bluuebunny/crossref_metadata_2025 huggingface dataset:
Benthic Cycling of Phosphate in the changing Arctic Ocean
Authors: Lefebvre Constance , S. Freitas Felipe , Hendry Katharine , Arndt Sandra
Published: March 2021

The Arctic Ocean is currently experiencing rapid oceanographic shifts and significant sea-ice loss as a result of regional atmospheric and oceanic warming. The Barents Sea is a notable example of these phenomena, having seen a near 40% decline of its April sea-ice extent since 1979, and a progressive northward expansion of Atlantic Water (i.e., Atlantification). Such changes affect primary productivity and nutrient cycling in ways that remain poorly understood. Longer ice-free periods and the inflow of warmer Atlantic Water are expected to lead to extended bloom seasons on short, near-future timescales and therefore increase nutrient uptake in upper water layers. The benthic recycling of nutrients is believed to play an important part in replenishing nutrient inventories in overlying waters thus maintaining high primary productivity over the continuously expanding growth season. Therefore, it is crucial to increase our understanding of nutrient dynamic controls in changing oceans to make more accurate predictions and decipher the complex feedbacks involved in these evolving environments. However, most efforts to constrain and quantify nutrient fluxes so far have been directed at silicon, nitrogen or iron. This study aims to provide specific insight into phosphorus (P) cycling through its response to OM fluctuations and coupling with iron cycling. An integrated data-model approach was used to investigate the dynamics of P cycling at the sediment-water interface across five locations along the 30°E meridian that were drilled in the framework of the ChAOS project in the Barents Sea. The model approach allowed to explore the sensitivity of P cycling to plausible ranges of reactive iron and OM inputs. Greater inputs of reactive iron were found to decrease benthic phosphate fluxes (JPO4) whereas greater inputs of OM increased phosphate return to the water column. The quality of these inputs is equally significant: JPO4 decreased when iron hydroxides were made more reactive and increased with more reactive OM. Our findings indicate that variation in climatically sensitive processes, such as burial of terrestrial sediments and iron cycling, could represent powerful feedbacks on JPO4 through adsorption/desorption mechanisms. Results also reveal significant oceanographic controls on JPO4, suggesting Atlantification of the Barents Sea will play into future phosphate availability.
Visualising and experiencing geological flows in Virtual Reality
Authors: Delage Emmanuel , Van Wyk de Vries Benjamin , Philippe Meven , Conway Susan , Morino Costanza , Manrique Llerena Nelida , Aguilar Contreras Rigoberto , Soncco Yhon , Sæmundsson Þorsteinn , Kristinn Helgason Jón
Published: March 2021

Resilience to natural hazards depends on a person's ability to envision an event and its consequences. While real life experience is precious, a real event experience is rare, and sometimes fatal. So, virtual reality provides a way to getting that experience more frequently and without the inconvenience of demise. Virtual reality can also enhance an event to make it more visible, as often things happen in bad weather, at night or in other inconvenient moments.

The 3DTeLC software (an output from an ERASMUS+ project, http://3dtelc.lmv.uca.fr/) can handle high-resolution 3D topographic models and the user can study natural hazard phenomena with geological tools in virtual reality. Topography acquired from drone or plane acquisitions, can be made more accessible to researchers, public and stakeholders. In the virtual environment a person can interact with the scene from the first person, drone or plane point of view and can do geological interpretation at different visualization scales. Immersive and interactive visualization is an efficient communication tool (e.g. Tibaldi et al 2019 – Bulletin of Volcanology DOI: https://dx.doi.org/10.1007/s00445-020-01376-6).

We have taken the 3DTeLC workflow and integrated a 2.5D flow simulation programme (VOLCFLOW-C). The dynamic outputs from VOLCFLOW-C are superimposed into a single visualization using a new tool developed from scratch, which we call VRVOLC. This coupled visualization adds dynamic and realistic understanding of events like lahars, lava flows, landslides and pyroclastic flows. We present two examples of this, one developed on the Digital Terrain Model of Chachani Volcano, Arequipa Peru, to assist with flood and lahar visualisation (in conjunction with INGEMMET, UNESCO IGCP project 692 Geoheritage for Resilience and Cap 20-25 Clermont Risk). And another with an Icelandic debris slide that occurred in late 2014 possibly related to permafrost degradation (in conjunction with the ANR PERMOLARDS project).

We thank out 3DTeCL colleagues, without which this would not be possible, and acknowledge financial support for the PERMOLARDS project from French National Research Agency (ANR-19-CE01-0010), and this is part of UNESCO IGCP 692 Geoheritage for Resilience.
Extreme sea levels at the Finnish coast due to large-scale wind storms
Authors: Särkkä Jani , Räihä Jani , Rantanen Mika , Jylhä Kirsti
Published: March 2021

In the Baltic Sea, the short-term sea level variation might be several meters, even if the tides in the Baltic Sea are negligible. The short-term sea level fluctuations are caused by passing wind storms, inducing sea level variation through wind-induced currents, inverse barometric effect and seiches. Due to the shape of the Baltic Sea with several bays, the highest sea levels are found in the ends of bays like the Gulf of Finland and the Bothnian Bay. The sea level extremes caused by the large-scale windstorms depend strongly on the storm tracks. Within the natural climatic variability during the past centuries, there have most likely been higher sea level extremes than the extreme values found in the tide gauge records.

To study this variability of sea levels, induced by varying tracks of the passing windstorms, we construct an ensemble of synthetic low-pressure systems. In this ensemble, the parameters of the low-pressure systems (e.g. point of origin, velocity of the center of the system and depth of the pressure anomaly) are varied. The ensemble of low pressure systems is used as an input to a numerical sea level model based on shallow-water hydrodynamic equations. The sea level model is fast to calculate, enabling a study of a large set of varying storm tracks. As a result we have an ensemble of simulated sea levels. From the simulation results we can determine the low-pressure system that induces the highest sea level on a given location on the coast. We concentrate our studies on the Finnish coast, but the method can be applied to the entire Baltic coast. 
Ice Memory
Authors: Ginot Patrick , Chappellaz Jérôme , Barbante Carlo , Schwikowski Margit , Ohlmann Anne-Catherine
Published: March 2021

With global change and its amplified impact at high altitudes or in certain regions of the world, mountain glaciers are particularly sensitive to warming. These same glaciers, which have been studied for several decades, have made it possible to reconstruct, through the study of ice cores, unique information on the evolution of the climate or the environment on a regional and global scale since they are located closer to the main regions and sources of aerosol emissions. Unfortunately, these archives are in the process of being altered and are disappearing. It is in this context that the international project ICE MEMORY was initiated in 2015. ICE MEMORY is built on four pillars : 1) Identify, select glacier and extract several complete ice cores, at least two, from sites that have already demonstrated their high scientific potential before they are altered, 2) Analyse one of the cores in order to extract the maximum parameters of information using all currently available technologies and make this data available to the scientific community of today and tomorrow, 3) Store the remaining cores in a naturally adapted site such as the French-Italien Concordia station in Antarctica so that they can be preserved and donated to future generations of scientists, and 4) to set up a sustainable governance system based on an accredited international organization in charge of managing these ice and data archives in the future.

This presentation will highlight all the operations, analyses and organization already achieved as well as the future vision and development of ICE MEMORY.
Embedding Spectral Decomposition Results in Broadband Simulation: Application to Rhine Graben Area
Authors: Razafindrakoto Hoby , Cotton Fabrice , Bindi Dino , Pilz Marco , Graves Robert
Published: March 2021

Over the past decade, there is growing consensus that physics-based simulations can be utilized in engineering applications. However, for the simulations to be accepted, they need to be calibrated and validated. This study presents the results of ground motion simulation calibration and validation using earthquakes that occurred in the Upper Rhine Graben with a modified version of the Graves-Pitarka (GP) hybrid ground-motion simulation methodology implemented on the Southern California Earthquake Center Broadband Platform, which uses an improved high-frequency computation. To calibrate the HF simulation, we take advantage of the growth of seismological data (including weak motions) in the region and the ability to evaluate critical seismic parameters such as anelastic attenuation, stress drop, and site effects through spectral decomposition methods (separate site-source-propagation from the datasets).  Hence in the simulation, the adopted anelastic attenuation and stress parameter are defined based on the spectral decomposition results. The additional modification of the standard GP method is the incorporation of compressional wave in the HF motion.

Results are compared with observations and simulations from the unmodified GP approach; we also use a range of ground motion intensity measures as summary statistics. We found that in general, the modification in the HF part (e.g., incorporation of compressional waves) was necessary to improve the fit with observations. Our findings also validate the fact that parameters from the spectral decomposition are giving well-calibrated time-histories (in terms of frequency and amplitude) when used as input parameters of the broadband simulations. The findings in this study support the incorporation of scenario-based ground motion simulations for use in the characterization of seismic hazard and other engineering applications. For simulation of future earthquakes, instead of using event-specific stress-drops, we use the average stress-drops taken from the distribution of the stress drops derived from spectral decomposition.
On the observation of very bright and abundant Noctilucent Clouds at Kühlungsborn/Germany (54°N, 12°E) in June 2019
Authors: Gerding Michael , Baumgarten Gerd , Lübken Franz-Josef , Clahsen Matthias , Zecha Marius
Published: March 2021

Noctilucent Clouds (NLC) are observed since 1997 by a RMR lidar at a mid-latitude site at Kühlungsborn/Germany (54°N, 12°E). In June 2019, we detected the brightest NLC so far, having a backscatter coefficient at 532 nm of ~50-10 /m/sr, while 2.5-10 /m/sr is a typical value at this location. Another three NLC in that period reached a backscatter coefficient of more than 20-10 /m/sr. These strong NLC allow, e.g., for high-resolved studies with temporal resolution of 10 seconds and vertical resolution of 45 m. We will show examples of high-frequency oscillations in our data that cannot be found with typical integration times of several minutes. The period in June 2019 was not only unique in terms of NLC brightness, but also regarding NLC occurrence. While the all-year average is ~6 %, the occurrence rate in 2019 was 13 % and, and 20% if we consider June only. In the past, we found an anti-correlation between solar activity and NLC occurrence: Increasing solar UV radiation results in enhanced radiative heating and photolytic water vapor destruction. However, the high number of NLC in 2019 can only partly be explained by solar activity, even if the Lyman-alpha flux was slightly lower compared to previous years. TIMED/SABER monthly averaged temperature profiles showed an unusual low mesopause in June 2019, related to lower-than-average temperatures below 83 km. We claim that this as the main reason for the comparatively frequent and bright NLC. At the same time, meridional wind data of our nearby meteor radar show only weak southward winds and even a wind reversal at 93 km, which is not typical for the season. We will discuss potential reasons for the strange dynamical situation. We note that the weather dependent lidar observations are in good agreement with the radar observations of ice particles, so-called Mesospheric Summer Echoes (MSE). Co-located radar observations also showed unusually large occurrence rates of MSE in June 2019 as well as the occasion of many MSE below 83 km altitude.
Future changes in North Atlantic winter cyclones in CESM-LENS: cyclone intensity and horizontal wind speed
Authors: Dolores Tesillos Edgar , Pfahl Stephan , Teubler Franziska
Published: March 2021

Strong low-level winds are among the most impactful effects of extratropical cyclones on society.  The wind intensity and the spatial distribution of wind maxima may change in a warming climate, however, the dynamics involved are not clear. Here, structural and dynamical changes of North Atlantic cyclones in a warmer climate close to the end of the current century are investigated with storm-relative composites based on Community Earth System Model Large Ensemble (CESM-LE) simulations. Furthermore, a piecewise potential vorticity inversion is applied, to attribute such changes in low-level winds to changes in PV anomalies at different levels.

We identify an extended wind footprint southeast of the cyclone centre, where the wind speed tends to intensify in a warmer climate. Both an amplified low-level PV anomaly driven by enhanced diabatic heating and a dipole change in upper-level PV anomalies contribute to this wind intensification. On the contrary, wind changes associated with lower- and upper-level PV anomalies mostly compensate each other upstream of the cyclone center. Wind changes at upper levels are dominated by changes in upper-level PV anomalies and the background flow. All together, our results indicate that a complex interation of enhanced diabatic heating and altered upper-tropospheric wave dynamics shape future changes in near-surface winds in North Atlantic cyclones.
Marine electromagnetic forward modeling in a resistivity model constrained by seismic and well log data from a field at Campos basin SE-Brazil
Authors: Benevides Artur , Meqbel Naser , Lima Williams , Fontes Sergio , Egbert Gary , Werdt Paulo , La Terra Emanuele
Published: March 2021

This work presents electromagnetic (EM) responses using both marine magnetotelluric (MMT) and controlled source electromagnetic (MCSEM) methods applied to a resistivity model typical of the Campos basin. The Campos basin is located in the Brazilian east margin, with origin in the Neocomian stage of the Cretaceous period 145–130 million years ago during the breakup of the supercontinent Gondwana (South America and Africa split). The clastic reservoirs in this basin have been the largest oil producer in Brazil for the past three decades and the present challenge moves to deeper waters, well known for great challenges in exploration enforced by the complex geology posed by the tectonics associated with giant saline bodies. The seismic reflection is the highest resolution geophysical method and the most used tool in hydrocarbon (HC) exploration; however, it finds difficulties in generating good images in complex geological environments (i.e., associated with the presence of salt and volcanic rocks) and is not a direct hydrocarbon indicator. EM methods, in contrast, are sensitive to resistive variations, and can therefore aid in indicating a reservoir HC-filled and/or in the obtaining subsurface images that can be integrated in joint approaches with seismic for producing less ambiguous interpretations. A set of geophysical data available in the study area includes: CSEM stations, 2D seismic lines, and 3D seismic cube, in addition to 33 well logs. The studies are still in an early stage and the main objective now is to evaluate the responses of the MMT and MCSEM methods in different scenarios involving hydrocarbon accumulations in a thin post-salt Maastrichtian reservoir. The EM forward modeling responses was performed using the modified version of Modular System for EM inversion (ModEM code) within a research project at Observatório Nacional – Brazil. The resistivity model used in this study incorporates vertical transverse isotropy (VTI) in resistivity and is derived from the interpretation of the seismic data and well logs present in the study area. The obtained EM responses demonstrate the effectiveness of the method for detecting thin reservoirs HC-filled, when compared to an environment without accumulation, and the exercise is valuable to compare and understand the real data collected in the study area.
Analysis of remote sensing and in situ datasets to estimate spatial precipitation in high mountain areas: case study Cordillera Blanca, Peru
Authors: Loarte Edwin , Medina Katy , Villavicencio Eduardo , León Hairo , Lavado Waldo , Rabatel Antoine , Jacome Gerardo , Hunink Johannes , Lopez-Baeza Ernesto
Published: March 2021

The Santa River basin has a climatology that is characterized by strong spatial gradients in precipitation. The influence of topography becomes increasingly important when smaller time scales are considered and convective and orographic processes have a more profound influence. This makes its estimation complex and of relevance for research on precipitation estimation in high mountain environments.

This study focused on estimating precipitation for the Santa basin located north of the capital of Peru, assessing spatial patterns and temporal variation. Precipitation products were used at a daily temporal resolution obtained from remote sensing datasets, including CHIRPS, PERSIANN-CCS, GPM and PISCO, altitude and vegetation products as NDVI-BOKU and GDEM. Also ground-based precipitation data from weather stations were collected from 35 meteorological stations (2012 -2019).

The in situ precipitation data was reviewed, cleaned and quality-checked for processing. The following operations were applied to the raster data: Gaussian filter, resampling at 1km, temporal homogenization (monthly) by accumulating the precipitation products until obtaining the monthly values, and averaging. Afterwards, a linear regression model was built based in which various of the remote sensing datasets served as predictions. The model was validated using the mean square error and the coefficient of determination.

The developed regression model provides a better estimate of the precipitation than the individual precipitation dataset. Overall, the resulting model performs relatively low in the dry season (May-September) but improves considerably in the wet season (October-April), with correlations that go up to 0.95. The outcomes of this research can be used to improve the estimation of precipitation patterns in high mountain regions with complex orography.
Fingerprint of volcanic forcing on the ENSO–Indian monsoon coupling
Authors: Singh Manmeet , Krishnan Raghavan , Goswami Bedartha , Choudhury Ayantika Dey , Panickal Swapna , Vellore Ramesh , Gopinathan Prajeesh A , Narayanasetti Sandeep , Venkataraman Chandra , Donner Reik V , Marwan Norbert , Kurths Jürgen
Published: March 2021

The coupling between the El Niño–Southern Oscillation (ENSO) and Indian Monsoon (IM) plays a significant role in the summer rainfall over the Indian subcontinent. In this study, we provide insights into the IM variability with regard to the degree of ENSO variability and radiative forcing from large volcanic eruptions (LVEs). Volcanic dust and gas injected into the stratosphere during major eruptions influence the ENSO from seasonal to interannual timescales. However, the effects of LVEs on the ENSO-IM coupling remain unclear. The relationship between ENSO and IM systems in the context of LVEs is examined using a panoply of datasets and advanced statistical analysis techniques in this study. We find that there is a significant enhancement of the phase-synchronization between ENSO and IM oscillations due to increase in angular frequency of ENSO in the last millennium. Twin surrogates-based statistical significance testing is also used to affirm this result and similar evidence is found in the combinations of 14 ENSO and 11 IM paleoclimate proxy records in the last millennium. Bayesian probabilities conditioned with and without LVEs show LVEs lead to a strong ENSO-IM phase-coupling, with the probabilities remaining higher till the fourth year from the eruption. A large-ensemble climate model experiment with and without the 1883 Krakatoa eruption is conducted using the IITM-ESM, and also with varied volcanic radiative forcing (VRF) depending on the evolved state of ENSO. The simulations show that LVEs force the ENSO-IM systems into a coupled state, and increase (decrease) in the VRF leads to an enhanced (decreased) probability of the phase synchronisation of ENSO-IM systems with a high chance of El Niño-IM drought in the year following the LVE. Our results promisingly pave a way not only for improving the seasonal monsoon prediction improvements but also for the regional impact assessment from the proposed geo-engineering activities over the South Asian region.
Adaptation to Saltwater inTrusion in sEa level RIse Scenarios (ASTERIS): hydrogeochemical surveys and aquifer modelling for groundwater behaviour assessing in the coastal areas of Fano and Ravenna (central-eastern Italy)
Authors: Nisi Barbara , Menichini Matia , Doveri Marco , Cabassi Jacopo , Vaselli Orlando , Botteghi Serena , Masetti Giulio , Raco Brunella , Franceschi Linda , Calvi Enrico , Trifirò Sandra
Published: March 2021

The Adriatic region is highly vulnerable to the adverse impacts of climate change. Although attention has been paid to understand the climate change impact and risks over the last decades, the Adriatic community still faces a lack of a common risk assessment. For this reason, ASTERIS project has been financed at the Call for proposal 2017 Priority Axis Safety and resilience of Interregional V Italy-Croatia 2014-2020 Program. To this overall objective, the project will provide two main outputs: i) a map of vulnerability to coastal salinization at the macro-regional scale (Adriatic) based on future scenarios for sea-level rise and the hydrological cycle and ii) best practice and guidelines for the management of vulnerable sites defined though the analysis of representative case studies in Italy and Croatia. Within these general purposes, hydrogeological and geochemical surveys in two specific shallow aquifer systems that develop in the coastal areas of Fano and Ravenna (central-eastern Italy), were carried out. Several periodical campaigns, aimed at measuring water level and physical-chemical parameters by vertical logs in wells or piezometers, were also conducted. Additionally, ground and surface water samples were also collected for chemical and isotopic analyses to define the compositional features and the main geochemical processes affecting the two shallow aquifers. Preliminary investigations suggested that the Ravenna shallow aquifer is already strongly spoiled by a significant seawater intrusion (up to 80 %), whereas at Fano the presence of the saline wedge can be regarded as negligible. This indicates that the aquifer system of Fano can be considered as a good proxy for evaluating and simulating potential processes of saline-fresh water interactions by either the increasing demand of water exploitation and sea level rise due to anthropogenic pressure and climate change, respectively. In order to simulate possible future ingressions of seawater in the aquifer system of Fano, groundwater flow and transport models are currently in progress. These models will be implemented and calibrated according to the hydrogeological and geochemical data collected within the framework of the ASTERIS project. The expected modelled scenarios, obtained through predictive simulations, are of pivotal importance for assessing the possible groundwater response to climate change and for a correct management and protection of water resources, which can be exported to other aquifers system along the Adriatic Sea.
Coupling Human - Earth Systems for Sustainability
Authors: Fu Bojie
Published: March 2021

Coupling Human - Earth Systems for Sustainability

 Bojie Fu

(State Key Lab of Urban and Regional Ecology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China

Faculty of Geographical Science, Beijing Normal University, Beijing, China)

Abstract: Human influence on the natural environment has intensified, and the earth has entered the stage of Anthropocene. Earth surface processes are gradually dominated by human behavior, resulting in numerous resources, disasters and ecological problems. The ecosystem services of 60% are degradation in the world. The one of major challenges facing the world’s people are meeting the needs of people today and in the future, and sustaining atmosphere, water, soil and biological products which provided by ecosystems. We will present how to coupling human-earth system and propose the research priorities. They are: (1) Integrating research on multiple processes of water, soil, air and ecosystem; (2) Cascades of ecosystem structure, functions and services; (3) Feedback mechanisms of natural and social systems; (4) Data, models and simulation of sustainable development;(5) Mechanism, approach and policy of sustainable development. Finally, a case study in the Loess plateau of China, an area suffered from severe soil erosion in the world was taken. The changes in four key ecosystem services including water regulation, soil conservation, carbon sequestration, and grain production were assessed and the trade off among the ecosystem services were analysed under the changing landscapes due to the Chinese government’s implementation of the Grain to Green Program (GTGP). We found that ecosystem services convert significantly. The adaptive management strategy was discussed aiming on restoring and improving the sustainable capability of ecosystems providing services, based on the understanding of structure, function and dynamics of ecosystem.
Salt marshes adjustment to anthropogenic pressures and sea-level rise
Authors: Carrasco A. Rita , Kombiadou Katerina , Amado Miguel
Published: March 2021

It is predictable that salt marshes in regions, where sediment loads are high, should be stable against a broader range of relative sea level scenarios than those in sediment-poor systems. Despite extensive theoretical and laboratory studies, additional syntheses of marsh ‘persistence’ indicators under human interventions and accelerated sea-level rise rates are still needed. This study investigates the recent lateral changes occurring in lagoon-type marshes of the Ria Formosa lagoon (south Portugal) in the presence of human interventions and sea-level rise, to identify the major drivers for past marsh evolution and to estimate potential future trends. The conducted analysis assessed the past geomorphological adjustment based on imagery analysis and assessed its potential future adjustment to sea-level rise (~100 years) based on modelled land cover changes (by employing the SLAMM model within two sea-level rise scenarios).

Salt marshes in the Ria Formosa showed slow lateral growth rates over the last 70 years (<1 mm∙yr-1), with localized erosion along the main navigable channels associated with dredging activities. Higher change rates were noted near the inlets, with stronger progradation near the natural inlets of the system, fed by sediment influx pulses. Any potential influence of sea-level increase to an intensification of marsh-edge erosion in the past, could not be distinguished from human-induced pressures in the area. No significant sediment was exchanged between the salt marshes and tidal flats, and no self-organization pattern between them was observed in past. The related analysis showed that landcover changes in the salt marsh areas are likely to be more prominent in the future. The obtained results showed evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate to the presence of critical thresholds and potential negative feedbacks within the system, with significant implications to marsh resilience.
Low wind spells characterization over Europe as seen from ERA5 reanalysis
Authors: Sanchez Enrique , Gutierrez Claudia , Molina Maria Ofelia , Ortega María
Published: March 2021

Light wind conditions can be a very relevant feature from the wind power perspective. If such values are below a certain threshold (fixed or relative to some percentile), from the renewable energy production perspective, the amount of such energy is then strongly reduced or even suppressed. Frequency and intensity of such conditions is therefore of high interest, and a characterization of how these conditions can remain in time (during several hours, or days) can be even more important. From a climatic perspective, those episodes could be named as spells. This is the case of dry or wet ones, when referring to precipitation and its absence, or hot or cold ones, when focusing on temperatures. There is plenty of literature focused on that extreme conditions, for example in the set of indices to define extreme events developed by the ETCCDI (the CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices: http://etccdi.pacificclimate.org/). However, no mention is made to wind there. Here, we will explore the application of those indices for temperature and precipitation, but now applied to wind values, when they remain below normal values during a certain period of time. Several considerations will first be made to define light wind thresholds. Then, the statistical characterization of the persistence of those conditions will be inspected. ERA5 reanalysis over Europe for the last 40 years is used as the database to perform such analysis, at a resolution of 0.25 degrees for the whole region. From ERA5 time frequency, we are able to analyze hourly scales, due to the high time variability of wind, which can be also of quite relevant interest from the energetic resource perspective. We also analyze daily scales, which is more typical from a climatic focus, and see how these results can be related to mean wind conditions at each point. Time climatic variability and spatial obtained patterns are also studied. Results from this work will be useful to advance in a more systematic and rigorous climatic description of such wind conditions, that would be very important from the energy perspective, for example. In particular, we are interested in exploring the recently developed concept of energy droughts (Raynaud et al., 2018).
Compositional modelling of impure gas injection into saline aquifers with the MUFITS simulator
Authors: Afanasyev Andrey , Vedeneeva Elena
Published: March 2021

We present a recent extension of the MUFITS reservoir simulator for numerical modelling of multicomponent gas injection into saline aquifers. The extension is based on the compositional module of the simulator that implements a conventional cubic equation of state (EoS) for predicting phase equilibria of reservoir fluids [1]. Now, the module is supplemented with a new library of EoS coefficients for accurate modelling of CO2, N2, CH4, H2, O2, H2S, and other hydrocarbon components solubility in NaCl brine. In general, we follow the approach proposed by Søreide and Whitson [2] for modelling aqueous solutions, which involves a different and dependent on brine salinity binary interaction coefficients for aqueous and non-aqueous phases. However, we also use several published modifications to the EoS coefficients that were originally proposed in [2] to improve prediction of the mutual solubilities.

The extension is validated against 3-D benchmark studies of pure supercritical CO2 injection into saline aquifers. Also, we consider two more complicated injection scenarios to demonstrate potential applications of the new development. First, we simulate impure CO2 injection into a saline aquifer. We show that even a small amount of air (N2 and O2) in the injected gas results in a significantly more rapid spreading of the gas plume. Second, we consider a 3-D study of CO2 injection into subsurface natural gas storage aiming at the cushion gas substitution with supercritical CO2. The mechanical dispersion in the porous medium is accounted for an accurate modelling of CO2 and CH4 mixing. We simulate the propagation of CO2 in the storage by modelling several seasons of natural gas (CH4) injection and extraction.

The authors acknowledge funding from the Russian Science Foundation under grant # 19-71-10051.

References

1. Afanasyev A.A., Vedeneeva E.A. (2020) Investigation of the efficiency of gas and water Injection in an oil reservoir. Fluid Dyn. 55(5), 621-630.

2. Søreide I., Whitson C.H. (1992) Peng-Robinson predictions for hydrocarbons, CO2, N2, and H2S with pure water and NaCl brine. Fluid Phase Equil. 77, 217-240.
Spatial variation of stream water chemistry in the Shimanto River Basin in southwestern Japan: A comparison of results in 1999 and 2020
Authors: Inagaki Yoshiyuki , Inagaki Masahiro , Shichi Koji , Yoshinaga Shuichiro , Yamada Tsuyoshi , Miura Satoru , Shinomiya Yoshiki , Fujii Kazumichi
Published: March 2021

Acidic deposition derived from human activities causes negative effects on nutrient cycling in forest ecosystems.  However, nutrient cycling of forest ecosystems is expected to recover because the emission of pollutants is generally decreasing in recent years.  However, the extent of recovery would be differed between forest ecosystems in different climatic conditions.  The study investigated changes of stream water chemistry of forest ecosystems in Shimanto River Basin in southwestern Japan.  The 92 samples of stream water were collected from forested watersheds in summer of 1999 and 2020 and chemistry of the samples was compared.  The mean pH value of the stream water in 2020 (7.60) was higher than that in 1999 (7.29).  The mean concentration of potassium ion increased by 2.1% whereas that of sodium, calcium, and magnesium ions decreased by 2.5%, 10.3%, and 8.6%, respectively.  The mean concentration of chloride, nitrate and sulfate ions decreased by 24.8%, 9.4% and 22.5%, respectively whereas that of bicarbonate increased by 0.7%. 　The relationship between mean annual temperature and the ratio of ion concentration in 2020 to that in 1999 was analyzed.  The ratio of calcium and manganese concentration was lower at warmer sites.  The ratio of sulfate concentration was lower at warmer sites whereas the ratio of chloride concentration was not related with mean annual temperature.  The results suggest that the runoff of sulfate and chloride from forest ecosystems in the Shimanto River Basin have decreased presumably due to the reduced input of these elements and that the residence time of sulfur in forest ecosystems is shorter in warmer sites as indicated by the greater reduction of sulfate concentration.

 
A model for gravity changes induced by lava fountaining at Mt Etna
Authors: Passarelli Luigi , Nikkhoo Mehdi , Rivalta Eleonora , Frischknecht Corine , Bonadonna Costanza , Carbone Daniele
Published: March 2021

Lava fountains represent a common eruptive phenomenon at basaltic volcanoes, which consist of jets of fluid lava ejected into the atmosphere from active vents or fissures. They are driven by rapid formation and expansion of gas bubbles during magma ascent. The dynamics of lava fountains is thought to be controlled by the gas accumulation in the foam layer at the top of a shallow magmatic reservoir, which eventually collapses triggering the lava fountaining. Gravity measurements taken from a location close to summit of Mt. Etna during the 2011 lava fountain episodes showed a pre-fountaining decrease of the gravity signal. The interplay between gas accumulation in the foam layer and its subsequent exsolution in the conduit has been interpreted as the mechanism producing the gravity decrease and eventually leading to the foam collapse and onset of the lava fountaining activity. Gravity measurements have proved helpful in recording the earliest phases anticipating the lava fountain episodes and inferring the amount of gas involved. However, more accurate estimates of the accumulating and ascending gas volume and total magma mass require considering the possible effect of non-spherical magma chamber geometries and magma compressibility.

Under task 4.4 of the H2020 NEWTON-g project, we are accomplishing a detailed study aimed to simulate the gravity signal produced in the stage prior to a lava fountain episode, through a magma chamber - conduit model. We use a prolate ellipsoidal chamber matching the inferred shape of the shallow chamber active at Mt. Etna during the lava fountain episodes, and calculate the surface gravity changes induced by inflow of new magma into the chamber-conduit system. We use a two-phase magma with fixed amount of gas mass fraction and account for magma compressibility. We find that a realistic chamber shape and magma compressibility play a key role and must be considered to produce realistic gravity changes simulations. We combine our physical model with empirical distributions of recurrence time and eruption size of the past lava fountains at Mt. Etna to stochastically simulate realistic time series of gravity changes. The final goal of this study is to develop a prediction model for the amount of magma and duration of lava fountains at Mt. Etna.
Quantification of key factors driving the microbial metabolism in the vadose zone – A microscale-modelling perspective
Authors: Golparvar Amir , Kästner Matthias , Thullner Martin
Published: March 2021

Organic carbon (C), either originated from soil organic carbon or introduced externally from anthropogenic sources, is the main pool for providing microorganisms with materials for biosynthesis (anabolism) and energy for catabolism. Routing the carbon source between catabolic and anabolic pathways eventually decides over the fate of C; either if it leaves the system as inorganic carbon (i.e. CO2) or, it stays in it due to anabolism and cell synthesis processes. The microbial carbon use efficiency (CUE) – and thus the proportion of the C that (potentially) remains in soil – depends on various factors.  Physio-chemical condition of the hosting environment, the composition and activity of the microbial community and in extreme cases, climatic changes can cause a high spatio-temporal variability in microbial activity and CUE. At microscale, also the pore-size distribution, pore connectivity and pore water-content can (directly or indirectly) alter the distribution of carbon and energy fluxes in soils. Across different soil types and conditions, the evolution of microbial community and of their CUE in the simultaneous presence of various factors are poorly understood.

In order to capture the in-situ dynamics of microbial activity and CUE in the dynamically changing environment of the vadose zone, we apply a pore-scale reactive transport modelling approach to disentangle the interplay of physio-chemical factors in the evolution of the soil carbon pool. Our modelling framework is capable providing a resolution of unsaturated water flow and solute transport at the microscale combined with capturing the underlying biogeochemical processes for tracking the evolution of microbial communities along with C pools in soil. Physical properties of the porous structure (such as pore geometry, pore size distribution and their connectivity) are accounted for via using digitized -CT images. Variable water flow and distribution is achieved by solving the Navier Stokes equation. A full set of advective-diffusive-reactive transport equation is solved for all chemical and microbial species to investigate their evolution in time and space. Model simulation cover various scenarios differing in properties of the solid matrix, imposed flow conditions and considered organic carbon substrates. Sensitivity simulations are performed to single out the effect of different bio-physio-chemical factors on evolution of microbial biomass and CUE.
A large ensemble decadal prediction system with MPI-ESM
Authors: Brune Sebastian , Koul Vimal , Nielsen David Marcolino , Hövel Laura , Pohlmann Holger , Düsterhus André , Baehr Johanna
Published: March 2021

Current state-of-the-art decadal ensemble prediction systems are run with an ensemble size of 10 to 40 members, their retrospective forecasts of the past are used to assess the system's prediction skill. Here, we present an attempt for a large ensemble decadal prediction system for the time period 1960-today, with an ensemble size of 80 members, based on the low resolution version of the Max Planck Institute Earth system model (MPI-ESM-LR). The ensemble is forced with CMIP6 conditions and initialized every year in November through a weakly coupled assimilation using atmospheric reanalyses via nudging and observed oceanic temperature and salinity profiles via a 16-member ensemble Kalman filter. To generate ensemble members beyond 16, we use additional physical perturbations at stratospheric height. The analysis of our large ensemble prediction system presented here aims for answering two questions: (1) How does the ensemble mean deterministic prediction skill for global and North Atlantic key climate indices change with ensemble size? (2) How well may the 80-member ensemble serve as a basis for a robust statistical analysis of probabilities of extremes in the North Atlantic sector? Preliminary results for global and regional air surface temperature show that in terms of ensemble mean ACC and full ensemble CPRSS with reference data, the 80-member ensemble leads to similar prediction skill as the 16-member ensemble. This indicates that the additional ensemble members may lead to a better sampling of the distribution of model trajectories, paving the way for a more robust statistical probabilistic analysis.
Formation of the double stratopause and elevated stratopause associated with the major stratospheric sudden warming in 2018/19
Authors: Okui Haruka , Sato Kaoru , Koshin Dai , Watanabe Shingo
Published: March 2021

After several recent stratospheric sudden warming (SSW) events, the stratopause disappeared and reformed at a higher altitude, forming an elevated stratopause (ES). The relative roles of atmospheric waves in the mechanism of ES formation are still not fully understood. We performed a hindcast of the 2018/19 SSW event using a gravity-wave (GW) permitting general circulation model containing the mesosphere and lower thermosphere (MLT), and analyzed dynamical phenomena throughout the entire middle atmosphere. An ES formed after the major warming on 1 January 2019. There was a marked temperature maximum in the polar upper mesosphere around 28 December 2018 prior to the disappearance of the descending stratopause associated with the SSW. This temperature structure with two maxima in the vertical is referred to as a double stratopause (DS). We showed that adiabatic heating from the residual circulation driven by GW forcing (GWF) causes barotropic and/or baroclinic instability before DS formation, causing in situ generation of planetary waves (PWs). These PWs propagate into the MLT and exert negative forcing, which contributes to DS formation. Both negative GWF and PWF above the recovered eastward jet play crucial roles in ES formation. The altitude of the recovered eastward jet, which regulates GWF and PWF height, is likely affected by the DS structure. Simple vertical propagation from the lower atmosphere is insufficient to explain the presence of the GWs observed in this event.
Empowering geoscientists to transform workplace climate through behavioral and institutional change, results from a workplace climate survey by the ADVANCEGeo Partnership
Authors: Marín-Spiotta Erika , Diaz Vallejo Emily , Magley Vicki , Schneider Blair , Mattheis Allison , Barnes Rebecca , Berhe Asmeret Asefaw , Hastings Meredith , Bell Christine Fabian , Maertens Julie , Williams Billy
Published: March 2021

The geosciences are one of the least diverse fields in the U.S., despite their societal relevance. Bias, discrimination, harassment and bullying create hostile climates that present serious hurdles to diversifying the field. These behaviors persist due to severe power imbalances, historical structures of exclusion, persistent marginalization of non-majority groups, and inadequate policies against misconduct. Here we discuss findings from a workplace climate survey of the earth and space sciences distributed via five professional associations: American Geophysical Union, Geological Society of America, Soil Science Society of America, Earth Science Women’s Network and the Association for Women Geoscientists. The survey asked about attitudes and experiences of support, inclusion, exclusion, psychological safety, incivility, and sexual harassment, as well as representation in the workplace. Quantitative results are complemented with qualitative data from the survey and focus groups. This is one of the first such community-wide surveys in the U.S. geosciences and is currently being replicated in the ecological sciences. 

We present the findings of the survey in the context of other work done by the ADVANCEGeo Partnership team and provide recommendations for moving forward. Our approach is informed by critical feminist approaches that seek to disrupt unequal power dynamics in strongly hierarchical workplaces. Expanding the focus from a gender equity program emphasis on sexual harassment to hostile climates, and centering how intersectionality shapes the experiences of those disproportionately impacted by exclusionary behaviors is key for addressing persistent demographic trends in the geosciences. A feminist ethics of care approach informs ADVANCEGeo’s main organizational change intervention, which is a community-based model for bystander intervention and workplace climate education that identifies harassment, bullying and discrimination as scientific misconduct and promotes the adoption of ethical codes of conduct.