bluuebunny/crossref_metadata_2025 huggingface dataset:
Who attended and presented at EGU General Assemblies 2015-2019?
Authors: Stadmark Johanna , Jesus-Rydin Claudia , Conley Daniel J.
Published: March 2021

The first step for institutions committed to equality, diversity and inclusion is to know their demographics. This presentation includes descriptive statistics for 5 consecutive years (2015–2019) based on paid registrations to the physical EGU General Assembly. EGU data is not perfect nor complete, but provides an insightful overview of who attended and presented at the EGU General Assembly for a period of 5 years.

In total more than 71 000 participants attended the EGU General Assemblies during the years 2015-2019 from a wide range of countries. More than 11400 (16%) of the participants were from Germany, followed by almost 6400 (8.9%) from the UK, 5300 (7.4%) from France, 5000 (7.0%) from Italy, 4600 (6.5%) from the US, and 3500 (4.9%) each from Austria and China. We found that the number of participants to the EGU General Assembly has increased continuously from 2015 to 2019 and that the largest proportions of participants are aged between 26 and 45.

Among the PhD students attending there are 7 females for every 10 males, and among the regular members there are around 4 females for every 10 males. The proportion of female participants decreases with increasing age. However, the ratio of females to males among participants has continuously increased from 0.48 in 2015 to 0.51 in 2018. Four countries had more females than males attending the EGU General Assembly (Bulgaria, Morocco, Iceland and Slovenia).

There are great possibilities to present one’s research at the meetings with ninety percent of the participants as first author on presentations (2015-2018, 94% 2019) and there was no difference between females and males. More than half (52-61%) of the male participants had oral presentations, while slightly fewer (46-52%) of the female participants had oral presentations. The major differences in oral presentations are found between participants from different countries. Note that the data do not reveal the participants’ preferred choice of presentations, only the outcome at the meetings. Around 70% of the participants presented a poster, with no differences between genders, which indicate that men had more presentations than women. On average males had 6.5% more presentations per person. Finally a slightly higher proportion of the male participants were convenors (15-18% versus 12-15% for females).

EGU General Assembly is the largest geosciences conference in Europe and still growing. Understanding the demographic evolution of various groups is a critical tool for EGU governing body to draw targeted actions ensuring that procedures are fair and that all in the community are being and feeling included.
In-cloud scavenging scheme for sectional aerosol modules – implementation in the framework of the Sectional Aerosol module for Large Scale Applications version 2.0 (SALSA2.0) global aerosol module
Authors: Holopainen Eemeli , Kokkola Harri , Laakso Anton , Kühn Thomas
Published: March 2021

Black carbon (BC) affects the radiation budget of the Earth by absorbing solar radiation, darkening snow and ice covers, and influencing cloud formation and life cycle. Modelling BC in remote regions, such as the Arctic, has large inter-model variability which causes variation in the modelled aerosol effect over the Arctic. This variability can be due to differences in the transport of aerosol species which is affected by how wet deposition is modelled.

 In this study we developed an aerosol size-resolved in-cloud wet deposition scheme for liquid and ice clouds for models which use a size-segregated aerosol description. This scheme was tested in the ECHAM-HAMMOZ global aerosol-climate model. The scheme was compared to the original wet deposition scheme which uses fixed scavenging coefficients for different sized particles. The comparison included vertical profiles and mass and number wet deposition fluxes, and it showed that the current scheme produced spuriously long BC lifetimes when compared to the estimates made in other studies. Thus, to find a better setup for simulating aerosol lifetimes and vertical profiles we conducted simulations where we altered the aerosol emission distribution and hygroscopicity.

 We compared the modelled BC vertical profiles to the ATom aircraft campaign measurements. In addition, we compared the aerosol lifetimes against those from AEROCOM model means. We found that, without further tuning, the current scheme overestimates the BC concentrations and lifetimes more than the fixed scavenging scheme when compared to the measurements. Sensitivity studies showed that the model skill of reproducing the measured vertical BC mass concentrations improved when BC emissions were directed to larger size classes, they were mixed with soluble compounds during emission, or BC-containing particles were transferred to soluble size classes after aging. These changes also produced atmospheric BC lifetimes which were closer to AEROCOM model means. The best comparison with the measured vertical profiles and estimated BC lifetimes was when BC was mixed with soluble aerosol compounds during emission.
Impact of planetary waves on infrasound propagation uncertainties
Authors: Blanc Elisabeth , Hupe Patrick , Kaifler Bernd , Kaifler Natalie , Le Pichon Alexis , Keckhut Philippe , Hauchecorne Alain
Published: March 2021

The uncertainties in the infrasound technology arise from the middle atmospheric disturbances, which are partly underrepresented in the atmospheric models such as in the European Centre for Medium-Range Weather Forecasts (ECMWF) products used for infrasound propagation simulations. In the framework of the ARISE (Atmospheric dynamics Research InfraStructure in Europe) project, multi-instrument observations are performed to provide new data sets for model improvement and future assimilations. In an unexpected way, new observations using the autonomous CORAL lidar showed significant differences between ECMWF analysis fields and observations in Argentina in the period range between 0.1 and 10 days. The model underestimates the wave activity, especially in the summer. During the same season, the infrasound bulletins of the IS02 station in Argentina indicate the presence of two prevailing directions of the detections, which are not reflected by the simulations. Observations at the Haute Provence Observatory (OHP) are used for comparison in different geophysical conditions. The origin of the observed anomalies are discussed in term of planetary waves effect on the infrasound propagation.
GeoERA´s Contribution Towards Resilience in Europe’s Raw Materials Supply Chains
Authors: Wittenberg Antje , de Oliveira Daniel P. S. , González Sanz F. Javier , Flindt Jørgensen Lisbeth , Held Tom
Published: March 2021

The well-being of society and the interdependencies of national economies depend heavily on reliably functioning supply chains as the COVID-19 pandemic proved this long-known statement in everyone's daily life. None of the supply chains can do without the mostly mineral raw materials. The United Nations sees raw materials as the key component for achieving all 17 Sustainable Development Goals (SDGs). The European Green Deal (COM(2019) 640 final) of the European Union as well as the Paris Agreement cannot be achieved without raw materials. The IPR Global Resources Outlook 2019 [1] foresees an increasing demand for raw materials worldwide regardless of all efforts to further close the raw material cycles. At the same time, the demand for responsible procurement under ethically, socially and ecologically sound conditions is becoming more and more stringent.

The four GeoERA Raw Materials projects EuroLITHOS, FRAME, MINDeSEA and Mintell4EU share expertise, information and focus on European on-shore and off-shore resources as a first step to take our share of responsibility to ensure responsible sourcing from domestic sources [2]. It is among the tasks of the GeoERA raw material projects to know and evaluate in a comparable way the raw materials of the geology under our feet and to visualize these results in accessible databases, maps and publications.

Results will be presented and discussed on the example of selected raw materials that are particularly important for the energy transition to make Europe climate-neutral by 2050.

 

 
Occurrence and impacts of heat waves events in a glacierized basin in the subtropical Andes
Authors: Bravo Claudio , Paredes Pablo , Donoso Nicolás , Cisternas Sebastián
Published: March 2021

Subtropical Andean glaciers are losing mass in response to the long-term atmospheric warming and precipitation decrease. Extreme events as heat waves, however, seems to potentially play a key role in the sustained ice loss detected in the last decades. Increased frequency of heat wave events have been detected in the central valley of Chile, however, the occurrence and impact of these events on the Andean cryosphere remain unknown. The main reason is associated with the lack of meteorological observations at higher elevations in the Andes. 

In filling this gap, we present an assessment of the occurrence of heat waves in the glacierized Río Olivares basin (33°S), which comprise an elevation range between ~1500  and ~6000 m a.s.l. and where a strong ice loss has been detected during the last decades. The main aim is to analyse the correspondence of heat waves events occurred with those in the nearby city of Santiago located in the central valley of Chile and to assess the potential impacts of these events on the glaciers located in this basin. Using meteorological observations in Río Olivares basin and in Santiago between the years 2013 and 2020, heat wave events were determined. We estimated the heat wave events using the monthly 90th percentile and the adjustment of a harmonic function. An additional adjustment relative to the climate period 1981-2010 was also introduced. The results determined 66 events in the Río Olivares basin while in Santiago were 53 events. These results reveal high spatial variability in the occurrences of heat waves as only 49% of the events in Santiago were detected in the Río Olivares basin. Ongoing work is focused on analysing the impacts of these events over the glaciers of the basin. Here, through the use of the computed basin-scale 0°C isotherm, the relation between glacier area under melt (i.e. glacier area located below the 0°C isotherm) and the heat wave events will be shown. The findings of this works reinforce the need for more observational efforts over high elevations in the Andes in order to robustly assess and at a basin scale, the impact of extreme events on the Andean cryosphere.
Hydrology and biogeochemistry of subglacial environment of Greenland ice sheet
Authors: Pramanik Ankit , Hayes Nick , Pattyn Frank , Arndt Sandra
Published: March 2021

The Greenland ice sheet surface melt has increased substantially in intensity and spatial extent over the recent decades. The rapid migration of melt towards upstream areas of Greenland ice sheet is expected to incur major changes in hydrological behaviour of the ice sheet and outlet glaciers along with changes in export fluxes of carbon, methane, and other nutrient fluxes, which, in turn, will further affect the downstream ecosystem of rivers, fjords and oceans. Subglacial environments are emerging as ecological hotspots, urging detailed understanding of interaction between subglacial hydrology and biogeochemistry. However, due to their inaccessibility, the hydrology and geochemistry of subglacial environment thus far lacks a detailed understanding. As such this area is now the focus of many major projects in Greenland and Antarctica. 

 

Under the NuttI (Nutrient factories under the Ice) project, we aim to develop a hydrological-biogeochemical model framework to investigate seasonal and inter-annual evolution of subglacial hydrology system and quantify carbon and nutrient export from subglacial environments to proglacial rivers. We use the subglacial hydrology model GlaDS (Glacier Drainage System model) to simulate seasonal and interannual evolution of distributed and channelized subglacial water flow while calculating subglacial water storage, residence time, water flux and effective pressure. A subglacial erosion scheme is coupled to the model to calculate physical weathering occurring especially in early melt and peak melt season due to glacier sliding and higher water flow, respectively. All these parameters are used in a geochemical model to quantify subglacial chemical weathering fluxes. The meltwater becomes chemically enriched subglacially and reaches the glacier outlet through subglacial channels. We also intend to further develop the model to investigate processes such as subglacial cycling of silica and production of methane.

 

We primarily use the coupled model to simulate Leverett glacier, a land-terminating outlet glacier in southwest Greenland which has been well studied with different geophysical measurements and long-term monitoring. The model output is validated with the in-situ measurement of discharge and export fluxes in the proglacial river of the land-terminating glacier. 
Overshooting warming targets – temperature reversibility and implications for impacts, adaptation needs and near-term mitigation
Authors: Schleussner Carl-Friedrich , Lejeune Quentin , Ciais Philippe , Gasser Thomas , Rogelj Joeri , Mengel Matthias
Published: March 2021

Limiting global mean temperature increase to politically agreed temperature limits such as the 1.5°C threshold in the Paris Agreement becomes increasingly challenging. This has given rise to a class of overshoot emissions pathways in the mitigation literature that limit warming to such thresholds only after allowing for a temporary overshoot. However, substantial biogeophysical uncertainties remain regarding the large-scale deployment of Carbon Dioxide Removal technologies required to potentially reverse global warming. Additionally, beyond global mean temperature very little is known about the benefits of declining temperatures on impacts and adaptation needs. Here we will provide an overview of the current state of understanding regarding the reversibility of global warming, as well as impacts and adaptation needs under overshoot pathways.

We highlight the characteristics of the overshoot scenarios from the literature, and especially those that are compatible with identified sustainability limits for Carbon Dioxide Removal deployment. We will compare those characteristics with uncertainties arising from the Earth System’s response which may complicate the efforts to achieve a decrease in Global Mean Temperature after peak warming is reached. This part will include latest results of the permafrost carbon feedback under stylized overshoot scenarios. Eventually, we will summarise the state-of-the-art knowledge and present new results regarding the impacts of overshoot scenarios for non-linear and time-lagged responses such as sea-level rise, permafrost and glaciers. This will allow for a preliminary assessment of the impact and adaptation benefits of early mitigation compatible with a no or low overshoot pathways.
Propagation of Thermohaline Anomalies and their predictive potential in the Northern North Atlantic
Authors: Langehaug Helene R. , Ortega Pablo , Counillon Francois , Matei Daniela , Maroon Elizabeth , Keenlyside Noel , Mignot Juliette , Wang Yiguo , Swingedouw Didier , Bethke Ingo , Yang Shuting , Danabasoglu Gokhan , Bellucci Alessio , Ruggieri Paolo , Nicolì Dario
Published: March 2021

In this study we assess to what extent seven different dynamical prediction systems can retrospectively predict the winter sea surface temperature (SST) in the subpolar North Atlantic and the Nordic Seas in the time period 1970-2005. We focus in particular on the region where warm water flows poleward, i.e., the Atlantic water pathway, and on interannual-to-decadal time scales. To better understand why dynamical prediction systems have predictive skill or lack thereof, we confront them with a mechanism identified from observations – propagation of oceanic anomalies from low to high latitudes – on different forecast lead times. This observed mechanism shows that warm and cold anomalies propagate along the Atlantic water pathway within a certain time frame. A key result from this study is that most models have difficulty representing this mechanism, resulting in an overall poor prediction skill after 1-2 years lead times (after applying a band-pass filter to focus on interannual-to-decadal time scales). There is a link, although not very strong, between predictive skill and the representation of the SST propagation. Observational studies demonstrate predictability several years in advance in this region, thus suggesting a great potential for improvement of dynamical climate predictions by resolving the causes for the misrepresentation of the oceanic link. Inter model differences in simulating surface velocities along the Atlantic water pathway suggest that realistic velocities are important to better circulate anomalies poleward, and hence, increase predictive skill on interannual-to-decadal time scales in the oceanic gateway to the Arctic.
Drought and wildfires in Portugal at the county scale
Authors: Pereira Mário , Parente Joana
Published: March 2021

Weather and climate extreme events contribute to the increase of wildfire risk. A recent study carried out in Mainland Portugal for the period 1981 – 2017, using Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) to assess drought conditions, revealed that drought affects 70% of the months and a very strong relationship between the occurrence of drought and the spatio-temporal distribution of extreme wildfires (> 5,000 ha). These results raised additional scientific questions that need to be answered, such as: Is the relationship between droughts and fires equally strong for wildfires of smaller size? The study was carried out at the country level, but what are the regions where the relationship is more and less strong? Therefore the objective of this study is to assess the influence of drought on fire incidence, considering all wildfires or classes of wildfire sizes and in each of the 278 counties of Continental Portugal characterized by different features (landscape, weather/climate, drought and fire incidence). This study benefits from the existence of long and reliable meteorological and wildfire datasets. The methodology comprises cluster analysis, contingency tables, accuracy metrics, statistical measures of association to test the independence and help find interactions between these two natural hazards. Main results include: (i) the characterization of spatio-temporal distribution of drought number, duration, severity, intensity, extension; (ii) wildfire space-time distribution within drought periods and affected area; and, (iii) the assessment of the relationship between droughts and wildfires at county scale. The authors believe that the findings of this study are very useful for the definition of adaptation and mitigation strategies for the impacts of droughts in wildfire occurrence and to assess the climatic wildfire hazard/risk.

Acknowledgements

This work was supported and conducted in the framework of the FEMME project (PCIF/MPG/0019/2017) funded by FCT - Portuguese Foundation for Science and Technology. The study was also supported by: i) National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020; and, ii) National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UID/AMB/50017/2019. Data were provided by the European Forest Fire Information System – EFFIS (http://effis.jrc.ec.europa.eu) of the European Commission Joint Research Centre.
Full-waveform inversion with wavefield gradients
Authors: Singh Sneha , Capdeville Yann , Igel Heiner , Hedjazian Navid , Bodin Thomas
Published: March 2021

Wavefield gradient instruments, such as rotational sensors and DAS systems, are becoming more and more accessible in seismology. Their usage for Full Waveform Inversion (FWI) is in sight. Nevertheless, local small-scale heterogeneities, like geological inhomogeneities, surface topographies, and cavities are known to affect wavefield gradients. This effect is in fact measurable with current instruments. For example, the agreement between data and synthetics computed in a tomographic model is often not as good for rotation as it is for displacement.

The theory of homogenization can help us understand why small-scale heterogeneities strongly affect wavefield gradients, but not the wavefield itself. It tells us that at any receiver measuring wavefield gradient, small-scale heterogeneities cause the wavefield gradient to couple with strain through a coupling tensor J. Furthermore, this J is 1) independent of source, 2) independent of time, but 3) only dependent on the receiver location. Consequently, we can invert for J based on an effective model for which synthetics fit displacement data reasonably well. Once inverted, J can be used to correct all other wavefield gradients at that receiver.

Here, we aim to understand the benefits and drawbacks of wavefield gradient sensors in a FWI context. We show that FWIs performed with rotations and strains are equivalent to that performed with displacements provided that 1) the number of data is sufficient, and 2) the receivers are placed far away from heterogeneities. In the case that receivers are placed near heterogeneities, we find that due to the effect of these heterogeneities, an incorrect model is recovered from inversion. In this case therefore, the coupling tensor J needs to be taken into account for each receiver to get rid of the effect.
Dual pure-rotational Raman channel design and implementation in a multiwavelength lidar system for the monitoring of aerosol optical properties.
Authors: Zenteno-Hernández José-Alex
Published: March 2021

Pure-rotational Raman (PRR) scattering has proven to be an efficient technique for the determination of atmospheric aerosol optical properties for lidar applications. We present the implementation of a UV-PRR and the design of a VIS-PRR in the EARLINET/UPC multi-wavelength lidar system (Barcelona, Spain). State-of-the-art computations of N2 and O2 differential backscatter cross-sections weighted by the optical losses inside the optical separation unit of the system allow for the theoretical estimation of the expected signal-to-noise ratios (SNR) in both UV and VIS channels. By means of customized optical interference filters UV-PRR signals from atmospheric N2 and O2 were detected and compared to the classical vibro-rotational Raman signals. UV-PRR detected signals have shown to possess high SNR and relative uncertainty levels lower than a tolerable 15% for daytime and nighttime measurements. The theoretical analysis of the VIS-PRR channel augurs improvements similar to those observed with the UV-PRR channel.
Suitability of phytoliths as a quantitative process tracer for soil erosion studies
Authors: Kraushaar Sabine , Konzett Matthias , Kiep Janika , Siebert Christian , Meister Julia
Published: March 2021

Phytoliths are a plant microfossil commonly used as qualitative archive markers in archaeological and paleoecological studies. Their potential uniqueness to the vegetation cover, robustness to weathering, and lack of chemical alteration along the paths make them a potentially suitable tracer for quantitative erosion studies.
In this pilot study, we explore the potential of phytoliths in a sediment fingerprinting study in the Ceguera catchment (28 km2) in NE Spain. The phytolith concentrations and morphologies of four land cover classes (agricultural land, badland, forest, and shrubland) were analyzed, and their contributions to four sediment mixture samples along the river course were modelled. Phytoliths concentrations allowed us to discriminate sources sufficiently, albeit with limited sample size. The performance of the phytoliths as the tracer was tested by reproducing the sources of artificial sediment mixture samples with satisfactory recall ratio. Results identified badlands to be the main contributor, with 84–96% of the sediment load to the sinks, followed by shrublands (median 5%) and agricultural lands (median 2%). Additionally, an intensively used agricultural area in the SW of the catchment was well indicated. These major findings can be reproduced by other conventional erosion studies from this area, indicating that phytoliths are suited to quantifying erosion patterns in mesoscale catchments.
Soil Moisture and Live Fuel Moisture Content as key remote sensing variables to unlock improved wildfire predictions
Authors: Briquemont Florian , Benali Akli
Published: March 2021

Large wildfires are amongst the most destructive natural disasters in southern Europe, posing a serious threat to both human lives and the environment.

Although wildfire simulations and fire risk maps are already very a useful tool to assist fire managers in their decisions, the complexity of fire spread and ignition mechanisms can greatly hinder their accuracy. An important step in improving the reliability of wildfire prediction systems is to implement additional drivers of fire spread and fire risk in simulation models.

Despite their recognized importance as factors influencing fuel flammability and fire spread, soil moisture and live fuel moisture content are rarely implemented in the simulation of large wildfires due to the lack of sufficient and accurate data. Fortunately, new satellite products are giving the opportunity to assess these parameters on large areas with high temporal and spatial resolution.

The purpose of this study is twofold. First, we aimed to evaluate the capabilities of satellite data to estimate soil moisture and live fuel moisture content in different landcovers.  Secondly, we focused on the potential of these estimates for assessing fire risk and fire spread patterns of large wildfires in Portugal. Ultimately, the goal of this study is to implement these estimated variables in fire spread simulations and fire risk maps.

We compared datasets retrieved from Sentinel 1, SMAP (Soil Moisture Active Passive radiometer) and MODIS (Moderate Resolution Imaging Spectrometer) missions. Several estimators of LFMC based on spectral indices were tested and their patterns were compared with field data. Based on these estimators, we assessed the impact of LFMC and soil moisture on the extent and occurrence of large wildfires. Finally, we built a database of detailed historical wildfire progressions, which we used to evaluate the influence of soil moisture and LFMC on the velocity and direction of the fire spread.
Pi-MEP Salinity – an ESA-NASA Platform for sustained satellite surface salinity validation 
Authors: Sabia Roberto , Guimbard Sebastien , Reul Nicolas , Lee Tony , Schanze Julian , Vinogradova Nadya , Le Vine David , Bingham Fred , Collard Fabrice , Scipal Klaus , Laur Henri
Published: March 2021

The Pilot Mission Exploitation Platform (Pi-MEP) for Salinity (www.salinity-pimep.org) has been released operationally in 2019 to the broad oceanographic community, in order to foster satellite sea surface salinity validation and exploitation activities.

Specifically, the Platform aims at enhancing salinityvalidation, by allowing systematic inter-comparison of various EO datasets with a broad suite of in-situ data, and also at enabling oceanographic process studies by capitalizing on salinity data in synergy with additional spaceborne estimates.

 

Despite Pi-MEP was originally conceived as an ESA initiative to widen the uptake of the Soil Moisture and Ocean Salinity (SMOS) mission data over ocean, a project partnership with NASA was devised soon after the operational deployment, and an official collaboration endorsed within the ESA-NASA Joint Program Planning Group (JPPG).

 

The Salinity Pi-MEP has therefore become a reference hub for SMOS, SMAP and Aquarius satellite salinity missions, which are assessed in synergy with additional thematic datasets (e.g., precipitation, evaporation, currents, sea level anomalies, ocean color, sea surface temperature). 

Match-up databases of satellite/in situ (such as Argo, TSG, moorings, drifters) data and corresponding validation reports at different spatiotemporal scales are systematically generated; furthermore, recently-developed dedicated tools allow data visualization, metrics computation and user-driven features extractions.

 

The Platform is also meant to monitor salinity in selected oceanographic “case studies”, ranging from river plumes monitoring to SSS characterization in challenging regions, such as high latitudes or semi-enclosed basins.

 

The two Agencies are currently collaborating to widen the Platform features on several technical aspects - ranging from a triple-collocation software implementation to a sustained exploitation of data from the SPURS-1/2 campaigns. In this context, an upgrade of the satellite/in-situ match-up methodology has been recently agreed, resulting into a redefinition of the validation criteria that will be subsequently implemented in the Platform.

 

A further synthesis of the three satellites salinity algorithms, models and auxiliary data handling is at the core of the ESA Climate Change Initiative (CCI) on Salinity and of ESA-NASA further collaboration.
Transport of energetic particles from reconnecting current sheets in flaring corona to the heliosphere
Authors: Browning Philippa , Gordovskyy Mykola , Inoue Satashi , Kontar Eduard , Kusano Kanya , Vekstein Gregory
Published: March 2021

In this study, we inverstigate the acceleration of electrons and ions at current sheets in the flaring solar corona, and their transport into the heliosphere. We consider both generic solar flare models and specific flaring events with a data-driven approach. The aim is to answer two questions: (a) what fraction of particles accelerated in different flares can escape into the heliosphere?; and (b) what are the characteristics of the particle populations propagating towards the chromosphere and into the heliosphere?

We use a combination of data-driven 3D magnetohydrodynamics simulations with drift-kinetic particle simulations to model the evolution of the magnetic field and both thermal and non-thermal plasma and to forward-model observable characteristics. Particles are accelerated in current sheets associated with flaring reconnection. When applied to a specific flare, the model successfully predicts observed features such as the location and relative intensity of hard X-ray sources and helioseismic source locations. This confirms the viability of the approach.

Using these MHD-particle models, we will show how the magnetic field evolution and particle transport processes affect the characteristics of both energetic electrons and ions in the the inner corona and the heliosphere. The implications for interpretation of in situ measurements of energetic particles by Solar Orbiter and Parker Solar Probe will be discussed.

 

 
Direct Measurement of Ion Cyclotron Resonance Between Wave Fields and Protons in Space Plasmas
Authors: Luo Qiaowen , Zhu Xingyu , He Jiansen , Cui Jun , Lai Hairong , Verscharen Daniel , Duan Die
Published: March 2021

Ion cyclotron resonance is one of the fundamental energy conversion processes through wave field-particle interaction in collisionless plasma. However, the key evidence for cyclotron resonance (i.e., the coherence between wave field and ion phase space density pertaining to the ion cyclotron resonance and responsible for the dissipation of ion cyclotron waves (ICWs)) has yet to be directly observed. Based on the high-quality measurements of space plasma by the Magnetospheric Multiscale (MMS) satellites, we observe that both the wave electromagnetic field vectors and the disturbed ion velocity distribution rotate around the background magnetic field. Moreover, we find that the gyrophase angle difference between the fluctuations in the ion velocity distribution functions and the wave electric field vectors are always in the range of (0, 90) degrees, clearly suggesting the ongoing energy conversion from wave fields to particles. By invoking plasma kinetic theory, we find that the field-particle correlation for the dissipative ion cyclotron waves in the theoretical model matches well with our observations. Furthermore, all the wave electric field vectors (Ewave), the ion current (Ji) and the energy transfer rate (Ji ·Ewave) exhibit quasi-periodic oscillations, and the frequency of Ji ·Ewave is about twice the frequency of Ewave and Ji, consistent with plasma kinetic theory. Therefore, our combined analysis of MMS observations and kinetic theory provides direct, thorough, and comprehensive evidence for ICW dissipation in space plasmas.
High-resolution color variations of Weichselian loess-palaeosol sequences in the Dnieper River basin (Ukraine)
Authors: Mroczek Przemysław , Łanczont Maria , Komar Maryna , Hołub Beata , Gozhik Petro , Nawrocki Jerzy
Published: March 2021

High-resolution colour analyses of key loess-soil sequences (LPSs) in the Ukrainian part of Dnieper River basin - one of the major European rivers and the largest river in the borderland between Central and Eastern Europe. The subject of the study were LPSs from the Last Glaciation with a thickness of up to 10 meters. The aim of our studies is to reconstruct the Upper Pleistocene paleogeographic transformations recorded in the Dnieper LPSs.

In our study area the causative geomorphological agent was dust was blown away by wind from the exposed surfaces rich in loose fine-grained material (e.g. from a wide valley of a big river) and deposited on the land surface as silt covers of different thickness and spatial extent; in warm (interphase, interstadial) periods of the Weichselian it was fixed by vegetation and was the parent rock for the successively developing soils of different pedogenesis types. In the Last Glaciation the zone of long (~1000 km) and generally sub-meridional valley of the Dnieper River was located in the peri- and extraglacial zone and characterized by strong spatial climate gradient depending on the distance from the ice sheet extent. In our times this river flows across several vegetation-landscape zones (forest→forest-steppe→steppe).

The spectrophotometer made it possible to carry out colour analyses of individual units distinguished within LPSs, taking into account a number of parameters such as: CIELAB color space variables L* (luminance, i.e. lightness [0-100]), a* (>0: red, < 0: green), and b* (>0: yellow, < 0: blue), derived parameters like the Redness Index (RI) and the RGB variables (min., max, average). The analysed LPSs showed relatively high variability of the above mentioned parameters reflecting activity of sedimentation processes (=primary loess) as well as pedogenic changes (soil horizons of different stratigraphic rank) and slope transformations (reworked material). The results of these analyses (presented mainly as curve lines and heatmaps) specify characteristics of environmental conditions of individual litho- and pedostratigraphic units. The advantage of the analysed parameters is their high sensitivity reflecting variability of environmental parameters having global, but also regional or even just local significance.

Research carried out as part of the grant of National Science Centre, Poland as the project no. 2018/31/B/ST10/01507 entitled “Global, regional and local factors determining the palaeoclimatic and palaeoenvironmental record in the Ukrainian loess-soil sequences along the Dnieper River Valley - from the proximal areas to the distal periglacial zone”.
Litter and deadwood water retention processes in a temperate mixed forest
Authors: Floriancic Marius G. , Allen Scott T. , Molnar Peter
Published: March 2021

Countless studies have demonstrated ways in which forests and trees affect catchment water balances. Water balance differences between forested and non-forested landscapes are often attributed to characteristics related to trees’ ability to take up and transpire water, as well as their ability to intercept precipitation. However, another potentially important characteristic of forests that has been largely overlooked in hydrologic studies is the retention and accumulation of debris, litter and deadwood on the forest floor. Here we leverage ongoing measurements at the new hillslope laboratory “Waldlabor” in Zurich, Switzerland, where water retention in forest litter, deadwood and the top soil layer has been investigated using frequent field campaigns and innovative new sensing techniques.

Several approaches were used to determine the maximum storage capacity as well as the storage dynamics of different types and layers of litter. In-lab saturation experiments revealed the maximum storage capacity of various litter types (i.e., leaf and needle litter). Those values were also supported with field pre- and post- rainfall sampling campaigns to determine in-situ litter storage dynamics, as well as to understand the interplay between litter interception and soil-water recharge. Importantly, recharge was often substantially smaller at plots with litter, compared to those without litter. The storage and water retention capacity of deadwood samples was measured in the field by logging the diurnal differences in deadwood weight over a six month period. Dew and fog deposition during the night led to larger water availability for evaporation during the day. We measured increased humidity at sensors in the forest at 1 and 3m heights respectively, compared to the humidity outside the forest. Daily weight measurements over eight weeks of 40 deadwood pieces at our forest site revealed differences in the storage capacity depended on the degree of decomposition. Additionally, we found that water stored in forest floor spruce cones (daily measurements of 20 pieces) actively contributed to evaporation fluxes.

The combination of continuous sensor measurements (soil moisture, deadwood water content), field measurements (litter and deadwood grab samples) as well as laboratory work (saturation experiments) revealed the water storage and retention capacity of litter and deadwood in a typical temperate mixed forest and their contribution to evaporation. These measurements are one component of the new ETH Zürich “Waldlabor” research infrastructure, which also includes measurements of precipitation, xylem water, soil water, groundwater, and discharge amounts, isotope ratios, and other chemical characteristics.
Temporal evolution of relative seismic velocity in the Golf of Corinth - Greece.
Authors: Delouche Estelle , Stehly Laurent
Published: March 2021

Our aim is to monitor the temporal evolution of the crust in Greece, with a particular focus on the Gulf of Corinth.  Indeed, Greece is one of the most exposed country to earthquakes in Europe. The Gulf of Corinth,  is known for its fast extension rate of about 15 mm/yr in the western part and 10mm/yr in the eastern part. This fast extension is associated with recurrent seismic swarms and by a few destructive earthquakes. This seismicity is likely the result of a combination of multiple driving processes including fluid migration at depth.

In the present work, we use seismic noise recorded from 2010 to 2020 by all seismic stations deployed in Greece, and in particular by the dense Corinth Rift Laboratory network, to compute the seismic velocity variation (dv/v) in several subregions. By comparing the result obtained at different periods, we are able to distinguish the temporal evolution of the upper, mid and lower crust. This temporal evolution is compared to the seismicity of the Gulf of Corinth.
Bi-directional exchange of ammonia above a corn crop canopy: from flux measurements to model parameterizations
Authors: Moravek Alexander , Singh Saumya , Pattey Elizabeth , Hdrina Amy , Li Theodora , Pelletier Luc , Admiral Stuart , Murphy Jennifer
Published: March 2021

Emissions of ammonia (NH3) from agriculture have a significant impact on the environment. Its atmospheric transport and subsequent deposition has been shown to alter nutrient-poor ecosystems thereby reducing biodiversity. As the most abundant base in the atmosphere, NH3 plays a key role in secondary aerosol formation impacting air quality and climate. Due to the lack of long term observations and challenges in performing NH3 flux measurements, large uncertainties exist in both emission quantification from fertilized crop fields and in the bi-directional exchange of NH3 with agroecosystems. We measured NH3 fluxes above a corn field using the eddy covariance technique together with a quantum cascade laser spectroscopy analyzer over two consecutive growing seasons in 2017 and 2018. We found that after initial NH3 emissions following fertilizer application, periods of both NH3 emission and deposition with similar flux magnitudes prevailed throughout the growing seasons (ranging approximately between ±300 ng m-2 s-1), highlighting the importance of the corn crop canopy for regulating the net NH3 exchange. To evaluate the underlying processes of the NH3 bi-directional exchange, a two-layer compensation point model was used. Based on the large range of environmental conditions encountered during the extensive flux measurements periods, the validity of different parameterizations could be assessed. In particular, processes regulating stomatal and non-stomatal flux pathways will be discussed.
A spectra classification methodology of infrared hyperspectral images to reach near real-time SO2 emission flux estimation of Mount Etna plume
Authors: Segonne Charlotte , Huret Nathalie , Payan Sébastien , Gouhier Mathieu
Published: March 2021

Monitoring active volcanoes activity passes through the detection of fluctuations in degassing levels which may reflect changes in the magma supply rate and help inform a short-term forecast of on-going eruptions. Infrared hyperspectral imagers, which is an imaging technology still little used for volcanoes monitoring, have been deployed for various field campaigns on active volcanoes recently. For example, the Hyper-Cam LWIR (LongWave InfraRed) ranging between 850-1300 cm-1 (7.7 - 11.8 µm) with a spectral resolution up to 0.25 cm-1, provided high spectral resolution images from ground-based measurements of the Mount Etna (Sicily, Italy) plume during IMAGETNA campaign in June 2015. Processing the raw data and retrieving the infrared spectra with the LATMOS (Laboratoire Atmosphères Milieux Observations Spatiales) Atmospheric Retrieval Algorithm (LARA), a robust and a complete radiative transfer model, require a calculation time of ~7 days per image.

One of the main ways of risk mitigation effects of explosive eruptions is to get a fast and accurate quantification of SO2 fluxes emitted by volcanoes. In this context, using the dataset acquired during IMAGETNA campaign at Mount Etna, a spectra classification methodology has been developed to drastically decrease the calculation time and reach near real-time retrievals of SO2 slant column densities. The methodology is based on a network built on two layers of information from the extraction of spectral features in the O3 and SO2 emission bands. A training dataset of five SO2 slant column densities images retrieved with the time-consuming pixel-by-pixel retrieval method allowed the creation of a library. The spectra classification makes it possible to process each hyperspectral image in less than 40 seconds. It opens the possibility to infer near real-time estimation of SO2 emission fluxes from IR hyperspectral imager measurements.
Detecting and Classifying Marine Plastic Debris from high-resolution multispectral satellite data
Authors: Kikaki Aikaterini , Kakogeorgiou Ioannis , Mikeli Paraskevi , Raitsos Dionysios E. , Karantzalos Konstantinos
Published: March 2021

Plastic debris in the global ocean is considered an essential issue with severe implications for human health and marine ecosystems. Remote sensing is a useful tool for detecting and identifying marine pollution; however, there are still few studies and benchmark datasets for developing monitoring solutions for marine plastic debris detection from high-resolution satellite data.

Here, we present an annotated plastic debris dataset from different geographical regions, seasons, and years, including annotations for sea surface features (e.g., foam), objects (e.g., ship) and floating macroalgae species such as Sargassum. Our dataset is based on high-resolution multispectral satellite observations collected mainly for the period 2014-2020 over the Gulf of Honduras (Caribbean Sea). Over this region, large plastic debris masses and Sargassum macroalgae blooms have been frequently reported, suggesting that it is an ideal region to examine satellite sensors' effectiveness in plastic debris identification, as well as monitoring along with sea surface circulation and meteorological data.

We also present a set of machine learning classification frameworks for marine debris detection on high-resolution satellite imagery, comparing qualitatively and quantitatively their overall performance. The new algorithms were validated against different regions that have been reported as major plastic polluted areas, as well as their performance was compared to well-established FAI and new promising FDI. This benchmark study can trigger more research and developement efforts towards the systematic detection and monitoring of marine plastic pollution.
Impact of compound events (heatwaves and ozone episodes) on mortality over the Mediterranean basin under climate change scenarios
Authors: Tarín-Carrasco Patricia , Palacios-Peña Laura , Montávez Juan P. , Jiménez-Guerrero Pedro
Published: March 2021

The Mediterranean Basin is nowadays considered as one of the most vulnerable areas worldwide to extreme climate/weather events, especially those related to photochemical pollution (tropospheric ozone) and extreme temperatures (e.g. heatwaves). Heatwaves and air pollution have a high impact on society, both from a health and an economical perspective, leading to increases on heat stroke hospital admissions and mortality. For this reason, heatwaves and their associated ozone pollution have to be taken into account for dwellers welfare.

In addition, in recent years, it has become increasingly clear that climatic or meteorological impacts often result from the compounding nature of several variables and/or events, even if they are not extreme when analysed independently. Such compound events can lead to socio-economic damage exceeding that expected if the individual hazards were to occur separately. For instance, compound events of heat wave and stagnation display higher temperature than stagnation events or heat wave events alone, so the formation of secondary pollutants like tropospheric ozone is enhanced relative to individual events.

Under this umbrella, this study assesses compound climate events using high-resolution regional chemistry/climate simulations, with the aim of characterizing and quantifying the influence of temperature/pollution compound events on mortality over Europe, with a special focus on the Mediterranean Basin. Model data from the REPAIR and ACEX projects (obtained from simulations with the on-line chemistry/coupled WRF-Chem model) is used in order to check the changes in mortality under both present-observed and future-forced conditions. The results presented in this contribution quantify the important increase in mortality causes associated to cerebrovascular diseases (CEV) and other pathologies during those compound events (especially under future climate change scenarios) with respect to episodes led by single drivers. This increase in mortality is more evident in northern countries in relative terms; and in southern European countries in absolute mortality incidence, since the concurrent presence of heatwaves and high levels of tropospheric ozone will have a higher frequency in future scenarios over the Mediterranean basin.