bluuebunny/crossref_metadata_2025 huggingface dataset:
Time-series within automatically generated ROIs from wildlife cameras are well able to explain variability in forest phenology on a temperature gradient
Authors: Uphus Lars , Menzel Annette
Published: March 2020

Using RGB camera data (e.g. webcams, wildlife cameras) has great potential to measure forest phenology over climate gradients, because of its very high temporal resolution, while at the same time being more objective and less time consuming than in situ observations. To make images useful for the purpose of measuring phenological events, such as Start of Season (SOS) and End of Season (EOS), there is need to derive Regions of Interest (ROI) objectively and (semi-)automatically. In order to answer this need, Bothmann et al. (2017) proposed a method which randomly sets a number of pinpricks in the image and calculates how greenness over time from all other pixels correlates to these different pinpricks. Subsequently, ROIs are created by discarding the pixels with low correlation, using multiple thresholds. Despite its advantage of being automated and more objective compared to prevailing expert-based ROIs, and therefore its potential applicability for phenological research using a large amount of cameras, the method has not been reproduced for this purpose so far. Therefore, we assess here how well this method is able to separate foliage of different deciduous species from evergreens and phenologically irrelevant components in time-lapse wildlife camera data and in that way how suitable it is in explaining variation in phenology over a temperature gradient. We used 73 Cuddleback wildlife cameras troughout Bavaria which were installed within nine quadrants of 6*6 kilometers spanning a temperature gradient of 2.5°C. Hourly taken images of deciduous forests in spring, summer and autumn 2019 were analysed. Half of them were facing canopy, and half of them were facing understory. We applied the principles of the method from Bothmann et al. (2017) and assigned the best matching ROI to foliage of Fagus sylvatica or other deciduous species. Within this ROI, mean Green Chromatic Coordinate (GCC), a greenness index, over all pixels within the ROI, was derived per time-stamp. Afterwards, a time-series was calculated on these GCC values and with a suitable combination of curve-fitting techniques, SOS and EOS were derived, expressed in Day of Year (DOY). We compared these SOS and EOS dates with weekly in situ observations of spring and autumn phenology, which were taken in the same quadrants. Despite that Bothmann's method was developed on a single tower-mounted scientific webcam which viewed on canopy from above, while we made use of wildlife cameras at 73 different locations facing either understory perpendicular or canopy from below, it was able to distinguish F. sylvatica and other deciduous foliage from phenologically less relevant information. Time-series derived from these ROIs were able to explain variability in phenology between understory and canopy and over the temperature gradient similarly and supplementary to in situ observations. 
The issue of switching between non-freezing and freezing in soils
Authors: Blöcher Johanna , Kuraz Michal
Published: March 2020

The freezing process in soils is important in many natural systems and, consequently, it is of great interest to model it accurately. 
The freezing of water in soil is coupled to the heat equation as freezing releases latent heat and temperature is an important variable that determines whether water is in solid or liquid state. In soils, water can remain liquid under sub-zero temperatures (freezing-point depression). This effect is often modeled with the Clapeyron equation. With the Clapeyron equation, a temperature dependent pressure head definition for the total water content (liquid + frozen water) and the liquid water can be derived. When the temperature of the soil system falls below the freezing point, the system switches between the pressure head definitions. However, this switch can cause a discontinuity at the freezing front leading to numerical issues and unrealistic results.

To compensate for the discontinuity, we discuss the use of regularisation of the switching term on, both, synthetic and experimental data of case studies of freezing column experiments. 
A statistical approach to estimate global heatwave risk
Authors: Sillmann Jana , Russo Simone , Sippel Sebastian , O'Neill Brian , Barcikowska Monika , Ghisetti Claudia , Smid Marek
Published: March 2020

Following the conceptual risk framing of the IPCC that defines risk as a function of hazard, exposure and vulnerability, we estimate global heatwave risk by using a statistical approach that combines the distribution of indicators for heatwave magnitude, population exposure and human development. We fit a general extreme value distribution (GEV) to the maxima of the heatwave magnitude index in a block of 10-years to estimate extreme heatwave conditions with a 500yr return period under current climate (HW500yr). To consider the impact of changes in heatwaves in populated regions of the world, we use a set of global, spatially explicit population projections that are consistent with the new Shared Socioeconomic Pathways (SSPs). As a proxy for vulnerability we use the Human Development Index (HDI) based on the geometric average of three dimensions: health, education and standard of living. We derive an illustrative heatwave risk indicator (expressed in %) for each location (i.e. grid box) of the globe as the product of the probability of occurrence of HW500Y multiplied by normalized population density and 1-HDI values with all components of the product being normalized. Using this illustrative heatwave risk indicator on a global scale, we project heatwave risk for global warming of 1.5 and 2 °C, in accordance with the Paris agreement, for two future pathways of societal development representing low and high vulnerability conditions (SSP1 and SSP4, respectively). This method demonstrates how including a measure of vulnerability could produce a distribution of risk that is different from the distribution of hazard or exposure under different scenarios. Our results show that the heatwave risk for the low and very high development countries would be significantly reduced if global warming is stabilized below 1.5 °C, and in the presence of rapid social development. The latter is most important for low development countries for decreasing their vulnerability towards heatwaves or other hazards being amplified by climate change. The results illustrate how hazard-specific policies could be better informed by analyses that account for vulnerabilities to the respective hazard. However, we also discuss several caveats associated with using a normalized risk indicator on a global scale with implications for the interpretation of risk on a local scale, including the need for better indicators to describe vulnerability to specific or multiple hazards.
Identification of source-sink relationships in southern Africa by stable water isotopes analysis and Lagrangian moisture source diagnostics
Authors: Geppert Marielle , Pfahl Stephan , Struck Ulrich , Kirchner Ingo , Shemang Elisha , Hartmann Kai , Riedel Frank
Published: March 2020

Many palaeoclimate reconstructions are based on the fact that stable water isotopes are conserved in different highly resolved paleo-archives such as ice cores or calcium carbonates. Stable water isotopes are tracers of moisture in the atmosphere because they record information about evaporation and condensation processes during the transport of air parcels. These processes cause isotopic fractionation that leads to isotopic enrichment or depletion. The isotopic composition of precipitation is strongly correlated with altitude above sea level, distance to the coast and local surface air temperature. Knowledge on the source and transport of moisture is thus crucial for the interpretation of stable isotopes in precipitation and in palaeo-archives.
Studies analysing the linkage between stable water isotope measurements and moisture sources in southern Africa are scarce. Yet, as changes in the transport pattern can influence precipitation patterns and amounts, in a semi-arid region like southern Africa that is threatened by droughts, this knowledge is of particular interest. Thus, the aims of this study are (1) to reveal the principal moisture source areas and transport routes of specific target areas in southern Africa, (2) to assess the influence of different transport patterns on the isotopic composition of precipitation and by this (3) to create a modern analogue for palaeoclimate studies in this region.
About 200 water samples, mainly from headwaters of rivers, but also from precipitation events, springs and lakes, were collected throughout southern Africa and the stable water isotope composition (δ2H and δ18O) was analysed. To detect moisture sources for this set of isotope measurements, backward air parcel trajectories were calculated from the sample location, using the LAGRANTO tool based on ERA5 reanalysis data. Variations in specific humidity along the trajectories were then used to detect moisture uptake.
The analysis reveals main transport patterns related to the Intertropical Convergence Zone and easterly winds as well as the effects of topographical forcing, which is, for example, very pronounced above Lesotho. The results provide detailed insights into the relationships between atmospheric circulation and δ2H and δ18O values of precipitation over southern Africa, which is a prerequisite for the interpretation of isotopic records that are used for palaeoclimatic reconstructions.
The impact of orbital forcing on the Arctic climate during the Last Interglacial simulated by the IPSL-CM6A-LR model
Authors: Sicard Marie , Kageyama Masa , Braconnot Pascale , Charbit Sylvie
Published: March 2020

The Last Interglacial (129 – 116 ka BP) is a time period with a strong orbital forcing which leads to a different seasonal and latitudinal distribution of insolation compared to the present. In particular, these changes amplify the Arctic climate seasonality. They induce warmer summers and colder winters in the high latitudes of the Northern Hemisphere. Such surface conditions favour a huge retreat of the arctic sea ice cover.
In this study, we try to understand how this solar radiation anomaly spreads through the surface and impacts the seasonal arctic sea ice. Using IPSL-CM6A-LR model outputs, we decompose the surface energy budget to identify the role of atmospheric and oceanic key processes beyond 60°N and its changes compared to pre-industrial. We show that solar radiation anomaly is greatly reduced when it reaches the Earth’s surface, which emphasizes the role of clouds and water vapor transport.
The results are also compared to other PMIP4-CMIP6 model simulations. We would like to thank PMIP participants for producing and making available their model outputs.
Quantifying uncertainty in future projections of ice loss from the Filchner-Ronne Ice Shelf System
Authors: Hill Emily , Rosier Sebastian , Gudmundsson Hilmar , Collins Matthew
Published: March 2020

Mass loss from the Antarctic Ice Sheet is the main source of uncertainty in projections of future sea-level rise, with important implications for coastal regions worldwide. Enhanced melt beneath ice shelves could destabilise large parts of the ice sheet, and further increase ice loss. Despite advances in our understanding of feedbacks in the ice sheet-ice shelf-ocean system, future projections of ice loss remain poorly constrained in many parts of Antarctica. In particular, there is ongoing debate surrounding the future of the Filchner-Ronne Ice Shelf (FRIS) region. The FRIS has remained relatively unchanged in recent decades, but an increase in air and ocean temperatures in the neighbouring Weddell Sea, could force rapid retreat in the near future. Indeed, previous modelling work has suggested the potential for widespread infiltration of warm water beneath the ice shelf in the second half of the twenty-first century, leading to a drastic increase in basal melting.

Here, we use the ice flow model Úa alongside the ocean box model PICO (Potsdam Ice-shelf Cavity mOdel) to understand the key physical processes and model variability in future projections of sea level rise from the FRIS region. We investigate uncertain model parameters associated with ice dynamics, surface melting and precipitation, ocean temperature forcing, and parameters relating to the strength of basal melt generated by PICO. We optimise the prior distributions of parameters in PICO using observations and a Bayesian approach, leading to improved posterior distributions for use in the following stages of uncertainty quantification. We then run our forward model through the 21st century for various RCP scenarios and extensive random sampling of uncertain parameters to train an emulator. From this, we present probabilistic projections of potential sea level rise from the FRIS region for different future climate change scenarios, together with a sensitivity analysis to identify the most important parameters that contribute to uncertainty in these projections.
TWIGA project activities for the enhancement of heavy rainfall predictions in Africa: low-cost GNSS network deployment and NWP model parameterization.
Authors: Mascitelli Alessandra , Meroni Agostino  Niyonkuru , Barindelli Stefano , Manzoni Marco , Tagliaferro Giulio , Gatti Andrea , Realini Eugenio , Venuti Giovanna , Monti Guarnieri Andrea
Published: March 2020

One of the objectives of the H2020 project TWIGA - Transforming Weather Water data into value-added Information services for sustainable Growth in Africa - is the improvement of heavy rainfall prediction in Africa. In this area, the scarcity of data to support such predictions makes it fundamental to enhance the monitoring of atmospheric parameters.

In this project, GNSS observations and SAR images from Sentinel missions are used to produce water vapor products to be assimilated into Numerical Weather Prediction Models (NWPs).

GNSS observations, collected by ad-hoc networks of geodetic and low-cost stations, are processed to obtain near real-time (NRT) Zenith Total Delay (ZTD) time series, while Sentinel-1 SAR images are used to derive Atmospheric Phase Screens, APSs. The free and open source GNSS software goGPS, developed by the Politecnico di Milano spin-off Geomatics Research and Development (GReD), is used for the retrieval of ZTDs time series.

After proper calibration and validation procedures, the delay maps from SAR and the delay time series from GNSS will be finally assimilated into NWP models to improve the prediction of heavy rainfall.

The GNSS-related activities will be presented in terms of network deployment and processing settings evaluation. A network of 5 single-frequency low-cost GNSS stations was installed in Uganda, and a new network of dual-frequency low-cost stations is going to be installed in Kenya. To improve the outputs provided by these networks, preliminary tests on ionospheric delay corrections at various distances were performed. Different methods, focused on the reconstruction of a synthetic L2 observation for the single-frequency receivers, were employed and evaluated with the aim to define the optimal approach.

In order to demonstrate the capability to achieve GNSS NRT processing within TWIGA, an automated procedure was set up to estimate hourly ZTDs from two geodetic permanent stations located in South Africa (Cape Town and Southerland) and to upload them to the TWIGA project web portal.

Meanwhile, first sets of WRF NWP model parameterizations have been defined for both South Africa and Kenya. A cooperation has been established with the Kenya Meteorological Department on the exploitation of 3DVAR tool for water vapor data assimilation into WRF. Studies to define a strategy for ZTD maps retrieval from InSAR APS have been performed on Italian datasets and further investigations on TWIGA-collected African datasets will follow.

 

  

 
The handbook for standardized field and laboratory measurements in terrestrial climate change experiments and observational studies (ClimEx)
Authors: Halbritter Aud , De Boeck Hans , Vandvik Vigdis ,   Amy E. Eycott  Sabine Reinsch  David A. Robinson  Sara Vicca  Bernd Berauer  Casper T. Christiansen  Marc Estiarte  José M. Grünzweig  Ragnhild Gya  Karin Hansen  Anke Jentsch  Hanna Lee  Sune Linder  John Marshall  Josep Peñuelas  Inger Kappel Schmidt  E
Published: March 2020

Climate change is a world‐wide threat to biodiversity and ecosystem structure, functioning and services. To understand the underlying drivers and mechanisms, and to predict the consequences for nature and people, we urgently need better understanding of the direction and magnitude of climate change impacts across the soil–plant–atmosphere continuum. An increasing number of climate change studies are creating new opportunities for meaningful and high‐quality generalizations and improved process understanding. However, significant challenges exist related to data availability and/or compatibility across studies, compromising opportunities for data re‐use, synthesis and upscaling. Many of these challenges relate to a lack of an established ‘best practice’ for measuring key impacts and responses. This restrains our current understanding of complex processes and mechanisms in terrestrial ecosystems related to climate change.

To overcome these challenges, we collected best‐practice methods emerging from major ecological research networks and experiments, as synthesized by 115 experts from across a wide range of scientific disciplines. Our handbook contains guidance on the selection of response variables for different purposes, protocols for standardized measurements of 66 such response variables and advice on data management. Specifically, we recommend a minimum subset of variables that should be collected in all climate change studies to allow data re‐use and synthesis, and give guidance on additional variables critical for different types of synthesis and upscaling. The protocols are also available online on the ClimEx handbook webpage (https://climexhandbook.w.uib.no/) and we encourage scientists from the climate change research community to get involved, give us feedback and make suggestions for updates to specific protocols. We hope that this is a way to amend the protocols and extend the shelf life of the ClimEx Handbook.

The goal of this community effort is to facilitate awareness of the importance and broader application of standardized methods to promote data re‐use, availability, compatibility and transparency. We envision improved research practices that will increase returns on investments in individual research projects, facilitate second‐order research outputs and create opportunities for collaboration across scientific communities. Ultimately, this should significantly improve the quality and impact of the science, which is required to fulfil society's needs in a changing world.
‘This advice is absurd’: issues with providing generic advice on community protection from chronic volcanic degassing
Authors: Horwell Claire J. , Elias Tamar
Published: March 2020

Around the world, there are a number of volcanoes which are passively degassing, chronically exposing communities to potentially-harmful gases and aerosols. The medical evidence, to date, is unclear about the long-term health impacts of such exposures, but there is evidence that people experience an exacerbation of existing respiratory disease, such as asthma, bronchitis, and COPD. In addition, there are a range of physiological and psychological symptoms which even otherwise healthy people experience, which can impact their lives and livelihoods. In Hawaii, prior to the end of the 2018 Lower East Rift Zone eruption crisis of Kīlauea Volcano, communities downwind of the vents were frequently exposed to volcanic pollution or ‘vog’, with exposures worsening during the 2018 crisis. Local emergency and health agencies provided generic advice on measures to reduce exposure but the usefulness and uptake of the advice was unknown. A survey of Hawai’i island residents in 2015, highlighted the range and severity of symptoms that they perceived to be caused by vog exposures, and exposed a lack of application of the official advice. Some respondents described how their lifestyles (e.g., the open structure of their homes and availability of air conditioning) didn’t allow them to implement key strategies such as closing doors and windows and staying indoors. The perceived irrelevance of official advice, and a perception, by some, that vog information was suppressed due to political pressures, led to mistrust in the official agencies by a subset of the population. The survey also revealed undocumented strategies that individuals were using to protect themselves and cope with symptoms of vog exposure. In partnership with local agencies, we rewrote the guidance to be more applicable to the local situation. Revised guidance incorporated successful local practices, where medical evidence of efficacy could be found. We also developed an online interagency ‘vog dashboard’ that provided a comprehensive source for vog information and advice. The ‘Vog Talk’ Facebook page was also initiated to provide a forum for informal discussion amongst community members and between communities and agency representatives. During the 2018 eruption crisis, these resources were extensively utilised and were considered primary sources of information for Hawaii residents, tourists and the world’s media. The experience in Hawaii demonstrates the importance of a multi-disciplinary approach to engaging communities, with health management professionals, physical and social scientists, and community representatives working together to ensure that issued advice is trusted, relevant and practical.
Turbulent transport and deposition of fog droplets in the Central Namib
Authors: Spirig Robert , Feigenwinter Christian , Vogt Roland
Published: March 2020

Regular, nocturnal fog is a defining and seasonally varying feature in the Namib desert. Historical observations were limited to the binary measure of fog occurrence and the concurrent fog water input is quantified only since 2014 via the FogNet using Juvik fog collectors. This installation opened new avenues of research such as the efficiency of the transport mechanism, sampling and spatial variation thereof. An eddy covariance setup of a cloud droplet probe and collocated sonic(s) was installed in turns at the two FogNet stations Vogelfederberg (23.10°S, 15.03°E, 515 m above sea level) and Gobabeb (23.56°S, 15.04°E, 406 m above sea level) for 2 years in the frame of the Namib Fog Life Cycle Analysis Field Measurements (NaFoLiCA-F) project. With this setup, we gathered duration, droplet size distribution, droplet concentration, liquid water content, turbulent liquid water flux and the fog water input via the Juvik fog collector with a total of over 150 fog events. We found that fog appears suddenly and front-like as seen by an increase of droplet numbers by several magnitudes and dissolves more gradually towards the morning. All droplet classes of the resolved range of 2 to 50 µm are present, but at the Vogelfederberg with around 2 to 3 times larger fog water input, the mean and median of the distribution are lower due to comparably fewer large droplets. Liquid water fluxes at both sites resulted in a net gain for the surface but the spatial discrepancy between fog water input recorded by fog collectors and the liquid water content indicates that drizzle, i.e. droplets outside the resolved range, may contribute to the larger total water deposition at Vogelfederberg.
Assessment of the human health risk due to the exposure to air pollution using air quality ensemble modelling data
Authors: Gilardi Lorenza , Erbertseder Thilo , Baier Frank , Bittner Michael
Published: March 2020

Several World Health Organization (WHO) studies have shown that air pollution is likely associated with an increased rate of premature mortality and morbidity, mainly attributable to respiratory and cardiovascular diseases [1]. The species normally considered for the evaluation are: PM10, PM2.5, O3 and NO2. All these compounds are typical sub products of processes of combustion and other anthropogenic activities and their presence in highly densely populated areas is commonly observed. As a result, a significant proportion of the European population is exposed to annual average concentrations of these pollutants exceeding the WHO Air Quality Guidelines (WHO-AQG), as the European Environment Agency (EEA)  reports for the year 2016 [1].  Data of air pollutants concentrations at high temporal resolution and on a large spatial scale are currently available from satellite remote sensing and air quality models. The data from the multi-year reanalysis of the Copernicus Atmospheric Monitoring Service (CAMS) and from the DLR / POLYPHEMUS, together with the health Relative Risk (RR) values provided by the WHO, are used as input-source for the method developed by Sicard [2] to estimate an overall increase in health risk due to short-term exposure to air pollution. With this operation it is possible to obtain a geographical representation of the Aggregate Risk Index (ARI). This approach allows for various estimates of the spatial distribution of the increased health risk for several health endpoints, in terms of ARI, and its temporal behavior. The Sicard’s method is tested by (spatial) correlation to a real-world health data base. We especially investigate the validity of the linear additive approach for different mixtures of pollutants.

References:

[1] European Environmental Agency, 2019, Air quality in Europe 2019 report, pages 61-70.

[2] Sicard, P.,et al., 2012. The Aggregate Risk Index: An intuitive tool providing the health risks of air pollution to health care community. Atm Env, 46, 11-16.
Possibility of lightning in the Venusian clouds due to Super-rotation
Authors: Neduncheran Adhithiyan , Uppalapati Sruthi
Published: March 2020

Lightning in Venus is still a matter of debate due to lack of evidence in optical and simultaneous radio emissions. Several evidence of electromagnetic emissions were previously measured by various landers and orbiters studying Venus atmosphere such as the Venera 13 and 14 landers, Venus Express and the Pioneer Venus Orbiter. This theoretical work proposes the mechanism of lightning is possibly due to the super-rotation of the clouds. Excessive amount of atmospheric turbulence and the formation of plumes in the clouds of Venus should possibly lead to the formation of charges in the clouds and thereby trigger lightning. As per Lorenz 2018, it is expected that there might exist charged aerosols in the lower atmosphere. This imposes another possibility of triboelectric charging mechanism which lead to lightning in the lower and middle cloud region. Lightning induced electromagnetic emissions that takes place in the clouds might be a result of momentum transfer and charge dispersion in the clouds of Venus. Venus can be considered to be an optically active planet with phenomenon like reflection and refraction ruling to some extent which possibly imposes a difficulty in lightning detection as the photons emitted during this process are scattered away. In the end, the possible lightning mechanism and difficulties related to its detection shall be discussed
Soil penetration resistance affected by root exudates
Authors: Mysore Janakiram Ravi Kumar , Brax Mathilde , Kroener Eva
Published: March 2020

The mechanical properties of soil and mucilage have a significant effect on root penetration resistance which can become a limiting factor for root growth in dry and compacted soils. Our hypothesis is that the way how root exudates alter penetration resistance in soil is controlled by the interplay of two mechanisms: on the one hand mucilage stabilizes the soil resulting in an increased penetration resistance, on the other hand mucilage holds water, which tends to reduce soil penetration resistance. To quantitatively test our hypothesis we consider fine-grained soil, a needle which has 30º apex angle and another needle with 60º. The needles are used for the penetration of the soil, which is used to simulate the plant root growth in the real condition. Chia seed mucilage was used in the study to mimic the effect of root mucilage. The growth of root was simulated by penetrating the needles at constant speed into the soil using a rheometer. Measurements were repeated for various water contents, compactions and at various mucilage concentrations (0%, 0.1%, 0.3%, 0.5%).

Our experiments show that the concentration of the mucilage affects penetration forces significantly in the soils. Penetration forces are significantly less in the soils for low concentration mucilage (0.1%) and high in the higher concentration mucilage (0.5%). This may be because higher concentration of mucilage stabilizes the loose soil by binding the soil particles together. While the low concentration mucilage softens the soil mass due to the presence of more water and in this way reduces the penetration forces. Results also show the penetration resistance is also significantly affected by root geometry. The 60º needle experienced higher penetration resistance than the 30º needle when the soil is dry and the density of the soil is low. The 30º needle experienced higher penetration resistance than the 60º when the soil wet and the density is high.
Effects of prospective climate change on pasture productivity in the Italian Alps.
Authors: Casale Francesca , Bocchiola Daniele
Published: March 2020

We present here preliminary results in fulfilment of the project IPCC MOUPA (Interdisciplinary Project for assessing current and expected Climate Change impacts on MOUntain PAstures) project, funded by Fondazione Cariplo of Italy, aimed to i) evaluate potentially modified productivity of pasture lands under climate change scenarios, and subsequent on socio-economic, wildlife and biodiversity impacts, within the Italian Alps, and ii) propose management strategies for pasture and multi-functional use of mountain areas.

In high mountain areas pastures are a source of living for local communities, and further agriculture and livestock supply ecosystems services (ES). In the last century, increase of temperature nearby +1.5°C was observed in the Alpine region, to increase hereon, and future climate scenarios display potential reduction of water availability, with an increase in precipitation extremes, potentially impacting soil moisture, vegetation, and pasture dynamics (phenology/timing), deeply dependent upon precipitation, temperature, and snow cover.

We here defined some fragility indices (FIs), to sketch the effects of climate change on pastures in the Alps, with special focus on Valtellina valley, in the central Alps of Italy. FIs can be used to highlight pressures experienced by pastures, and thresholds for failure, and to develop policies to i) determine zones needing particular management, and adaptation, ii) monitor trends of global environmental stability, iii) evaluate the overall impact of climate change and anthropic influence, and iv) investigate the dynamics of pasture fragility. We chose indices of climate, productivity, and water usage. Some of these FIs can be evaluated starting from observations, but others have to be calculated using models of pasture growth, and water availability. For this reason, a pasture model Poli-Pasture has been set up to simulate the pasture growth, and to evaluate FIs in the target area.

To explore the broad range of variability under uncertain future climate, FIs are calculated for present conditions of pastures, and for future projected conditions using i) three climatic scenarios of AR5 of IPCC (RCP 2.6, RCP 4.5 and RCP 8.5) as depicted by three Global Circulation Models GCMs (EC-Earth, Echam6.0, CCSM4), and ii) four climatic scenarios of the AR6 (RCP 2.6, RCP 4.5, RCP 7.0, RCP 8.5) depicted by three GCMs (EC-Earth3, Echam6.3, CESM2), and some preliminary conclusion are reported for future pasture dynamics, and management therein.
Monitoring deep fractured reservoirs with ambient noise correlation: importance of acousto-elastic effects
Authors: Azzola Jérôme , Schmittbuhl Jean , Zigone Dimitri , Lengliné Olivier , Masson Frédéric
Published: March 2020

An emerging technique for a continuous and low cost geophysical monitoring of deep reservoirs like Enhanced Geothermal Systems (EGS) is based on ambient seismic noise correlation and in particular Coda Wave Interferometry (CWI) from temporal stacks of ambient noise cross-correlation functions (or ANCCFs). We present here a forward numerical model simulating the propagation of scattered waves through a reservoir during its deformation, including non-linear acousto-elastic effects. Our approach is based on the case study of the Rittershoffen geothermal reservoir (France). We validate the numerical model by reproducing seasonal variations of the relative changes in seismic velocity observed from ANCCFs and provide a physical interpretation of this seismic signal. We extend our modelling to the in-situ deformation of the reservoir by considering either a hydraulic pressure increase or an aseismic shear of an embedded fault. The sensitivity of the scattered waves to small strain perturbations enables to detect small travel time changes as dt/t ~ 10-5, which opens perspectives for the application of ambient noise based techniques to the continuous monitoring of local mechanisms in deep geothermal reservoirs.
The challenge of non-stationary feedbacks within the response of debris-covered glaciers to climate forcing
Authors: Wirbel Anna , Nicholson Lindsey , Mayer Christoph , Lambrecht Astrid
Published: March 2020

The challenge of non-stationary feedbacks within the response of debris-covered glaciers to climate forcing

Debris-covered glaciers are a feature of many mountain ranges around the world and their proportion is expected to increase under continued climate warming.

The impact of debris cover on glacier behavior, via its profound modification of the glacier ablation regime, causes debris-covered glaciers to respond to the same climate forcing in a markedly different way to clean ice glaciers. In order to better understand how debris cover impacts the glacier’s response to climate forcing, we revisit the concept of steady state and examine it for a debris-covered glacier system. We present simple modeling results to explore how the development and evolution of debris cover affects the potential for steady-state and how feedbacks instigated by supraglacial debris cover complicate the glacier’s response to a prescribed steady climate. These investigations highlight the non-stationarity induced by the presence of debris and as a result, that debris cannot be considered as a static component, as it is a highly dynamic component which affects the glacier system in different ways.
The NEWTON-g "gravity imager": a new window into processes involving subsurface fluids
Authors: Carbone Daniele , Cannavò Flavio , Greco Filippo , Messina Alfio , Contrafatto Danilo , Siligato Giuseppe , Lautier-Gaud Jean , Antoni-Micollier Laura , Hammond Giles , Middlemiss Richard , Toland Karl , van Zeeuw de-Dalfsen Elske , Koymans Mathijs , Rivalta Eleonora , Nikkhoo Mehdi , Bonadonna Costanza , Frischknecht Corine
Published: March 2020

Gravimetry is the only method able to directly track redistributions of bulk masses. Hence, it can supply unique information on geophysical processes that involve subsurface fluids like water, hydrocarbons, and magma. 
Nevertheless, the high cost of currently available gravimeters and the difficulty to use them in field conditions, has limited the applicability of the gravity method, that is indeed not as widely adopted as other geophysical methods.
A new system for gravity measurements is being developed  in the framework of the H2020 NEWTON-g project. This system, called “gravity imager”, includes an array of MEMS gravimeters, anchored to an absolute quantum device. It will enable, for the first time, gravity measurements at high spatio-temporal resolution. 
After the phases of design and production of the new devices, NEWTON-g involves a 2-year phase of field tests at Mt. Etna volcano (Italy), starting in the summer of 2020.
Summertime surface ozone variation over East Asia in CCMI
Authors: Wie Jieun , Park Hyo-Jin , Lee Hyomee , Moon Byung-Kwon
Published: March 2020

The concentration of surface ozone in East Asia is high due to strong solar radiation, but decreases in areas affected by summer monsoons. This study analyzes the summer surface ozone variations in East Asia using meteorological and atmospheric chemistry variables in 12 models participating in Chemistry-Climate Model Initiative (CCMI) for the period of 1979 to 2010. The concentration of 850 hPa ozone was identified two modes by Empirical Orthogonal Functions (EOF) analysis. The first mode is an increase in all regions over East Asia, mainly in eastern China. This mode was associated with downward wind, weak horizontal wind speed, increase in temperatures, decrease in precipitation. The second mode showed high ozone concentrations in eastern China and low in northern Japan. In eastern China, temperatures and precipitation are decreased, and shortwave radiation reaches the surface is increased. In addition, the concentration of nitrogen oxides and carbon monoxide and the net ozone production are increased. The second mode was highly correlated with El Nino-Southern Oscillation (ENSO) and western North Pacific subtropical high (WNPSH) indices and was found to be closely associated with East Asian summer monsoons.

 

Acknowledgements: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2019R1A2C1008549). We acknowledge the modeling groups for making their simulations available for this analysis, the joint WCRP SPARC/IGAC Chemistry–Climate Model Initiative (CCMI) for organizing and coordinating the model simulations and data analysis activity, and the British Atmospheric Data Centre (BADC) for collecting and archiving the CCMI model output.
The Great Geysir and tectonic interactions in South Iceland
Authors: Thorbjarnardóttir Bergthóra S. , Bjarnason Ingi Th. , Parameswaran Revathy M.
Published: March 2020

The Great Geysir is within a tectonically active region bordering the eastern flank of the Western Volcanic Zone (WVZ), south of Langjökull glacier. The geothermal area has been active at least throughout the Holocene (Torfason, 1985). It is a high-temperature system, which is not common in Iceland for geothermal areas located outside the neovolcanic zones. Its longevity suggests continuously active tectonics in the region. Indeed, half a century of seismic monitoring shows relatively high activity of minor earthquakes (magnitude<4.0). The general pattern of seismicity is rather constant through time, but comes in bursts of activity. We attempt to elucidate the driving forces in this unusual and poorly tectonically understood area, by analyzing the most modern seismic data collected in the years 1995-2016 within a study area ~25x25 km2 enclosing the Geysir area. It is, for instance, observed how the large (Mw~6.5) earthquakes in June 2000, located ~45 km south and southwest of Geysir in the South Iceland Seismic Zone (SISZ), induced seismicity kilometers away within hours after their occurrence. The heightened level of activity, an order of magnitude in terms of number of earthquakes, lasted half a year after the 2000 events in large parts of the study area and finally tapered down in 2001. Within the first two weeks of the 2000 events, the main activated faults are within 5 km of the Great Geysir. The activation is mostly at shallow depth (< 4 km). However, none pass directly through the Geysir geothermal area. That may explain the only minor change observed in the dormant state of the Great Geysir, which has now lasted approximately a century. There are historic accounts on how several large South Iceland earthquakes in the SISZ activated the Great Geysir, lasting for years or decades. The last such activation was in 1896. In its full might, it erupts up to a height of 70-80 m (Torfason, 1985).  Its currently active neighbor, Strokkur geysir, usually erupts to heights of 15-20 m.  Cross-sections of the seismicity near Geysir suggest several near vertical  right-lateral ~NNE trending faults.  Focal mechanisms indicate strike-slip movements, but also oblique-normal and thrust events in between. This may suggest fault jogs and high horizontal stresses. Approximately 6 km north of Geysir, in the Sandfell and Sandvatn area, there is a persistent ~ENE trending ~5 km long seismic pattern with main activity between 4-8 km depth. This seismicity has occurred, on and off, through the history of seismic observations. Here the faulting is also complicated (strike-slip and thrust), but focal mechanisms suggest the main component to be normal to oblique normal. Cross-sections, although unclear, suggest possible dip to the ~SSE. We intend to calculate stress inversions in the study area prior to the conference.
Extremes for high dimensional chaotic systems
Authors: Kuna Tobias , Lucarini Valerio , Faranda Davide , Wouters Jerouen , Baladi Viviane
Published: March 2020

Extremes are related to high impact and serious hazard events and hence their study and prediction have been and continue to be highly relevant for all kind of applications in geoscience and beyond. Extreme value theory is promising to be able to predict them reliably and robustly. In the last fifteen years the classical extreme value theory for stochastic processes has been extended to dynamical systems and has been related to properties of physical measure (statistical properties of the system), return and hitting times. We will review what one can say for highly dimensional perfectly chaotic systems.  We will concentrate on relations between the index of the extreme distribution and invariants of the underlying dynamical system which are stable, in the sense that they will continuously depend on changing parameters in the dynamics.  Furthermore, we explore whether there exists a response theory for extremes, that is, whether the change of extremes can be quantitatilvely expressed  in terms of changing parameters. 

 
25 years of EUGEN – a history of connecting geoscience students in Europe
Authors: Hollinetz Marianne Sophie ,   EUGEN e.V. - European Geoscience Student Network
Published: March 2020

EUGEN (European Geoscience Student Network) is an association that provides a platform for the international exchange between geoscience students in Europe. The network organizes annual meetings which take place during the first week of August. From the first EUGEN meeting in 1996 which was organized in Germany the network looks back on a history of annual meetings held in 13 different countries in Europe.

During an EUGEN meeting participants are offered to join a scientific program consisting of field trips and evening lectures. Excursions cover a broad range of geoscientific topics and give an introduction to the geology of the host country. Evening lectures give a deeper insight into topics conveyed during excursions and are organized in cooperation with local universities and supporting organizations. Moreover, participants can use this platform to present their Bachelor or Master thesis. In addition to that, activities like the ‘geolympics’ – a geological-sportive team competition – and one cultural daytrip complete the program. To sum up, EUGEN aims to enhance the scientific exchange across all geoscientific disciplines between both geoscience students and graduates. By combining the accompanying program of a scientific conference with the fun atmosphere of a geological field camp, an EUGEN meeting provides the ideal atmosphere for students to acquire international connections and lay the foundations of future professional collaborations. Participation in such a network is especially advantageous for those who are intending to study abroad and to internationalize their professional network.

EUGEN is a non-profit association which is funded by donations, membership- and participation fees. As such, the network depends on the active participation of committed members in the association. Future challenges comprise finding more and new ways to connect with students from all over Europe in order to increase the diversity of participating counties. Moreover, the association intends to internationalize its organization structure which is at the moment strongly focused on Germany. For the 25th anniversary meeting the network goes back to its roots in the Black forest region in Germany. We invite students from all over the world to save the date (3rd – 9th of August 2020) and join us for an unforgettable experience!
Use of Mohid-Land to model water balance for implementation of deficit irrigation in vineyards
Authors: Capello Giorgio , Biddoccu Marcella , Simionesei Lucian , Ramos Tiago , Oliveira Ana , Grosso Nuno , Podder Pritimoy , Rabino Danilo , Bagagiolo Giorgia , Neves Ramiro
Published: March 2020

The Water4ever project aims to increase irrigation water and fertilization efficiencies through precision irrigation. The project has 3 major components: A technological component devoted to the development of measuring technologies based on optical sensors; a modelling component addressing both the local and the catchment scales; and a fieldwork component based on 3 case studies dedicated to vineyards and fruit trees where the new sensor and modelling tools will be combined with field data obtained by conventional monitoring and remote sensing. The project aims also to improve modelling at plot and catchment scale in order to quantify the effect of agriculture practices on water availability and quality. MOHID-Land is a physically-based, spatially distributed, continuous, variable time step model for the water and property cycles. It integrates four compartments or mediums (atmosphere, porous media, soil surface, and river network). In this study, the MOHID-Land model has been calibrated and implemented at plot scale in two of the project’s study cases, located in Portugal and Italy, that are representative of local vineyards, with different management, climate and topographical conditions: (i) the Vinha do Mel - Companhia das Lezírias (Portugal) is an irrigated vineyard of 14000 m2 with limited slope, while (ii) the Cannona Erosion Plots (NW Italy) are 1200 m2 portions of a rainfed hillslope experimental vineyard, with different inter-rows’ management. Water inputs (precipitation and irrigation), meteorological parameters and soil water content at different depths have been monitored in both plots during two years (2017-2018), using field sensors. Direct runoff measurements are available for the Cannona Erosion Plots. The vegetative development of the vineyards has been estimated from remote imagery. The field and remote datasets were used to calibrate and validate the MOHID-Land model, by comparing with simulated values of soil water content and LAI, with satisfactory to good efficiency of the model. The performance of the model was considered acceptable to support the IrrigaSys decision support system, using the Portuguese study case as reference for weekly irrigation recommendation in the region. The Italian study case was also used to estimate the water balance in two growing seasons with contrasting weather conditions, in order to evaluate the different behaviour with respect to the adopted soil management and the needing to introduce irrigation in a region where vines are traditionally rainfed.

WATER4EVER is co-funded by the European Commission under the framework of the ERA-NET COFUND WATERWORKS 2015 Programme.