bluuebunny/crossref_metadata_2025 huggingface dataset:
User involvement to prepare a Pan-European climate visualisation platform targeted at decision makers and educational purposes
Authors: Hoy Andreas , Ustrnul Zbigniew , Wypych Agnieszka , Gordov Evgeny , Gordova Yulia , Leander Elin
Published: March 2021

This contribution relates to preparatory efforts for creating a transnational, multilinguistic visualisation tool of past, present, forecasted and future (weather and) climate information in Europe, targeted to a large range of users. There is no scarcity of observed or modelled climate data, especially in Europe. However, existing climate information are often hidden, poorly explained or not accessible (in their complexity and structure) for non-scientists in many countries, especially in Eastern Europe and Russia. Needed are hence clear, reliable, and concise facts to easily understand the complex topic of climate change, supported by a high spatial resolution of climate information for local concernment.

We identified two superordinated target groups: 1) decision makers, demanding easily accessible and digestible, as well as for decision making processes usable climate information and 2) educational institutions and the general public, who will profit from more intuitive ways teaching and informing about climate change. We here present results of a user survey carried out in five countries (in native language) and of key stakeholder interviews within the same countries.

In the surveys, we approached potential users within different countries to explore what climate data they need, in which complexity, spatio-temporal detail, actuality and visualisation style. We also aimed to explore if similar actors of different countries may have similar or different needs, and how we may prepare an optimal product useful for a large range of users located in different countries. Follow-up key stakeholder interviews helped us deepening the level of understanding of user needs. Such interviews allowed us to go into more details than the questionnaire. It also enabled us to present the users content of existing webpages presenting climate information, to identify what the users like, dislike or miss in existing tools - e.g., in terms of data visualisation, handling, comparison and comprehensiveness. Coordinating country partners served as multipliers to reach users in their national language and to evaluate the results. Those activities disseminated the ideas of our planned platform in those countries and between different users there.
Temporal and spatial variability in Atlantic Water in the Arctic from observations
Authors: Richards Alice , Johnson Helen , Lique Camille
Published: March 2021

Observational data from across the Arctic are used to investigate temporal and spatial variability in Atlantic Water throughout the Arctic basin from the 1980s to the present day, with a focus on Atlantic Water heat and its potential influence on the upper water column. MIMOC climatological data are also used in the analysis. The inferred mechanisms behind Atlantic Water spread in the Arctic – both vertically and laterally into sub-basin interiors – are discussed, along with the local and remote influences on the Atlantic Water layer in different Arctic regions. The usefulness of the Atlantic Water core in tracking changes in the Atlantic Water layer is also assessed. 
Characteristics of the Russian shelf seas in the Arctic Ocean regarding the content of heavy minerals in surface sediments: new data
Authors: Popova Elena
Published: March 2021

Such factors as climate, currents, morphology, riverine input, and the source rocks influence the composition of the sediments in the Arctic Ocean. Heavy minerals being quite inert in terms of transport can reflect the geology of the source rock clearly and indicate the riverine input. There is a long history of studying the heavy mineral composition of the sediments in the Arctic Ocean. The works by Vogt (1997), Kosheleva (1999), Stein (2008), and others study the distribution of the minerals both on a sea scale and oceanwide. The current study covers Russian shelf seas: Barents, Kara, Laptev, East Siberian, and Chukchi Seas. To collect the material several data sources were used: data collected by the institute VNIIOkeangeologia during numerous expeditions since 2000 for mapping the shelf, data from the old expedition reports (earlier than 2000) taken from the geological funds, and datasets from PANGAEA (www.pangaea.de). About 82 minerals and groups of minerals were included in the joint dataset. The density of the sample points varied significantly in all seas: 1394 data points in the Barents Sea, 713 in the Kara Sea, 487 in the Laptev Sea, 196 in the East Siberian Sea, and 245 in the Chukchi Sea. These data allowed comparing the areas in terms of major minerals and associations. Maps of prevailing and significant components were created in ODV (Schlitzer, 2020) to demonstrate the differences between the seas and indicate the sites of remarkable changes in the source rocks. Additionally, the standardized ratio was calculated to perform quantitative comparison: the sea average was divided by the weighted sea average and then the ratio of that number to the mineral average was found. Only the minerals present in at least four seas and amounting to at least 20 points per sea were considered. As a result, water areas with the highest content of particular minerals were detected. The ratio varied from 0 to 3,4. Combining the ratio data for various minerals allowed mapping specific groups or provinces for every sea and within the seas.

 

Kosheleva, V.A., & Yashin, D.S. (1999). Bottom Sediments of the Arctic Seas. St. Petersburg: VNIIOkeangeologia, 286pp. (in Russian).

PANGAEA. Data Publisher for Earth & Environmental Science https://www.pangaea.de/

Schlitzer, R. (2020). Ocean Data View, Retrieved from https://odv.awi.de.

Stein, R. (2008). Arctic Ocean Sediments: Processes, Proxies, and Paleoenvironment. Oxford: Elsevier, 602pp.

Vogt, C. (1997). Regional and temporal variations of mineral assemblages in Arctic Ocean sediments as a climatic indicator during glacial/interglacial changes. Berichte Zur Polarforschung, 251, 309pp.
Career obstacles facing Early Career Scientists (ECS) and a first look at solutions 
Authors: Turton Jenny , Blom Nienke , Bittner Meriel , Wenner Michaela , Mason Emily
Published: March 2021

Despite the growing number of PhDs awarded in the geosciences in the last decade, the availability of permanent or more senior positions hasn’t matched this trend. Recent estimates suggest that less than 1% of graduates become professors/senior lecturers and only 30% stay in academic roles after graduation (The Royal Society, 2010). To analyse the impact of these developments on the Early Career Scientist (ECS) community, the ‘Careers and Jobs Working Group’ of the EGU representatives designed a survey. The survey focused on the motivation as well as obstacles faced by ECS in their decision to pursue a career in academia and on suggestions for resources to help them with their career decisions. The survey was distributed to ECS via social media platforms, webinars and newsletters.

Here, we present the preliminary outcome of the survey, received up until December 2020. The survey highlights that despite high interest in remaining in academia, many scientists are also interested in alternative careers, but face a number of barriers in their quest for both academic and non-academic positions. Some of the most prominent hurdles to a continued career in academia include poor job security and lack of support for families. The interest in non-academic careers varies by career stage and family status (whether single, in a relationship or a parent). The importance of this research is underlined by the recent ‘Graduate student happiness and wellbeing report’ conducted at the University of California, Berkley, which identified job insecurity and low career prospects as having a large negative impact on the mental health of ECS.

ECS are particularly interested to learn more about work fields that are related to their subject of study, about transferable skills and are keen to participate in events such as webinars and networking events. These findings highlight the role that international organisations (such as EGU, AGU, ERC) can play to help and guide ECS in finding a career path. Through their extensive networks both inside and outside of academia, such organisations are in a powerful position to facilitate interactions between members of different career stages and work fields. We suggest that a stronger focus on career development within such organisations – for example by creating a dedicated point of contact for careers information and regularly organising career-related events- will create a better outlook for ECS whilst also contributing to their mental health and overall wellbeing.
Investigating infrasound sources within Illgraben debris-flows
Authors: Belli Giacomo , Marchetti Emanuele , Walter Fabian , McArdell Brian , Chmiel Małgorzata , Wenner Michaela
Published: March 2021

Debris flows are episodic gravitational currents, consisting of mixtures of water and debris in varying proportions. They occur in steep mountain torrents with volumes commonly exceeding thousands of m3. Given their unpredictability and their capability to transport large boulders, debris flows rank among the most dangerous natural hazards in mountain environments. Nevertheless, moderate flow velocities (typically < 10 m/s) make early warning in principle possible if the flows are detected early upon formation.

Infrasound studies of debris flows increased significantly in the last decade, focusing mostly on event detectability and application for early-warning. The use of infrasound arrays and the combined use of collocated seismic and infrasound sensors have turned out to be efficient systems for reliable detection of debris flows in near-real time.

Despite these advances, open questions remain about the possibility to infer debris-flow source characteristics and event magnitude from recorded infrasonic signals. This requires theoretical and/or empirical source models describing elastic energy radiation in the atmosphere, in the form of infrasound, and relating it with fluid dynamic processes within a debris flow. Infrasound radiated by debris-flows is believed to be generated by standing waves that develop at the free surface of the flow, but details of the involved dynamic processes are not fully understood.

Here, we present the analysis of infrasonic signals recorded with a small aperture array during the 2017-2020 debris-flow seasons in the Illgraben catchment (Switzerland, Canton Valais), including more than 20 events of variable sizes. In order to better understand infrasound source mechanisms and to investigate the fluid dynamics processes involved in the infrasonic energy generation, debris-flow infrasound signals are quantitatively compared with independent hydraulic information of the flow (velocity, maximum flow depth and flow density). Finally, we discuss the use of extrapolated empirical relationships between infrasound signal features and flow characteristics for debris-flow monitoring and risk management.

 
Episodic earthquake swarms in the Mineral Mountains, Utah driven by the Roosevelt hydrothermal system
Authors: Mesimeri Maria , Pankow Kristine , Baker Ben , Hale J. Mark
Published: March 2021

 The Mineral Mountains are located in south-central Utah within the transition zone from the Basin and Range to Colorado Plateau physiographic provinces, near the Roosevelt Hot Springs. First evidence of swarm-like activity in the area was found in 1981, when a six-station temporary network detected a very energetic swarm of ~1,000 earthquakes. More recently, in mid-2016, a dense local broadband seismic network was installed around the Frontier Observatory for Research in Geothermal Energy (FORGE) in southcentral Utah, ~10 km west of the Mineral Mountains. Beginning in 2016, the University of Utah Seismograph Stations detected, located, and characterized 75 earthquakes beneath the Mineral Mountains. In this study, we build an enhanced earthquake catalog to confirm the episodic swarm-like nature of seismicity in the Mineral Mountains. We use the 75 cataloged earthquakes as templates and detect 1,000 earthquakes by applying a matched-filter technique. The augmented catalog reveals that seismicity in the Mineral Mountains occurs as short-lived earthquake swarms followed by periods of quiescence. Earthquake relocation of ~800 earthquakes shows that activity is concentrated in a <2 km long E-W striking narrow zone, ~4 km east of the Roosevelt hydrothermal system. Two fault orientations, both N-S and E-W parallel to the Opal Mound and Mag Lee faults, respectively, are observed after computing composite focal mechanisms of highly similar earthquakes. After examining the spatial and temporal patterns of the best recorded earthquake swarm in October 2019, we find that a complex mechanism of fluid diffusion and aseismic slip is responsible for the swarm evolution with migration velocities reaching 10 km/day. We hypothesize that these episodic swarms in the Mineral Mountains are primarily driven by migrating fluids that originate within the Roosevelt hydrothermal system.
Benthic Oxygen dynamics: Influence of pore water advection and microphytobenthos in a permeable sediment
Authors: Werna Werna , Forster Stefan
Published: March 2021

The benthic oxygen consumption rate (OCR) has been widely used to measure the total benthic organic carbon degradation rate, while the oxygen distribution provides the general biogeochemistry state of marine sediments. In shallow coastal environments the light driven photosynthesis by benthic microalgae, resulting in large diurnal oscillations of oxygen concentration, further affects the oxygenation of the sediment. Yet, for permeable sediments, studies incorporating pore water advection driven by physical forces into oxygen consumption and distribution measurements are  still limited. Here we examine the combined effect of benthic oxygen production and advective oxygen transport on oxygen dynamics and consumption rate in a microphytobenthos-dominated sediment (permeability k =2 x 10-11 to 5 x 10-11 m2) in a laboratory simulation with stirred benthic chambers at 40 rpm. Under alternating light (50 μE m−2 s-1) and flow regimes, oxygen concentration, penetration depth and consumption rates were monitored by means of micro-profiling and planar optode measurements. In all cases, we found that oxygen penetration depth increased up to a factor of 2 with pore water flow simulation. On the other hand, advective transport was found to reduce maximum oxygen concentration in the sediment by up to 30 %.  The OCR were up to 2-times higher with only light (28 ± 3.5 µM/min) compared to combined light and flow simulation, however the total oxygen uptake was generally uniform in all chambers (41.83 ± 5.9 mmol/m2 d-1), suggesting the local redistribution of oxygen with flow without marked overall changes in O2 consumption. Our result emphasized the importance of advective transport controlling benthic oxygenation in photic permeable sediment.
Seasonal impact-based mapping of compound hazards
Authors: Hillier John K. , Dixon Richard S.
Published: March 2021

Impact-based, seasonal mapping of compound hazards is proposed. It is pragmatic, identifies phenomena to drive the research agenda, produces outputs relevant to stakeholders, and could be applied to many hazards globally. Illustratively, flooding and wind damage can co-occur, worsening their joint impact, yet where wet and windy seasons combine has not yet been systematically mapped. Here, seasonal impact-based proxies for wintertime flooding and extreme wind are used to map, at 1° × 1° resolution, the association between these hazards across Europe within 600 years as realized in seasonal hindcast data. Paired areas of enhanced-suppressed correlation are identified (Scotland, Norway), and are shown to be created by orographically-enhanced rainfall (or shelter) from prevailing westerly storms. As the hazard metrics used are calibrated to losses, the maps are indicative of the potential for damage.

 

https://iopscience.iop.org/article/10.1088/1748-9326/abbc3d
On the influence and limitations of hyper-resolution hydrological modelling – application of the 1 km PCR-GLOBWB model over Europe
Authors: Hoch Jannis , Sutanudjaja Edwin , van Beek Rens , Bierkens Marc
Published: March 2021

Developing and applying hyper-resolution models over larger extents has long been a quest in hydrological sciences. With the recent developments of global-scale yet fine data sets and advances in computational power, achieving this goal becomes increasingly feasible.

We here present the development, application, and results of the novel 1 km version of PCR-GLOBWB for the period 1981 until 2020. Even though employing global data sets only, we developed, ran, and evaluated the 1 km model for the continent Europe only. In comparison to past versions of PCR-GLOBWB, input data was replaced with sufficiently fine data, for example the recent SoilGrids and MERIT-DEM data. Preliminary results indicate an improvement of model outcome when evaluating simulated discharge, evaporation, and terrestrial water storage.

Additionally, we aim to answer the question to what extent developing hyper-resolution models is actually needed of whether the run times could be saved by using hyper-resolution state-of-the-art meteorological forcing. Therefore, the relative importance of model resolution and forcing resolution was cross-compared. To that end, the ERA5-Land data set was employed at different resolutions, matching the model resolutions at 1 km, 10 km, and 50 km.

Despite multiple challenges still lying ahead before achieve true hyper-resolution, this application of a 1 km model across an entire continent can form the basis for the next steps to be taken.
Magnetospheric-Ionospheric-Lithospheric coupling model. Observations  during the August 5, 2018 Bayan Earthquake
Authors: Piersanti Mirko , Materassi Massimo , Battiston Roberto , Carbone Vincenzo , Cicone Antonio , D'Angelo Giulia , Diego Piero , Ubertini Pietro
Published: March 2021

The short-term prediction of earthquakes is an essential issue connected with human life protection and related social and economics matter. Recent papers have provided some evidence of the link between the lithosphere, lower atmosphere, and ionosphere, even though with marginal statistical evidence. The basic coupling hypothesized being via atmospheric gravity wave (AGW)/acoustic wave (AW) channel. In this work we analyse the scenario of the low latitude earthquake (Mw=6.9) occurred in Indonesia on August 5, 2018, through a multi-instrumental approach, using ground and satellites high quality data. As a result, we derive a new analytical lithospheric-atmospheric-ionospheric-magnetospheric coupling model with the aim to provide quantitative indicators to interpret the observations around 6 hours before and at the moment of the earthquake occurrence.
Diagnosing the vorticity balances of the Weddell Gyre
Authors: Styles Andrew , Marshall David , Bell Mike
Published: March 2021

Antarctic Bottom Water formed in the Weddell Sea is transported by the Weddell Gyre (WG) into the Antarctic Circumpolar Current (ACC). From here, this water is exported to the world ocean and influences the global overturning circulation. Studying the dynamics of the WG could therefore improve our understanding of the Southern Ocean carbon and energy budget.

The dynamics of the WG in a NEMO global model is investigated at various resolutions. The WG transport is largest at intermediate resolution (R4) and only the low-resolution model (R1) has a transport close to observations. We attempt to identify the physical processes responsible for this difference by studying the vorticity diagnostics. These physical processes include (but are not limited to) wind stress curl, lateral friction and bottom pressure torques.  

A textbook understanding of gyres relies on the idea of vorticity balance and this idea is extended to identify the physical processes spinning the WG up and down. We integrate the vorticity diagnostics outputted by NEMO over the area enclosed by the WG streamlines. These integrations are equal to the work done by separate forces on fluid parcels circulating around the gyre.

In the future we also hope to apply this analysis to an idealised model representing the Weddell Sea. This model will also use NEMO but have analytic forcing, bathymetry and a prescribed ACC.
Tillage-induced management impact on soil properties and initial soil erosion in degraded calcareous soils in Mediterranean fig orchard
Authors: Bogunovic Igor , Telak Leon Josip , Dugan Ivan , Ferreira Carla S. S. , Pereira Paulo
Published: March 2021

High majority of soil erosion studies focus on cereal croplands, vineyards, olive, avocado, citrus, almond, persimmon, apple, and apricot orchards. To date, there is a lack of information about the possible impacts of tillage management on soil properties and hydrological response in fig orchards. Understanding this will be crucial to design efficient soil conservation practices and degradation control. Therefore, the aim of this research was to study the initial soil erosion in fig plantations and temporal evolution of initial soil erosion after the tillage intervention on undeveloped, Calcic Fluvisol in Dalmatia, Croatia. The study was conducted by collecting undisturbed soil samples, followed by rainfall simulations (58 mm h-1, during 30 min, over 0.785 m2 plots) in eight repetitions per measurement 2 days, 1 month, and 3 months after the intensive tillage. The results showed a clear difference among soil properties trough time. Seasonal effect significantly modifies soil properties and hydrological response. Soil bulk density and mean weight diameter increase (p < 0.05), while water holding capacity, water stable aggregates, soil organic content, and available phosphorus decrease (p < 0.05) by time after tillage. The highest runoff was measured 1 month (100.5 m3 ha-1), followed by 3 months (82 m3 ha-1), and 0 months (48.3 m3 ha-1) after tillage. Sediment losses were highest at 3 months (3488.9 kg ha-1), followed by 3.5 times lesser losses at 1 month (990.6 kg ha-1), and 8.2 times lower right after the tillage (426.1 kg ha-1). Temporal variations of soil erodibility in this study were under the influence of soil natural consolidation and precipitation. Fig orchards on young, undeveloped soils are highly erodible forms of land use and conservation practices need to be deploy in order to mitigate land degradation.

Keywords: soil physical properties, runoff, permanent plantation, short-term changes, undeveloped soil

Acknowledgments

This work was supported by Croatian Science Foundation through the project "Soil erosion and degradation in Croatia" (UIP-2017-05-7834) (SEDCRO).
North Atlantic Ocean Circulation Response to Stochastic Mesoscale Weather Systems
Authors: Zhou Shenjie , Zhai Xiaoming , Renfrew Ian
Published: March 2021

The ocean is forced by the atmosphere on a range of spatial and temporal scales. In ocean and climate models the resolution of the atmospheric forcing sets a limit on the scales that are represented. For typical climate models this means mesoscale (< 400 km) atmospheric forcing is absent. Previous studies have demonstrated that mesoscale forcing significantly affects key ocean circulation systems such as the North Atlantic Subpolar gyre and the Atlantic Meridional Overturning Circulation (AMOC). However, the approach of these studies has either been ad hoc or limited in resolution. Here we present ocean model simulations with and without realistic mesoscale atmospheric forcing that represents scales down to 10 km. We use a novel stochastic parameterization – based on a cellular automaton algorithm that is common in weather forecasting ensemble prediction systems – to represent spatially coherent weather systems over a range of scales, including down to the smallest resolvable by the ocean grid. The parameterization is calibrated spatially and temporally using marine wind observations. The addition of mesoscale atmospheric forcing leads to coherent patterns of change in the sea surface temperature and mixed-layer depth. It also leads to non-negligible changes in the volume transport in the North Atlantic subtropical gyre (STG) and subpolar gyre (SPG) and in the AMOC. A non-systematic basin-scale circulation response to the mesoscale wind perturbation emerges – an in-phase oscillation in northward heat transport across the gyre boundary, partly driven by the constantly enhanced STG, correspoding to an oscillatory behaviour in SPG and AMOC indices with a typical time scale of 5-year, revealing the importance of ocean dynamics in generating non-local ocean response to the stochastic mesoscale atmospheric forcing. Atmospheric convection-permitting regional climate simulations predict changes in the intensity and frequency of mesoscale weather systems this century, so representing these systems in coupled climate models could bring higher fidelity in future climate projections.
Unveiling ductile deformation during fast exhumation of a granitic pluton in a transfer zone
Authors: Spiess Richard , Langone Antonio , Caggianelli Alfredo , Stuart Finlay M. , Zucchi Martina , Bianco Caterina , Brogi Andrea , Liotta Domenico
Published: March 2021

Exhumation and cooling of upper crustal plutons is generally assumed to develop in the brittle domain, thus determining an abrupt passage from crystallization to faulting. To challenge this general statement, we have applied an integrated approach involving meso- and micro-structural studies, thermochronology, geochronology and rheological modeling. We have analyzed the Miocene syn-tectonic Porto Azzurro pluton on Elba (Tuscan archipelago – Italy), emplaced in an extensional setting, and have realized that its fast exhumation is accompanied by localized ductile shear zones, developing along dykes and veins, later affected by brittle deformation. This is unequivocally highlighted by field studies and the analysis of microstructures with EBSD. In order to constrain the emplacement and exhumation rate of the Porto Azzurro pluton we performed U-Pb zircon dating and (U+Th)/He apatite thermochronology. It results in a magma emplacement age of 6.4 ± 0.4 Ma and an exhumation rate of 3.4 to 3.9 mm/yr. By thermo-rheological modeling we were able to establish that localized ductile deformation occurred at two different time steps: within felsic dykes when the pluton first entered into the brittle field at 380 kyr, and along quartz-rich hydrothermal veins at c. 550 kyr after pluton emplacement. Hence, the major conclusion of our data is that ductile deformation can affect a granitic intrusion even when it is entered into the brittle domain in a fast exhuming extensional regime.
Weekly cycle of NOx emissions as laboratory of atmospheric chemistry
Authors: Beirle Steffen , Dörner Steffen , Kumar Vinod , Wagner Thomas
Published: March 2021

Satellite observations provide unique information on the amount and spatial distribution of tropospheric NO2. Several studies use such datasets for deriving NOx emissions. However, due to nonlinearities in the NOx chemistry (i.e., the dependency of the OH concentration and thus the NO2 lifetime on the NO2 concentration), the observed column densities of NO2 are not directly proportional to the underlying NOx emissions. Consequently, a certain reduction in NOx emissions could result in disproportionate reduction of the corresponding NO2 columns, which could be stronger or weaker depending on the chemical state (O3, NOx and VOC levels) and conditions like temperature, humidity and acitinic flux. This effect complicates the quantification of NOx emissions from satellite measurements of NO2, and e.g. biases the emission reduction as derived from the reduction of NO2 column densities observed during recent lockdowns.  

Here we quantify the nonlinearity of the NOx system for different cities as well as power plants by investigating the effect of reduced NOx emissions on days of rest, i.e. Fridays/Sundays in Muslim/Christian culture, respectively. The reduction of NOx emissions is thereby quantified based on the continuity equation by calculating the divergence of the mean NO2 flux. This method has been proven to be sensitive for localized sources, where the uncertainties due to NO2 lifetime are small (Beirle et al., Sci. Adv., 2019). This reduction in emissions is then set in relation to the corresponding reduction of NO2 columns integrated around the source, which strongly depend on the NO2 lifetime.
Contribution of meteorological factors to AOD variability during the dusty season over Iran
Authors: Yousefi Robabeh , Wang Fang , Ge Quansheng , Shaheen Abdallah
Published: March 2021

Atmospheric aerosols considered as one of the main concerns in the ongoing climate change. Meteorological changes have a significant role in the inter-decadal Aerosols variation. In this talk, long term (2000-2019) aerosol optical depth (AOD) and metrological factors data from the reanalysis-based Modern Era Retrospective Analysis for Research and Applications (MERRA-2) were used provide deep insight into the relationship between meteorological factors and AOD variability over Iran during the dusty season (MJJA: May, June, July, and August). Prior to regression analyses, Iran was divided into three parts based on the climatological conditions (west part: dusty area, north part: wetter, and center: dry area). Using a multiple linear regression model, AOD variability over Iran was significantly linked to sea level pressure and soil moisture. Winter surface temperatures and relative humidity are the main contributors to MJJA AOD variability over the western and northern parts.  AOD was not affected by precipitation. Our results suggested that climatic variations strongly affect the dust cycle, with a strong dependence on wintertime conditions in the region.
Hydraulic and mechanical constraints on the magnitude Ml 5.2 earthquake of 11 November 2019 at Le Teil (France)
Authors: Burnol André , Armandine Les Landes Antoine , Aochi Hideo , Maury Julie , Allanic Cécile
Published: March 2021

On 11 November 2019,  a Ml 5.2 earthquake broke the Rouvière fault in southeast France at Le Teil, close to the Rhone river. This recent seismic event is the strongest earthquake ever felt in France since the Arette (Pyrenees) earthquake in 1967. A priori, it is also a historically unprecedented earthquake in the surrounding low strain and stable continental region. By using an updated geological model, we focus this work on the comparison of the effect of hydraulic recharge linked to the infiltration of meteoric water in the period preceding the earthquake and the effect of the exploitation of a large limestone quarry in the vicinity of the epicenter.

At first, we carry out a complete inventory of local seismicity in a rectangular area of ​​50 km x 25 km around the Teil quarry. We put these seismic events in temporal relation with the rainfall measurements from the weather station at Montélimar. The three most intense rainy events between 2010 and 2019 are all followed by a seismic event in this restricted area, which occurs between 8 and 18 days after these rainy episodes.

Afterward, we describe the different geological configurations from the updated geological model and the boundary conditions, that are used to calculate the pressure variations along the Rouvière fault using two-dimensional (2D) double porosity double permeability models. The BRGM Compass code is used with the surface soil moisture data acquired by the SMOS satellite between 2010 and 2019, as surface boundary conditions and the Rhône river as edge boundary conditions. The main result of these hydrogeological simulations is that at the intersection of the Rouvière fault and a sub-vertical fault, the calculated increase in pore fluid pressure is maximum just before the earthquake of November 11, 2019.

A sensitivity study carried out on the hydraulic parameters and on the configuration of the fault system of the 2D model, allows us to estimate that at about 1000 m depth, the overpressure linked to the hydraulic recharge is between 0.3 and 0.6 MPa. Finally, we compare the variation in normal stress linked to a mechanical discharge from the surface quarry and the hydraulic overpressure linked to a meteoric water recharge, by choosing the same fault geometry. The comparison shows that the overpressure associated with hydraulic recharge has an impact that is an order of magnitude greater than that of the normal mechanical stress due to the decharge of the limestone quarry.
Uncertainty in East Antarctic firn thickness constrained using a model ensemble approach
Authors: Verjans Vincent , Leeson Amber , McMillan Malcolm , Stevens Max , van Wessem Jan Melchior , van de Berg Willem Jan , van den Broeke Michiel , Kittel Christoph , Amory Charles , Fettweis Xavier , Hansen Nicolaj , Boberg Fredrik , Mottram Ruth
Published: March 2021

Mass balance assessments of the East Antarctic ice sheet are highly sensitive to changes in firn thickness resulting from variability in firn compaction rates and surface mass fluxes (snowfall, sublimation, melt). To better constrain uncertainty in firn thickness and in the underlying processes, we develop a model-based ensemble of firn evolution scenarios over 1992-2017. We combine statistical emulation of nine firn-densification models, climatic output from three regional climate models and different assumptions about surface snow density to generate a comprehensive set of 54 model scenarios. The ensemble agrees that firn thickness changes in the interior are minor, but there are pronounced thickening and thinning patterns in coastal areas.  At basin level, model uncertainty in firn thickness change ranges between 0.2–1.0 cm yr-1 (15–300%). Statistical analysis of the ensemble uncertainty demonstrates that climatic forcing is the primary contributor of model spread on firn thickness estimates. However, in basins characterised by warmer temperatures, high snowfall or increasing snowfall, the contributions of firn compaction and surface snow density can account for up to 46 and 28% of the spread, respectively.

By comparing the ensemble scenarios with satellite measurements of elevation changes over the same 1992-2017 period, we find that these estimates are consistent over a majority of basins. Nonetheless, we identify several basins where model estimates of firn thickness change do not match altimetry measurements. These discrepancies can be explained by different causes: (1) the model ensemble may fail to represent the real firn thickness change over our period of interest, (2) the uncertainty range associated with the altimetry data may not capture the true signal and (3) a component of the elevation change signal may be related to ice dynamical imbalance. As such, our analysis serves to highlight specific areas where further focus on potential sources of errors in model and altimetry results is needed in order to better constrain mass balance assessments in East Antarctica.
Evaluating the role soil nutrients play in regulating soil greenhouse gas fluxes from the pristine tropical forests: evidence from a nutrient manipulation experiment in Uganda
Authors: Tamale Joseph , Hüppi Roman , Griepentrog Marco , Turyagyenda Laban Frank , Barthel Matti , Doetterl Sebastian , Fiener Peter , van Straaten Oliver
Published: March 2021

The exchange of the climate-relevant greenhouse gases (GHGs) at the soil-atmospheric interface is regulated by both abiotic and biotic controls. However, evidence on nutrient limitations of soil GHG fluxes from African tropical forest ecosystems is still rare. Therefore, an ecosystem-scale nutrient manipulation experiment (NME) consisting of nitrogen (N), phosphorus (P), N + P, and control treatments was set up in a tropical forest in northwestern Uganda. Soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes were measured monthly using static vented chambers for 14 months. A root trenching treatment was also done in all the experimental plots in order to disentangle the contribution of root and microbial respiration to total soil CO2 effluxes. In parallel to soil GHG flux measurements, soil temperature, soil moisture, and mineral N were determined. Lifting the N limitation on the soil nitrifiers and denitrifiers through N fertilization significantly increased N2O fluxes in N, and N + P addition plots in the transitory phase (0-28 days after N fertilization, p < 0.01). However, sustained N fertilization did not significantly affect background (measured more than 28 days after fertilization) N2O fluxes. Alleviation of the P limitation on soil methanotrophs through P fertilization marginally and significantly increased CH4 consumption in the transitory (p = 0.052) and background (p = 0.010) phases, respectively. Simultaneous addition of N and P (N + P) significantly affected transitory soil CO2 effluxes (p = 0.010), suggesting a possible co-limitation of N and P on soil respiration. Microbial CO2 effluxes were significantly larger than root CO2 effluxes (p < 0.001) across all treatment plots so was the contribution of microbial respiration to the total soil CO2 effluxes (about 70 %, p < 0.001). Despite the fact that soil respiration was affected through N + P fertilization, neither heterotrophic nor autotrophic respiration significantly differed in either the N + P or the other treatments. Overall, the study findings suggest that the contribution of tropical forests to the global soil GHG budget could be altered by changes in N and P availability in these biomes.

Key words: Soil greenhouse gas fluxes, nutrient manipulation experiment, soil nutrient limitation, and Ugandan tropical pristine forest.
Observed Seasonal and Interannual Controls on Coastal Oxygen and Dead Zones in the Indian Ocean
Authors: Pearson Jenna , Resplandy Laure , Poupon Mathieu
Published: March 2021

A major concern is that global de-oxygenation will expand Oxygen minimum zones (OMZs) and favor coastal dead zones (DZs) where already low oxygen levels threaten ecosystems and adjacent coastal economies. The northern Indian ocean is home to both intense OMZs and DZs, and is surrounded by many kilometers of biodiverse and commercially valuable coastline. Exchanges between OMZs and shelf waters that contribute to coastal DZs are subject to the strong monsoonal seasonal cycle and the interannual variability of the Indian Ocean Dipole (IOD).  There is, however, no observational constraints on how these exchanges influence coastal DZs at the scale of the entire northern Indian Ocean.

In this work, we examine the timing and processes that favor low-oxygen concentrations along the coasts of the Bay of Bengal (BoB) and Arabian Sea (AS) using multi-decadal time series of oxygen profiles (Bio-Argo, World Ocean Database and repeat hydrography) combined with a suite of satellite data. Seasonally, we show that coastal oxygen is lowest during winter/spring in the BoB and summer/fall in the AS, closely following the seasonal propagation of coastal waves and wind-driven upwelling. Interannually, observations indicate that positive IODs increase coastal O2 in summer/fall in the AS, partly offsetting the seasonal signal; a result in agreement with prior modeling work (Vallivattathillam et al 2017). Observations reveal, however, that positive IODs favor low coastal O2 conditions and increase the risk of coastal DZs year-round in the BoB and in winter/spring in the AS, whereas negative IODs favor low O2 in summer/fall in the AS.

 
Time scale dependence of wind speed patterns - implications for wind power site assessment
Authors: Suteanu Cristian
Published: March 2021

Characterizing properties of wind speed variability and their dependence on the temporal scale is important: from sub-second intervals (for the design and monitoring of wind turbines) to longer time scales – months, years (for the evaluation of the wind power potential). Wind speed data are usually reported as averages over time intervals of various length (minutes, days, months, etc). The research project presented in this paper addressed the following questions: What aspects of the wind pattern are changed, in what ways and to what extent, in the process of producing time-averaged values? What precautions should be considered when time-averaged values are used in the assessment of wind variability? What are the conditions to be fulfilled for a meaningful comparison of wind pattern characteristics obtained in distinct studies? Our research started from wind speed records sampled at 0.14 second intervals, which were averaged over increasingly longer time intervals. Variability evaluation was based on statistical moments, L-moments, and detrended fluctuation analysis. We present the change suffered by characteristics of temporal variability as a function of sampling rate and the averaging time interval. In particular, the height dependence of wind speed variability, which is of theoretical and practical importance, is shown to be progressively erased when averaging intervals are increased. The paper makes recommendations regarding the interpretation of wind pattern characteristics obtained at different sites as a function of sampling rate and time-averaging intervals.
Envisaged transfer projects: New technologies in the water sustainability
Authors: Abbasi Naseer Ahmed , Xu Xiangzhou
Published: March 2021

Abstracts: Influenced by global climate change, water shortages and other extreme weather, water scarcity in the world is an alarming sign. This article provides evidences regarding the Tunnel and Tianhe project’s feasibility and their technical, financial, political, socioeconomic and environmental aspects. Such as how to utilize the water vapour in the air and to build a 1000 km long tunnel project to fulfill the goal of solving water shortage in China. The projects are promising to solve the problem of water, food and drought in the country. In addition, the telecoupling framework helps to effectively understand and manage ecosystem services, as well as the different challenges associated with them. Such efforts can help find the ways for proper utilization of water resources and means of regulation.

Key words: Sustainability; water shortage; transfer project
Active Fault Systems in the inner North West Apennines: an updated view
Authors: Molli Giancarlo , Bennett Rick , Malavieille Jacques , Serpelloni Enrico , Storti Fabrizio , Bigot Aurelien , Pinelli Gabriele , Giacomelli Serena , Angeli Luca , Giampietro Tiziano , Lucca Alessio , Porta Lorenzo
Published: March 2021

As part of an ongoing project of mapping, structural studies and fault characterization we present an updated tectonic scheme and data set for the active fault systems that shaped the inner portion of the Apennines north of the Arno river. Geomorphology, stratigraphy of Plio-Quaternary sediments, GPS data, historical and instrumental seismicity have been reviewed and combined with structural studies to define the neotectonic history of the investigated region. Within the studied area, first-order physiographic and structural features allow to define different structural domains related to a set of ranges with a dominant NW-SE direction separated by intramontane or continental/marine morphotectonic depressions of the Lunigiana, Garfagnana, Lucca-Mt.Albano, La Spezia-Carrara and the off-shore Viareggio basin. The main boundary faults and internal fault segments of the different structural domains were described while the Plio-Quaternary sedimentary records has been used to constrain their long to short term deformation and rates, with the aim to improve current Italian catalogues - DISS (INGV) and Ithaca (ISPRA) - with some utilities for the seismic microzonation local projects. Moreover, our work aims to draw the attention of the scientific community to the seismotectonics of a region in which the seismic hazard is largely considered medium to low despite the occurrence, one century ago, of one of the most destructive earthquakes that have struck the Italian peninsula, the 1920 Fivizzano EQ, with an estimated Mw 6.5 similar to the main shock of the 2016 Central Italy seismic sequence.

 
Optimal Selection of Favorable Areas for CO2 Geological Storage in the Majiagou Formation in the Ordos Basin
Authors: Lu Ping , Jiao Zunsheng , Zhou Lifa
Published: March 2021

CO2 geological storage (CGS) technology is currently one of the best choices for large-scale low-cost CO2 emission reduction in the world, and the primary issue of CO2 geological storage is the optimization of the selection of favorable areas for CO2 storage. In view of the insufficient research on the optimization of favorable areas for CO2 geological storage in the Majiagou Formation in the Ordos Basin, this study aims to determine the boundaries of the CO2 geological storage area in the Ordos Basin by studying the temperature and pressure conditions, reservoir conditions, structural conditions, caprock conditions , and the salinity conditions of the formation water using a large amount of geological, drilling, geophysical and experimental laboratory data. After the regional boundary of the CO2 geological sequestration is determined, it can be optimized and CO2 geological sequestration can be conducted in the areas that have favorable reservoir conditions, are relatively close to CO2 emission sources, have a high degree of exploration, have an appropriate formation depth and have a small impact on the development of other mineral resources. The results show that (1) the areas suitable for the geological storage of CO2 in the Ordos Basin are located in the distribution area of the Majiagou Formation in the Tianhuan Depression, except for the missing areas in the central paleo-uplift. The ares to the east of the Baiyanjing-Shajingzi fault, to the north of the northern margin of the Weibei uplift, to the west of the Yellow River fault, and to the south of the Yimeng uplift are suitable for CO2 geological storage. (2) Based on the three aspects of technology, safety, and economic feasibility, it was determined that the Wushenqi-Jingbian-Yan'an karst slope area (I1) is the best CO2 geological storage area, and the Yulin-Mizhi karst basin area (I2) is a favorable area for the geological storage of CO2 in the Ordos Basin.

 
Weak Equatorial Superrotation During the Past 250 Million years
Authors: Lan Jiawenjing , Yang Jun , Hu Yongyun
Published: March 2021

For modern Earth, the annual-mean equatorial atmosphere is flowing from east to west or called easterly winds. This is mainly due to the deceleration effect of the seasonal cross-equatorial flows of the Hadley cells, against the acceleration effect of equatorial Rossby and Kelvin waves excited from tropical convection and latent heating release. In this work, we examine the evolution of equatorial winds during the past 250 million years (Ma) using the global Earth system model CESM1.2.2. Three climatic factors different from the modern Earth, solar constant, atmospheric CO2 concentration, and land-sea configuration, are considered in the simulations. We find that the equatorial winds in the upper troposphere change the sign to westerly flows or called atmospheric superrotation in certain eras. The strength of the superrotation is comparable to the magnitude of the present easterly winds, several meters per second, not strong. This phenomenon occurs when the waves are relatively stronger and/or the Hadley cells are relatively weaker, which in turn are due to the changes in the three factors.