by sharp negative carbon excursions (NCIE) in both oceanic and terrestrial carbonates. The sequence of events triggering this disturbance and the source of the 13C-depleted carbon for the NCIE remains controversial. External perturbation such as volcanism, associated with the setup of the North Atlantic Igneous Province (NAIP), is suspected to be one of the mechanisms responsible for this abrupt climate upheaval. One proxy for investigating the possible link between the establishment of the NAIP and perturbation associated with the PETM is to study mercury (Hg) concentrations record in marine and continental sedimentary successions.

In this study, we present new high-resolution mercury and stable isotopic records from peripheral basins of the Pyrenean orogen across the PETM. The four studies sections vary from continental to bathyal deposit environment and offer the potential to evaluate how major climatic disturbances are associated with the PETM record through a continental to marine transect.

The data obtained reveal the occurrence of two main NCIEs. Based on biostratigraphy and similarity of shape and amplitude of the isotopic excursions with global records, the largest NCIE is interpreted as the PETM. This sharp excursion is preceded by another one that we interpreted as the Pre-Onset Excursion (POE), founded in some other profiles worldwide. These two NCIEs are systematically associated with important mercury anomalies, whatever the environment considered. Increase in Hg contents shows no correlation with clay or total organic carbon contents, suggesting that the influences of local processes or Hg scavenging by organic matter appear to be insignificant. These results show that multiple pulses of volcanism, probably associated with the emplacement of the NAIP, contributed to the onset and the long duration of the PETM. In addition, our study highlights the possibility to get reliable information about past extreme climate events from sedimentary successions even if deposited within active tectonic domains.

This work is financed and carried out within the framework of the BRGM-TOTAL Source-to-Sink project.
Estimating the best spatial resolution of remotely sensed surface soil moisture based on their uncertainty 
Authors: van Hateren Theresa C. , Chini Marco , Matgen Patrick , Pulvirenti Luca , Pierdicca Nazzareno , Teuling Adriaan J.
Published: March 2021

Validation of remotely sensed soil moisture is a well-known issue. Reference data with the correct spatial and temporal resolution on large scales are sparse and lack spatial representativeness. Moreover, due to the heterogeneity of soil moisture in both space and time, even reference data cannot be considered to be “ground truth”. As such, uncertainties are difficult to quantify. Additionally, in remotely sensed soil moisture there are trade-offs between spatial resolution and temporal resolution, resolution and accuracy, and resolution and computing time. Here, we try to identify the best spatial resolution for Sentinel-1 based soil moisture estimation, considering the trade-off between product resolution and accuracy. We use the uncertainty  of the soil moisture estimate as a guide parameter, and focus on how product accuracy depends on factors as soil wetness, and characteristics of the vegetated canopy.  To this end, we compare Sentinel-1 soil moisture estimates to both in situ data and global reference data sets with a lower spatial resolution. Remotely sensed surface soil moisture data were obtained by applying the MULESME algorithm  (Pulvirenti et al., 2018) on Sentinel-1 data throughout 2020. An extensive field campaign was performed, where TDR data and volumetric soil samples were gathered. A nearby setup of permanent soil moisture probes additionally provided continuous measurements of soil moisture at different depths, from 10 to 60 centimetres. Global datasets were obtained from the SMOS satellite constellation, GLDAS, MERRA-2 and ESA CCI.

Pulvirenti, L., Squicciarino, G., Cenci, L., Boni, G., Pierdicca, N., Chini, M., Versace, P. & Campanella, P. (2018). A surface soil moisture mapping service at national (Italian) scale based on Sentinel-1 data. Environmental Modelling & Software, 102, 13-28.
Bringing transparency into ensemble cluster analysis with the aid of interactive visualization
Authors: Modali Kameswarrao , Rautenhaus Marc
Published: March 2021

Ensemble forecasting has become a standard practice in numerical weather prediction in forecasting centres across the world. The large data sets generated by ensemble forecasting systems carry much information, that is difficult to analyse in short time periods, requiring well-designed workflows in order to be useful.

Clustering is one of the ensemble analysis methods that are applied to discover similarities between ensemble members. Cluster analysis involves different steps like dimensionality reduction, core clustering algorithm and evaluation. A large of number of methods have been proposed in the literature for each of these steps, however, only few have been applied to clustering of ensemble forecasts. A major challenge is that for a given ensemble forecast, different choices of methods and data domains can lead to very different clustering results. For example, Kumpf et al. (2018, IEEE Transact. Vis. Comp. Graph.) have demonstrated the sensitivity of clustering results to even small changes in the considered domain. The challenge equally exists for choices in clustering methods and method parameters.

In our work, we are attempting to open up the clustering black box by introducing a visualization workflow that makes transparent to the user how different choices in methods and method parameters lead to different clustering results. To achieve this, a clustering analysis library that works in tandem with the ensemble visualization software “Met.3D” () is being developed. We present the current state of the system and demonstrate its use by analysing an ensemble forecast case study.
Wind Speed, Surface Flux, and Convection Coupling from CYGNSS Data
Authors: Maloney Eric , Bui Hien , Riley Dellaripa Emily , Singh Bohar
Published: March 2021

This study analyzes wind speed and surface latent heat flux anomalies from the Cyclone Global Navigation Satellite System (CYGNSS), aiming to understand the physical mechanisms regulating intraseasonal convection, particularly associated with the Madden-Julian oscillation (MJO). The importance of wind-driven surface flux variability for supporting east Pacific diurnal convective disturbances during boreal summer is also examined. An advantage of CYGNSS compared to other space-based datasets is that its surface wind speed retrievals have reduced attenuation by precipitation, thus providing improved information about the importance of wind-induced surface fluxes for the maintenance of convection. Consistent with previous studies from buoys, CYGNSS shows that enhanced MJO precipitation is associated with enhanced wind speeds, and that associated surface heat fluxes anomalies have a magnitude about 7%-12% of precipitation anomalies. Thus, latent heat flux anomalies are an important maintenance mechanism for MJO convection through the column moist static energy budget. A composite analysis during boreal summer over the eastern north Pacific also supports the idea that wind-induced surface flux is important for MJO maintenance there. We also show the surface fluxes help moisten the atmosphere in advance of diurnal convective disturbances that propagate offshore from the Colombian Coast during boreal summer, helping to sustain such convection.  
Long-term legacy of delayed climate mitigation in global glacier response
Authors: Maussion Fabien , Lejeune Quentin , Marzeion Ben , Mengel Matthias , Rounce David , Schleussner Carl , Schuster Lilian
Published: March 2021

Mountain glaciers have a delayed response to climate change and are expected to continue to melt long after greenhouse gas emissions have stopped, with consequences both for sea-level rise and water resources. In this contribution, we use the Open Global Glacier Model (OGGM) to compute global glacier volume and runoff changes until the year 2300 under a suite of stylized greenhouse gas emission characterized by (i) the year at which anthropogenic emissions culminate, (ii) their reduction rates after peak emissions and (iii) whether they lead to a long-term global temperature stabilization or decline. We show that even under scenarios that achieve the Paris Agreement goal of holding global-mean temperature below 2 °C, glacier contribution to sea-level rise will continue well beyond 2100. Because of this delayed response, the year of peak emissions (i.e. the timing of mitigation action) has a stronger influence on mit-term global glacier change than other emission scenario characteristics, while long-term change is dependent on all factors. We also discuss the impact of early climate mitigation on regional glacier change and the consequences for glacier runoff, both short-term (where some basins are expected to experience an increase of glacier runoff) and long-term (where all regions are expecting a net-zero or even negative glacier contribution to total runoff), underlining the importance of mountain glaciers for regional water availability at all timescales.
Geochemical evidence of a floating Arctic ice sheet and underlying freshwater in the Arctic Mediterranean in glacial periods
Authors: Geibert Walter , Matthiessen Jens , Stimac Ingrid , Wollenburg Jutta , Stein Ruediger
Published: March 2021

Numerous studies have addressed the possible existence of large floating ice sheets in the glacial Arctic Ocean from theoretical, modelling, or seafloor morphology perspectives. Here, we add evidence from the sediment record that support the existence of such freshwater ice caps in certain intervals, and we discuss their implications for possible non-linear and rapid behaviour of such a system in the high latitudes.

We present sedimentary activities of 230Th together with 234U/238U ratios, the concentrations of manganese, sulphur and calcium in the context of lithological information and records of microfossils and their isotope composition. New analyses (PS51/038, PS72/396) and a re-analysis of existing marine sediment records (PS1533, PS1235, PS2185, PS2200, amongst others) in view of the naturally occurring radionuclide 230Thex and, where available, 10Be from the Arctic Ocean and the Nordic Seas reveal the widespread occurrence of intervals with a specific geochemical signature. The pattern of these parameters in a pan-Arctic view can best be explained when assuming the repeated presence of freshwater in frozen and liquid form across large parts of the Arctic Ocean and the Nordic Seas.

Based on the sedimentary evidence and known environmental constraints at the time, we develop a glacial scenario that explains how these ice sheets, together with eustatic sea-level changes, may have affected the past oceanography of the Arctic Ocean in a fundamental way that must have led to a drastic and non-linear response to external forcing.

This concept offers a possibility to explain and to some extent reconcile contrasting age models for the Late Pleistocene in the Arctic Ocean. Our view, if adopted, offers a coherent dating approach across the Arctic Ocean and the Nordic Seas, linked to events outside the Arctic.